As expected, the blogosphere is exploding (haha) with news about the SpySat getting hit by a Navy missile last night.
So what happened? At 10:26 p.m. Eastern time last night, the USS Lake Erie, an Aegis warship, shot a Standard Missile 3 (SM3) at the satellite, and a direct hit was recorded 247 kilometers (150 miles) above the Pacific ocean. It's not completely clear at this time that the hydrazine tank was hit or disrupted, but it seems likely since a spectral analysis showed hydrazine int he expanding debris cloud. The bulk of the debris will re-enter Earth's atmosphere over the next two days, but it will take more than a month for the last of it to fall.
The missile was not equipped with an explosive warhead; just the impact is enough to destroy a satellite. Orbital speeds are very high -- the missile impacted the satellite at over 10 kilometers per second (6 miles per second). Impact speeds like that generate enough heat from the kinetic energy of motion to do a huge amount of damage. Just ask the dinosaurs.
The DoD has pictures from the launch, which are amazing. This is one of their launch shots.
I would imagine that we'll be seeing video of the debris coming down very soon; if you happen to see any, let me know in the comments.