Go to http://cosmictusk.com/moon-to-earth-new-lro-lunar-crater-analysis-has-potential-to-revise-impact-frequency-for-terrafirma/ … by comparing modern images of the surface of the moon with images collected by Apollo missions in the 1970s it has been found five new craters have appeared in the past 40 years. That, a planetary geologist says, will help determine how frequently objects strike the moon, and the data could also fill a gap in knowledge of contemporary collision rates for the earth because it should be proportional to their size. Small objects fall undetected or disintegrate in the atmosphere – but leave a mark on the moon. NASAs Lunar Reconnaissance Orbiter has been circling the moon since 2009 taking photographs and mapping the surface – with especial interest in the dark side of the moon. At www.go.nature.com/oDK7he there is plenty of information on water on the moon but George Howard is interested in impact craters – and how frequently they might occur. There was a Lunar Science Forum at the NASA Ames Research Centre in July (2010) which prompted this post. Dennis Cox comments, the ground is being ignored as the idea the atmosphere dissipates the blast from atmospheric explosions is pretty widespread but it has actually been disproved by using super computers to simulate the dynamics. An impact vortice will hit the ground as a supersonic blast of ionised plasma which must scar the surface in some way. He then directs a reader to http://dropbox.com/u/2268163/Mountain%20Flows.pdf which is basically a single image of a geological anomaly.