Astronaut Benny travels to Vega, the fifth brightest star in the night sky, leaving his 36.0 year-old twin sister Jenny behind on Earth. Benny travels with a speed 0.990 c, and Vega is 25.3 light-years from Earth.
a. how much does benny age if he travels to vega with a speed of 0.9996 c ? b. How much time is required for the trip according to Jenny?