During its mission, the Galileo spacecraft returned a number of images of Earth's only natural satellite. Galileo surveyed the moon on Dec. 7, 1992, on its way to explore the Jupiter system in 1995-1997.
This color mosaic was assembled from 18 images taken by Galileo's imaging system through a green filter. On the upperleft is the dark, lava-filled Mare Imbrium, Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right.
This image shows part of the rim of crater Milichius A. Milichius A is a Copernican-aged crater (meaning it is less than 1.1 billion years old) in the middle of Mare Insularum. The "cracked" appearance of the rim exterior is a result of melted rock flowing out after impact. This outflow is fairly common among craters of similar size and age to Milichius A.
Rima Ariadaeus is one of several linear rille systems nestled in the highlands between Mare Vaporum and Mare Tranquillitatis. Some rilles, such as Vallis Schroteri, were formed by volcanic eruptions. Other, such as Rima Ariadaeus, are believed to be faults that formed as a result of tectonic activity.
Some scientists believe that the linear rilles might have formed after large impact events, while others believe that the rilles were formed as a surface manifestation of deep-seated dike systems when the moon was still volcanically active.
Aratus is an unusual depression and possible volcanic vent. This depression is about 9.5 km long and 3 km wide, located at the termination of a north-south trending wrinkle ridge known as Dorsum Owen. After the mare lavas erupted and cooled, contractional tectonic forces generated wrinkle ridge features.
Most lunar scientists think this unique depression is a product of both volcanism and tectonic collapse. Each lobe is distinct, for example, Vallis Lorca is a collapse pit crater, while the lobe to the east named Rima Sung-Mei is a small rille. Stratigraphy and cross-cutting relationships indicate multiple tectonic and volcanic events. This image of the Vallis Lorca lobe shows "rings" around the rim, indicative of collapse.
The LCROSS mission -- in which NASA shot a payload at the moon to study the material that came out of the impact -- caught this view of the moon while waiting for the crash.
Many lunar impact craters display an asymmetric ejecta blanket. During the Apollo era, NASA scientists used high speed projectiles to replicate the conditions of impact at different angles. Real asteroids hit the moon at fantastically high speeds, greater than 35,000 mph. As the angle between the asteroid path and the surface becomes smaller, no change in the crater shape is seen until an oblique angle of 15 degrees or less. At these small angles, non-circular craters or non-uniform distribution of ejecta occurs. Craters that display these characteristics are known as oblique impact craters, such as this one.
When you look at the moon, you'll notice right away that the moon is covered with impact craters. The size of an impact crater is related to the size of the object that struck the moon (such as an asteroid or comet). Smaller impacts happen much more frequently than large impacts, so the moon has many small craters. Smaller impact craters also tend to be younger than larger impact craters because they are easily destroyed during the formation of other craters.
Twelve people walked on the Moon in an era before cell phones, before hybrid cars, and before laptop computers.
Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (LM) "Eagle" during the Apollo 11 extravehicular activity (EVA). Astronaut Neil A. Armstrong, commander, took this photograph with a 70mm lunar surface camera.
Apollo 8, the first manned mission to the moon, entered lunar orbit on Christmas Eve, Dec. 24, 1968. That evening, the astronauts -- Commander Frank Borman, Command Module Pilot Jim Lovell, and Lunar Module Pilot William Anders -- held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft. Said Lovell, "The vast loneliness is awe-inspiring and it makes you realize just what you have back there on Earth." They ended the broadcast with the crew taking turns reading from the book of Genesis. Visit the Apollo 8 page for audio and video of the historic mission.
A mosaic of the Earth's Moon compiled from photos taken by the spacecraft Clementine in 1994. This image represents the side of the Moon familiar to Earth dwellers. The Moon revolves around the Earth about once every 28 days. Since its rate of rotation about its axis is also once in 28 days, it always keeps the same face toward the Earth.
A mosaic of about 750 images of the north pole of the Moon, taken by the Clementine satellite. The nearside of the Moon is the bottom half of this mosaic, and the top half is the farside. In contrast to the south pole, the north pole shows very little area in permanent shadow (only about 500 square kilometers). This suggests that any cold traps in this region of the Moon are very restricted and little ice could be stable in this part of the Moon.
Astronaut Alan L. Bean, lunar module pilot, deploys components of the Apollo Lunar Surface Experiments Package during the first Apollo 12 spacewalk on the moon. The photo was taken by astronaut Charles "Pete" Conrad Jr., commander.
Peary, an irregularly-shaped impact lunar crater sits adjacent to the lunar north pole. Peary has areas along its crater floor cast in permanent shadow, but it also has areas along its rim that may be permanently illuminated by the Sun.
The world's first view of Earth as released to the public taken by a spacecraft from the vicinity of the Moon. The photo was transmitted to Earth by the United States Lunar Orbiter I and received at the NASA tracking station at Robledo De Chavela near Madrid, Spain. This crescent of the Earth was photographed August 23, 1966 at 16:35 GMT when the spacecraft was on its 16th orbit and just about to pass behind the Moon.
Common in the lunar mare, wrinkle ridges are found in nearly all of the lunar maria, and lunar scientists think that there is a genetic relationship between the basalts they deform and the ridges themselves. Basalt is much denser than the crust on which the mare basalts are deposited. As the basalt fills in low areas in the crust, the increased weight causes sagging and the mare deposit is compressed, resulting in tectonic deformation in the form of wrinkle ridges.
Tycho is an one of the most prominent craters on the moon. It appears as a bright spot in the southern highlands with rays of bright material that stretch across much of the nearside. Its prominence is not due to its size: at 85 km in diameter, it's just one among thousands of this size or larger. What really makes Tycho stand out is its relative youth. It formed recently enough that its beautiful rays, material ejected during the impact event, are still visible as bright streaks.
As NASA eliminates its manned moon missions, we take a look through decades of incredible photos that remind us where we've been -- and won't be returning for quite a while.