I clicked the "speculation" link thinking it would be a forum thread full of scientist debating whether it was caused by volcanism or something similar, I didn't expect to be trolled by APOD.
I was really hoping for a Hollow Mars diagram when I saw that "speculation" link.
i don't get why they do that?
Scientists are some of the world's greatest comedians.
Well, that's one way of putting it.
I always thought that in some parallel universe, Clifford Stoll has a pretty successful stand-up career. In this one he makes lovely klein bottles for people though, so we might have the better deal - http://www.kleinbottle.com/