I know that when light is sent out of a moving object, its speed still remains the same as if it was sent out of a stationary object. Keep in mind that there is red-shift and blue-shift in light waves though. Now, my question is: Do other waves follow the same principle as light waves? If I hit a metal pole with a hammer, would the sound waves traveling through it move faster if the pole was on a moving object versus the pole just sitting still in a stationary position? Or would the speed of sound remain the same, and instead the doppler effect would occur. Also note to yourself that the speed of light changes through mediums (it slows), and the speed of sound can change through mediums as well.
I can't test my question since I'm only 17, but It would be nice for someone to tell me so I can get it off of my mind.
I also wonder, if special relativity doesn't apply to other waves, then how do we know it does to light? Would we notice a change in 30 mph added to lights speed already?|||okkkaayy. Here's a reply.. so stop complaining about not getting replies... hahahaha. I'm sorry, I couldn't resist %26lt;3|||Sound waves or "pressure waves" do get blue or red shifted like light waves (doppler shift), but the actual velocity of the wave won't change. What will change is the wavelength.
Here is a good treatment on the doppler effect.
http://en.wikipedia.org/wiki/Doppler_effect
Tuesday, December 6, 2011
According to the special theory of relativity, physical laws are the same in frames of reference which?
According to the special theory of relativity, physical laws are the same in frames of reference which ...
accelerate.
move at uniform velocity.
move in ellipses.
move in circles.|||move at uniform velocity|||Move at uniform velocity. Any differences in relative speed will cause some time dilation. In special relativity, the time dilation effect is reciprocal. That's a fancy way of saying that as observed from the point of view of any two clocks which are in motion with respect to each other it will always look to you (or your frame of reference) like the other guy's clock is running slower or faster.
accelerate.
move at uniform velocity.
move in ellipses.
move in circles.|||move at uniform velocity|||Move at uniform velocity. Any differences in relative speed will cause some time dilation. In special relativity, the time dilation effect is reciprocal. That's a fancy way of saying that as observed from the point of view of any two clocks which are in motion with respect to each other it will always look to you (or your frame of reference) like the other guy's clock is running slower or faster.
Do all waves apply to special relativity?
I know that when light is sent out of a moving object, its speed still remains the same as if it was sent out of a stationary object. Keep in mind that there is red-shift and blue-shift in light waves though. Now, my question is: Do other waves follow the same principle as light waves? If I hit a metal pole with a hammer, would the sound waves traveling through it move faster if the pole was on a moving object versus the pole just sitting still in a stationary position? Or would the speed of sound remain the same, and instead the doppler effect would occur. Also note to yourself that the speed of light changes through mediums (it slows), and the speed of sound can change through mediums as well.
I can't test my question since I'm only 17, but It would be nice for someone to tell me so I can get it off of my mind.
I also wonder, if special relativity doesn't apply to other waves, then how do we know it does to light? Would we notice a change in 30 mph added to lights speed already?|||When something moves at constant speed ist usually a wave.This is inertial motion as opposed to gravitational motion, where the speed changes with changing distance and time.
Special Relativity does not apply to gravitational motion at all.
So the Only thing it could apply to is wave motion since it moves at constant velocity..The reason is that a wavelenght can be shorten and time of period dilated. The speed of the wave is medium dependent .And a wave is a disturbance in the medium. If light moves as foloowing the rules of a wave and it moves at constant velocity than special relativity would applly to the motion of light.
A wave by definition cannot exist without a medium . If a medium does not exist then the wave doesnot exist.
So if it is believed that a wave propagation can take place without a medium it would go against the definiton of what constitutes a wave.
The responce to the disturbance in the medium is based on the density of the medium. If Space is a medium for a wave and the density is not homogenous,then the speed of the wave is not the same thruout the medium.
In real life motion takes place in a gravity field no matter what the density of the field. So all motion are basically gravitational.However if the density of the gravity field is weak ,that we can aproximate the motion as being inertial.|||special relativity applies to all inertial frames. The first postulate is the main fundamental. the second postulate is in fact derived from the first postulate itself. the first postulate says that you can not conduct any experiment which can tell u whether u r moving with constant velocity, or are at rest.
hence relativity applies to all things in the universe, not only light. However the rest of the things move very slowly, compared to c, hence the effects of relativity are not noticeable. If a sound wave is moving with a speed of, say 20m/s, an obvserver moving with 10m/s in the opp direction will see it move with 30m/s. Actually, the speed observed is slightly less than 30, but the difference just cant be measured.|||SR is based on the observation that in vacuum the speed of light is the same regarless of the movement of the observer. SR applies to inertial frames (ie ones that are not acclerating) but by extension the principle of the constancy of the speed of light must apply to non-inertial frames (can you see why this is obvious? - imagine creating momentarily comoving frames to describe a non-inertial frame instantaneously).
In fact, this speed constancy applies not only to light but to all zero rest mass particles. In particular it applies to all gauge bosons - these are the particles that mediate all of the forces of nature.
Sound does not fall into this category. Sound is a propagating distortion of a medium, and the distortion is actually mediated by the electrostatic force between atoms, and that is mediated of course by photons and they do indeed move at the speed of light. But the distortion (sounds) does not - it moves at a speed determined by the response time of the atoms.
I can't test my question since I'm only 17, but It would be nice for someone to tell me so I can get it off of my mind.
I also wonder, if special relativity doesn't apply to other waves, then how do we know it does to light? Would we notice a change in 30 mph added to lights speed already?|||When something moves at constant speed ist usually a wave.This is inertial motion as opposed to gravitational motion, where the speed changes with changing distance and time.
Special Relativity does not apply to gravitational motion at all.
So the Only thing it could apply to is wave motion since it moves at constant velocity..The reason is that a wavelenght can be shorten and time of period dilated. The speed of the wave is medium dependent .And a wave is a disturbance in the medium. If light moves as foloowing the rules of a wave and it moves at constant velocity than special relativity would applly to the motion of light.
A wave by definition cannot exist without a medium . If a medium does not exist then the wave doesnot exist.
So if it is believed that a wave propagation can take place without a medium it would go against the definiton of what constitutes a wave.
The responce to the disturbance in the medium is based on the density of the medium. If Space is a medium for a wave and the density is not homogenous,then the speed of the wave is not the same thruout the medium.
In real life motion takes place in a gravity field no matter what the density of the field. So all motion are basically gravitational.However if the density of the gravity field is weak ,that we can aproximate the motion as being inertial.|||special relativity applies to all inertial frames. The first postulate is the main fundamental. the second postulate is in fact derived from the first postulate itself. the first postulate says that you can not conduct any experiment which can tell u whether u r moving with constant velocity, or are at rest.
hence relativity applies to all things in the universe, not only light. However the rest of the things move very slowly, compared to c, hence the effects of relativity are not noticeable. If a sound wave is moving with a speed of, say 20m/s, an obvserver moving with 10m/s in the opp direction will see it move with 30m/s. Actually, the speed observed is slightly less than 30, but the difference just cant be measured.|||SR is based on the observation that in vacuum the speed of light is the same regarless of the movement of the observer. SR applies to inertial frames (ie ones that are not acclerating) but by extension the principle of the constancy of the speed of light must apply to non-inertial frames (can you see why this is obvious? - imagine creating momentarily comoving frames to describe a non-inertial frame instantaneously).
In fact, this speed constancy applies not only to light but to all zero rest mass particles. In particular it applies to all gauge bosons - these are the particles that mediate all of the forces of nature.
Sound does not fall into this category. Sound is a propagating distortion of a medium, and the distortion is actually mediated by the electrostatic force between atoms, and that is mediated of course by photons and they do indeed move at the speed of light. But the distortion (sounds) does not - it moves at a speed determined by the response time of the atoms.
Help with a hard special relativity question?
I understand the basic concepts of special relativity, but I can't figure out how to solve this question, remembering that both length and time change.
The star Alpha Centauri is 4 light years away. At what constant velocity must a spacecraft travel from Earth if it is to reach the star in 3 years, as measured by the travellers on the spacecraft?
Thanks.|||It takes the ship 3 years to reach the star while
moving at v. Hence the contracted distance is:
D = v*t = v*3 = 4c*sqrt(1-v^2/c^2)
=%26gt;v = sqrt(16/25)c|||Thank you.
|||1 Lightyear = 9.461 * 10^15 meters
Velocity = Distance/Time
Velocity = 4(9.461 * 10^15m) / (3(60s)(60)(24)(365)) (This value here is the equivalent of 3 years in seconds (3, 60 seconds, 60 minutes, 24 hours, 365 days))
Velocity = 400008455.9m/s
The star Alpha Centauri is 4 light years away. At what constant velocity must a spacecraft travel from Earth if it is to reach the star in 3 years, as measured by the travellers on the spacecraft?
Thanks.|||It takes the ship 3 years to reach the star while
moving at v. Hence the contracted distance is:
D = v*t = v*3 = 4c*sqrt(1-v^2/c^2)
=%26gt;v = sqrt(16/25)c|||Thank you.
Report Abuse
|||1 Lightyear = 9.461 * 10^15 meters
Velocity = Distance/Time
Velocity = 4(9.461 * 10^15m) / (3(60s)(60)(24)(365)) (This value here is the equivalent of 3 years in seconds (3, 60 seconds, 60 minutes, 24 hours, 365 days))
Velocity = 400008455.9m/s
Einstein's Theory of Relativity led to the discovery of what type of energy?
Einstein's Theory of Relativity led to the discovery of what type of energy?|||because of the theory atomic energy was discovered.|||well sweetie I think it didn't lead to the discovery of any energy. unless you mean gravity.... well einstein discovered how gravity works so that doesn't really mean that he discovered the actual thing. just how it works. I hope this helps . good question . -B-|||LMFAO MAN. Doing your homework i see!
Kinetic Energy??? (NO CLUE)|||nuclear|||E=mc^2, nuclear energy. The mass lost when fission occurs can be multiplied by the square of the speed of light. The key word being "lost" What that means is the mass of an atom is more than the combined mass of all of the fission fragments that remain after fission. The difference in mass is what you use as your m. The mass that is lost is called the Binding energy or Mass defect. Protons repel each other normally in classical physics, but when they get incredibly close together a non classical force, called nuclear force causes them to be attracted to each other. This magically makes two protons in a nucleus weigh slightly more than the two protons were they seperate. Also neutrons are in the nucleus and weigh slightly more combined, than alone. A good analogy in nature is phase changes in water, etc. It is called the latent heat of vaporazation, fusion, etc. where potential energy must be added to make water change phase. So at atmospheric pressure, if you add energy at a constant rate, temperature will rise up to 212 F, and will then hold constant at 212 F while all the water flashes to steam gradually, and will not heat above 212 until all the water has flashed to steam. This is energy required to cause a phase change. Mass isn't changed, but density is. In nuclear fission, it is mass that drops to give off energy, but in fusion, energy is added to force nucleus's together to create more mass.|||rest energy, e=mc[squared] means that an object can have energy as long as it has mass
he helped develop the atomic bomb, relativity assisted by recognizing that the nucleus has stored energy in a rest state and can be released via a nucear reaction (fusion or fission)|||more than likely dark energy, since the general theory was to do with space and gravity.....|||Atomic energy. That the Energy (in Joules) contained in an object is equal to its Mass (in grams) times the speed of light (in centimeters per second) squared. That energy and mass are interchangeable by that formula. This was a result of his theory, although the theory is really about the invariance of the speed of light.|||The theory of relativity, or simply relativity, refers specifically to two theories: Albert Einstein's special relativity and general relativity.
The term "relativity" was coined by Max Planck in 1908 to emphasize how special relativity (and later, general relativity) uses the principle of relativity.
The special theory of relativity was proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies". Some three centuries earlier, Galileo's principle of relativity had stated that all uniform motion was relative, and that there was no absolute and well-defined state of rest; a person on the deck of a ship may be at rest in his opinion, but someone observing from the shore would say that he was moving. Einstein's theory generalized Galilean relativity from only mechanics to all laws of physics including electrodynamics. To stress this point, Einstein not only widened the postulate of relativity, but added the second postulate - that all observers will always measure the speed of light to be the same no matter what their state of uniform linear motion is.[1]
This theory has a variety of surprising consequences that seem to violate common sense, but all have been experimentally verified. Special relativity overthrows Newtonian notions of absolute space and time by stating that distance and time depend on the observer, and that time and space are perceived differently, depending on the observer. It yields the equivalence of matter and energy, as expressed in the mass-energy equivalence formula E = mc², where c is the speed of light in a vacuum. Special relativity agrees with Newtonian mechanics in their common realm of applicability, in experiments in which all velocities are small compared to the speed of light.
The theory was called "special" because it applies the principle of relativity only to inertial frames. Einstein developed general relativity to apply the principle generally, that is, to any frame, and that theory includes the effects of gravity. Special relativity does not account for gravity, but it can deal with accelerations.
Although special relativity makes some quantities relative, such as time, that we would have imagined to be absolute based on everyday experience, it also makes absolute some others that we would have thought were relative. In particular, it states that the speed of light is the same for all observers, even if they are in motion relative to one another. Special relativity reveals that c is not just the velocity of a certain phenomenon - light - but rather a fundamental feature of the way space and time are tied together. In particular, special relativity states that it is impossible for any material object to accelerate to light speed.
Special relativity
Main article: Special relativity
Special relativity is a theory of the structure of spacetime. It was introduced in Albert Einstein's 1905 paper "On the Electrodynamics of Moving Bodies". Special relativity is based on two postulates which are contradictory in classical mechanics:
The laws of physics are the same for all observers in uniform motion relative to one another (Galileo's principle of relativity),
The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light.
The resultant theory has many surprising consequences. Some of these are:
Time dilation: Moving clocks tick slower than an observer's "stationary" clock.
Length contraction: Objects are observed to be shortened in the direction that they are moving with respect to the observer.
Relativity of simultaneity: two events that appear simultaneous to an observer A will not be simultaneous to an observer B if B is moving with respect to A.
Mass-energy equivalence: E = mc², energy and mass are equivalent and transmutable.
The defining feature of special relativity is the replacement of the Galilean transformations of classical mechanics by the Lorentz transformations. (See Maxwell's equations of electromagnetism and introduction to special relativity).
General relativity
Main article: General relativity
General relativity is a theory of gravitation developed by Einstein in the years 1907–1915. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. The upshot of this is that free fall is inertial motion: In other words an object in free fall is falling because that is how objects move when there is no force being exerted on them, instead of this being due to the force of gravity as is the case in classical mechanics. This is incompatible with classical mechanics and special relativity because in those theories inertially moving objects cannot accelerate with respect to each other, but objects in free fall do so. To resolve this difficulty Einstein first proposed that spacetime is curved. In 1915, he devised the Einstein field equations which relate the curvature of spacetime with the mass, energy, and momentum within it.
Some of the consequences of general relativity are:
Time goes slower at lower gravitational potentials. This is called gravitational time dilation.
Orbits precess in a way unexpected in Newton's theory of gravity. (This has been observed in the orbit of Mercury and in binary pulsars).
Even rays of light (which are weightless) bend in the presence of a gravitational field.
The Universe is expanding, and the far parts of it are moving away from us faster than the speed of light. This does not contradict the theory of special relativity, since it is space itself that is expanding.
Frame-dragging, in which a rotating mass "drags along" the space time around it.
Technically, general relativity is a metric theory of gravitation whose defining feature is its use of the Einstein field equations. The solutions of the field equations are metric tensors which define the topology of the spacetime and how objects move intertially.|||the splitting of the atom|||??? it didn't lead to the discovery of any energy. unless you mean gravity.... well einstein discovered how gravity works so that doesn't really mean that he discovered the actual thing. just how it works...
