# Twin Paradox and Time Travel (Special Relativity)

by scurry18
Tags: paradox, relativity, special, time, travel, twin
 P: 12 1. The problem statement, all variables and given/known data Identical twins Speedo and Goslo join amigration from the Earth to Planet X. It is 20.0 light years away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same time on different spacecrafts. Speedo's craft travels steadily at .950c, and Goslo's travvels at .750c. Calculate the age difference between the twein after Goslo's spacecraft lands on Planet X. Which twin is older? 2. Relevant equations (1-v^2/c^2)^1/2 x time of travel 3. The attempt at a solution Speedo travels for 21 years.
P: 370
 Quote by scurry18 [b] 3. The attempt at a solution Speedo travels for 21 years.
That's in the frame of reference in which the planets are at rest. How long does it take on Speedo's clock?
 P: 12 I'm really unsure on how to figure that out.
P: 370

## Twin Paradox and Time Travel (Special Relativity)

What concepts that could be relevant here have you encountered so far in special relativity?
 P: 12 Just the above equation and length contraction
 P: 370 It's really time dilation that you would use together with your result of "21 years", but length contraction will work, too, in a slightly indirect way.

 Related Discussions Special & General Relativity 7 Introductory Physics Homework 22 Introductory Physics Homework 3 Special & General Relativity 0 Special & General Relativity 4