for National Geographic magazine
Astronomer Arlin Crotts is trying to solve a 400-year-old puzzle.
Ever since the invention of the telescope, said the Columbia University astrophysicist, observers around the world have occasionally watched small areas of the moon brighten or "turn fuzzy." Sometimes they even turn reddish.
Because the bright patches are ephemeral, lasting only last a few minutes, these events have come to be known as transient lunar phenomena, or TLPs. "About 1,500 of these have been reported," Crotts said.
Astronomers already know they're not meteorite impacts. Those produce brighter, briefer flashes as the meteorite hits the surface and vaporizes.
But nobody yet knows what TLPs are—or even whether they truly exist. Many astronomers think they're simply optical illusions or figments of observers' tired eyes and overactive imaginations.
Crotts believes the time has come to put the riddle to rest once and for all. Scientists have long believed the moon to be a dead world, but if TLPs are real, then some form of geological activity must still be going on.
In that case, said his colleague Peter Schultz of Brown University, "if we were to go back to the moon, we might be able to go to these places and discover something absolutely new about its ancient history or its deep interior."
Catching a Fleeting Phenomenon in the Act
Funded in part by a grant from the National Geographic Society's Committee for Research and Exploration, Crotts, Schultz, and their team have set up two 10-inch (25-centimeter) robotic telescopes, one in New York City and one at the Cerro Tololo Inter-American Observatory in northern Chile. The instruments are far enough apart that, most nights, at least one will have clear skies.
In a project begun last year and expected to continue at least into 2010, each telescope is photographing the moon every 20 seconds. At each site, the images are fed into computers that can examine them for changes that might signal a TLP.
"We want to start catching these things in the act," Crotts said.
That may sound easy, but it's not. Minor disturbances in Earth's atmosphere can also cause lunar features to brighten, dim, or distort.
SOURCES AND RELATED WEB SITES