View Single Post
Doc Al
Doc Al is offline
#10
Oct4-05, 10:23 AM
Mentor
Doc Al's Avatar
P: 40,877
Quote Quote by Sam Woole
Maybe you knew that my question has something to do with time dilation. The whole sentence reads: "1 year of your time on a spaceship traveling at such a speed would be 3.944 years on earth."
This means that folks on earth would measure 3.944 years passing on earth while the folks on the spaceship only experienced 1 year. Note that this is according to the earth. Things get interesting--and unambiguous--when the spaceship is able to make a round trip.

When the twin on the spaceship met his twin brother on earth, it means both twins have spent an equal time interval t, from departure on earth to meeting on earth. There could not have been two time intervals. Then a question has arisen. In this same time interval t, what has the planet earth done? Has it gone round the sun 1 time, or 3.944 times? Which is right, 1 or 3.944?
Again you have to realize that time is not an absolute, it really does depend on the relative motion of the frame doing the measuring. When the ship returns to earth, the two brothers will really be different ages!

Undoubtly there can be only one right, the 3.944.
The 1 year on the spaceship is wrong. Does this mean that time dilation is nothing but false? It cannot be justified any way we try.
If you are really interested in learning about time dilation and relativity, stick around and ask questions. (You aren't ready to understand the traveling twins quite yet--you first need to understand the relativity of simultaneity!) But please don't start up again with the accusations of lying, cheating, and claiming that relativity is "nothing but false". It's tiresome.