Montes Jura Montes Jura is a mountain range in the northwest part of the Moon. It has a diameter of 422 km, with mountains rising to 6100m, which form a visually pleasing semi-circular ring around the Sinus Iridum, a bay along the northwestern edge of Mare Imbrium. The Islands to the south of the bay are Montes Recti and Montes Tenerife is just below brightly overexposed. Grimaldi Basin Grimaldi is a large basin located near the western limb of the Moon. The large crater with the peak in the middle is the crater associated with the basin. The inner wall of Grimaldi has been heavily worn and eroded by subsequent impacts that it forms a low, irregular ring of hills, ridges and peaks, rather than a typical crater rim.  The approximate diameter of the inner rim is 140 kilometers. Marsh of Sleep The area above is known as the Palus Somni (Latin for "Marsh of Sleep") and in 1907 it was described as having "a color which is unique upon the moon, a kind of light brown, quite u...

The Moon is Earth's only proper natural satellite. It is one-quarter the diameter of Earth (comparable to the width of Australia), making it the largest natural satellite in the Solar System relative to the size of its planet.  It is the fifth largest satellite in the Solar System and is larger than any dwarf planet. The Moon orbits Earth at an average lunar distance of 384,400 km (238,900 mi), or about 30 times Earth's diameter. Its gravitational influence produces Earth's tides and slightly lengthens Earth's day.  The Moon is classified as a planetary-mass object and a differentiated rocky body. It lacks any significant atmosphere, hydrosphere, or magnetic field, and its surface gravity is about one-sixth of Earth's (0.1654 g). Jupiter's moon Io is the only satellite in the Solar System known to have a higher surface gravity and density. The Moon is tidally locked to Earth, which means that the length of a full rotation of the Moon on its own axis (a lunar day...