Quick question on Special Relativity

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
2 replies · 2K views
hmvince
Messages
44
Reaction score
0
Just to make sure I'm doing things right:
Alpha Centauri is located 4 light years away. A spacecraft travels at 0.8c towards this star, as seen from earth. How long will the spacecraft take to reach its destination?

The spacecraft sees the distance to Alpha Centauri as 2.4 light years due to length contraction.
This means that the spacecraft will reach Alpha Centauri in:
t = d/v = 2.4/0.8 = 3 years ( spacecraft s reference frame)

Then, because of time dilation, the observer on Earth sees:
3 * gamma = 5 years go by.

This then matches up with:
t = d/v = 4/0.8 = 5 years (according to Earth's observer).

Is this all correct?
 
on Phys.org