Section: Natural Sciences

30) According to Einstein's theory of relativity, as the speed of a spaceship approaches the speed of light,

1. metabolism and mass decrease
2. metabolism and mass increase
3. metabolism and mass remain constant
4. aging, relative to earth, would speed up
5. aging, relative to earth, would slow down

Speed and time are measured by an observer on a rocket traveling at a speed near the speed of light are different than the speed and time measured by an observer on earth. To this space traveler, light from earth is catching up to the spaceship at one speed; to the observer on earth, light is catching up to the spaceship at a different speed. Both observers are correct.