A new spaceship that can travel at a speed of0.900c. Mary, the astronaut,boards the spaceship to travel to Barnard's star, which is the second nearest star to our solar system after Alpha Centauri and is5.98 ly away. After reaching Barnard's star, the spaceship travels slowly around the star system for 3 years doing research before returning back to Earth.
(a) How much time does the journey take?(years)
(b) How much older is her twin Frank when she returns?(years)