A Spaceship from Another Galaxy Passes Over the Solar System

Multiple Choice

A spaceship from another galaxy passes over the solar system directly above a radial line from the sun to the Earth. (We measure that distance to be 1.5 × 10¹¹ m.) On Earth, the spaceship is observed to be traveling at a speed of 0.80 c, for which γ = 5/3. As measured on Earth it takes the spaceship 625 seconds to travel from the sun to Earth. When a scientist in the spaceship measures the Earth-sun distance and the time it takes her to travel that distance, she finds the results are respectively

A) 9.0 × 10¹⁰ m; 375 s.
B) 9.0 × 10¹⁰ m; 625 s.
C) 1.5 × 10¹¹ m; 625 s.
D) 2.5 × 10¹¹ m; 625 s.
E) 2.5 × 10¹¹ m; 1042 s.