1. Look up the distance to the nearby star Alpha Centauri. Andlook up the distance to the center of the Milky Way. Convert (orget) both of those distances in light years. Now imagine travelingto both of those places in a spaceship that can travel at half thespeed of light. To answer these questions, you might want to lookup “length contraction”. In the frame of reference of thatspaceship, traveling to Alpha Centauri, how far away is AlphaCentauri? In the frame of reference of another spaceship, travelingto the Galactic Center, how far away is the Galactic Center? Howlong does it take to get to those two locations? Give two answers:One for the reference frame of the Earth (essentially at rest inthe Galaxy), and one for the reference frame of the astronauts onthe spaceship.

2. Look up the “twin paradox” and answer the followingquestions: Imagine one of your friends is a flight attendant andspends five years flying around in jet planes. By how much willyour friend’s age be different than it would have been if thefriend had spent that time hanging out at home. Older or younger?Now imagine the same but for a friend who is on the InternationalSpace Station for five years? (In detail this question is weirdbecause flights and space stations go around the Earth, not out andback. But just do the calculation as if your friend just went outand back. The answer you get is close to the true answer.) Nowimagine the same but for a friend who spends five years on ajourney to a distant star, traveling at 0.2 c. Now the same but0.99 c. Here you might want to say how much has your friend aged,instead of the correction to the age.