lunar image of the month

february: lunar nearside

The familiar face of Earth's Moon shines with the reflected light of the Sun. Here, at full moon, the Sun is on the opposite side of the Earth and the entire Earthward-facing side of the Moon is illuminated.

During a month the Moon will revolve once around the Earth. For two weeks it will travel towards the same side of the Earth as the Sun, and progressively less of the visible side of the Moon will be lit up (waning). Then for the next two weeks it will return to the opposite side and back to being full (waxing).

Over the same period it will also rotate once on its axis, so essentially the same face remains turned towards the Earth - a surprisingly common phenomenon called captured rotation.

Image: Lick Observatory.