Time dilation experiment

either way, both perceptions are valid

look at that grin at the end!

40 billionth of a second? WTF, thats so small.

But never the less it means a lot.

I have a problem with time dilation.

Imagine we have two clocks.

One clock is sent to the Andromeda galaxy at a constant speed close to speed of light and then back to earth.

The traveling clock should have measured less time than the earth clock.

But since uniform motion is relative, we may as well say that the first clock was stationary and the earth and the Andromeda galaxy were moving!

Then the earth clock should have measured less time.

What is wrong here?

Because movement is in reference to space time. Space isnt nothingness. It is a substance of sorts. As you travel through space time moves slower for you (although you dont notice it because your thought is slowed along with it) So while earth may be moving in reference to the clock sent to Andromeda it is not moving nearly as much in reference to space.

@xderDoktor
That would mean that uniform movement is NOT relative, and that there is an "absolute" frame of reference, no?

@PeiperJ2

You may be right about that. I didnt mean to state what I said as a fact although after re reading it that is what it sounds like. I was just speculating. I am just starting to get into learning about physics. Could it be that which object is the one that is "moving" and thus experiencing time at a slower rate be determined by which one accelerated the most to reach the speed that each object appears to be traveling in reference to the other?

You have a reference speed of 0 m/s, which was the speed the clock from start here on the earth. The clocks velocity increases relative to the Earth, NOT propelling the Andromeda Galaxy. As the clock approaches the speed of light, time dilation will be more and more apparent. If the clock moved at 99.99% of the speed of light on a trip to the Andromeda Galaxy and back, the clock would read over 56000 years as opposed to the 4 million years we would have to wait for it to come back.

Yep, that is a problem, and it's super hard to get your head around. Read some on special relativity. Tho that will probably make matters worse ;) It's annoyingly complex stuff for us non-einstein people ;)