The most visible celestial object from Earth has been the source of human fascination for millennia, yet we’re still discovering more about it all the time.
Orbiting at a distance of anywhere between 362,570 kilometres and 405,410 kilometres (225,000 to 252,000 miles) and moving away from the Earth at almost four centimetres (1.57 inches) per year, all 74 billion trillion kilograms (160 billion trillion pounds) of blasted grey rock that is the Moon never fails to make for fascinating viewing. Its topography is a pattern of ‘maria’ – impact basins once filled with lava – and giant craters that are clearly visible from Earth.
Most notable of these is Tycho on the near side of the Moon. Despite being around 86 kilometres (53 miles) in diameter and 4.8 kilometres (three miles) deep, it’s not the largest of the Moon’s impact features: that accolade goes to the South Pole-Aitken basin on the far side, which is 2,500 kilometres (1,550 miles) in diameter, 13 kilometres (eight miles) deep and one of the biggest craters in the Solar System. But with its distinctive ray system fanning out for hundreds of kilometres across the surface in all directions, Tycho is the Moon’s most recognisable feature.
We’re still learning about the Moon, the most recent major mission being the Gravity Recovery and Interior Laboratory (GRAIL) mission that generated the highest resolution gravity map of any celestial body.