Friday, December 2, 2011

What are the fundamental theories of Quantam Mechanics, and why do they clash with General Relativity?

I have a good understanding of General and Special Relativity, but not Quantum Mechanics. Please give your answer as simply as possible.|||That's quote from Omar needs a citation. It seems to be used without credit in many places on the web, so finding one isn't easy. The earliest reference I see is at:





http://searchcio-midmarket.techtarget.co…





... from 2006, and you can read the rest of the article there.





Omar: If you're going to cut-and-paste your answers, don't paste the tail end of a bullet-point into the main text. The final paragraph shouldn't be all about the uncertainty principle.





Meanwhile, the description looks right for QM. The main idea is that QM describes nature on a very small scale--small enough that the wave nature of particles becomes evident--and does so very accurately, provided that the calculations can actually be carried out. General relativity describes large-scale behavior of masses large enough that the difference from Newtonian gravity is noticeable. Again, the results agree very well with observation.





Apparently, though, at small scale and at extreme gravitation conditions found near the event horizon of a black hole, the two theories predict different behavior. (I don't know the details...that's just what I've read.) That's the clash, as far as I know.|||- Quantum theory is the theoretical basis of modern physics that explains the nature and behavior of matter and energy on the atomic and subatomic level. In 1900, physicist Max Planck presented his quantum theory to the German Physical Society. Planck had sought to discover the reason that radiation from a glowing body changes in color from red, to orange, and, finally, to blue as its temperature rises. He found that by making the assumption that energy existed in individual units in the same way that matter does, rather than just as a constant electromagnetic wave - as had been formerly assumed - and was therefore quantifiable, he could find the answer to his question. The existence of these units became the first assumption of quantum theory.


Planck wrote a mathematical equation involving a figure to represent these individual units of energy, which he called quanta. The equation explained the phenomenon very well; Planck found that at certain discrete temperature levels (exact multiples of a basic minimum value), energy from a glowing body will occupy different areas of the color spectrum. Planck assumed there was a theory yet to emerge from the discovery of quanta, but, in fact, their very existence implied a completely new and fundamental understanding of the laws of nature. Planck won the Nobel Prize in Physics for his theory in 1918, but developments by various scientists over a thirty-year period all contributed to the modern understanding of quantum theory. The Quantum Theory depends so much on the uncertainity principle by heisenberg which states that it is impossible to determine the velocity and location of an electron which means that the Quantum Theory depends so much on randomness , and then Einstein said his famous phrase that " God is not playing with dice " which makes the Quantum Theory the opposite of the relativity .

What's the difference between "Cultural Relativity" & Ethnocentrism?

I'm writing a paper on multiculturalism and us/them divisions and I'm having trouble defining them. I understand that ethnocentrism is looking at the world from the viewpoint of one's own culture, but is the meaning of cultural relativity: "beliefs and activities should be interpreted in terms of one's own culture?"|||I like Tehabwa's definition.


The differences and conflicts would be


(i) scope/applicability:


cultural relativism: a fact or event is meaningful only within its cultural context


ehtnocentrism: everything outside one's cultural context also gets a sweeping qualification from MY cultural standards.


(ii) what constitutes inappropriate/invalid interpretation


cultural relativism: any qualification where the fact or event is interpreted out of its cultural context


ethnocentrism: any qualification where the fact or event is interpreted out of MY cultural context


These contrasts show how each of the two might differ in direct contradiction of the other.|||I think I have pondered on this one before myself. Not a lot of difference - for everyday language. But if you're doing a dissertation - you better be spot on. So disregard my "unresearched" ramble.


What's the difference between one's cultural background and one's ethnic background? It's get quite cloudy.|||Cultural relativity says that there's no better or worse, or right or wrong, except as defined by each culture.





Ethnocentrism says MY culture is superior; all the rest are inferior.

Why does special relativity say that c is constant?

As I understand it, special relativity says that all the laws of electromagnetism are the same for observers in all reference points. I also know that this is why the speed of light remains the same for all observers. But what law of electromagnetism states, or predicts, that light has to be exactly the speed it is? I think it has something to do with Maxwell's equations, but I've not been able to connect the dots. Can someone explain in a non-technical way why the speed of light specifically is one of the laws that remains the same for all observers?|||First: That's special relativity, which deals with non-accelerating inertial reference frames. NOT every reference frame, you need general relativity for that. With that in mind...