Kinetic Energy??? (NO CLUE)|||nuclear|||E=mc^2, nuclear energy. The mass lost when fission occurs can be multiplied by the square of the speed of light. The key word being "lost" What that means is the mass of an atom is more than the combined mass of all of the fission fragments that remain after fission. The difference in mass is what you use as your m. The mass that is lost is called the Binding energy or Mass defect. Protons repel each other normally in classical physics, but when they get incredibly close together a non classical force, called nuclear force causes them to be attracted to each other. This magically makes two protons in a nucleus weigh slightly more than the two protons were they seperate. Also neutrons are in the nucleus and weigh slightly more combined, than alone. A good analogy in nature is phase changes in water, etc. It is called the latent heat of vaporazation, fusion, etc. where potential energy must be added to make water change phase. So at atmospheric pressure, if you add energy at a constant rate, temperature will rise up to 212 F, and will then hold constant at 212 F while all the water flashes to steam gradually, and will not heat above 212 until all the water has flashed to steam. This is energy required to cause a phase change. Mass isn't changed, but density is. In nuclear fission, it is mass that drops to give off energy, but in fusion, energy is added to force nucleus's together to create more mass.|||rest energy, e=mc[squared] means that an object can have energy as long as it has mass
he helped develop the atomic bomb, relativity assisted by recognizing that the nucleus has stored energy in a rest state and can be released via a nucear reaction (fusion or fission)|||more than likely dark energy, since the general theory was to do with space and gravity.....|||Atomic energy. That the Energy (in Joules) contained in an object is equal to its Mass (in grams) times the speed of light (in centimeters per second) squared. That energy and mass are interchangeable by that formula. This was a result of his theory, although the theory is really about the invariance of the speed of light.|||The theory of relativity, or simply relativity, refers specifically to two theories: Albert Einstein's special relativity and general relativity.
The term "relativity" was coined by Max Planck in 1908 to emphasize how special relativity (and later, general relativity) uses the principle of relativity.
The special theory of relativity was proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies". Some three centuries earlier, Galileo's principle of relativity had stated that all uniform motion was relative, and that there was no absolute and well-defined state of rest; a person on the deck of a ship may be at rest in his opinion, but someone observing from the shore would say that he was moving. Einstein's theory generalized Galilean relativity from only mechanics to all laws of physics including electrodynamics. To stress this point, Einstein not only widened the postulate of relativity, but added the second postulate - that all observers will always measure the speed of light to be the same no matter what their state of uniform linear motion is.[1]
This theory has a variety of surprising consequences that seem to violate common sense, but all have been experimentally verified. Special relativity overthrows Newtonian notions of absolute space and time by stating that distance and time depend on the observer, and that time and space are perceived differently, depending on the observer. It yields the equivalence of matter and energy, as expressed in the mass-energy equivalence formula E = mc², where c is the speed of light in a vacuum. Special relativity agrees with Newtonian mechanics in their common realm of applicability, in experiments in which all velocities are small compared to the speed of light.
The theory was called "special" because it applies the principle of relativity only to inertial frames. Einstein developed general relativity to apply the principle generally, that is, to any frame, and that theory includes the effects of gravity. Special relativity does not account for gravity, but it can deal with accelerations.
Although special relativity makes some quantities relative, such as time, that we would have imagined to be absolute based on everyday experience, it also makes absolute some others that we would have thought were relative. In particular, it states that the speed of light is the same for all observers, even if they are in motion relative to one another. Special relativity reveals that c is not just the velocity of a certain phenomenon - light - but rather a fundamental feature of the way space and time are tied together. In particular, special relativity states that it is impossible for any material object to accelerate to light speed.
Special relativity
Main article: Special relativity
Special relativity is a theory of the structure of spacetime. It was introduced in Albert Einstein's 1905 paper "On the Electrodynamics of Moving Bodies". Special relativity is based on two postulates which are contradictory in classical mechanics:
The laws of physics are the same for all observers in uniform motion relative to one another (Galileo's principle of relativity),
The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light.
The resultant theory has many surprising consequences. Some of these are:
Time dilation: Moving clocks tick slower than an observer's "stationary" clock.
Length contraction: Objects are observed to be shortened in the direction that they are moving with respect to the observer.
Relativity of simultaneity: two events that appear simultaneous to an observer A will not be simultaneous to an observer B if B is moving with respect to A.
Mass-energy equivalence: E = mc², energy and mass are equivalent and transmutable.
The defining feature of special relativity is the replacement of the Galilean transformations of classical mechanics by the Lorentz transformations. (See Maxwell's equations of electromagnetism and introduction to special relativity).
General relativity
Main article: General relativity
General relativity is a theory of gravitation developed by Einstein in the years 1907–1915. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. The upshot of this is that free fall is inertial motion: In other words an object in free fall is falling because that is how objects move when there is no force being exerted on them, instead of this being due to the force of gravity as is the case in classical mechanics. This is incompatible with classical mechanics and special relativity because in those theories inertially moving objects cannot accelerate with respect to each other, but objects in free fall do so. To resolve this difficulty Einstein first proposed that spacetime is curved. In 1915, he devised the Einstein field equations which relate the curvature of spacetime with the mass, energy, and momentum within it.
Some of the consequences of general relativity are:
Time goes slower at lower gravitational potentials. This is called gravitational time dilation.
Orbits precess in a way unexpected in Newton's theory of gravity. (This has been observed in the orbit of Mercury and in binary pulsars).
Even rays of light (which are weightless) bend in the presence of a gravitational field.
The Universe is expanding, and the far parts of it are moving away from us faster than the speed of light. This does not contradict the theory of special relativity, since it is space itself that is expanding.
Frame-dragging, in which a rotating mass "drags along" the space time around it.
Technically, general relativity is a metric theory of gravitation whose defining feature is its use of the Einstein field equations. The solutions of the field equations are metric tensors which define the topology of the spacetime and how objects move intertially.|||the splitting of the atom|||??? it didn't lead to the discovery of any energy. unless you mean gravity.... well einstein discovered how gravity works so that doesn't really mean that he discovered the actual thing. just how it works...
Whats the problem between the theory of Relativity and Quantum Physics?
I understand that the Theory of Relativity explains the space/time fabric of the universe, gravity effect on it, energy and mass/the speed of light, and ect. and that Quantum physics is about atomic sized partials (i know less about it than Relativity) but i have herd that the two theory's don't quite agree with each other i heard some explanations but i don't quite understand them.|||General relativity is a classical theory--it explains the behavior of objects at low energy scales.
Quantum mechanics describes the behavior of objects at very high energy and small distance scales.
Because the quantum of gravity carries so little energy, the quantum nature of gravity has never manifest itself in any experiment or natural phenomenon. General relativity works fine. But given enough energy (maybe more than we will ever generate experimentally), GR should break down.
There are theories of quantum gravity that have GR as a low energy limit, just as classical gravity is a low mass, long distance limit of GR. The problem with them, though, is that they are non-renormalizable. There are infinite energies that can't be ignored or hand-waved away as they are in other quantum field theories (because gravity couples to energy). String theory does successfully reconcile classical GR with quantum mechanics, but we are a long way from being able to test it in any other way.
Quantum mechanics describes the behavior of objects at very high energy and small distance scales.
Because the quantum of gravity carries so little energy, the quantum nature of gravity has never manifest itself in any experiment or natural phenomenon. General relativity works fine. But given enough energy (maybe more than we will ever generate experimentally), GR should break down.
There are theories of quantum gravity that have GR as a low energy limit, just as classical gravity is a low mass, long distance limit of GR. The problem with them, though, is that they are non-renormalizable. There are infinite energies that can't be ignored or hand-waved away as they are in other quantum field theories (because gravity couples to energy). String theory does successfully reconcile classical GR with quantum mechanics, but we are a long way from being able to test it in any other way.
How clear do I need to be on Newtonian mechanics in order to understand general relativity?
for example, if I dont understand 3-4 problems per chapter in a book of fundamentals, will it severely hinder me from understanding relativity|||General relativity is non-intuitive and really hard to fully understand. It is really easy to say that the speed of light is constant and that time slows as velocity increases and mass increases as velocity increases, but it doesn't really make a whole lot of sense. So, if you are having trouble with Newtonian mechanics, which does make a lot of sense, then I think you are going to have trouble with relativity.
Could somebody verify my understanding of special relativity?
Since light has the property of special relativity space and time must distort and dilate respectively to accommodate this. However the effects are only noticeable to humans are speeds approaching light speed.|||Not quite.
The speed of light is an absolute and because of this space, time, mass and volume must be variable to match this and they are all measurements dependent on the speed of motion. In the case of Special Relativity the frame of reference is special and unique to the observer.
One of the Laws of Physics says that the speed of light, in a vacuum is absolute and an unchanging maximum. Then when the SI System defines a meter to be the wave length of a specific element they tie absolute distance to the speed of light; thus fixing our relative frames of reference.
Normally the effects of dilation are only noticed at near light speeds, but they have been observed and proven on air craft flights around the world and on the Space Shuttle using atomic clocks. The GPS system is satellite based and since the satellites are moving so much faster than the surface of the earth their clocks are adjusted to keep "earth time" not their own relative time. Forgetting this little issue would introduce a constant error in GPS calculations.
According to Wikipedia: http://en.wikipedia.org/wiki/Special_Rel…
"Special relativity (SR) (aka the special theory of relativity (STR)) is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies"[1]. It generalizes Galileo's principle of relativity — that all uniform motion was relative, and that there is no absolute and well-defined state of rest (no privileged reference frames) — from mechanics to all the laws of physics, including electrodynamics.
To stress this point, Einstein not only widened the postulate of relativity, but added the second postulate that all observers will always measure the speed of light to be the same no matter what their state of uniform linear motion."|||Yes, the effects are noticeable only when you get up to speeds of at least 10% of light speed. At that speed, things are distorted by about 5%.
At 90% of light speed, things are distorted by a factor of 3.2
At 99% of light speed, things are distorted by a factor of 10.|||o ya ,, i know that light speed can be distorted by heavenly body's ego black holes so time must also distort but then again it might not as time is relevant to distance as measured from our starting point,,and any theory's about that just that theory's..
The speed of light is an absolute and because of this space, time, mass and volume must be variable to match this and they are all measurements dependent on the speed of motion. In the case of Special Relativity the frame of reference is special and unique to the observer.
One of the Laws of Physics says that the speed of light, in a vacuum is absolute and an unchanging maximum. Then when the SI System defines a meter to be the wave length of a specific element they tie absolute distance to the speed of light; thus fixing our relative frames of reference.
Normally the effects of dilation are only noticed at near light speeds, but they have been observed and proven on air craft flights around the world and on the Space Shuttle using atomic clocks. The GPS system is satellite based and since the satellites are moving so much faster than the surface of the earth their clocks are adjusted to keep "earth time" not their own relative time. Forgetting this little issue would introduce a constant error in GPS calculations.
According to Wikipedia: http://en.wikipedia.org/wiki/Special_Rel…
"Special relativity (SR) (aka the special theory of relativity (STR)) is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies"[1]. It generalizes Galileo's principle of relativity — that all uniform motion was relative, and that there is no absolute and well-defined state of rest (no privileged reference frames) — from mechanics to all the laws of physics, including electrodynamics.
To stress this point, Einstein not only widened the postulate of relativity, but added the second postulate that all observers will always measure the speed of light to be the same no matter what their state of uniform linear motion."|||Yes, the effects are noticeable only when you get up to speeds of at least 10% of light speed. At that speed, things are distorted by about 5%.
At 90% of light speed, things are distorted by a factor of 3.2
At 99% of light speed, things are distorted by a factor of 10.|||o ya ,, i know that light speed can be distorted by heavenly body's ego black holes so time must also distort but then again it might not as time is relevant to distance as measured from our starting point,,and any theory's about that just that theory's..
Theory of relativity says that when an object is on a speed of light you will shrink from back and front?
Like a pancake right. when we see a car passing at top speed we only see a flash like a rectangle object has passed. is that the same? So relativity of object at a speed of light is no different than that?|||"for the observer in relative movement, the length of the object is measured by subtracting the simultaneously measured distances of both ends of the object". See:
http://en.wikipedia.org/wiki/Length_cont…
But also read:
http://math.ucr.edu/home/baez/physics/Re…|||front|||Yeah, flat %26amp; dense as that speed is approached. Time slows also and in theory may even go backwards if the speed is exceeded.|||The closer one approaches light speed, the shorter the length in the direction of travel. The reason for seeing a rectangular shape is it's very low speed, even at 200 mph. The same object traveling faster than 66% light speed will appear bulbous.
http://en.wikipedia.org/wiki/Length_cont…
But also read:
http://math.ucr.edu/home/baez/physics/Re…|||front|||Yeah, flat %26amp; dense as that speed is approached. Time slows also and in theory may even go backwards if the speed is exceeded.|||The closer one approaches light speed, the shorter the length in the direction of travel. The reason for seeing a rectangular shape is it's very low speed, even at 200 mph. The same object traveling faster than 66% light speed will appear bulbous.
How have Einstein's theories of relativity changed the world?
I have:
* Time dilation has led to the development of satellites.
* E=mc虏 -%26gt; foundation to the development of atomic energy.
* led to the Manhattan project and first atomic Bomb which has changed history.
I don't know if E=mc虏 is part of Einstein's theories though..
also how else have his theories of relativity changed the world? has it changed how we view the Universe was formed?|||okay... E=mc^2 is part of special relativity, for sure, but was originally published in an almost forgotten article... it is more properly stated as E = p^2m^4 + m^2c^4. e=mc^2 only refers to the rest energy of mass, and does not take into account if the particle is moving (e.g., if it has kinetic energy). The equation I gave above is the full version.. p=momentum, and takes into account ALL particles, motionless or in motion.
Time dilation did not lead to the development of satellites.... it helps in synchronizing them.
Relativity first helped explain PRECESSION (of Mercury), which you probably could say has helped us in looking for extra-solar planets.
Yes, E=mc^2 did lead, via Roosevelt, to atomic energy (the Manhattan project, etc).
I would focus more on particle physics if you want to go further. If (like with the LHC -- large hadron collider) we accelerate particles with a small mass to nearly the speed of light, then they take on more mass and more energy. Einstein's theory has lead to discovery of new elements in the periodic table. It has provided a fundamental basis for a lot of the things in quantum mechanical theory,. even though quantum mechanics, as of now, does not work with relativity.
BLACK HOLES -- as the center of each galaxy -- is all Einstein.
Some stars periodically shine light on us brighter than entire galaxies... determining what those were is all Einstein... neutron stars (half-dead stars that originally had more mass than the sun but not enough to become a black hole).
Astronauts in space have to use a special clock... for many purposes, if your clock is off by .01%, then it doesn't matter. Re-entry into the atmosphere... then it does matter. Going nearly 30 k/hr orbiting the earth does make clock run slower compared to an observer on earth... so relativity definitely contributed to the space program.
The original theory of general relativity contained a "cosmological" constant that as supposed to make the universe static (unchanging). His original calculations showed that the universe should be expanding. Edwin Hubble proved that the universe WAS INDEED expanding, and Einstein removed the cosmological constant, calling it the biggest blunder of his life.
Today, though, the idea of a cosmological constant is still thought about.. embraced. Amazingly, it has something to do, sometimes, with quantum mechanical effects.
I could go on forever, but relativity definitely changed everything.
* Time dilation has led to the development of satellites.
* E=mc虏 -%26gt; foundation to the development of atomic energy.
* led to the Manhattan project and first atomic Bomb which has changed history.
I don't know if E=mc虏 is part of Einstein's theories though..
also how else have his theories of relativity changed the world? has it changed how we view the Universe was formed?|||okay... E=mc^2 is part of special relativity, for sure, but was originally published in an almost forgotten article... it is more properly stated as E = p^2m^4 + m^2c^4. e=mc^2 only refers to the rest energy of mass, and does not take into account if the particle is moving (e.g., if it has kinetic energy). The equation I gave above is the full version.. p=momentum, and takes into account ALL particles, motionless or in motion.
Time dilation did not lead to the development of satellites.... it helps in synchronizing them.
Relativity first helped explain PRECESSION (of Mercury), which you probably could say has helped us in looking for extra-solar planets.
Yes, E=mc^2 did lead, via Roosevelt, to atomic energy (the Manhattan project, etc).
I would focus more on particle physics if you want to go further. If (like with the LHC -- large hadron collider) we accelerate particles with a small mass to nearly the speed of light, then they take on more mass and more energy. Einstein's theory has lead to discovery of new elements in the periodic table. It has provided a fundamental basis for a lot of the things in quantum mechanical theory,. even though quantum mechanics, as of now, does not work with relativity.
BLACK HOLES -- as the center of each galaxy -- is all Einstein.
Some stars periodically shine light on us brighter than entire galaxies... determining what those were is all Einstein... neutron stars (half-dead stars that originally had more mass than the sun but not enough to become a black hole).
Astronauts in space have to use a special clock... for many purposes, if your clock is off by .01%, then it doesn't matter. Re-entry into the atmosphere... then it does matter. Going nearly 30 k/hr orbiting the earth does make clock run slower compared to an observer on earth... so relativity definitely contributed to the space program.
