ESTIMATE the Lorentz factor of a spaceship which travels to a nearby star 10pc from the solar system in 50 years spaceship time.
Lorentz factor: γ = 1/√(1 - v^2/c^2 )
Time dilation: Δt' = γΔt
The Attempt at a Solution
Using the distance and time given, from the spaceship's point of view, it is travelling at a velocity of 0.65c.
I think I need to figure out the velocity from the point of view of Earth and then put that into the lorentz factor, however I don't know how to do that and that doesn't seem like an estimate to me.
I also thought that perhaps if I could work out the time it took to get there from the point of view of Earth I could rearrange the time dilation equation and get gamma from that.
I think my problem is I don't know what I can reasonably assume/estimate without getting this completly wrong.