It is contracting. It is expanding. Only the rim is expanding. Only the center is contracting.
I gave my students this multiple choice question: According to the Big Bang Theory, how is the universe changing?

Only one answer is correct among these 4 choices:
- It is contracting.
- It is expanding.
- Only the rim is expanding.
- Only the center is contracting.

Could you tell me which one is correct?

It is expanding.