among the most prominent features of the moon's sky is earth. earth shows phases, just like the moon does for observers on earth. the phases, however, are opposite; when the observer on earth sees the full moon, the lunar observer sees a "new earth", and vice versa. the full earth glows over 50 times brighter than the full moon at its brightest for the observer on earth. earth light reflected on the moon's darker half is bright enough to be visible from earth, and is known as known as earthshine.