Moonquakes!

Gah. I am so behind the times. Science Tuesday of the New York Times, that is. But thanks to the web you can still read about the wonders of Lunar Seismology, feauturing my own amiga Renee Bulow! Her work is also mentioned in Discover, and she won the Outstanding Student Paper Award for Planetary Sciences at the AGU conference. From Kenneth Chang's article in the Times:

Nearly identical squiggles emerged from the Moon seismographs over and over, indicating that certain parts of the Moon's interior broke repeatedly in the same way, almost like someone cracking his knuckles. Dr. Nakamura and other scientists counted 108 of these regions, which they called nests. The rate of moonquakes seemed to ebb and flow on every 27 days, the time it takes the Moon to circle the Earth, suggesting that they were caused by the pull of tidal forces.

A wonderful demonstration of how every force has an equal and opposite force--and smaller objects get more acceleration from the same force. We just have tides. The moon has quakes!