No kidding. Shoot an 8-foot 2x4 at the Earth at 100km/sec and guess how fast the carbon-fluff will be going when it hits. The pieces of anything that breaks up

No kidding. Shoot an 8-foot 2x4 at the Earth at 100km/sec and guess how fast the carbon-fluff will be going when it hits. The pieces of anything that breaks up as it descends will quickly slow to their terminal velocity at that height. NASA says the February Russian fireball was going about 11.6 miles/sec when it blew up (14 miles up) but there's a lot of denser atmo in that 14 miles. http://neo.jpl.nasa.gov/news/fireball_130301.html http://neo.jpl.nasa.gov/news/fireball_130301.html