Reminder about "Deep Impact" on night of July 3 http://science.nasa.gov/headlines/y2005/images/deepimpact/skymap_north.gif here is a skymap NASA will send this 820 pound copper slug into the guts of comet Tempel 1 at 11 PM Pacific Daylight Time on 3 July For people with home telescopes in, like, LA, who can watch it, Tempel 1 will be in the constellation Virgo near the bright star Spica here is the press release http://science.nasa.gov/headlines/y2005/28jun_deepimpact.htm?list45222 the projectile will impact the comet at a speed of 23,000 mph, it says. I forget what that amounts to in kiloton TNT equivalent kinetic energy. it is a lot of energy. I guess something will be learned from watching the crater and the ejecta. tough on the comet.