The original theory of general relativity contained a "cosmological" constant that as supposed to make the universe static (unchanging). His original calculations showed that the universe should be expanding. Edwin Hubble proved that the universe WAS INDEED expanding, and Einstein removed the cosmological constant, calling it the biggest blunder of his life.
Today, though, the idea of a cosmological constant is still thought about.. embraced. Amazingly, it has something to do, sometimes, with quantum mechanical effects.
I could go on forever, but relativity definitely changed everything.
Physics: How does the Correspondence principle relate to the special theory of relativity?
Could someone eplain the Correspondence principle and how it relates to the special theory of relativity?
Will be quick to award BA, thanks in advance for any help|||in Quantum Mechanics, the correspondence principle is that for large quantum numbers (large energies) the classical limit is reached.
Likewise, in relativity, the correspondence principle is that for slow speeds relative to the velocity of light, classical mechanics is recovered (as it should!).
One example:
The relativistic energy obeys the equation:
E = mc^2/sqrt(1-v^2/c^2)
if v%26lt;%26lt;c, the the square root can be approximated by
1/sqrt(1-v^2/c^2) ~ 1 + 1/2 v^2/c^2 + O(v^4/c^4).
Hence, for small v/c, the relativistic energy reduces to:
E ~ mc^2 ( 1 + 1/2 v^2/c^2) = mc^2 + 1/2 m v^2.
The constant term mc^2 is the rest energy. The kinetic energy is read of as 1/2 m v^2 , the classical result.
Will be quick to award BA, thanks in advance for any help|||in Quantum Mechanics, the correspondence principle is that for large quantum numbers (large energies) the classical limit is reached.
Likewise, in relativity, the correspondence principle is that for slow speeds relative to the velocity of light, classical mechanics is recovered (as it should!).
One example:
The relativistic energy obeys the equation:
E = mc^2/sqrt(1-v^2/c^2)
if v%26lt;%26lt;c, the the square root can be approximated by
1/sqrt(1-v^2/c^2) ~ 1 + 1/2 v^2/c^2 + O(v^4/c^4).
Hence, for small v/c, the relativistic energy reduces to:
E ~ mc^2 ( 1 + 1/2 v^2/c^2) = mc^2 + 1/2 m v^2.
The constant term mc^2 is the rest energy. The kinetic energy is read of as 1/2 m v^2 , the classical result.
If the speed of light was infinite but the postulates of special relativity still held, then?
If the speed of light was infinite but the postulates of special relativity still held, then
time dilation would be obvious at low speeds.
length contraction would not occur.
objects could have negative kinetic energy.
any moving object would have infinite momentum.|||The universe would come undone! lol
"any moving object would have infinite momentum."
This sounds like the most reasonable answer since the work required to move an object increases as it approaches the speed of light so if the speed of light was infinity no work would be required to move an object. Energy would be meaningless as everything would have infinite energy... or momentum.|||D.|||Yeah man, woh!!!
Pack me up one.
time dilation would be obvious at low speeds.
length contraction would not occur.
objects could have negative kinetic energy.
any moving object would have infinite momentum.|||The universe would come undone! lol
"any moving object would have infinite momentum."
This sounds like the most reasonable answer since the work required to move an object increases as it approaches the speed of light so if the speed of light was infinity no work would be required to move an object. Energy would be meaningless as everything would have infinite energy... or momentum.|||D.|||Yeah man, woh!!!
Pack me up one.
Does the 1st Law of Thermodynamics contradict with Einstein General Theory of Relativity?
The 1st Law of Thermodynamics said that energy can not be created nor destroyed. But part of Einstein General Theory of Relativity (E=mc^2) said that energy can be created from matter. A one Kg matter contains enormous amount of energy.|||It is not a violation. You'd have no problem with "kinetic energy" or "potential energy" conversions, right? "Storage as mass" is just another form of potential energy. "Storage as rotational kinetic energy" as in a flywheel, "storage as flowing charge in a superconductor", "storage as vibrating molecules " (heat), and "storage as mass raised in a gravitational field" are other methods you might recognize.|||But matter is energy, you haven't destroyed nor created it. The amount of energy in the Universe is a constant.
At the big bang we had no mass only energy. Fundamental particles where then created from the energy. However we have lost no energy as energy and mass is the same thing.
Therefore no, it does not contradict.
All E=mc^2 says is that mass and energy is interchangeable.|||The equation doesn't say that energy can be CREATED from matter - it says that mass is just another form of energy. It says that mass and energy are equivalent quantities that are simply measured in different ways. They are two sides to the same coin.
At the big bang we had no mass only energy. Fundamental particles where then created from the energy. However we have lost no energy as energy and mass is the same thing.
Therefore no, it does not contradict.
All E=mc^2 says is that mass and energy is interchangeable.|||The equation doesn't say that energy can be CREATED from matter - it says that mass is just another form of energy. It says that mass and energy are equivalent quantities that are simply measured in different ways. They are two sides to the same coin.
How to explain Theory of Special Relativity?
In my essay I have to explain Einstein's Theory of Relativity in a way that anyone can understand it. It can't be that long either. About 30 or 40 words. Can someone help me explain the theory in a easy way?
Thanks|||Observe a ball falling when left through a car moving with uniform velocity.you will observe its motion to be linearly downwards.Now let us observe this ball from outside.You will observe its motion to be projectile.this theory says that both the observers have right opinion.No one is wrong.In other words, all the frames of references are equal in the description of all physical laws.|||SRT in 30 or 40 words - "Einstein's Special Relativity Theory (SRT) explains the motion of moving bodies with respect to one another." In a nutshell that's it. (General Relativity gets really complex and mathematically heavy and adds gravity to the mix.) Now, there's a lot more to the theory if you consider what Einstein is really trying to do with these moving systems, how he derived his equations, and how he reaches his orginal conclusions. In order for SRT to make sense, you have to understand concepts like "time dilation" and "length contraction," which are essential to SRT.
I'm a contrarian when it comes to SRT. However, I explain how Einstein arrives at his theory (as derived in his 1905 paper and in his Relativity book) and have prepared a set of 4 video clips that explains moving systems. The 4th video explains SRT and the key assumptions you have to make, and why if you make those assumptions you must accept concepts like time dilation and length contraction. (Although, you should probably watch all 4 so that you understand the terminology I use.) You can see these short videos at my blog at http://blog.relativitychallenge.com - Episodes 12 through 15.
Good luck with your essay.
Steven|||the whole theory in 30 or 40 words? wow...
motion is relative, no point of view is better than any other and either can be correct. a stationary observer sees time slow down for an object moving very fast. that same observer also sees that object contract, and get more massive. the observer moving very fast could argue that he was motionless, and everything else was moving. so he could same the same things about the stationary observer. nothing can travel faster than the speed of light.
good enough? i give you permission to copy that directly.
Thanks|||Observe a ball falling when left through a car moving with uniform velocity.you will observe its motion to be linearly downwards.Now let us observe this ball from outside.You will observe its motion to be projectile.this theory says that both the observers have right opinion.No one is wrong.In other words, all the frames of references are equal in the description of all physical laws.|||SRT in 30 or 40 words - "Einstein's Special Relativity Theory (SRT) explains the motion of moving bodies with respect to one another." In a nutshell that's it. (General Relativity gets really complex and mathematically heavy and adds gravity to the mix.) Now, there's a lot more to the theory if you consider what Einstein is really trying to do with these moving systems, how he derived his equations, and how he reaches his orginal conclusions. In order for SRT to make sense, you have to understand concepts like "time dilation" and "length contraction," which are essential to SRT.
I'm a contrarian when it comes to SRT. However, I explain how Einstein arrives at his theory (as derived in his 1905 paper and in his Relativity book) and have prepared a set of 4 video clips that explains moving systems. The 4th video explains SRT and the key assumptions you have to make, and why if you make those assumptions you must accept concepts like time dilation and length contraction. (Although, you should probably watch all 4 so that you understand the terminology I use.) You can see these short videos at my blog at http://blog.relativitychallenge.com - Episodes 12 through 15.
Good luck with your essay.
Steven|||the whole theory in 30 or 40 words? wow...
motion is relative, no point of view is better than any other and either can be correct. a stationary observer sees time slow down for an object moving very fast. that same observer also sees that object contract, and get more massive. the observer moving very fast could argue that he was motionless, and everything else was moving. so he could same the same things about the stationary observer. nothing can travel faster than the speed of light.
good enough? i give you permission to copy that directly.
What do you think the real confusion is in the twin "paradox" and special theory of relativity?
It is easy enough to go through and prove there is no paradox in relativity.
Makes sense - it is a mathematical theory derived from established mathematics. People still don't buy it though.
I think the real problem is the conclusion we try to draw from "thought experiments." Creating fictitious situations has a way of masking reality.
Case in point, if you REALLY put a person in a space ship and flew him at half-light speed to a distant star and back, would he really come back that much younger than his earthbound twin?
I'm guessing no, because the simple twin-paradox problem neglects way too many other factors that would actually come into play.|||The confusion is simply the result of the contridiction of our common sense based on our earthly observations vs. the reality of how the universe actually works.
The same confusion existed when it was proposed that the earth was not flat - or the stationary center of the universe.
The twin paradox is absolutely real.
Time slows with accelleration, greater gravtational fields and speeds approaching that of light. All actual observations and experiments have confirmed this phenomenon to be exactly as predicted by Einstein's formulas and equations.
If a real person were to be accellerated into space, fly at half light speed for a while and accellerate back, he would find that the earth and the people on it have aged more than he has.
When time slows due to this phenomenon, all processes slow - from biological right down to the molecular levels.
Before you consider that the person sent from earth has found the fountain of youth - consider this:
If two people can perform a task in one hour and they start at identical times on earth - and then one of them is accellerated into space. When the one on earth has finished his task - the one in the spaceship would still be working on it - his hour has been stretched out.
If the one accellerated sends a message back to his buddy on earth, the one on earth would have to tape the message and speed up the playback to make it understandable.
In other words - the perceived time for both is the same - it litterally takes two earth years for the one in the spaceship to perform the same tasks as the one on earth has finished in a year (relative to earth time).
The twin paradox occurs when the two different references are brought back together and compared.|||If motion would exist without acceleration and change in direction, then the Pun that Einstein indicated would be real. In the real world verses the imaginary, every thing continually changes direction and so does velocity.Time also changes per Universe time levels.
|||"...if you REALLY put a person in a space ship and flew him at half-light speed to a distant star and back, would he really come back that much younger than his earthbound twin?..."
Einstein's theory that leads to time dilation--which is what's going on with the so-called twins' paradox---has been shown over and over again to be an actual phenomenon by careful and very precise experiments. The most well-known deals with two atomic clocks that have been exactly synchronized. One clock is flown around for a prolonged period aboard a high-speed jet then brought back. The once-synchronized clocks no longer show the same time.|||No paradox: http://en.wikipedia.org/wiki/Twin_parado…
The two frames are NOT symmetrical, therefore, you cannot apply reverse Lorentz contraction to the stationary twin.
Time dilation exists, all GPS satellites have demonstrated a time error due to relativistic effects:
http://en.wikipedia.org/wiki/Global_Posi…|||The twin paradox on exists in special relativity. If you consider general relativity it goes away. Here is why:
In order for the equations of special relativity to apply you can not have acceleration. But in the twin paradox you have accelerate one twin to a velocity close to c, then he decelerates to a stop reverses direction and accelerates to high velocity again. When you consider all these accelerations you can distinguish which twin will age slower, and the paradox disappears.|||There is no paradox. General Relativity put the supposed paradox to rest.
You have it wrong, however, because the travelling twin would in fact be younger. There is nothing wrong with the thought experiments of Einstein, I think you just don't quite understand them.|||Ahh...as with all physics, there is both positive and negative values. Would not the return trip yeild a recinsion of any effect acheived by the away journey?
One must first fully grasp the concept of relativity. As it relates to lightspeed, the concept is that TIME itself flows as defined by change in space. no movement, no time. Movement relative to what?
Could you not say that when one twin leaves earth at half lightspeed, he could think himself as standing still and his brother as moving? Could not BOTH brothers see the other's time as being faster?
What happens if they were triplets and the third brother, halfway to that star, launches away from the second brother's spaceship at 3/4 lightspeed relative to the spaceship? Does the first brother witness 1.25 lightspeed from his vantage?
NO! Nothing travels faster than light. Since their space is traversed at different near lightspeed velocities, IT IS THE TIME THAT CHANGES AS THEY VIEW THE TIME OF OTHERS.
BUT, THAT IS RELATIVE!!
The triplets are assumed to return to the same "space" and relative velocity. They will return to a place where they measure time the same.
Let us say that a year has gone by. Is it the same year for all three? Each will say:
"Only a year has gone by, but your time was faster than mine."
All three say that same thing.
SAME YEAR, SAME AGE, SAME TIME (for now) - NO PARADOX.
The near lightspeed velocity alters the time, but only RELATIVE to how they see time flowing upon another, and not upon themselves.
YOU might right now be travelling at close to lightspeed relative to another place in space. Without a change in space, there can be no time, Since lightspeed is the absolute, then time itself becomes a deviation of that...relatively speaking.
Makes sense - it is a mathematical theory derived from established mathematics. People still don't buy it though.
I think the real problem is the conclusion we try to draw from "thought experiments." Creating fictitious situations has a way of masking reality.
Case in point, if you REALLY put a person in a space ship and flew him at half-light speed to a distant star and back, would he really come back that much younger than his earthbound twin?
I'm guessing no, because the simple twin-paradox problem neglects way too many other factors that would actually come into play.|||The confusion is simply the result of the contridiction of our common sense based on our earthly observations vs. the reality of how the universe actually works.
The same confusion existed when it was proposed that the earth was not flat - or the stationary center of the universe.
The twin paradox is absolutely real.
Time slows with accelleration, greater gravtational fields and speeds approaching that of light. All actual observations and experiments have confirmed this phenomenon to be exactly as predicted by Einstein's formulas and equations.
If a real person were to be accellerated into space, fly at half light speed for a while and accellerate back, he would find that the earth and the people on it have aged more than he has.
When time slows due to this phenomenon, all processes slow - from biological right down to the molecular levels.
Before you consider that the person sent from earth has found the fountain of youth - consider this:
If two people can perform a task in one hour and they start at identical times on earth - and then one of them is accellerated into space. When the one on earth has finished his task - the one in the spaceship would still be working on it - his hour has been stretched out.
If the one accellerated sends a message back to his buddy on earth, the one on earth would have to tape the message and speed up the playback to make it understandable.
In other words - the perceived time for both is the same - it litterally takes two earth years for the one in the spaceship to perform the same tasks as the one on earth has finished in a year (relative to earth time).
The twin paradox occurs when the two different references are brought back together and compared.|||If motion would exist without acceleration and change in direction, then the Pun that Einstein indicated would be real. In the real world verses the imaginary, every thing continually changes direction and so does velocity.Time also changes per Universe time levels.
Report Abuse
|||"...if you REALLY put a person in a space ship and flew him at half-light speed to a distant star and back, would he really come back that much younger than his earthbound twin?..."
Einstein's theory that leads to time dilation--which is what's going on with the so-called twins' paradox---has been shown over and over again to be an actual phenomenon by careful and very precise experiments. The most well-known deals with two atomic clocks that have been exactly synchronized. One clock is flown around for a prolonged period aboard a high-speed jet then brought back. The once-synchronized clocks no longer show the same time.|||No paradox: http://en.wikipedia.org/wiki/Twin_parado…
The two frames are NOT symmetrical, therefore, you cannot apply reverse Lorentz contraction to the stationary twin.
Time dilation exists, all GPS satellites have demonstrated a time error due to relativistic effects:
http://en.wikipedia.org/wiki/Global_Posi…|||The twin paradox on exists in special relativity. If you consider general relativity it goes away. Here is why:
In order for the equations of special relativity to apply you can not have acceleration. But in the twin paradox you have accelerate one twin to a velocity close to c, then he decelerates to a stop reverses direction and accelerates to high velocity again. When you consider all these accelerations you can distinguish which twin will age slower, and the paradox disappears.|||There is no paradox. General Relativity put the supposed paradox to rest.
You have it wrong, however, because the travelling twin would in fact be younger. There is nothing wrong with the thought experiments of Einstein, I think you just don't quite understand them.|||Ahh...as with all physics, there is both positive and negative values. Would not the return trip yeild a recinsion of any effect acheived by the away journey?
One must first fully grasp the concept of relativity. As it relates to lightspeed, the concept is that TIME itself flows as defined by change in space. no movement, no time. Movement relative to what?
