You are in a rocket moving away from Earth at one-third the speed of light relative to Earth. A friend is on Earth, and an astro
naut in another rocket is moving toward Earth at one-third the speed of light (in the Earth reference frame), on a path collinear with your path. If each of you records the duration of your journey in your three respective reference frames, which of you records the proper time interval?
Check all that apply.
a. Your friend records your proper time interval.
b. The astronaut records your proper time interval.
c. You record your own proper time interval.
d. Nobody records your proper time interval.
