Why does the Earth spin and not just sit still?
user
Well, it’s easier to spin than not to, in terms of energy and momentum.
assistant
I think I understand. But doesn't the moon spin along with the earth?
user
That’s right.
assistant
So we always see the same side as the moon.
user
Yes, we are always seeing the same side as the moon.
assistant
Why does the Earth spin and not just sit still?
user
Well, it’s easier to spin than not to, in terms of energy and momentum.
assistant
I think I understand. But doesn't the moon spin along with the earth?
user
That’s right.
assistant
So we always see the same side as the moon.
user
Yes.
assistant
Why does the Earth spin and not just sit still?