Exploration of the Moon Exploration of the Moon The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes; having made his own telescope in 1609, the mountains and craters on the lunar surface were among his
Ghost craters on Mercury interpreted to have formed after the wrinkle ridges. If a graben cuts across a ridge and appears to be modified, then it is interpreted to be older, and to have formed before the ridges. The presence of both graben and wrinkle ridges within ghost craters is a feature unique to Mercury. This combination is because of the tectonic processes that formed the graben and wrinkle ridges. The graben and wrinkle ridges came from rapidly accumulating lava flows that cooled within impact craters while the planet was experiencing global contraction from interior cooling. Other planetary bodies such as the Moon and