Question

<Basic Physics (Conceptual)>

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

2. Look up the “twin paradox” and answer the following questions: Imagine one of your friends is a flight attendant and spends five years flying around in jet planes. By how much will your friend’s age be different than it would have been if the friend had spent that time hanging out at home. Older or younger? Now imagine the same but for a friend who is on the International Space Station for five years? (In detail this question is weird because flights and space stations go around the Earth, not out and back. But just do the calculation as if your friend just went out and back. The answer you get is close to the true answer.) Now imagine the same but for a friend who spends five years on a journey to a distant star, traveling at 0.2 c. Now the same but 0.99 c. Here you might want to say how much has your friend aged, instead of the correction to the age.

Answer 1

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