Space / Cosmology

The Moon: Cold, Wet, and Breathing

Bombing our closest neighbor pays off with a trove of information.

D. Hurst/ALAMY

It is our closest neighbor in space, yet the moon continues to surprise us as new lunar missions overturn old ideas about Earth’s satellite.

In October NASA intentionally crashed the 2.8-ton upper stage of a Centaur rocket into a crater near the lunar south pole. Four minutes later, the Lunar Crater Observation and Sensing Spacecraft (LCROSS) followed, analyzing the dust kicked up by the impact. NASA anticipated a debris plume 30 miles high, which should have been visible from Earth with a 10-inch telescope. The smashup proved more whimper than bang for amateur observers, but LCROSS team members were thrilled. 

“We got wonderful measurements from all phases of the impact: the flash, the ejecta plume, and the resulting crater formed by Centaur,” says LCROSS principal investigator Anthony Colaprete of NASA’s Ames Research Center.

He and colleagues are still analyzing the data from ultraviolet, visual, and infrared spectroscopy to measure the chemical composition of the lunar material. “We’re looking for water vapor or ice, as well as hydrocarbons and other volatiles,” he says.