1 November 2008
Check out this true color and exaggerated color view of Mercury, taken by MESSENGER during the recent flyby!
In one of my classes on Thursday, we were speculating about why Mercury craters seem to have such long rays on the fresh craters. Our conclusion was that it’s probably just the higher gravity. Mercury is small but very dense, so it’s surface gravity is greater than the moon’s. So with equivalent impacts, the moon will lose a lot of the ejecta, but Marcury’s gravity pulls more of the ejecta back in, resulting in longer streaks like the ones seen here.