Relative time... atomic clocks on an airplane.?

Question

Time is apparently relative in the sense that objects that move very fast also zip through time faster. This was proven by an atomic clock on an airplane that "ticked" ever so slightly slower than an identical clock on the ground? Right? Anyway, if those two clocks were moving relative to each other, why would one zip through time and the other move through time at a "normal" pace? If the two clocks are brought back together after the trip, who is to say which one was "moving really fast" and which one was stationary if they were only moving relative to each other. In other words...For pilots on the airplane, they would experience normal pace of time, so why wouldn't they see that the Ground clock which was moving relative to them, ticked at a slower pace?

Answer 1

This is an example of the so called twin paradox. Relativity says the twins should be equivalent if in intertial frames.

The resolution, though, does not require acceleration as Wikipedia incorrectly claims. It really has to do with the fact that more than two inertial frames are involved.

Imagine setting it up like this. A clock stays home. A clock flies off 500 miles. At 500 miles it meets a clock going back the other way and transmits the time it is showing. Now nothing accelerated, but you can easily see why the paradox is resolved - there are three frames involved here. The one at home. The one leaving. The one returning. A space-time diagram explains the rest.

Answer 2

You've presented a good scenario describing time dilation effects of relativity.

Not to muddy up the water, but another significant point is that neither the stationary nor moving clock showed the "correct" time. In other words they were both correct..! To anyone left behind with the stationary clock its rate of time would appear normal, *but* the same thing would be true for those aboard the jet with the moving clock. This illustrates very well the fact that time is strictly relative and not absolute, as though there was some Cosmic Master Clock somewhere ticking off the "correct" time.

Answer 3

nope. In your own frame of reference, you will age normally. Nothing will be different. To the observer, you will age very slowly. This all depends not only on relativity being true, but true in a way that treats time as a real thing rather than just a measurement. All the theory about time dilation is derived from time as a measurement, not some kind of real physical entity. And all the supposed experimental verifications depend on the equivalence principle being valid, and in particular, so completely valid that whatever is true for gravitational fields must be true for all accelerated frames of reference. I'll try to explain that last sentence in only one paragraph. General relativity depends very heavily on the "equivalence principle," which says that the modeling used to describe accelerated frames of reference also can describe gravitational fields, so that the two are "equivalent." This doesn't mean they're the same thing. It doesn't mean the models are PRECISELY equivalent, instead of merely similar in form. And it doesn't mean that confirming the model for one confirms it for the other. Many completely unrelated things can be described by similar mathematics. Even if the math is precisely similar, they're still not the same thing, and if the math turns out right for one of them, it can still be wrong for the other. So data about time in gravitational fields is irrelevant to near-light-speed travel. Few scientists understand this, because they rarely study philosophy or math. With that in mind, relativity's predictions about near-light-speed travel are based on thought-experiment, a very weak form of demonstration. Thought experiment can involve subtly invalid premises that nobody notices, sometimes for centuries. For example, imagine a cannonball and a baseball dropped from a tall tower. Which will hit the ground first? Most people who never heard of Galileo will say the cannonball. It took a real-world experiment to demonstrate that they actually fall at the same rate. Nowadays, ancient people look like morons for never testing the premise that heavy things fall faster. There may be unnoticed premises lurking behind relativity's thought experiments that will make us look damn stupid too. So all that talk about aging faster, and twins and paradoxes, take it with a grain of salt. It may, in the end, be nothing but bullshit. Until someone takes a spaceship on that fast a journey, nobody will really know.

Answer 4

During October, 1971, four cesium atomic beam clocks were flown on regularly scheduled commercial jet flights around the world twice, once eastward and once westward, to test Einstein's theory of relativity with macroscopic clocks. From the actual flight paths of each trip, the theory predicted that the flying clocks, compared with reference clocks at the U.S. Naval Observatory, should have lost 40+/-23 nanoseconds during the eastward trip and should have gained 275+/-21 nanoseconds during the westward trip ... Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59+/-10 nanoseconds during the eastward trip and gained 273+/-7 nanosecond during the westward trip, where the errors are the corresponding standard deviations. These results provide an unambiguous empirical resolution of the famous clock "paradox" with macroscopic clocks."

Dr. H

Answer 5

the question you posed: "who is to say which one was "moving really fast" and which one was stationary if they were only moving relative to each other" is known as the "twin paradox". check out the wikipedia article below. the difference is that the clock on the plane experienced acceleration from its inertial frame, whereas the clock on the ground essentially continued on its inertial path.

Answer 6

The difference as to which one was moving and which one wasn't is that one of them underwent acceleration (both speeding up and slowing down, in physics, is acceleration). That is the difference. It is the one which is sped up and slowed down that time will pass slower for. See

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

Answer 7

Relativity sets up near and close to the speed of light.
V= 0.9 c
If this occurs time gets slower.

Answer 8

They used to say movement relative to the fixed stars.