Could you not say that when one twin leaves earth at half lightspeed, he could think himself as standing still and his brother as moving? Could not BOTH brothers see the other's time as being faster?
What happens if they were triplets and the third brother, halfway to that star, launches away from the second brother's spaceship at 3/4 lightspeed relative to the spaceship? Does the first brother witness 1.25 lightspeed from his vantage?
NO! Nothing travels faster than light. Since their space is traversed at different near lightspeed velocities, IT IS THE TIME THAT CHANGES AS THEY VIEW THE TIME OF OTHERS.
BUT, THAT IS RELATIVE!!
The triplets are assumed to return to the same "space" and relative velocity. They will return to a place where they measure time the same.
Let us say that a year has gone by. Is it the same year for all three? Each will say:
"Only a year has gone by, but your time was faster than mine."
All three say that same thing.
SAME YEAR, SAME AGE, SAME TIME (for now) - NO PARADOX.
The near lightspeed velocity alters the time, but only RELATIVE to how they see time flowing upon another, and not upon themselves.
YOU might right now be travelling at close to lightspeed relative to another place in space. Without a change in space, there can be no time, Since lightspeed is the absolute, then time itself becomes a deviation of that...relatively speaking.
The prospect of a singular time-frame and the theory of relativity?
We all like to perceive time as a linear dimension of "before's" and "after's". But what if this is our way of making sense out of time? Could it be possible that everything happens all at once, and humans perceive time as happening "before then after"? How would this fit into the theory of relativity?|||no|||haha i cant believe this got the correct answer.
heres my real response.
1. you overestimate the power of the brain, which is hard to do.
2. why does our brain only perceive the events that take place within our 80 or so year long life time? why dont we perceive the birth of the universe?
heres my real response.
1. you overestimate the power of the brain, which is hard to do.
2. why does our brain only perceive the events that take place within our 80 or so year long life time? why dont we perceive the birth of the universe?
Report Abuse
Do intelligent people believe in relativity, or question it?
Open your mind folks. The theory of relativity is just a theory. Einstein says the geometry of the universe is locally Lorentzian. Are you just going to take that?|||intelligent people question everything.|||Intelligent people regularly review all the things they believe or hold as factual to compare them against new information gathered since they last reviewed.
By the way, we also know relativity is fatally flawed. It is by mathematical definition an analog solution, however, under quantum physics, quantum gravity must be a digital/discrete solution.|||On matters of physics, I'm generally prepared to trust einstein. I'm sure intelligent people do question it however.|||did you ever read a book about the subject???
everything in the special and general relativity has been proven over and over into the smallest detail.
even the cosmic constant which Einstein introduced and later thought of as his biggest mistake was found in the '80's|||Anything that we can not prove to be an exact truth is technically a theory. Actually, life is a theory. Hah! =)|||Einstein used Riemann geometry, not Lorentzian.|||Intelligent Falling TEACH THE CONTROVERSY!
rAmen|||I question it. But I'm just not up to the task of presenting any challenge, that's for sure. Way beyond my level.|||Yes it is just a theory, and that is what it is called. It is written in modern times, in a language that is current, is not 'quoted' by page and paragraph and sentence by millions of people each day that swear that it is the key to salvation. Einstein is not worshiped nor is he displayed as a martyr or a savior.
So....what's your point?|||You could not be more wrong!! All the Intelligent people believe in relativity!!
Even the christian ones!!
The Pope, Catholic Church, Church of England and mainstream churches all accept evolution and the big bang!!
Lord Carey the former Archbishop of Canterbury put it rather well – “Creationism is the fruit of a fundamentalist approach to scripture, ignoring scholarship and critical learning, and confusing different understandings of truth”!!
Surely even you can see that you need to reconsider your ill thought out ideas when christians and atheists unite to laugh at you!!!
Your ignorance of basic facts is shown in your idea that the theory of relativity came from Einstein!!
The theory of relativity was invented by gallilaeo and called Heliocentrism!! The church then forced him to recant and kept him under house arrest for years until he died!!
Einstines theories were: The Special theory of relativity and The General theory of relativity.
So if you want to appear intelligent at least do a little research and get your facts right first!!
By the way, we also know relativity is fatally flawed. It is by mathematical definition an analog solution, however, under quantum physics, quantum gravity must be a digital/discrete solution.|||On matters of physics, I'm generally prepared to trust einstein. I'm sure intelligent people do question it however.|||did you ever read a book about the subject???
everything in the special and general relativity has been proven over and over into the smallest detail.
even the cosmic constant which Einstein introduced and later thought of as his biggest mistake was found in the '80's|||Anything that we can not prove to be an exact truth is technically a theory. Actually, life is a theory. Hah! =)|||Einstein used Riemann geometry, not Lorentzian.|||Intelligent Falling TEACH THE CONTROVERSY!
rAmen|||I question it. But I'm just not up to the task of presenting any challenge, that's for sure. Way beyond my level.|||Yes it is just a theory, and that is what it is called. It is written in modern times, in a language that is current, is not 'quoted' by page and paragraph and sentence by millions of people each day that swear that it is the key to salvation. Einstein is not worshiped nor is he displayed as a martyr or a savior.
So....what's your point?|||You could not be more wrong!! All the Intelligent people believe in relativity!!
Even the christian ones!!
The Pope, Catholic Church, Church of England and mainstream churches all accept evolution and the big bang!!
Lord Carey the former Archbishop of Canterbury put it rather well – “Creationism is the fruit of a fundamentalist approach to scripture, ignoring scholarship and critical learning, and confusing different understandings of truth”!!
Surely even you can see that you need to reconsider your ill thought out ideas when christians and atheists unite to laugh at you!!!
Your ignorance of basic facts is shown in your idea that the theory of relativity came from Einstein!!
The theory of relativity was invented by gallilaeo and called Heliocentrism!! The church then forced him to recant and kept him under house arrest for years until he died!!
Einstines theories were: The Special theory of relativity and The General theory of relativity.
So if you want to appear intelligent at least do a little research and get your facts right first!!
Can someone try to explain the Theory of Relativity to me?
I understand some parts of it, i know that it encompasses two theories of Albert Einstein: special relativity and general relativity. I would like a further explanation of it.|||A comprehensive video series
http://www.youtube.com/watch?v=j72bPmXsy…|||Here are two short videos that explain it:
http://www.wimp.com/timerelativity/
http://www.wimp.com/relativitytheory/
http://www.youtube.com/watch?v=j72bPmXsy…|||Here are two short videos that explain it:
http://www.wimp.com/timerelativity/
http://www.wimp.com/relativitytheory/
Can someone talk in simple terms about the theory of Relativity?
A friend of mine is a physics professor, and he challenged me to research the theory of relativity. I have never had any physics, but I have a pretty good head for math, I just have no background in physics at all. So can someone talk in general terms about this theory? Why is it important, how does it work, just some basic background so I have a foundation to go on. I want to understand enough to ask intelligent questions, and he can explain the more complicated aspects.
And if you have suggestions for websites that would be helpful I would appreciate it.
Thanks!|||If you have a good grasp of basic algebra, you should be able to tackle the theory of Special Relativity. It deals with measurement of basic physical quantities like distance, time and speed in different frames of reference under the assumption that the speed of light is constant and that the laws of physics are the same in all inertial reference frames (i.e. they don't accelerate relative to each other).
I don't know of any websites, but wikipedia is probably a good place to start (see below). However, the best place to look is at your local library. A book that helped me was "An idea of relativity" by H. S. Perlman published by Monash University in Australia, but there should be others as well as various encyclopedias.
The theory of General Relativity is much more mathematically demanding. It deals with an explanation for gravity as well as dynamics and stuff.|||Basically the theory of relativity states that how we look at things is relative. For example when driving in a car you are stationary and the ground underneath you is moving. If your friend is driving in a car next to you and traveling at the same speed, they are also stationary. This is an over simplification but should give you some basis to start with.|||The theory of Relativity is broken into 2 distinct parts. The Special theory and the general theory. Though mathematically Special Relativity is much easier to understand than conceptually. General relativity is much easier to visualize, but much harder to get mathematically.
Special relativity all deals with the behavior of objects when they approach the speed of light from different frames of reference. The usual frames of reference are the observer and the person or object travelling at near light speeds. This leads to a couple of interesting phenomenon. Time dilation and length contraction.
Time dilation occurs when a person reaches near light speeds, the observer (stationary) will notice the with the person travelling time appears to slow down and stop as they're in a rocket flying through space the closer they approach the speed of light.
However to the moving observer the opposite will have happened, they'll observe time passing as normal, but depending on the distance they travel and come back, the stationary observer will be older than the moving observer due to the effects of time dilation. The person moving at near light speeds doesn't notice the slow down in the effect of time on them. The stationary observer goes through time at the normal speed.
This is commonly referred to as the twin paradox. 1 twin travels for several light years in a rocket at near the speed of light and comes back to greet his stationary twin, but notices that his stationary twin has aged much more than he has due to the effects of time dilation.
Length contraction is also another phenomenon of special relativity. As a moving object approaches light speed it's length appears to contract to the stationary observer. However to the moving observer the distance of objects in front of them seem to contract and they notice none of the effects of the length contraction.
General relativity is the theory about how gravity affects space and time. It predicts strange objects such as neutron stars, black holes, worm holes, etc. The best way to visualize it would be to imagine space and time as a soft sheet of rubber. The stars, galaxies, planets, etc. create dips in the sheet due to their gravitational influence.
To explain the orbits of planets General Relativity states that they orbit the sun like the sun is sunk into the sheet at a fair depth depending on how strong the sun's gravity is. The planets orbits are like rolling a marble along the side of an upright bucket, they're moving fast enough to keep their momentum going and not move up or down along the walls of the divot too far.
If they start to move down the walls that means the sun is drawing them closer and they're losing their orbital momentum, but if they start to move up the sides they're gaining orbital momentum and may escape the sun's pull and go flying off into space.
It also predicts the behavior or stars in certain circumstances, such as stars the collapse and become neutron stars and possibly black holes. It also shows how light is affected by gravity, and that gravity can visibly bend light if it's strong enough.
Light is said to travel along space and time like a golf ball along a green, if it goes near a gravity well it'll dip along the side and right itself again or change it's angle. Much like a golfball that runs just at the edge of the cup on the green but doesn't go in, how it diverts it's straight path a bit.
I realize this is a long explanation, but it's the shortest one I could come up with and still manage to cover most of the bases for both theories. I hope this helps.|||We measure the speed of another reference frame from our reference frame as v.
Both of us measure the speed of light whether it is approaching or receding from us as C.
That is the speed of light is independent of the speed of the observer.
If the speed of light were infinite, then the distance and time as measured by both the observers will be absolute.
Since the speed of light is definite and absolute, we have to choose different measuring units for distance and time for the one who is moving relative to us.
Length and time becomes relative to the observer and not absolute.
The one moving with a half the speed of light and we who are at rest both measure the speed of light coming toward us as C.
Our common sense says that the one who is moving must measure the speed of light as C+ C/2, since he is approaching the light.
But he is measuring it as C only. That implies that his measuring instruments have contracted to an extent so as to measure the speed as C, whichever is the direction of light.
Keeping the speed of light absolute makes all other things relative.
We select shoes according to the size of foot.
In an imaginary world, the sizes of shoes are fixed and constant. How would then the people of that world wear shoes?
One has to accept that people’s foot are adjusting and accommodating to fit for the fixed size of the shoe.|||Before Einstein, physicists thought there were special "privileged reference frames". If you were motionless relative to these special reference frames, you would have a special, optimized view of the universe, and of the laws of physics.
Then Einstein came along with two theories that shattered this myth:
1. General Relativity
2. Special Relativity
They are named "relativity" because they show that there are no privileged reference frames. All movements are relative to each other. There is no absolute reference frame. A "motionless" observer will deduce the same laws of physics as an observer traveling at extremely high (but constant) speed.
General relativity shows how space is curved by the presence of mass, and that the curvature affects other masses, altering their trajectories, and can even affect the path of a ray of light. It is currently the accepted theory of the nature of gravity, and it predicted the existence of black holes (regions with so much gravity that light is bent backwards and cannot escape).
Special relativity describes how physics changes when velocities become extremely large (a significant fraction of the speed of light). It predicted a number of bizarre phenomena which were later verified:
1. Time dilation - An object traveling near the speed of light experiences the passage of time more slowly than other objects.
2. Length contraction - An object traveling near the speed of light is dramatically shrunken in the direction of travel, as measured by an outside observer.
3. Mass increase - An object traveling near the speed of light increases in mass.
4. Energy and mass are interchangeable, related by E=m*c^2|||There are two main theories of relativity: General and Special.
General relativity basically relates to gravity and spacetime. It was invented be Einstein and is still used to this day (even though it's nowhere near complete).
Special Rev, also created by Einstein, has to do with our four dimensions and how they can change depending on the observer. The four dimensions (up/down, left/right, in/out, and time) are merely conceptual, and can change depending on several factors, mainly speed and gravity. For example, time will slow down for people deep in a gravitational field or people who are moving near the speed of light. Also, length will change for people who are moving near the speed of light.|||Here's the theory of relativity in a nutshell:
1. The laws of physics are the same regardless of inertial frame of reference.
2. The speed of light in free space is a constant in all inertial frames of reference.
The above are known as the postulates of special relativity.
When you consider accelerating reference frames you have what is known as general relativity.
Since nothing can go faster than the speed of light in a vacuum, some strange things happen when you travel near the speed of light (i.e., time dilation, length contraction).
Time dilation refers to time slowing down when you travel close to the speed of light.
Length contraction refers to the shrinking of an object's length in the direction of travel when the object travels close to the speed of light.
The theory of relativity was able to explain the precession of the perihelion of Mercury's orbit and it explains why muons reach the Earth when they have such a short life span.
The theory of relativity states that gravity is curved space-time due to the presence of mass versus the Newtonian gravity of a force acting over a distance.
And if you have suggestions for websites that would be helpful I would appreciate it.
Thanks!|||If you have a good grasp of basic algebra, you should be able to tackle the theory of Special Relativity. It deals with measurement of basic physical quantities like distance, time and speed in different frames of reference under the assumption that the speed of light is constant and that the laws of physics are the same in all inertial reference frames (i.e. they don't accelerate relative to each other).
I don't know of any websites, but wikipedia is probably a good place to start (see below). However, the best place to look is at your local library. A book that helped me was "An idea of relativity" by H. S. Perlman published by Monash University in Australia, but there should be others as well as various encyclopedias.
The theory of General Relativity is much more mathematically demanding. It deals with an explanation for gravity as well as dynamics and stuff.|||Basically the theory of relativity states that how we look at things is relative. For example when driving in a car you are stationary and the ground underneath you is moving. If your friend is driving in a car next to you and traveling at the same speed, they are also stationary. This is an over simplification but should give you some basis to start with.|||The theory of Relativity is broken into 2 distinct parts. The Special theory and the general theory. Though mathematically Special Relativity is much easier to understand than conceptually. General relativity is much easier to visualize, but much harder to get mathematically.
Special relativity all deals with the behavior of objects when they approach the speed of light from different frames of reference. The usual frames of reference are the observer and the person or object travelling at near light speeds. This leads to a couple of interesting phenomenon. Time dilation and length contraction.
Time dilation occurs when a person reaches near light speeds, the observer (stationary) will notice the with the person travelling time appears to slow down and stop as they're in a rocket flying through space the closer they approach the speed of light.
However to the moving observer the opposite will have happened, they'll observe time passing as normal, but depending on the distance they travel and come back, the stationary observer will be older than the moving observer due to the effects of time dilation. The person moving at near light speeds doesn't notice the slow down in the effect of time on them. The stationary observer goes through time at the normal speed.
This is commonly referred to as the twin paradox. 1 twin travels for several light years in a rocket at near the speed of light and comes back to greet his stationary twin, but notices that his stationary twin has aged much more than he has due to the effects of time dilation.
Length contraction is also another phenomenon of special relativity. As a moving object approaches light speed it's length appears to contract to the stationary observer. However to the moving observer the distance of objects in front of them seem to contract and they notice none of the effects of the length contraction.
General relativity is the theory about how gravity affects space and time. It predicts strange objects such as neutron stars, black holes, worm holes, etc. The best way to visualize it would be to imagine space and time as a soft sheet of rubber. The stars, galaxies, planets, etc. create dips in the sheet due to their gravitational influence.
