Phases of the Moon

Most recent answer: 05/28/2013

Q:
Why the moon is sometimes half is it broken and if it is so why it appears full at sometimes?
- zaryab javed (age 14)
Chakwal,Punjab,Pakistan
A:

Hi Zaryab,

No, the moon is not broken. Nor does it change its shape. However, it appears to change size and shape as the positions of the earth, moon, and sun change. We only see part of it lit up by the sun. You can find nice visualizations online, like .

On rare occasions, one might see an eclipse: the shadow of the earth on the moon. This was some of the first evidence that the earth is round: a sphere is the only object that always casts a circular shadow.

David


(published on 05/28/2013)