In case you missed it yesterday, Yahoo had a story about a website that calculates impact effects for various things that could hit the earth. It's a dandy little time-waster.

For example, my office sits roughly 10 miles from Boston. Would I die if, say, an asteroid 100 meters in diameter made up of dense rock hit the city at a 60 degree angle?

The short answer is no, but there'd be a hell of a racket. While there'd be seismic and thermal effects, the air blast would cause the most damage, almost completely knocking down wood frame houses, shattering glass, and knocking down most trees.

Now, a comet of the same dimension and make-up (assuming it's physically possible) would do much more damage, thanks I assume to its greater velocity. Thermal effects would cause first degree burns, we'd get some ejecta, and the air blast would pretty much level everything around here. Hope I'm near a ditch.