The Earth and Moon as seen by the NEAR spacecraft, as it passed beneath their South poles (note Antarctica, at center Earth image) in January of 1998. As dark as the Moon appears in comparison to the Earth, it is actually five times darker yet, as its brightness was enhanced by that much in creating this picture. (NEAR Spacecraft Team, JHUAPL, NASA, apod980129)

     The Moon's distance from the Earth changes by 6% from its average distance as it moves toward perigee, or apogee. As a result, the apparent size increases or decreases by 6%, as well. These images show the apparent size of the Moon at apogee (on the left), and at perigee (on the right). (The change in size is not so obvious when the time between the extremes is two weeks, as when images are placed side by side.) When at apogee, the Moon moves less than 12 degrees per day to the East among the stars, whereas at perigee, it moves nearly 15 degrees per day. (António Cidadão, apod041021)

     Eagle's-eye image of Copernicus, taken by Apollo 17 astronauts in 1972. The nearly 60-mile wide crater has terraced walls and central peaks, both of which are characteristic of craters of this size. (Apollo 17, NASA, apod010513)

     The far side of the Moon, as seen by Apollo 16 astronauts, in April of 1972. Since the Moon is locked in synchronous rotation with the Earth, and always keeps one side toward us, the appearance of the far side was completely unknown, until the space age. Surprisingly, unlike the near side, which has many large maria, the far side is almost entirely lacking in maria, and is instead completely covered by ancient craters, dating back to nearly the beginning of the Solar System. The reason for the difference between the near and far sides is not known, but it is suspected that the crust on the far side is thicker, making it harder for the molten material which formed the maria to force its way through cracks in the lunar crust, and reach the surface. (Apollo 16, NASA, apod981008)

     An earlier (July, 1969) closeup of twenty-mile wide "Crater 308", on the lunar farside, taken by the Apollo 11 crew, emphasizes the extreme cratering typical of lunar highlands and, particularly, the almost entirely cratered "dark side" of the Moon. Obviously, at the time this image was taken, it wasn't at all dark in this part of the Moon. Every part of the Moon, save for some of the deeper craters near the Poles, sees the Sun slowly rise, cross the sky, and set, then rise again, 29 1/2 days after the previous sunrise. When we see the Moon going through a cycle of phases, we are seeing daylight slowly move across the front side of the Moon, during its waxing phases (from new, to quarter, to full Moon), then slowly move across the back side of the Moon, while darkness creeps across the front side, during its waning phases (from full, to quarter, to new Moon again). (Apollo 11, NASA, apod030312)

     Mare Orientale, one of the most striking lunar features, as photographed by Lunar Orbiter 4, in 1967. Because it is located on the extreme western edge of the "near side" of the Moon, it is difficult to see from the Earth. The 600-mile wide structure was formed by the impact of an asteroid-sized (probably 20 to 40 miles in diameter) object, more than three billion years ago. The shock of the collision created ripples in the lunar crust, resulting in three sets of concentric circular features, centered on the mare. The sudden removal of hundreds of miles of crustal material caused the subsurface rocks to melt, and also allowed already partially molten material in the Moon's mantle to reach the surface, and flood the interior of the impact site. A similar impact on Mercury, closer to 4 billion years ago, created a similar structure, the Caloris Basin. (NASA, Lunar Orbiter 4, apod021123)

     Mare Orientale, as seen from the Earth, during a favorable libration (as the Moon goes around us, its orbital speed varies, but its rotation doesn't, so sometimes we can see a little around one side or the other; this change in our view is called libration). Even though very little of the Mare is shown in this view, it is still a much better view than usual, as you can tell by comparing how much further Grimaldi is from the limb ("edge") of the Moon in this image, compared to its more normal position in the full-moon view near the top of this page. (Gary Seronik, Sky and Telescope)

     A quarter-millimeter (one-hundredth of an inch) glass spherule brought back from the Moon by Apollo 11 astronauts. Produced when a meteorite hit the Moon, splattering melted surface rocks in all directions, the spherule was subsequently impacted by microscopic meteoroids, creating the small craters visible on its surface. (Timothy Culler (UCB) et al., Apollo 11 Crew, NASA, apod030112)