|MadSci Network: Astronomy|
South Pole Aitken Basin is the largest impact structure, relative to its parent body, within our solar system. It is roughly 2500 km (~1550 miles) across, and its average depth is 10 km (~6.2 miles)--–the deepest sections can be up to 13 km (~8 miles) deep. The radius of the Moon is only 1738 km (~1100 miles)! The distance from Boston to San Francisco is roughly 2500 miles, so the entire Moon would almost cover the United States. But South Pole Aitken Basin would cover over half of the U. S.! The largest crater on Earth is only 170 km wide (~105 miles). South Pole Aitken Basin is a giant crater indeed!
The Moon’s gravity is a factor of 6 smaller than the Earth’s. Earth’s gravity is 9.8 meters per second squared (m/s^2), while the Moon’s gravity is 1.63 m/s^2. If you were to jump out of a plane right above the deepest section of the South Pole Aitken Basin, you would fall the 13 km in 126 seconds. If you were to fall the same distance on Earth, it would only take you 51.5 seconds. Of course, on Earth, you should always use a parachute, which would slow your speed considerably! [A parachute wouldn't make any difference on the Moon, of course, because the Moon has no atmosphere.]
You might also want to check out a Clementine slidesets for more information about the Clementine Mission to the Moon and South Pole Aitken Basin. Also, there is a lot of information and images about craters on Earth at the Canadian National Resource’s Web site.
Try the links in the MadSci Library for more information on Astronomy.