Mercury's orbit is inside Earth's orbit. That means it goes through phases, just like Venus and Earth's Moon. When Mercury is between the Sun and Earth, the side of Mercury that faces Earth is completely in shadow. This is called the new phase. Continuing in its orbit, Mercury moves farther away from Earth. The planet appears to get smaller because of the greater distance between it and Earth. However, more and more of the side lit up by the Sun is visible. Mercury waxes from new, to crescent, to half, and to gibbous. Because of the Sun's glare, however, it can't be seen with the naked eye. When Mercury is on the opposite side of the Sun from Earth, the side of Mercury facing Earth is completely lit. At this point,
