A question on Caloris Basin
You know that really big crater Mariner 10 saw at the day-night
terminator of Mercury called Caloris Basin:
http://www.brera.mi.astro.it/apod/ap960120.html
Why did it look so vague in the MESSENGER images?
The crater has huge mountains rimming it - how can it appear so
flat even accounting for different lighting between the two images?
In other words - why did it look so cool in 1974 and so bland in 2008?
