NASA is planning to launch the Kepler telescope at 10:49 pm EST today from Cape Canaveral in Florida. This new space telescope will search for signs of Earth-like planets by observing the brightness of over 100,000 stars over 3.5 years. The Kepler mission should tell us whether planets like our own are common or rare in the universe.
Light-collecting devices in the telescope are sensitive enough to detect slight changes in the number of photons emanating from more than 100,000 target stars in the telescope's field of view. Some of changes will be due to planets passing in front of their parent stars and temporarily blocking a bit of light.
Scientists already have found more than 340 planets circling stars beyond our solar system, but none of those worlds are as small as Earth. Kepler is the first instrument designed solely to hunt Earth-sized worlds circling their parent stars at the proper distance for liquid water to exist. Water is believed to be a necessary ingredient for life.
"Kepler is not going to find out about the atmospheres, or whether there is water on these planets," said Gibor Basri, a Kepler scientist with the University of California at Berkeley. "It's really an assay of what the real estate market is out there for rocky planets."