February 7, 2009
An Ancient Ring?
image by K.C. Pau, Hong Kong
The face of the Moon that we see is merely the last of many faces that the Moon has exposed to Earth over the last 4.5 billion years. We can imagine what the Moon looked like before the most recent craters formed, but its harder to imagine all the craters that previously existed but are now gone. Sometimes there are hints of what might have been. For example, is the curved mare ridge in the center all that is left of a large crater? Based on the curve it would have been about a 200 km wide crater, nearly as big as another slightly younger crater Deslandres. There really should be craters on top of craters on top of craters.
February 4, 2009; 12:34 UT
Rükl plate 42
Yesterday's LPOD: Up And Down, All Around
Tomorrow's LPOD: Burying Craters