When astronauts could travel at v = 0.980c, we on Earth would state it takes (4.20/0.980) = 4.29 years to reach Alpha Centauri, 4.20 light-years away. The astronauts disagree.
(i) Determine how much time passes on the clocks of astronauts?
(ii) Find out the distance to Alpha Centauri as evaluated by the astronauts?