astro

Call that a meteorite?

catdynamics | June 12, 2006

As reported by Uncertain Principles and Bad Astronomy, there was a meteorite impact in Northern Norway - Tromsø area. Initial reports were "impact compared to atomic bomb"...here is the proper report, including seismic signal - really did impact. Current reports suggest it was a ~ 10kg rocky meteorite. Meteors hit at 10-40 km/sec, typically, or 108-9 J/kg of energy. Now there are 4.2 GigaJoules per ton of TNT. So the impact energy was actually about the same as a few hundred pounds of explosive, comparable, say, to a couple of 500pound USAF bombs. Consistent with the eyewitness accounts.…

The Origin of Dust

catdynamics | June 8, 2006

Spitzer has an interesting press release... Dusty SN2003gd The Spitzer infrared space observatory recently did followup imaging of a type II supernova in the nearby spiral galaxy M74. Type II supernovae occur when a short lived massive star (> 8 times the mass of the Sun, or so) exhaust the fusionable fuel in their core, and the core collapses to a neutron star, with the outer layers of the star blown off in a very spectacular explosion. To cut a long story short, the supernova remnant is full of hot dust, when imaged in the infrared.paper on Science Express This is a step to solving a…