Aristarchus crater

The brightest spot on the Moon

Aristarchus is the brightest place on the Moon. It reflects twice as much light as the ground around it, so in a telescope it shines like a torch. Next to it is Schröter's Valley, the Moon's biggest 'snake track' — a path where lava once flowed.

Aristarchus crater (40 km wide, 3.7 km deep) is ~450 million years old and has an albedo twice the lunar average — its walls expose young rock that has not yet darkened. It sits on the Aristarchus Plateau, a volcanic region with Schröter's Valley (a 160 km lava channel) and pyroclastic deposits. It is the most frequent site of 'transient lunar phenomena' — mysterious flashes of light. Radon gas emissions have been measured (Apollo 15, Lunar Prospector). Named after Aristarchus of Samos, the first to propose a Sun-centred model.

Fun facts

• Aristarchus is so bright it can be seen even on the Moon's night side, lit by earthshine.
• Schröter's Valley is the track of the Moon's biggest lava river, 10 km wide.
• Aristarchus of Samos said Earth orbits the Sun — 1,800 years before Copernicus!