Posted: Fri, Aug 31, 2001, 10:55 AM ET (1455 GMT)
A new study released this week shows that it may be possible in the near future to examine the weather on Earth-like extrasolar planets. Princeton University scientists published a paper in the journal Nature this week that shows how the Earth's brightness varies by over 150 percent over the course of a day because of shifting cloud patterns, as well as the differing reflectivities of land and water. Viewed from another star, this lightcurve — the brightness of the planet as a function of time — would allow one to determine that the Earth has clouds, land, and oceans, even without being able to observe more than a pinpoint of light. Such analyses could be applied to future studies of extrasolar planets, the authors noted. While the technology does not exist yet to be able to directly observe Earth-like extrasolar planets, missions like the Terrestrial Planet Finder coming in the next decade or so could permit such studies.

Related Links:

•  Princeton University press release
•  New Scientist article