How would you test the idea of general relativity using a clock?

I've been reading about general relativity and this was one of the "brain twister" questions..


Does anyone have any cool ideas? And how accurate do you think the clock used would have to be?|||Send it on a rocket round trip and you will find it has lost a bit of time during the trip.Very roughly, while it was cruising at speed v, the time went more slowly by the factor sqrt(1 - v^2/c^2)





c is 300,000km/sec and if we were orbiting the earth, our v wd be about 10km/sec So the clock has lost .0002 % (roughly).


I believe this nhas been measured with a VERY accurate clock.|||This is actually being tested as we type. A super precise crystal clock based on the vibration frequency of the crystal was launched some years ago in a satellite. The expectation is that when the clock is recoverd, we will discover that it has been running slow compared to the same kind of clock on Earth. That slowness is predictable via the theory of relativity.





The clock has to be super precise because the degree of slowness will be waaaaaaaay below a second after several years orbiting. For example, if the satellite travels at 17,000 mph in orbit for one year, that will result in the on board clock being 0.0102 sec slower at the end of the year than the similar clock on Earth. [See source.]





Clearly, to measure .0102 sec differential over a year, your clock would have to be way more precise than down to a 100th of a second. I would suggest a 1000th of a second precision at the minimum if you can run the experiment over a year Earth time. Shorter periods would of course demand even greater precision.





BTW: Accuracy and precision are not the same thing. One can say it's hot out and be accurate, but that's not very precise. Or one can say it's 98 deg F out and be precise, but not at all accurate if it happens to really be 99 deg F. What you need most in your clock is precision to meaure down to the millisecond or finer.


|||Yes that's one way to do it. The experiment has been done. In fact the clocks used for the GPS system have to take relativity into account, or they would gradually lose time compared with time on earth, because in orbit they move very fast (and also because they are further from the centre of the earth).