There's a couple of logical roads to go down here





Maxwell's equations imply that the speed of light is c in a vacuum. You generally think of waves as propagating through SOMETHING, like sound waves propagate through matter. Take away the matter and they don't, hence no sound in the vacuum of space. Maxwell's equations don't say anything about reference frames, basically if you have a changing electric or magnetic field, you get a transverse wave traveling at c.





So just from Maxwell's equations alone there are two conclusions. One is that it means c with respect to an ABSOLUTE reference frame. In other words light IS propagating through something, and that something is something we just can't see or detect, it's everywhere, including a vacuum, and everything is moving through it and the speed of light through this "aether" (as it was called) is what's c. Well they disproved this using the motion of the earth. If you shine light in the same direction the earth is moving, well the earth is moving pretty quick. So the light should appear to be going slower from our POV on earth then if shone the opposite way earth is moving. The experiment proved that in fact it was identical for both cases.





The less obvious conclusion was reached by Einstein, that for ANY inertial observer (which we basically were on earth looking at the light from either side of its motion)it's c.





Einstein himself reached the conclusion by deciding that magnetic fields were really electric fields...but from the POV of the particle in motion(a moving charge being what causes magnetic fields)





It's just not something you can be told directly from Maxwell's equations(though you see that Maxwell's equations don't invalidate them, they're perfectly true)and it's the next logical step. Just like how you simply can NOT derive the Bohr model of the atom (or more sophisticated quantum theories) from Newton's equations. Einstein made the next "jump" in understanding|||speed of light does not change|||The ratio by which it is slowed is called the refractive index of the medium and is always greater than one.* This was discovered by Jean Foucault in 1850.





Why? There is no answer. It just is.|||If you look at the laws that describe electric and magnetic forces at microscopic levels, they only work (and prove) that the speed of light is constant, no matter how fast a person is travelling. this is a consequence of the world we live in and can not be changed. as other's have said, it just is.|||Special relativity says that c is constant because, and this might be unsatisfying, the constancy of c is one of the postulates of special relativity.





There are two postulates that are used to derive all of the laws of special relativity...





1) all reference frames are equivalent





2) the speed of light is the same in all reference frames





The reason that the equations "predict" this "outcome" is that it is one of the first assumptions of the whole theory. This was accepted by Einstein as a postulate because it was the result of experiment.





The speed of light can be predicted (not by the theory of relativity) by using Maxwell's equations.





del E = -(dB/dt) and del X B = (mu)(epsilon)(dE/dT)





The derivatives should be partial, but I don't know how to write partials on yahoo answers.





This reduces to...





v = 1/[(epsilon)(mu)]^(1/2) = c/n





in a vacuum, n = 1, and v = c





Note that this does not rely on the theory of relativity. To say that the theory of relativity predicts this outcome is a bit tautological.|||Its a postulate of special relativity

How can i demonstrate Einsteins General theory of Relativity?

How can i demonstrate Einsteins General theory of Relativity using props or a drawing in a black board or an animation on the internet.|||perhaps the easiest way is to reproduce the situation that Eddington photographed while on the island of Principe in 1919.





(curvature of space-time near the sun - which bent the path of light from distant stars - even though photons are massless!).


http://en.wikipedia.org/wiki/Arthur_Stan…





and see the image at the upper right of this link


http://en.wikipedia.org/wiki/Spacetime





note this picture is 2D in the sense that it shows only one plane being curved. in reality all planes look like this. but i think you get the idea...





cheers

Thursday, November 24, 2011

What's the equation relating general relativity and Newtonian mechanics?

To put it another way, how (which constants etc.) does general relativity prove that Earth's gravity is about 9.80N/kg on it's surface?|||'Die Grundlage der allgemeinen Relativitätstheorie', (The foundation of the General theory Relativity) was published by Einstein in 1916. He provided a field equation for a gravitational field tensor 'G' in terms of the stress-energy tensor 'T'.