To explain the orbits of planets General Relativity states that they orbit the sun like the sun is sunk into the sheet at a fair depth depending on how strong the sun's gravity is. The planets orbits are like rolling a marble along the side of an upright bucket, they're moving fast enough to keep their momentum going and not move up or down along the walls of the divot too far.
If they start to move down the walls that means the sun is drawing them closer and they're losing their orbital momentum, but if they start to move up the sides they're gaining orbital momentum and may escape the sun's pull and go flying off into space.
It also predicts the behavior or stars in certain circumstances, such as stars the collapse and become neutron stars and possibly black holes. It also shows how light is affected by gravity, and that gravity can visibly bend light if it's strong enough.
Light is said to travel along space and time like a golf ball along a green, if it goes near a gravity well it'll dip along the side and right itself again or change it's angle. Much like a golfball that runs just at the edge of the cup on the green but doesn't go in, how it diverts it's straight path a bit.
I realize this is a long explanation, but it's the shortest one I could come up with and still manage to cover most of the bases for both theories. I hope this helps.|||We measure the speed of another reference frame from our reference frame as v.
Both of us measure the speed of light whether it is approaching or receding from us as C.
That is the speed of light is independent of the speed of the observer.
If the speed of light were infinite, then the distance and time as measured by both the observers will be absolute.
Since the speed of light is definite and absolute, we have to choose different measuring units for distance and time for the one who is moving relative to us.
Length and time becomes relative to the observer and not absolute.
The one moving with a half the speed of light and we who are at rest both measure the speed of light coming toward us as C.
Our common sense says that the one who is moving must measure the speed of light as C+ C/2, since he is approaching the light.
But he is measuring it as C only. That implies that his measuring instruments have contracted to an extent so as to measure the speed as C, whichever is the direction of light.
Keeping the speed of light absolute makes all other things relative.
We select shoes according to the size of foot.
In an imaginary world, the sizes of shoes are fixed and constant. How would then the people of that world wear shoes?
One has to accept that people’s foot are adjusting and accommodating to fit for the fixed size of the shoe.|||Before Einstein, physicists thought there were special "privileged reference frames". If you were motionless relative to these special reference frames, you would have a special, optimized view of the universe, and of the laws of physics.
Then Einstein came along with two theories that shattered this myth:
1. General Relativity
2. Special Relativity
They are named "relativity" because they show that there are no privileged reference frames. All movements are relative to each other. There is no absolute reference frame. A "motionless" observer will deduce the same laws of physics as an observer traveling at extremely high (but constant) speed.
General relativity shows how space is curved by the presence of mass, and that the curvature affects other masses, altering their trajectories, and can even affect the path of a ray of light. It is currently the accepted theory of the nature of gravity, and it predicted the existence of black holes (regions with so much gravity that light is bent backwards and cannot escape).
Special relativity describes how physics changes when velocities become extremely large (a significant fraction of the speed of light). It predicted a number of bizarre phenomena which were later verified:
1. Time dilation - An object traveling near the speed of light experiences the passage of time more slowly than other objects.
2. Length contraction - An object traveling near the speed of light is dramatically shrunken in the direction of travel, as measured by an outside observer.
3. Mass increase - An object traveling near the speed of light increases in mass.
4. Energy and mass are interchangeable, related by E=m*c^2|||There are two main theories of relativity: General and Special.
General relativity basically relates to gravity and spacetime. It was invented be Einstein and is still used to this day (even though it's nowhere near complete).
Special Rev, also created by Einstein, has to do with our four dimensions and how they can change depending on the observer. The four dimensions (up/down, left/right, in/out, and time) are merely conceptual, and can change depending on several factors, mainly speed and gravity. For example, time will slow down for people deep in a gravitational field or people who are moving near the speed of light. Also, length will change for people who are moving near the speed of light.|||Here's the theory of relativity in a nutshell:
1. The laws of physics are the same regardless of inertial frame of reference.
2. The speed of light in free space is a constant in all inertial frames of reference.
The above are known as the postulates of special relativity.
When you consider accelerating reference frames you have what is known as general relativity.
Since nothing can go faster than the speed of light in a vacuum, some strange things happen when you travel near the speed of light (i.e., time dilation, length contraction).
Time dilation refers to time slowing down when you travel close to the speed of light.
Length contraction refers to the shrinking of an object's length in the direction of travel when the object travels close to the speed of light.
The theory of relativity was able to explain the precession of the perihelion of Mercury's orbit and it explains why muons reach the Earth when they have such a short life span.
The theory of relativity states that gravity is curved space-time due to the presence of mass versus the Newtonian gravity of a force acting over a distance.
Theory of relativity and the twin paradox: is the aging biological?
The twin paradox is a very well-known example to present the theory of relativity. One of twins jumps into a space ship and the other one stays on Earth. Each of the twins moves in relation to each other. The traveler-twin, once back on Earth, is younger than the twin who stayed.
What I don't understand is what this aging really means. I DO understand that the watches each of them is wearing show a difference in time. But does the traveler really change BIOLOGICALLY? Does he "look younger" than the other twin? In practice, would the traveler-twin get gray hair later than the other twin? Or does aging in this context mean something else? So my question, shortly put, is: does aging in the context of theory of relativity mean 1)just impression that time is going faster on Earth than in space 2)real changes in biology, real physical aging? The twin who returns back from the space ship journey: does he look exactly as old as the other twin or has he really remained younger?|||Yes. It means that for the twin that stayed on Earth, the time really passed for him, and for the twin who traveled, less time passed.
The older twin doesnt just "look" older, he really is older. He really experience that time. And the younger twin really experienced less time passing.|||The twin paradox, sometimes called the "clock paradox", stems from Paul Langevin's 1911 thought experiment in special relativity: one of two twin brothers undertakes a long space journey with a high-speed rocket at almost the speed of light, while the other twin remains on Earth. When the traveler returns to Earth, he is younger than the twin who stayed put. Or, as first stated by Albert Einstein (1911):
If we placed a living organism in a box ... one could arrange that the organism, after any arbitrary lengthy flight, could be returned to its original spot in a scarcely altered condition, while corresponding organisms which had remained in their original positions had already long since given way to new generations. For the moving organism the lengthy time of the journey was a mere instant, provided the motion took place with approximately the speed of light. (in Resnick and Halliday, 1992)
Like all paradoxes, this occurs because of faulty assumptions. This one happens because one twin undergoes acceleration while the other does not, something that isn't taken into account when this twin-paradox story was invented.
Contents [hide]
1 Specific Example
2 Origin of the Paradox
3 Resolution of the Paradox in Special Relativity
4 What it looks like: the relativistic Doppler shift
4.1 The asymmetry in the Doppler shifted images
5 Calculation of elapsed time from the Doppler diagram
5.1 The distinction between what they see and what they calculate
5.2 Simultaneity in the Doppler Shift calculation
6 Resolution of the Paradox in General Relativity
7 See also
8 References
9 External links
[edit]
Specific Example
Consider a space ship going from Earth to the nearest star system a distance d = 4.45 light years away, at speed v = 0.866c (i.e. 86.6% of the speed of light). The round trip will take t = 2d / v = 10.28 years in Earth time (i.e. everybody on earth will be 10.28 years older when the ship returns). Ignoring the effects of the earth's rotation on its axis and around the sun (at speeds negligible compared to the speed of light), those on Earth predict the aging of the travellers during their trip as reduced by the factor , the inverse of the Lorentz factor. In this case ε = 0.5 and they expect the travellers to be 0.5×10.28 = 5.14 years older when they return.
The ship's crew calculate how long the trip will take them. They realize that the distant star system and the earth are moving relative to the ship at speed v during the trip. Therefore, the distance between the earth and the star system will be shortened (by the length contraction) to εd = 0.5d = 2.23 light years, for both the outward and return journeys. Each half of the journey takes 2.23 / v = 2.57 years, and the round trip takes 2×2.57 = 5.14 years. The crew arrives home having aged 5.14 years, just as those on Earth expected.
If a pair of twins were born on the day the ship left, and one went on the journey while the other stayed on earth, the twins will meet again when the traveller is 5.14 years old and the stay-at-home twin is 10.28 years old. This outcome is predicted by Einstein's special theory of relativity. It is a consequence of the experimentally verified phenomenon of time dilation, in which a moving clock is found to experience a reduced amount of proper time as determined by clocks synchronized with a stationary clock. Examples of the experimental evidence can be found in the time dilation page.
[edit]
Origin of the Paradox
The strange result of twins of different physical age was not the central problem of the "twin paradox". As early as 1905, Einstein predicts that a clock which is moved away and brought back, will lag behind on stationary clocks. Einstein calls that result "peculiar", but the calculation is straightforward and the example is not presented as paradoxical, despite his suggestion in the introduction of the same paper that only relative motion between objects should matter.
In 1911, Langevin discusses the evolution of the concepts of space and time in physics and presents the principal aspects of special relativity. He suggests that special relativity implies the existence of a stationary ether and states: "Every change of speed, every acceleration, has an absolute sense". To stress this fact he provides several examples such as that accelerated electric charges emit electromagnetic radiation. He proceeds with a thought experiment similar to the specific example above. Langevin next explains the different aging of the twins: "Only the traveller has undergone an acceleration that changed the direction of his velocity." According to Langevin, acceleration is here "absolute", in the sense that it is the cause of the asymmetry (and not of the aging itself). Also in this discussion there seems nothing paradoxical about it.
However, it was Einstein's objective to show that all motion is "relative", and he thought to have reached that objective with General relativity. Thus he stated in 1916, in his introduction to that theory: "The laws of physics must be of such a nature that they apply to reference systems in any kind of motion" (including accelerated motion). And he concluded about two relatively accelerated systems K and K': "From the physical standpoint, the assumption readily suggests itself that the systems K and K' may both with equal right be looked upon as "stationary", that is to say, they have an equal title as systems of reference for the physical description of phenomena." In other words, all observers are equivalent, and no particular frame of reference is privileged.
The perception of paradox is rooted in a misunderstanding of the meaning of equivalent frames in relativity and therefore arises in both SR and GR. The Principle of Relativity states that the mathematical forms of the laws of physics – say, mechanics and electrodynamics — are identical in all frames of reference independent of their relative motion; i.e., all frames are equivalent in this restricted but important sense that the laws of physics are invariant from one frame to another, whether the frames are accelerating or not. In the twin problem, although the respective frames are equivalent in this sense, they are not dynamically symmetric since only the traveling twin experiences acceleration. However, if one assumes that the frames of the traveling and stay-at-home twin are dynamically symmetric and confuses dynamic symmetry with equivalence (and perhaps, additionally, falsely infers equivalence to mean identical calculations in all frames), one erroneously concludes the same result for each twin's time dilation as calculated by the other twin; i.e., one expects the traveler upon return, to have aged more and less than his twin – which is clearly impossible. In this connection, it is important to understand that relativity does not claim that all observers make identical measurements when observing the same phenomena; generally they do not. Nor does relativity claim that a time dilation calculation that each observer performs for his twin is a "law of physics" that must remain invariant from one observer or frame to another. However, these calculations would be expected to be identical for dynamically symmetric frames!
It is to be noted, however, that time dilatation has no relationship whatsoever to the amount, direction, or duration of acceleration. Even the time dilatation of particles in the Fermilab ring is determined only by their speed, in spite of the huge accelerations they undergo. In the usual resolution of the twin paradox, it is only the bare fact of acceleration which is invoked, and not any measured quantity. Some might object that, while the travelling twin experiences acceleration, so does the stay-at-home twin, both by ordinary motion and by being in a gravity field. Why one has the "better" acceleration which controls the direction of time dilataion is not apparent. Also, the journey can be arranged so that the stay-at-home twin experiences exactly the same accelerations as the traveller (by moving around on a stationary gravitating planet to exactly match the accelerations of the traveller whose rocket ship always accelerates at one planet gravity).
The erroneous belief that the twins are in dynamically symmetric frames is likely rooted in Einstein's attempt to formulate a theory in which physical phenomena could be fully explained in terms of relative motion. In his landmark 1905 paper, “On the Electrodynamics of Moving Bodies”, when offering a motivating example for his Principle of Relativity, Einstein states that it is immaterial whether one considers the coil or the magnet as moving, and that only relative motion matters since the resultant induced current is the same. Thus, part of the misconception of what the Principle of Relativity means — which is essentially responsible for the perception of "paradox" — probably stems from these comments. That is, Einstein’s casually–stated claim that all motion is relative (as well as his original objective for relativity theory), can easily mislead in its suggestion that equivalent frames (with respect to invariance of the laws of physics) are necessarily symmetric with respect to motion.
Although the paradox is necessarily implied if one assumes dynamic frame symmetry, showing that it is non-existent due to the acceleration of one twin is just a necessary condition for resolution of the paradox, but not by itself sufficient. For sufficiency, one must perform the calculations to demonstrate that from the point of view of each twin, the traveler returns younger. Moreover, this must be done independently in both SR and GR, since the problem appears in both theories.
In 1918, Einstein reacts to objections to his relativity theory and issues arising in connection with the twin paradox. In that paper he reconfirms the differential aging prediction of special relativity, and points out that the equations of special relativity are only valid for inertial frames, that one twin is in an accelerating frame (if modeled in one frame throughout), and that the twins are not in symmetric frames for the reasons explained above. Next, after affirming the general principle of relativity, he sets out to show in a detailed example with clocks, that general relativity yields the same answer as special relativity and he claims that he thus "fully explained the paradox".
[edit]
Resolution of the Paradox in Special Relativity
The usual resolution of the paradox as presented in physics text books ignores its origin (it only surfaced with general relativity, see above) and regards it as a problem due to misunderstanding of special relativity. Here the Earth and the ship are not in a symmetrical relationship: the ship has a "turnaround" in which it feels inertial forces, while the Earth has no such turnaround. Since there is no symmetry, it is not paradoxical if one twin is younger than the other. Nevertheless it is still useful to show that special relativity is self-consistent, and how the calculation is done from the standpoint of the traveling twin.
Of course the traveling twin comes home younger. Special relativity does not claim that all observers are equivalent, only that all observers in inertial reference frames are equivalent. But the space ship jumps frames (accelerates) when it does a U-turn. The twin on Earth rests in the same inertial frame for the whole duration of the flight (no accelerating or decelerating forces apply to him) and he is therefore able to distinguish himself as "privileged" compared with the space ship twin. The accepted resolution of the paradox is that the crew must make a different calculation from that above, a calculation which explicitly recognizes the change of reference frame, and the change in simultaneity which occurs at the turnaround.
There are indeed not two but three relevant inertial frames: the one in which the stay-at-home twin remains at rest, the one in which the traveling twin is at rest on his outward trip, and the one in which he is at rest on his way home. It is during the acceleration at the U-turn that the traveling twin switches frames. That's when he must adjust the calculated age of the twin at rest. Here's why.
In special relativity there is no concept of absolute present. A present is defined as a set of events that are simultaneous from the point of view of a given observer. The notion of simultaneity depends on the frame of reference (see relativity of simultaneity), so switching between frames requires an adjustment in the definition of the present. If one imagines a present as a (three-dimensional) simultaneity plane in Minkowski space, then switching frames results in changing the inclination of the plane.
Twins paradox Minkowski diagramIn the spacetime diagram on the right, the first twin's lifeline coincides with the vertical axis (his position is constant in space, moving only in time). On the first leg of the trip, the second twin moves to the right (black sloped line); and on the second leg, back to the left. Blue lines show the planes of simultaneity for the traveling twin during the first leg of the journey; red lines, during the second leg. Just before turnover, the traveling twin calculates the age of the resting twin by measuring the interval along the vertical axis from the origin to the upper blue line. Just after turnover, if he recalculates, he'll measure the interval from the origin to the lower red line. In a sense, during the U-turn the plane of simultaneity jumps from blue to red and very quickly sweeps over a large segment of the lifeline of the resting twin. The resting twin has suddenly "aged" very fast, in the reckoning of the traveling twin.
[edit]
What it looks like: the relativistic Doppler shift
Now, how would each twin observe the other during the trip? Or if each twin|||Yes. It would be biological. Because our biology and the aging process is based on time. The heart of the twin paradox is that time would move differently for each of the two twins.
The bodies and actual cells would be a different age. The cellular processes that are associated with aging would progress at a normal rate in the relative time frame for _each_ twin.|||Tut, tut, tut, Justin. Be very careful about any observer seeing events go "many times" faster. If two observers are moving at CONSTANT, unaccelerated velocity relative to one another, EACH sees the clocks of the other running slowly. This was the source of the twin paradox, with acceleration ignored.
