- What is a light-year?
- Have you noticed on television that when people talk to each other from different parts of the world, there is a definite delay between the time when one person finishes talking and the other person answers? Why is this?
- What would a radio conversation between you and a person on Saturn be like? You would say "hello," and then what?
- How long does it take for a radio signal to get to the robot vehicles we have on Mars? Could you control them the way you can a remote control vehicle here on Earth?
- The astronomer from Wellesley College uses the example of a postcard from a friend in Italy that was written a week before you receive it. What idea about light coming from objects far outside our solar system is she trying to explain?
