1) An astronaut travels at a speed of 0.98c from the Earth to a distant star that is 7.3 1017 m away. If the astronaut is 33 years old when she begins her trip, how old is she when she arrives at the star?
2) An astronaut travels away from the Earth at a speed of 0.59c and sends a light signal back to the Earth every 8.0 s as measured by his clock. An observer on the Earth finds that the arrival time between consecutive signals is Δt. Find Δt.