The only time an observer can see other clocks running faster is during acceleration or when in a very strong gravitational field, as on the surface of a star.
The resolution of the twin paradox lies in one of the twins being accelerated and the other not.|||YES|||You got me thinking. Aging is merely the disintegration of the atoms due to oxygen. Without air, there'd be no life and no aging. Oxygen causes us to age from the day we're born.|||Yes. The aging is biological. Biological aging is just the reaction of the body to the passage of time. That's why the twin's paradox is used to illustrate the concept. Biological bodies are clocks! Irreversible clocks. So yes, the passage of time is faster on earth, so the earth-bound twin will have gray hair, etc.|||Well, aging is ALWAYS a biological process. I mean you age and get gray hair and wrinkled skin and eventually die BECAUSE of the passage of time.
But there is nothing biological at all about the twin paradox. The twin paradox is really a TIME paradox, but the example usually used to explain it involves either two twins or two people carrying clocks. The clock or aging person is just a familiar way to measure the passage of time. It is time itself that is acting weird in relativity.|||Yes he would look and be biologically younger, less time has passed for him. The watch is not broken in the example, it is telling true time and less time really did pass for the traveler. Humans tend to age at fairly steady rates so the traveler would have literally aged less.|||You are not understanding the theory of relativity.
The theory uses this analogy to explain that the closer you get to the speed of light (in other words the faster you go), the more time changes for you versus how fast time was moving at the slower (normal) speed.
If you have two twins and one goes out to space and travels to near the speed of light (the speed is the key factor, not the fact he is in space), and comes back, to him only a few hours may have past, but to his twin a whole lifetime may have.
This is because, as Einstein explained, when you approach the speed of light, time slows down for you. Of course you can't notice this yourself because to you everything is going normally. However if it were capable for you to look out the window and watch earth's events as you are travelling near the speed of light, you would see events moving many times faster than it should be, because of the time difference.
What I don't understand is what this aging really means. I DO understand that the watches each of them is wearing show a difference in time. But does the traveler really change BIOLOGICALLY? Does he "look younger" than the other twin? In practice, would the traveler-twin get gray hair later than the other twin? Or does aging in this context mean something else? So my question, shortly put, is: does aging in the context of theory of relativity mean 1)just impression that time is going faster on Earth than in space 2)real changes in biology, real physical aging? The twin who returns back from the space ship journey: does he look exactly as old as the other twin or has he really remained younger?|||Yes. It means that for the twin that stayed on Earth, the time really passed for him, and for the twin who traveled, less time passed.
The older twin doesnt just "look" older, he really is older. He really experience that time. And the younger twin really experienced less time passing.|||The twin paradox, sometimes called the "clock paradox", stems from Paul Langevin's 1911 thought experiment in special relativity: one of two twin brothers undertakes a long space journey with a high-speed rocket at almost the speed of light, while the other twin remains on Earth. When the traveler returns to Earth, he is younger than the twin who stayed put. Or, as first stated by Albert Einstein (1911):
If we placed a living organism in a box ... one could arrange that the organism, after any arbitrary lengthy flight, could be returned to its original spot in a scarcely altered condition, while corresponding organisms which had remained in their original positions had already long since given way to new generations. For the moving organism the lengthy time of the journey was a mere instant, provided the motion took place with approximately the speed of light. (in Resnick and Halliday, 1992)
Like all paradoxes, this occurs because of faulty assumptions. This one happens because one twin undergoes acceleration while the other does not, something that isn't taken into account when this twin-paradox story was invented.
Contents [hide]
1 Specific Example
2 Origin of the Paradox
3 Resolution of the Paradox in Special Relativity
4 What it looks like: the relativistic Doppler shift
4.1 The asymmetry in the Doppler shifted images
5 Calculation of elapsed time from the Doppler diagram
5.1 The distinction between what they see and what they calculate
5.2 Simultaneity in the Doppler Shift calculation
6 Resolution of the Paradox in General Relativity
7 See also
8 References
9 External links
[edit]
Specific Example
Consider a space ship going from Earth to the nearest star system a distance d = 4.45 light years away, at speed v = 0.866c (i.e. 86.6% of the speed of light). The round trip will take t = 2d / v = 10.28 years in Earth time (i.e. everybody on earth will be 10.28 years older when the ship returns). Ignoring the effects of the earth's rotation on its axis and around the sun (at speeds negligible compared to the speed of light), those on Earth predict the aging of the travellers during their trip as reduced by the factor , the inverse of the Lorentz factor. In this case ε = 0.5 and they expect the travellers to be 0.5×10.28 = 5.14 years older when they return.
The ship's crew calculate how long the trip will take them. They realize that the distant star system and the earth are moving relative to the ship at speed v during the trip. Therefore, the distance between the earth and the star system will be shortened (by the length contraction) to εd = 0.5d = 2.23 light years, for both the outward and return journeys. Each half of the journey takes 2.23 / v = 2.57 years, and the round trip takes 2×2.57 = 5.14 years. The crew arrives home having aged 5.14 years, just as those on Earth expected.
If a pair of twins were born on the day the ship left, and one went on the journey while the other stayed on earth, the twins will meet again when the traveller is 5.14 years old and the stay-at-home twin is 10.28 years old. This outcome is predicted by Einstein's special theory of relativity. It is a consequence of the experimentally verified phenomenon of time dilation, in which a moving clock is found to experience a reduced amount of proper time as determined by clocks synchronized with a stationary clock. Examples of the experimental evidence can be found in the time dilation page.
[edit]
Origin of the Paradox
The strange result of twins of different physical age was not the central problem of the "twin paradox". As early as 1905, Einstein predicts that a clock which is moved away and brought back, will lag behind on stationary clocks. Einstein calls that result "peculiar", but the calculation is straightforward and the example is not presented as paradoxical, despite his suggestion in the introduction of the same paper that only relative motion between objects should matter.
In 1911, Langevin discusses the evolution of the concepts of space and time in physics and presents the principal aspects of special relativity. He suggests that special relativity implies the existence of a stationary ether and states: "Every change of speed, every acceleration, has an absolute sense". To stress this fact he provides several examples such as that accelerated electric charges emit electromagnetic radiation. He proceeds with a thought experiment similar to the specific example above. Langevin next explains the different aging of the twins: "Only the traveller has undergone an acceleration that changed the direction of his velocity." According to Langevin, acceleration is here "absolute", in the sense that it is the cause of the asymmetry (and not of the aging itself). Also in this discussion there seems nothing paradoxical about it.
However, it was Einstein's objective to show that all motion is "relative", and he thought to have reached that objective with General relativity. Thus he stated in 1916, in his introduction to that theory: "The laws of physics must be of such a nature that they apply to reference systems in any kind of motion" (including accelerated motion). And he concluded about two relatively accelerated systems K and K': "From the physical standpoint, the assumption readily suggests itself that the systems K and K' may both with equal right be looked upon as "stationary", that is to say, they have an equal title as systems of reference for the physical description of phenomena." In other words, all observers are equivalent, and no particular frame of reference is privileged.
The perception of paradox is rooted in a misunderstanding of the meaning of equivalent frames in relativity and therefore arises in both SR and GR. The Principle of Relativity states that the mathematical forms of the laws of physics – say, mechanics and electrodynamics — are identical in all frames of reference independent of their relative motion; i.e., all frames are equivalent in this restricted but important sense that the laws of physics are invariant from one frame to another, whether the frames are accelerating or not. In the twin problem, although the respective frames are equivalent in this sense, they are not dynamically symmetric since only the traveling twin experiences acceleration. However, if one assumes that the frames of the traveling and stay-at-home twin are dynamically symmetric and confuses dynamic symmetry with equivalence (and perhaps, additionally, falsely infers equivalence to mean identical calculations in all frames), one erroneously concludes the same result for each twin's time dilation as calculated by the other twin; i.e., one expects the traveler upon return, to have aged more and less than his twin – which is clearly impossible. In this connection, it is important to understand that relativity does not claim that all observers make identical measurements when observing the same phenomena; generally they do not. Nor does relativity claim that a time dilation calculation that each observer performs for his twin is a "law of physics" that must remain invariant from one observer or frame to another. However, these calculations would be expected to be identical for dynamically symmetric frames!
It is to be noted, however, that time dilatation has no relationship whatsoever to the amount, direction, or duration of acceleration. Even the time dilatation of particles in the Fermilab ring is determined only by their speed, in spite of the huge accelerations they undergo. In the usual resolution of the twin paradox, it is only the bare fact of acceleration which is invoked, and not any measured quantity. Some might object that, while the travelling twin experiences acceleration, so does the stay-at-home twin, both by ordinary motion and by being in a gravity field. Why one has the "better" acceleration which controls the direction of time dilataion is not apparent. Also, the journey can be arranged so that the stay-at-home twin experiences exactly the same accelerations as the traveller (by moving around on a stationary gravitating planet to exactly match the accelerations of the traveller whose rocket ship always accelerates at one planet gravity).
The erroneous belief that the twins are in dynamically symmetric frames is likely rooted in Einstein's attempt to formulate a theory in which physical phenomena could be fully explained in terms of relative motion. In his landmark 1905 paper, “On the Electrodynamics of Moving Bodies”, when offering a motivating example for his Principle of Relativity, Einstein states that it is immaterial whether one considers the coil or the magnet as moving, and that only relative motion matters since the resultant induced current is the same. Thus, part of the misconception of what the Principle of Relativity means — which is essentially responsible for the perception of "paradox" — probably stems from these comments. That is, Einstein’s casually–stated claim that all motion is relative (as well as his original objective for relativity theory), can easily mislead in its suggestion that equivalent frames (with respect to invariance of the laws of physics) are necessarily symmetric with respect to motion.
Although the paradox is necessarily implied if one assumes dynamic frame symmetry, showing that it is non-existent due to the acceleration of one twin is just a necessary condition for resolution of the paradox, but not by itself sufficient. For sufficiency, one must perform the calculations to demonstrate that from the point of view of each twin, the traveler returns younger. Moreover, this must be done independently in both SR and GR, since the problem appears in both theories.
In 1918, Einstein reacts to objections to his relativity theory and issues arising in connection with the twin paradox. In that paper he reconfirms the differential aging prediction of special relativity, and points out that the equations of special relativity are only valid for inertial frames, that one twin is in an accelerating frame (if modeled in one frame throughout), and that the twins are not in symmetric frames for the reasons explained above. Next, after affirming the general principle of relativity, he sets out to show in a detailed example with clocks, that general relativity yields the same answer as special relativity and he claims that he thus "fully explained the paradox".
[edit]
Resolution of the Paradox in Special Relativity
The usual resolution of the paradox as presented in physics text books ignores its origin (it only surfaced with general relativity, see above) and regards it as a problem due to misunderstanding of special relativity. Here the Earth and the ship are not in a symmetrical relationship: the ship has a "turnaround" in which it feels inertial forces, while the Earth has no such turnaround. Since there is no symmetry, it is not paradoxical if one twin is younger than the other. Nevertheless it is still useful to show that special relativity is self-consistent, and how the calculation is done from the standpoint of the traveling twin.
Of course the traveling twin comes home younger. Special relativity does not claim that all observers are equivalent, only that all observers in inertial reference frames are equivalent. But the space ship jumps frames (accelerates) when it does a U-turn. The twin on Earth rests in the same inertial frame for the whole duration of the flight (no accelerating or decelerating forces apply to him) and he is therefore able to distinguish himself as "privileged" compared with the space ship twin. The accepted resolution of the paradox is that the crew must make a different calculation from that above, a calculation which explicitly recognizes the change of reference frame, and the change in simultaneity which occurs at the turnaround.
There are indeed not two but three relevant inertial frames: the one in which the stay-at-home twin remains at rest, the one in which the traveling twin is at rest on his outward trip, and the one in which he is at rest on his way home. It is during the acceleration at the U-turn that the traveling twin switches frames. That's when he must adjust the calculated age of the twin at rest. Here's why.
In special relativity there is no concept of absolute present. A present is defined as a set of events that are simultaneous from the point of view of a given observer. The notion of simultaneity depends on the frame of reference (see relativity of simultaneity), so switching between frames requires an adjustment in the definition of the present. If one imagines a present as a (three-dimensional) simultaneity plane in Minkowski space, then switching frames results in changing the inclination of the plane.
Twins paradox Minkowski diagramIn the spacetime diagram on the right, the first twin's lifeline coincides with the vertical axis (his position is constant in space, moving only in time). On the first leg of the trip, the second twin moves to the right (black sloped line); and on the second leg, back to the left. Blue lines show the planes of simultaneity for the traveling twin during the first leg of the journey; red lines, during the second leg. Just before turnover, the traveling twin calculates the age of the resting twin by measuring the interval along the vertical axis from the origin to the upper blue line. Just after turnover, if he recalculates, he'll measure the interval from the origin to the lower red line. In a sense, during the U-turn the plane of simultaneity jumps from blue to red and very quickly sweeps over a large segment of the lifeline of the resting twin. The resting twin has suddenly "aged" very fast, in the reckoning of the traveling twin.
[edit]
What it looks like: the relativistic Doppler shift
Now, how would each twin observe the other during the trip? Or if each twin|||Yes. It would be biological. Because our biology and the aging process is based on time. The heart of the twin paradox is that time would move differently for each of the two twins.
The bodies and actual cells would be a different age. The cellular processes that are associated with aging would progress at a normal rate in the relative time frame for _each_ twin.|||Tut, tut, tut, Justin. Be very careful about any observer seeing events go "many times" faster. If two observers are moving at CONSTANT, unaccelerated velocity relative to one another, EACH sees the clocks of the other running slowly. This was the source of the twin paradox, with acceleration ignored.
The only time an observer can see other clocks running faster is during acceleration or when in a very strong gravitational field, as on the surface of a star.
The resolution of the twin paradox lies in one of the twins being accelerated and the other not.|||YES|||You got me thinking. Aging is merely the disintegration of the atoms due to oxygen. Without air, there'd be no life and no aging. Oxygen causes us to age from the day we're born.|||Yes. The aging is biological. Biological aging is just the reaction of the body to the passage of time. That's why the twin's paradox is used to illustrate the concept. Biological bodies are clocks! Irreversible clocks. So yes, the passage of time is faster on earth, so the earth-bound twin will have gray hair, etc.|||Well, aging is ALWAYS a biological process. I mean you age and get gray hair and wrinkled skin and eventually die BECAUSE of the passage of time.
But there is nothing biological at all about the twin paradox. The twin paradox is really a TIME paradox, but the example usually used to explain it involves either two twins or two people carrying clocks. The clock or aging person is just a familiar way to measure the passage of time. It is time itself that is acting weird in relativity.|||Yes he would look and be biologically younger, less time has passed for him. The watch is not broken in the example, it is telling true time and less time really did pass for the traveler. Humans tend to age at fairly steady rates so the traveler would have literally aged less.|||You are not understanding the theory of relativity.
The theory uses this analogy to explain that the closer you get to the speed of light (in other words the faster you go), the more time changes for you versus how fast time was moving at the slower (normal) speed.
If you have two twins and one goes out to space and travels to near the speed of light (the speed is the key factor, not the fact he is in space), and comes back, to him only a few hours may have past, but to his twin a whole lifetime may have.
This is because, as Einstein explained, when you approach the speed of light, time slows down for you. Of course you can't notice this yourself because to you everything is going normally. However if it were capable for you to look out the window and watch earth's events as you are travelling near the speed of light, you would see events moving many times faster than it should be, because of the time difference.
Does the theory of relativity depend on the speed of light in vacuum or in air?
