The moon is bombarded by so much space rock that its surface gets a complete facelift every 81,000 years, according to a study of Nasa data. This churn – affecting the top 2cm (nearly an inch) of mostly loose moon dust – happens 100 times more frequently than previously thought, scientists have reported. The study also estimates that asteroids and comets crashing into the moon create on average 180 new craters at least 10 metres (33ft) in diameter every year. The moon has next to no atmosphere – only contains about 100 molecules of gases and elements per cubic centimetre. Earth’s atmosphere at sea level, by contrast, has about 100 billion billion molecules per cubic centimetre.

Source: The Guardian October 13, 2016 00:22 UTC