Sunday, September 23, 2007

Not a whole lot after all?

A few months ago there was great excitement when a number of mysterious dark features were discovered on the surface of Mars. It very much looked like these might be cavernous entrances to underground caves, but a new image shot from a different angle has unfortunately demolished this theory. It looks like rather than caves, these features are pits. The newest image, with the sun shining from the west, shows the side of the pit, allowing geologists to make a good guess at the true size and nature of the feature, which it must be said, is still pretty impressive.

From the shadow of the rim cast onto the wall of the pit, it seems it is at least 78 meters (255 feet) deep and 150 x 157 meters (492 x 515 feet) across. Something similar has been observed here on earth, where pits form on volcanoes in Hawaii. These "pit craters" generally do not connect to long open caverns but are the result of deep underground collapse.

A shame then that the secret entrances to a long lost Martian civilisation have not been discovered, but a good lesson that it's worth waiting for the Fat Martian to sing before jumping to conclusions.