How do you messure the speed of light - in air or in vacuum - in order to properly be able to set up the formulas in the theory of relativity? And then if it is in air, how do you explain that different colors travels in different speeds?|||the speed of light as we know it is based on the structure of the space around us but may actually vary in different parts of the universe. the age of our sun and the processes that it goes through determine the make-up of our region of space.
other star systems at varying levels of development and size convert elements into heavier elements. heavy elements are unstable to us and decay but may be the norm around other systems, especially the ones that have gone nova and seed the space around it with this exotic material which eventually forms new stellar and planetary systems.
read the link below and you will see that light is manipulated when it goes through exotic materials. therefore the speed of light is determined by our placement in the universe and how light reacts as it crosses the spacial material from it's source to our eyes.|||vacuum.|||vacuum|||The theory of relativity mandates that the velocity of propogation of light through vacum is a constant value.
http://www.bartleby.com/173/
The different colours of light come from different frequencies - they all travel at the same speed.|||The velocity of light is a constant.It is never the velocity of less than light or the velocity of greater than light.|||The theory of relativity depends on the speed of light in a vacuum. It *is* possible to go faster than the speed of light in air. When that happens, Cerenkov radiation is released.|||Vacuum. There are too many variables with air.|||I think you are confusing wavelength with speed. ALL light travels at C.
other star systems at varying levels of development and size convert elements into heavier elements. heavy elements are unstable to us and decay but may be the norm around other systems, especially the ones that have gone nova and seed the space around it with this exotic material which eventually forms new stellar and planetary systems.
read the link below and you will see that light is manipulated when it goes through exotic materials. therefore the speed of light is determined by our placement in the universe and how light reacts as it crosses the spacial material from it's source to our eyes.|||vacuum.|||vacuum|||The theory of relativity mandates that the velocity of propogation of light through vacum is a constant value.
http://www.bartleby.com/173/
The different colours of light come from different frequencies - they all travel at the same speed.|||The velocity of light is a constant.It is never the velocity of less than light or the velocity of greater than light.|||The theory of relativity depends on the speed of light in a vacuum. It *is* possible to go faster than the speed of light in air. When that happens, Cerenkov radiation is released.|||Vacuum. There are too many variables with air.|||I think you are confusing wavelength with speed. ALL light travels at C.
Acc to theory of relativity mass of object will become zero if that travels with speed of light?
Acc to theory of relativity mass of object will become zero if that travels with speed of light or mass decreases if its speed nears speed of light,how can mass decrease,mean how can number of atoms or molecules(i.e. the mass) decrease in an object?|||No, according to relativity, the relativistic mass of an object would become infinite if it traveled at the speed of light.
That is a tiny bit more than zero.|||No, it does the opposite. It increases to infinity. That is why it is impossible for something with rest mass to accelerate to the speed of light; it would take an infinite amount of energy.
It's not that the number of atoms changes. There are two different kinds of mass. Rest mass (the kind you usually experience) and mass due to kinetic energy (which is not apparent except at high speeds. You are likely familiar with Einstein's Equation:
E=mc^2
This includes both types of mass. As the kinetic energy increases, the mass attributable to that kinetic energy increases, even though the atoms themselves still have the same rest mass.
You can learn more here: http://en.wikipedia.org/wiki/Mass-energy…|||HEY NICE THOUGHT AND QUESTION ALSO,
LOOK, YOUR QUESTIONS ANSWER IS TOTALLY DEPENDS ON THE TERM "CONTROL VOLUME".
WHAT IS CONTROL VOLUME?
IT IS FIX VOLUME OF SPACE WHICH CONTAINS FIX QUANTITY OF MASS.
NOW RETURN TO UR QUESTION, LET U HAVE THROWN IDEALLY OBJECT WITH MASS "m" kg IN THE SPACE WITH VELOCITY OF LIGHT.
NOW IF U TAKE CONTROL VOLUME AS OBJECT THEN UR ASSUMPTION IS TOTALLY RIGHT BUT THE MASS CAN NOT BE ZERO IN THAT SYSTEM.
NOW IF U TAKE CONTROL VOLUME AS WHOLE SPACE WITHIN THAT OBJECT THEN UR PREDICTION IS TOTALLY WRONG. WHAT HAPPENS ACTUALLY ENERGY CONTAINS SMALL PACKET OF PHOTON ENERGY, WHICH HAS TINY MASS. SO WHOLE OBJECT IS CONVERTED IN TO ENERGY, BUT WE CAN NOT NEGLECT ENERGY AS SYSTEM WHICH HAS NO MASS...!!!!! SO
IF U NOT SATISFIED THEN CALL ME ON 0919328093207
That is a tiny bit more than zero.|||No, it does the opposite. It increases to infinity. That is why it is impossible for something with rest mass to accelerate to the speed of light; it would take an infinite amount of energy.
It's not that the number of atoms changes. There are two different kinds of mass. Rest mass (the kind you usually experience) and mass due to kinetic energy (which is not apparent except at high speeds. You are likely familiar with Einstein's Equation:
E=mc^2
This includes both types of mass. As the kinetic energy increases, the mass attributable to that kinetic energy increases, even though the atoms themselves still have the same rest mass.
You can learn more here: http://en.wikipedia.org/wiki/Mass-energy…|||HEY NICE THOUGHT AND QUESTION ALSO,
LOOK, YOUR QUESTIONS ANSWER IS TOTALLY DEPENDS ON THE TERM "CONTROL VOLUME".
WHAT IS CONTROL VOLUME?
IT IS FIX VOLUME OF SPACE WHICH CONTAINS FIX QUANTITY OF MASS.
NOW RETURN TO UR QUESTION, LET U HAVE THROWN IDEALLY OBJECT WITH MASS "m" kg IN THE SPACE WITH VELOCITY OF LIGHT.
NOW IF U TAKE CONTROL VOLUME AS OBJECT THEN UR ASSUMPTION IS TOTALLY RIGHT BUT THE MASS CAN NOT BE ZERO IN THAT SYSTEM.
NOW IF U TAKE CONTROL VOLUME AS WHOLE SPACE WITHIN THAT OBJECT THEN UR PREDICTION IS TOTALLY WRONG. WHAT HAPPENS ACTUALLY ENERGY CONTAINS SMALL PACKET OF PHOTON ENERGY, WHICH HAS TINY MASS. SO WHOLE OBJECT IS CONVERTED IN TO ENERGY, BUT WE CAN NOT NEGLECT ENERGY AS SYSTEM WHICH HAS NO MASS...!!!!! SO
IF U NOT SATISFIED THEN CALL ME ON 0919328093207
Is the theory of relativity more accepted by people than the big bang theory?
Both theories have proven points. Both theories have points that arent proven.
Would you say that relativity more widely accepted?|||Yes, theory of relativity is accepted by most of scientifically thinking people.
Many accept (buy) the theory of Big Bang only because it is the "only available package presently in the shelf" in certain stores (books).
The facts that make theory of relativity much more acceptable, compared to the Big Bang myth, are:
- Experiments today allow to build evidence for theory of relativity.
- Theory of relativity does not contradict common sense.
- Theory of relativity is part of natural science (physics)
- Big Bang myth in itself is a religion because you have to believe it against scientific contradictions - and if you reject that belief, some people (Big Bang fundamentals) tell you that you are not educated.|||I think you may be looking at it the wrong way. There's nothing in the Big Bang theory or the theory of Relativity that "requires" proving.
These theories were created to explain phenomena that have *already* been observed. These theories exist because there was strong evidence for them to begin with, not because Einstein had a wild guess about the nature of space-time.
I'm fairly certain that any scientist that "accepts" Relativity also accepts that the Big Bang occurred.
Relativity per se shouldn't conflict with any religious beliefs, but the Big Bang certainly does, since it's estimated to have occurred 13.7 billion years ago, which is much older than the 6000 years that some (special) people postulate the Earth to be.|||Yes
No
Not sure that I believe in the theory of gravity or the theory that the earth is round either..........|||its all relative :)|||There's not much difference between them. The Big Bang Theory IS Relativity. Or rather, a subset of Relativity. GR implies that the universe either had a beginning and is finitely old (Big Bang) or did not have a beginning and is infinitely old (Steady State). Since the observational evidence excludes Steady State, the universe must be Big Bang. In GR, there is no other choice. Since SS is already falsified, anything that falsified BB would exclude all possible free parameters of GR and therefore falsify Relativity as well.
So again, physicists make little distinction between the two theories. Big Bang is an application of GR.
There's no such thing as "proving" a theory.
Finally, scientists don't accept or reject theories on the basis of how challenging they are to religion. That is not a factor.|||it is all confusing but i think the theory of relativity is more accepted. the big bang theory is still kinda crappy.|||No, both are equally accepted by the people and the scientific community. You take it granted that Special theory of relativity is a real truth because it is supported by observations and is mathematically consistent.
General theory of relativity also supports big bang.It is also well supported by many experiments though many of them are still continuing. But, this theory is incompatible with Quantum mechanics. So, many theoretical physicists are still working to modify GR.
Big bang theory is also not a mere idea as it is well supported by the discovery of cosmic microwave background radiation (Discoverers were awarded Nobel Prize).
Would you say that relativity more widely accepted?|||Yes, theory of relativity is accepted by most of scientifically thinking people.
Many accept (buy) the theory of Big Bang only because it is the "only available package presently in the shelf" in certain stores (books).
The facts that make theory of relativity much more acceptable, compared to the Big Bang myth, are:
- Experiments today allow to build evidence for theory of relativity.
- Theory of relativity does not contradict common sense.
- Theory of relativity is part of natural science (physics)
- Big Bang myth in itself is a religion because you have to believe it against scientific contradictions - and if you reject that belief, some people (Big Bang fundamentals) tell you that you are not educated.|||I think you may be looking at it the wrong way. There's nothing in the Big Bang theory or the theory of Relativity that "requires" proving.
These theories were created to explain phenomena that have *already* been observed. These theories exist because there was strong evidence for them to begin with, not because Einstein had a wild guess about the nature of space-time.
I'm fairly certain that any scientist that "accepts" Relativity also accepts that the Big Bang occurred.
Relativity per se shouldn't conflict with any religious beliefs, but the Big Bang certainly does, since it's estimated to have occurred 13.7 billion years ago, which is much older than the 6000 years that some (special) people postulate the Earth to be.|||Yes
No
Not sure that I believe in the theory of gravity or the theory that the earth is round either..........|||its all relative :)|||There's not much difference between them. The Big Bang Theory IS Relativity. Or rather, a subset of Relativity. GR implies that the universe either had a beginning and is finitely old (Big Bang) or did not have a beginning and is infinitely old (Steady State). Since the observational evidence excludes Steady State, the universe must be Big Bang. In GR, there is no other choice. Since SS is already falsified, anything that falsified BB would exclude all possible free parameters of GR and therefore falsify Relativity as well.
So again, physicists make little distinction between the two theories. Big Bang is an application of GR.
There's no such thing as "proving" a theory.
Finally, scientists don't accept or reject theories on the basis of how challenging they are to religion. That is not a factor.|||it is all confusing but i think the theory of relativity is more accepted. the big bang theory is still kinda crappy.|||No, both are equally accepted by the people and the scientific community. You take it granted that Special theory of relativity is a real truth because it is supported by observations and is mathematically consistent.
General theory of relativity also supports big bang.It is also well supported by many experiments though many of them are still continuing. But, this theory is incompatible with Quantum mechanics. So, many theoretical physicists are still working to modify GR.
Big bang theory is also not a mere idea as it is well supported by the discovery of cosmic microwave background radiation (Discoverers were awarded Nobel Prize).
In which year did Einstein propound his theories of relativity?
I'm doing a project on the Theories of Relativity(General and Special) and I'd like to know when he made these theories known to the world and how.|||The theory of special relativity was received for publication on June 30, 1905. It was published in "Annalen der Physik" on September 27, 1905. General Relativity was published on November 25, 1915.
http://www.einstein.caltech.edu/|||SR was published in 1905, GR in 1915. GR didn't gain much acceptance until after Arthur Eddington gave his presentation on the Principe Eclipse Expedition (May 1919) to the Royal Society in (I think) November 1919.|||1915 was the year
In 1917, Einstein published an article in Physikalische Zeitschrift that proposed the possibility of stimulated emission, the physical process that makes possible the maser and the laser . He also published a paper introducing a new notion, a cosmological constant, into the general theory of relativity in an attempt to model the behavior of the entire universe.
http://www.einstein.caltech.edu/|||SR was published in 1905, GR in 1915. GR didn't gain much acceptance until after Arthur Eddington gave his presentation on the Principe Eclipse Expedition (May 1919) to the Royal Society in (I think) November 1919.|||1915 was the year
In 1917, Einstein published an article in Physikalische Zeitschrift that proposed the possibility of stimulated emission, the physical process that makes possible the maser and the laser . He also published a paper introducing a new notion, a cosmological constant, into the general theory of relativity in an attempt to model the behavior of the entire universe.
Relativity?
General relativity was developed by Einstein in the years 1911 - 1915. General relativity is a geometrical theory which postulates that the presence of matter "curves" spacetime, and this curvature affects the path of free particles (and even the path of light). It uses the mathematics of differential geometry and tensors in order to describe gravitation without the use of the force of gravity. This theory considers all observers to be equivalent, not only those moving with uniform speed...In other words...this is some complicated shlt!|||A man sits with a pretty girl for an hour and it seems shorter than a minute. But tell that same man to sit on a hot stove for a minute, it is longer than any hour. That's relativity.
Albert Einstein
|||It means with respect to something(from one point of view)|||One word is not a ?|||Encyclopedia?|||Relativity is a property of our physical world. Einstein published 2 papers in the early 1900's that stuns the world and change it forever: Special Relativity and General Relativity.
Special Relativity deals with objects traveling at constant velocity, and General Relativity deals with objects traveling under constant acceleration. The essential concepts introduced by Einstein are: (1) speed of light is constant in all reference frames, (2) time is NOT absolute, it depends on the speed of the moving object (3) space and time are intricately connected and is affected by the matter and energy within it, (4) the effects of matterand energy on spacetime is equivalent to gravity (i.e. this is what gravity is).|||Albert Einstein published his theory of relativity in 1920. Here's a quote of his explaining it in terms the average person can understand:
"Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity."|||Relativity principle? A statement that different points of observation are equivalent. Relativity theory derives from that principle.|||The speed of light is a constant (3E8 m/sec) in all frames of reference.|||It's been a century since 25 year old Einstein introduced relativity to to the world. Based on a trully simple fact, that modern experiments results didn't match with physics theories, he reconstructed physics right from the start. Some things taken for granted, such as time and space were redefined and proven to be relative to state of movement. Speed of light, and electomagnetic waves in general, which was thought to be subject to change, now is considered constant. The most famous equasion in the word (E=mc^2) proved scientifically the fact that matter and energy is the same thing in different forms.Einstein's conclusions were radical and magnificent, exceeding the wildest imagination, touching science fiction, or metaphysic and philosophical concepts. At this moment, humanity is trying to surpass the 3 dimensional cage of how our brain is used to work, to come a little closer to the actual truth.
Albert Einstein
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|||It means with respect to something(from one point of view)|||One word is not a ?|||Encyclopedia?|||Relativity is a property of our physical world. Einstein published 2 papers in the early 1900's that stuns the world and change it forever: Special Relativity and General Relativity.
Special Relativity deals with objects traveling at constant velocity, and General Relativity deals with objects traveling under constant acceleration. The essential concepts introduced by Einstein are: (1) speed of light is constant in all reference frames, (2) time is NOT absolute, it depends on the speed of the moving object (3) space and time are intricately connected and is affected by the matter and energy within it, (4) the effects of matterand energy on spacetime is equivalent to gravity (i.e. this is what gravity is).|||Albert Einstein published his theory of relativity in 1920. Here's a quote of his explaining it in terms the average person can understand:
"Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity."|||Relativity principle? A statement that different points of observation are equivalent. Relativity theory derives from that principle.|||The speed of light is a constant (3E8 m/sec) in all frames of reference.|||It's been a century since 25 year old Einstein introduced relativity to to the world. Based on a trully simple fact, that modern experiments results didn't match with physics theories, he reconstructed physics right from the start. Some things taken for granted, such as time and space were redefined and proven to be relative to state of movement. Speed of light, and electomagnetic waves in general, which was thought to be subject to change, now is considered constant. The most famous equasion in the word (E=mc^2) proved scientifically the fact that matter and energy is the same thing in different forms.Einstein's conclusions were radical and magnificent, exceeding the wildest imagination, touching science fiction, or metaphysic and philosophical concepts. At this moment, humanity is trying to surpass the 3 dimensional cage of how our brain is used to work, to come a little closer to the actual truth.
Relativity?
As determined by observer O a red light flashes, and, 10^-6s later, a blue light flashes 600 m father out on the x axis. What are the magnitude and direction of the velocity of a second observer, O', if he measures the red and blue flashes to occur simultaneously?|||diy
Relativity ......... ?
Travel in future is bit unconvincing to me or can someone here put it up in simple language here ?? What about the size of object out of which the light is released as sun is too big hence the light coming out of the Sun is expected to be with higher speed then compare to the one releases from a torch light which goes to a distance and stops.
