The image of the Moon is a mosaic of images from Clementine. The Mercury image is a Mariner 10 mosaic.
The diameter of the Moon is 3468 km; Mercury's diameter is 4880 km.
These images show Mercury and the nearside of the Moon at their correct relative brightness. On average, the surface of Mercury is about 15% darker at visible wavelengths than is the nearside of the Moon. This is perplexing to planetary scientists because Mercury's surface is lower in iron, the element in lunar rocks that contributes most to absorbing light. MESSENGER observations will help to solve this puzzle.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
For information regarding the use of MESSENGER images, see the image use policy.