posted by ashley --- HELP PLEASEE!!! on .
Consider a situation where immediately after birth, twins are separated. One continues to live on earth, while the other is whisked away in a space ship at 90% of the speed of light. After 65 years they are reunited. Will they look the same?
I know that the twin that was whisked away will look older
Your answer is not correct. The twin who is "whisked away" at high speed and then returns (presumably at the same speed) will have aged less, by a factor of sqrt[1-(0.9)^2] = 0.436
He will have aged 28.3 Earth years.