So In this case how can we decide the light of speed is constant whereby it depends on the object. I might be wrong, please correct me if I am misunderstood somewhere.|||The source of light has no influence at all on the velocity of the light. Light does not always go from one point to another at the same speed. That can depend on the medium it is travelling in. And different frequencies (colors) of light travel at different speeds in the same material medium. But ALL electromagnetic radiation moves at the same speed in a vacuum. It would make no difference at all -whether it came from the sun or an LED bulb, or a fire-fly.
The speed of light is even independent of the speed of the light source.
So In this case how can we decide the light of speed is constant whereby it depends on the object. I might be wrong, please correct me if I am misunderstood somewhere.|||The source of light has no influence at all on the velocity of the light. Light does not always go from one point to another at the same speed. That can depend on the medium it is travelling in. And different frequencies (colors) of light travel at different speeds in the same material medium. But ALL electromagnetic radiation moves at the same speed in a vacuum. It would make no difference at all -whether it came from the sun or an LED bulb, or a fire-fly.
The speed of light is even independent of the speed of the light source.
Relativity?
Two springs with spring constants k1 = 1,813 N/m and k2= 1,429 N/m are placed on a smooth horizontal plane. The springs, both relaxed along a line , are attached one after the other and a weight, mass M = 3.7 kg , is attached to the free end of the second spring. The weight is displacet from the equilibrium in the direction of springs. Calculate the the period of the small oscillations of the weight (in s)|||No, this is not a relativity question, but a harmonic oscillation problem.
Relativity?
what does that mean "a body moves relative to air"?
n do we use this term "relative" only for objects in same reference frame?|||It's all to do with inertial frames of reference. E.g. If you were in a car and travelling at 60km/h and somebody fired a gun of which the bullet was travelling at 60km/h also, to YOU (traveling in the same F.o.R) its relative speed would be 0km/h because for you it would seem to be standing still. The term relative IS used when talking about frames of reference and it is used, usually to describe something being compared to another, i.e the bullet's speed relative to the car(you)|||To simply give the object's velocity is meaningless without referring to a reference frame. "Relative to the air" means in the frame in which the air is motionless.
n do we use this term "relative" only for objects in same reference frame?|||It's all to do with inertial frames of reference. E.g. If you were in a car and travelling at 60km/h and somebody fired a gun of which the bullet was travelling at 60km/h also, to YOU (traveling in the same F.o.R) its relative speed would be 0km/h because for you it would seem to be standing still. The term relative IS used when talking about frames of reference and it is used, usually to describe something being compared to another, i.e the bullet's speed relative to the car(you)|||To simply give the object's velocity is meaningless without referring to a reference frame. "Relative to the air" means in the frame in which the air is motionless.
Relativity?
In terms of nanosecond does west bound flight travel the same distance (with same speed) in lesser time than east bound flight?|||The rotational speed of earth at equator is 465m/s toward East.
1674 km/ hour.
This speed is with respect to a fixed star, say sun.
The plane which is at rest on a station on the equator is rest with respect to the ground.
But for an outside observer from a star both the earth and plane are having a speed of 1674 km/h toward east.
If the plane now starts and flies toward east, the observer on the station says that the flight is toward east with a speed of say 1000 km/ hour.
For the observer on the star the station rotates with a speed of
1674m/ hour and the plane flies with a speed of 1674 + 1000 = 2674km/ hour toward east.
In one hour the distance traveled by the plane as per the outside observer is 2674 km.
By this time the station has also moved through a distance of 1674 km.
The distance of separation of between the station and flight is 2764 - 1674 = only 1000 km.
If the plane flies with this speed toward west, the observer at the star will say that the earth is rotating with a speed of 1674km/h toward east and the plane is moving with a speed of 1674 -1000 = 674 km/toward East . Note the direction it is not west.
In one hour the distance traveled by the flight is only 674 km toward East. But the earth has rotated through a distance of 1674 km toward East.
The distance of separation between the station and flight is 1674 - 674 = 1000 km for both the observers.
An interesting case is when the plane is flying with a speed of 1674 km/ hour toward west.
Now the outside observer will say that the earth is rotating with a speed of 1674 km/h toward east and the plane is (1674 - 1674 = 0.) at rest.
But the distance of separation is 1674 since the earth is rotating.
The ground observer will say the earth is not moving where as the plane is moving with a speed of1674 toward west.
After all what we say about the speed of the flight is with respect to the ground and it is immaterial whether the flight is toward west or east.|||I suppose so.
The only doubt it may not is bcos of rotation of earth. Now, when we say they have same speed, this speed is with respect to ground (note that when flight lands and is still, speed is 0).
So, distance = speed * time which has to be same for both the flights for the same speed and time.|||This is no relativity question.|||If you are talking about flights on a spinning Earth, you cannot describe it with special relativity because you are dealing with an accelerating reference frame. There are any number of different reference frames that will give you any number of results.
You must either specify your reference frame and look for the result, or specify the result and look for the reference frame. You can find a reference frame in which the westbound flight takes more time, in which the eastbound flight takes more time, and in which they take the same amount of time.
1674 km/ hour.
This speed is with respect to a fixed star, say sun.
The plane which is at rest on a station on the equator is rest with respect to the ground.
But for an outside observer from a star both the earth and plane are having a speed of 1674 km/h toward east.
If the plane now starts and flies toward east, the observer on the station says that the flight is toward east with a speed of say 1000 km/ hour.
For the observer on the star the station rotates with a speed of
1674m/ hour and the plane flies with a speed of 1674 + 1000 = 2674km/ hour toward east.
In one hour the distance traveled by the plane as per the outside observer is 2674 km.
By this time the station has also moved through a distance of 1674 km.
The distance of separation of between the station and flight is 2764 - 1674 = only 1000 km.
If the plane flies with this speed toward west, the observer at the star will say that the earth is rotating with a speed of 1674km/h toward east and the plane is moving with a speed of 1674 -1000 = 674 km/toward East . Note the direction it is not west.
In one hour the distance traveled by the flight is only 674 km toward East. But the earth has rotated through a distance of 1674 km toward East.
The distance of separation between the station and flight is 1674 - 674 = 1000 km for both the observers.
An interesting case is when the plane is flying with a speed of 1674 km/ hour toward west.
Now the outside observer will say that the earth is rotating with a speed of 1674 km/h toward east and the plane is (1674 - 1674 = 0.) at rest.
But the distance of separation is 1674 since the earth is rotating.
The ground observer will say the earth is not moving where as the plane is moving with a speed of1674 toward west.
After all what we say about the speed of the flight is with respect to the ground and it is immaterial whether the flight is toward west or east.|||I suppose so.
The only doubt it may not is bcos of rotation of earth. Now, when we say they have same speed, this speed is with respect to ground (note that when flight lands and is still, speed is 0).
So, distance = speed * time which has to be same for both the flights for the same speed and time.|||This is no relativity question.|||If you are talking about flights on a spinning Earth, you cannot describe it with special relativity because you are dealing with an accelerating reference frame. There are any number of different reference frames that will give you any number of results.
You must either specify your reference frame and look for the result, or specify the result and look for the reference frame. You can find a reference frame in which the westbound flight takes more time, in which the eastbound flight takes more time, and in which they take the same amount of time.
Relativity?
A mu-meson moves, as measured in the system S, at speed v= c/1.06 and from its creation to its decay it travels L = 3.0 km. Calculate the proper lifetime of the mu-meson (in ns) .|||Huh?|||"proper lifetime" in this case means the lifetime of the muon measured in a the rest frame of the muon.
first, calculate the lifetime in a reference fame moving at v=c/1.06 relative to the muon.
t = L/v = (3.0*10^3 m)/(3.00*10^8 m/s /1.06)
= 1.06*10^-5 s
to transform this time into the time measured by an observer traveling in the rest frame of the muon, use the relationship
t = gamma*t0
where gamma is the Lorentz factor
gamma = 1/sqrt( 1 - (v/c)^2 )
and t0 is the "proper lifetime" of the muon
t0 = sqrt( 1 - (1/1.06)^2) * 1.06*10^-5 s
= 3.52*10^-6 s
= 3.52*10^3 ns
(1 ns = 1*10^-9 s)|||really..? here?
first, calculate the lifetime in a reference fame moving at v=c/1.06 relative to the muon.
t = L/v = (3.0*10^3 m)/(3.00*10^8 m/s /1.06)
= 1.06*10^-5 s
to transform this time into the time measured by an observer traveling in the rest frame of the muon, use the relationship
t = gamma*t0
where gamma is the Lorentz factor
gamma = 1/sqrt( 1 - (v/c)^2 )
and t0 is the "proper lifetime" of the muon
t0 = sqrt( 1 - (1/1.06)^2) * 1.06*10^-5 s
= 3.52*10^-6 s
= 3.52*10^3 ns
(1 ns = 1*10^-9 s)|||really..? here?
Relativity?
A motorcyclist is riding through a shower of rain that is coming down vertically. The rider's speed is 72km/h and it appears to him that the rain is driving into him at an angle of arctan(1/4) to the horizontal. Find the terminal speed of the raindrops in m/s.|||rain speed = riders speed * tan (angle)
= rider's speed / 4|||Yeah.
= rider's speed / 4|||Yeah.
Relativity?
A swimmer heads directly across a river of width 10m at a speed of 1.2m/s. If there is a constant cross-current along the shore of 0.8m/s, find the angle that his course makes with the far bank, and determine how far downstream he has been swept by the current when he arrives at the opposite bank.|||10m at 1.2m/s means he will arrive on shore in 10/1.2 or 8.33s. In this time he has drifted downstream .8m/s*8.33s or 6.67m. Using trig: the angle with the far bank = tan^-1(10/6.67) = 56.3 degrees
Relativity??????
There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.|||I don't think it ultimatly matters if there's only a hundred billion stars in the galaxy, because there's an infinite amount of galaxies in the universe, and there's still tons of space we have yet to discover. I guess our galaxy would have economic numbers, while the rest of the universe has astronomical numbers, relatively speaking.|||That sounds like something Ellen Degeneres would say, even though it's Richard Feynman that's the author.|||This has nothing to do with philosophy but rather more suitable with science and mathematics or maybe economics.|||That galaxy covers less than a trillionth of the available space.Its been calculated that the number of probable planets in the universe is as many as ten billion trillion(Carl Sagen)thats quite astronomical|||Like good old Albert said: "If the facts don't fit the theory, change the facts".
Good luck!|||that display meaning of evolution, humanity itself does not produce abundance but debt..Still precise numbers or simply numbers it is only guessing of humanity as a whole, another attempt to limit universe according to image and likeness of human (humanity). Including smartest ones.|||thers not just one galaxy.there r otheres with miooins of stars in it.
Good luck!|||that display meaning of evolution, humanity itself does not produce abundance but debt..Still precise numbers or simply numbers it is only guessing of humanity as a whole, another attempt to limit universe according to image and likeness of human (humanity). Including smartest ones.|||thers not just one galaxy.there r otheres with miooins of stars in it.
Relativity?
The theory of relativity indicates that a space ship (matter), approaching the speed of light, foreshortens in the direction of motion and increases in mass, and time slows relative to the rest of the universe. True or false. If false, explain.|||All true. The main point you mention is "...relative to the rest of the universe..." Aboard the spaceship everything, including time, is 'normal.'|||uuhhh..... i think its false. because i remember that the theory youre talking about has a different name.|||Its all true. I am not explaining as you say explain if false.|||I just laughed a little because my husband loves Star Trek, Star Wars and all that stuff and we have debated this many times. I pretty much just like to pick on him about it though, I actually agree that the faster the ship goes the more mass it would gain and light speed would be almost impossible to reach and maintain.|||It is true. Try researching it.|||True (mostly).
When you are traveling at relativistic speeds, lengths contract and times dilate.
In modern notation, we don't say that mass increases. Mass should be defined as rest mass which is a Lorentz-invariant quantity. Some folks and old texts still use the concept of a relativistic mass, though, which increases at relativistic speeds. So you could answer either way on that. It's just a semantics issue.|||True, that is the prediction from the theory of relativity.|||Those changes would only be seen by someone back at the launch pad. They would not be seen by the people on the space ship.The people on the space ship would see those changes happening to everything else, but not to themselves.|||false, but only technically.
at relativistic speeds, lenth is contracted in the direction of motion and inertial mass does increase which means the faster it goes, it becomes more and more difficult to accelerate the object (ie: change it's direction and/or speed).
so you're statement is correct so far.
time dilates, but this doesn't mean it slows relative to the rest of the universe. it slows relative to a refrence that is not moving in the same direction as fast or faster. so relative to some other reference like a spaceship or planet, not to the "rest of the universe" as there might be something in the universe with the same velocity or more speed in the same direction, and the time will be observed differently depending on your observational frame of reference.
for instance, if your reference frame is another ship moving the same direction at the same speed, a second in one frame will be identical to a second in the other frame.
but of course, as you put it, it's relative. time wouldn't slow down for the ship as it sees it...it would see time move no differently in their frame...no matter what your frame is, to you, a second is a second is a second according to you in your frame. it's not like a guy going near the speed of light will look down at his watch and it's moving slower than normal. so if ship A is the one with a velocity at relativistic speeds compared to ship B (we can just take ship B to be at rest as velocity is always measured with respect to something else...no such thing as actual rest, just what we define to be rest or observe to be rest in our own reference frame) then ship A comes back to meet up with ship B. then the amount of time that passed that ship A observed will be less than what ship B observes.
this type of thing is also seen in varying regions of a gravity well since there is more gravitational acceleration at the earth's surface than in orbit aroud earth and relativity works no matter how something is accelerated (if your in a ship with no windows and you accelerate, you can't tell if you got a push from say engine thrust or if you are in a planet's gravity), so a satellite's "clock" will be slower than what the same clock would measure on earth.
relativity is weird, but it's all provable with both math and experiment and general relativity is probably the most elegant theory in all of science. you should really pick up a copy of einstein's paper on special and general relativity. it's practically all conceptual, no math involved...and it's so brilliantly simple and obvious after you read it just like all the best science is. i'm surprised it has not become the law of general relativity with all the proof there is for it, but whatever. takes a few centuries to become a law usually.|||True.
When you are traveling at relativistic speeds, lengths contract and times dilate.
In modern notation, we don't say that mass increases. Mass should be defined as rest mass which is a Lorentz-invariant quantity. Some folks and old texts still use the concept of a relativistic mass, though, which increases at relativistic speeds. So you could answer either way on that. It's just a semantics issue.|||True, that is the prediction from the theory of relativity.|||Those changes would only be seen by someone back at the launch pad. They would not be seen by the people on the space ship.The people on the space ship would see those changes happening to everything else, but not to themselves.|||false, but only technically.
at relativistic speeds, lenth is contracted in the direction of motion and inertial mass does increase which means the faster it goes, it becomes more and more difficult to accelerate the object (ie: change it's direction and/or speed).
so you're statement is correct so far.
time dilates, but this doesn't mean it slows relative to the rest of the universe. it slows relative to a refrence that is not moving in the same direction as fast or faster. so relative to some other reference like a spaceship or planet, not to the "rest of the universe" as there might be something in the universe with the same velocity or more speed in the same direction, and the time will be observed differently depending on your observational frame of reference.
for instance, if your reference frame is another ship moving the same direction at the same speed, a second in one frame will be identical to a second in the other frame.
but of course, as you put it, it's relative. time wouldn't slow down for the ship as it sees it...it would see time move no differently in their frame...no matter what your frame is, to you, a second is a second is a second according to you in your frame. it's not like a guy going near the speed of light will look down at his watch and it's moving slower than normal. so if ship A is the one with a velocity at relativistic speeds compared to ship B (we can just take ship B to be at rest as velocity is always measured with respect to something else...no such thing as actual rest, just what we define to be rest or observe to be rest in our own reference frame) then ship A comes back to meet up with ship B. then the amount of time that passed that ship A observed will be less than what ship B observes.
this type of thing is also seen in varying regions of a gravity well since there is more gravitational acceleration at the earth's surface than in orbit aroud earth and relativity works no matter how something is accelerated (if your in a ship with no windows and you accelerate, you can't tell if you got a push from say engine thrust or if you are in a planet's gravity), so a satellite's "clock" will be slower than what the same clock would measure on earth.
relativity is weird, but it's all provable with both math and experiment and general relativity is probably the most elegant theory in all of science. you should really pick up a copy of einstein's paper on special and general relativity. it's practically all conceptual, no math involved...and it's so brilliantly simple and obvious after you read it just like all the best science is. i'm surprised it has not become the law of general relativity with all the proof there is for it, but whatever. takes a few centuries to become a law usually.|||True.
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