QUOTE (Editor Bob @ Dec 21 2007, 2:21 pm)

No asteroid impact like this has ever been observed anywhere in the Universe.
Well, there was
Comet Shoemaker-Levy 9 which ploughed into Jupiter back in 1994. OK, that was a comet and not an asteroid, but if you're right at the impact site watching it zoom in on you, that fine distinction may seem irrelevant.
QUOTE (Marshbot @ Dec 21 2007, 2:30 pm)

It says the dust plume might be visible from Earth through telescopes. I have no idea but how well can you see mars through household telecopes? Are they talking about observatories or backyard style?
I may be wrong, but I would guess that you would need something much more powerful than a small amateur telescope to be able to see anything of the impact.
Sometimes I wonder what would happen if astronomers were to spot a huge chunk of rock headed on a direct collision course with Earth. I don't mean with something like a 1-in-100 chance, but suppose they spotted something that is going to slam into us with absolute certainty in only a few days time. No time to evacuate a whole continent, or organise an operation to fire off nuclear missiles to deflect it away from us. Nothing anyone can do. Would they make a public announcement, and unleash worldwide blind panic? Or would they keep quiet and pretend they hadn't noticed anything? I once asked a professional astronomer who specialised in comets, what the plans would be for such a situation. I got the feeling he was trying to avoid giving a straight answer, but he finally replied: "Oh well, if it was heading for our side of the planet, we would just go round to the other side".