# How long will the journey take according to the twin on Earth?

VitaminK
Homework Statement:
Just want to check if I got this right.
A star system is located 4.37 light-years away from us. During an experiment, where one of the twins was left back on Earth while the other one was on a spaceship, heading towards the star system. Assume that the spaceship was traveling at 50% of the speed of light and that the twin traveled to the star system and back.

a) how long will the journey take according to the twin on Earth?
b) how long will the journey take according to the twin on the spaceship?
Relevant Equations:
t=to/sqrt(1-(v^2/c^2)), where t= time on Earth and to=time on space ship
a) Speed of the spaceship is 0,5 light years/year. Time that it take to travel to the star system, according to the twin on Earth, is:
4,37/0,5 ¨¨¨¨=8,74 years. Total travel time is 17,5 years

b) time dilation formula gives to= 15 years

is this correct?

Homework Helper
Gold Member
Looks good. (You might want to include another significant figure in your answer for part b)

VitaminK