The LPL at the U of A has a website now with a catastrophe calculator to see what effect an incoming asteroid would have on impact. You can pick its size and the city you want it to fall on. It was reported on Yahoo! today so the site could be busy today; should get lots of "hits"! :-) http://www.space.com/scienceastronomy/mystery_monday_040412.html Jack -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.