Twin's paradox
On your 30th birthday your twin who is an astronaut went towards a star system in a spaceship at 0.6 and returns on your 40th birthday.
How old is he in years?
*Assume the accelerations were instant and ignore any effect of acceleration *
The answer is 38.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
t'=(t)/√(1-((0.6C)/C)²)
10=t/0.8
t=8
Therefore, your twin's age = 30+8 =38