G = 8πT





or in the expanded form: -





.. α .. α β


∂Γ + Γ Γ = -κ(T - ½g T)


_ μν μβ να .... μν ... μν


∂x


.. α





√-g = 1








In section 21 of this famous paper, Einstein considered Newton's theory as a first approximation. To do this he considered space-time to be essentially that found at spacial infinity, which means that only tensor components μ = ν = 4 may need to be considered!





Thus he derived the Newtonian equivalent equation: -





∇²g₄₄ = κρ





Where ρ = T₄₄ or the matter in the stress-energy tensor.





He then reduced this equation to one for the equivalent Newtonian gravitational potential 'V': -





-κ.⌠ρdτ


__ | _


8π⌡r





or units of time to match Newtonian theory





V =-K.⌠ρdτ


..... __ | _


..... c².⌡r








Where K = G = 6.7 x 10¯⁸ (10^-8 Einstein's cgs units, now 10^-11 SI units), with κ = 8πK /c²





Thus, Einstein's first order approximation gives a similar result to Newton's gravitational theory.





Since F = -dV/dr, a conservative central force field: -





Newtonian g = GM/r²





or Einstein's approximation





g =K.ρdτ


..... ___


..... c²r²





and from E = Mc² = ρ, we have with the proper time dτ = 1 second





g =K.M


..... ___


..... r²








Thus, to answer your question - to a first approximation, general relativity proves that Earth's gravitational acceleration is about 9.80N/kg on it's surface!!!!|||g=GM/R^2, where G=6.67*10-11, M-Earth mass, R-radius|||Luv a duck,gee whizz.

Are General Relativity and the idea of the Graviton compatible?

Say that scientists had experimental data that proved that Gravitons exist... Would this make General Relativity wrong?





If it wouldn't make General Relativity wrong, how do the theory of Gravitons and General Relativity both... Cooperate?





:)) Thankss.|||"...how do the theory of Gravitons and General Relativity both... Cooperate?..."





Relativity has shown us that gravity is actually the warping of spacetime due to the presence of mass. We've yet to explain *how* mass does this, but the graviton could well be the mediating particle involved, like the photon mediates electromagnetism.|||The concepts are independent. The graviton has been proposed as a virtual particle mediating the gravitational force. But we don't know whether there is one, or whether there is a need for one. So far we have no quantum theory of gravity, and again, we don't even know if we need one.

Saturday, November 19, 2011

How come creationists don't have a problem with the theory of relativity or germ theory?

The same scientific principles and epistemological methodologies that were used by scientists to devise those theories are the same ones which were used to create the theory of evolution.








So if you think scientists are lying to you about the evidence for evolution, how come you don't think the same way about the theory of relativity, the germ theory of disease, cell theory or atomic theory?|||Anyone who would use a straw man fallacy by making up a creationist's opinion in order to criticize it is not worth debating. Learn how to argue without being fallacious.The science is the same. It is certainly possible to look at the evidence and come up with a different conclusion to the Darwin evolutionary position. Indeed, many would see that the evidence fits perfectly well with a design position.



Edit: As works in progress, many scientific theories just keep getting revised. For example, we base our current evolutionary theory of when humans diverged from apes on the fossil record. But every time a new fossil is found, the date gets pushed back.



In any case, this means is that any information given in student text books is considered to be “true” only at the time the book is published. (Now you see why you always have to buy the newest editions of those expensive college texts?)



Here are a couple ...



There are 109 Elements in the Period Table ... New information: Since 1994, six new elements have been discovered.



Prior to scientists embracing the notion that the universe was created as the result of the Big Bang, it was commonly believed that the size of the universe was an unchanging constant—it had always been the size it was, and always would be. The idea stated that that the total volume of the universe was effectively fixed, and that the whole construct operated as a closed system. The theory found its biggest adherent in Albert Einstein—the Static Universe is often known as “Einstein’s Universe”—who argued in favor of it and even calculated it into his theory of general relativity.|||Let me put it like this...just because a person may use the English language (or whatever other one you choose) to tell a lie, doesn't mean the entire language is invalid.





Simply because a scientist utilizes, as you put it, "The same scientific principles and epistemological methodologies" that are valid in one instance, this does not make them valid in all instances.





