Earth rotates on its axis. Earth revolves around the sun. The stars are moving through space. The gravity of the moon attracts the stars.
I gave my students this multiple choice question: Two students notice that the constellation Scorpio is directly overhead as they enter a building. When they leave the building several hours later, Scorpio is no longer directly overhead. Which of these statements explains why Scorpio appears to be in a different location?

Only one answer is correct among these 4 choices:
- Earth rotates on its axis.
- Earth revolves around the sun.
- The stars are moving through space.
- The gravity of the moon attracts the stars.

Could you tell me which one is correct?

Earth rotates on its axis.