[r9etb]

Somebody at Space.com wrote this? The moon is full when it’s exactly 180 degrees away?

I suppose you could put it this way:

A full moon occurs when the angle between the sun-Earth vector, and the vector along the projection of the Earth-moon vector onto the ecliptic plane, is 180 degrees.

However, since the moon is only about 5 degrees from the ecliptic anyway, "180 degrees" is close enough.

[djf]

I never been to the ecliptic plane.

Lol! Close enough for gummint work!