If one were to be quite factual in the explanation of the "evolution" of the evolution theory, it would be shown that the evolutionary theory is a varied and extremely broad collection of ideas from many different individuals and institutions, not just one. Just as it can be said of the Creationists...there are many different philosophical and ideological variations. Jeez, you can't even get two Baptists to agree on everything let alone the entire religious world.|||Because those aren't the ones that conflict with their beliefs.



I bet if creationists had a bone to pick with relativity, we'd be flooded with asinine misrepresentations and lies about how it does or doesn't work, how it's supposedly false, or that it, too, is some kind of conspiracy against religion.|||Someone should really do a study to see if rhetorical questions actually make the person realize anything new or if they're pointless.





I'm pretty sure you know the answer to your question. That's why I say that. And I'm just interested in if this is an effective strategy. Unless your goal is to annoy... then good job lol|||How come evolutionists, who don't believe in God, have no problem with saying "God bless you" when the person next to them sneezes?





...or "thank God" when something amazing happens?





...or plead "please, God" when they're in a fox hole?





iamnotbut....I know [the Great] I AM|||Why is it that people so smart that can figure out all that stuff ignore what is right in front of their faces and see that always kind produces kind. Even their stupid degrees are because they went to a school of that kind and it produced the same. Get real.|||The theory of relativity was devised by mathematical means. Cell theory was based on observations.


Evolution was based on observations and guesses (natural selection only selects from what is available. Darwin was wrong).|||Simple, they start with the premise of creationist beliefs then attack anything that contradicts it. That's how a belief works. It is not intellectual dishonesty, it's just how beliefs work.|||how is babby formed, how is babby formed, how girl get pragnat|||god did not create the world in 6 days, and we werent one of the first things he put on earth at all.


this just proves that the story was WRONG, so why bother listening to creationists. theyre wrong.|||Oh...they would have an issue with big chunks of General Relativity if they actually understood the implications.|||They conveniently select what they think scientists are right about to fit into the existence of their God.|||Because they doesn't discredit their magical creation myth like evolution does.|||Or the theory of electronicism...|||Gravity is just a theory!!!!!!!!





*floats off sulkily*|||Creationists are funny like that.|||They used to have a problem with the earth going around the sun. Didn't make sense.|||it doesn't inconvenience them or their beliefs.|||First Cause|||I don;t have a problem with evolution. God did create us though. We can still only guess at and imagine how it was done.|||You still think evolution is science?





All through history evolution has been discredited by scientists.





Darwin understood that his beliefs were not scientific.





He wrote;





“I am quite conscious that my speculations run beyond the bounds of true science . . . . It is a mere rag of an hypothesis with as many flaw(s) and holes as sound parts.”


Charles Darwin to Asa Gray, cited by Adrian Desmond and James Moore, Darwin, )New York: W.W. Norton and Company, 1991) p. 456, 475).





And scientists spent the next 150 years proving him right (i.e. that his speculations ran beyond the bounds of true science) by disproving his ideas.


First, 4 of Darwin's contemporaries challenged Darwin's idea;





1. Charles Lyell (1797 – 1875) wrote "No geologists, who are in possession of all the data now established respecting fossil remains, will for a moment contend for the doctrine in all its detail, as laid down by the great chemist to whose opinions we have referred. But, naturalists, who are not unaquainted with recent discoveries, continue to defend the ancient doctrine in a somewhat modified form. (The Principles of Geology Ch 9 pg. 145 par 2)


2. Gregor Mendel (1822-1884) conducted experiments with peas which showed that one species could not transmute into another one. (The Evolution Handbook - TEH p. 20)


3. Louis Pasteur (1822-1895) disproved the theory of spontaneous generation (i.e. life cannot arise from non-living materials). (TEH p. 20)


4. August Friedrich Leopold Weismann (1834-1914) cut of the tails of 901 young white mice in 19 successive generations, yet each new generation was born with a full-length tail. (TEH p. 20)


Then, in 1953 Stanley Miller sparked a non-oxygen mixture of gases for a week and produced some microscopic traces of non-living amino acids and proved that the act of producing amino acids would produce right-handed amino acids which clog the body machinery and kill the life form (TEH p. 265).





TEH - The Evolution Handbook by Vance Ferrell contains over 3000 scientific facts and is available in book form and online at www.evolution-facts.org|||'Theory' is a nicer word for not completely true.|||Because youre a fruit.