So Many Earth-Like Planets, So Few Telescopes
Source: By Dennis Overbye, The New York Times. Front page story.
Excerpts: Astronomers announced on Tuesday that they had found eight new planets orbiting their stars at distances compatible with liquid water, bringing the total number of potentially habitable planets in the just-right “Goldilocks” zone to a dozen or two, depending on how the habitable zone of a star is defined. NASA’s Kepler spacecraft, now in its fifth year of seeking out the shadows of planets circling other stars, has spotted hundreds, and more and more of these other worlds look a lot like Earth — rocky balls only slightly larger than our own home, that with the right doses of starlight and water could turn out to be veritable gardens of microbial Eden. ...Reviewing the history of exoplanets, Debra Fischer, a Yale astronomer, recalled that the first discovery of a planet orbiting another normal star, a Jupiter-like giant, was 20 years ago. Before that, she said, astronomers worried that “maybe the ‘Star Trek’ picture of the universe was not right, and there is no life anywhere else.” Dr. Fischer called the progress in the last two decades “incredibly moving.” And yet we still do not have a clue that we are not alone. “We can count as many as we like,” said Sara Seager, a planet theorist at the Massachusetts Institute of Technology who was not involved in the new work, “but until we can observe the atmospheres and assess their greenhouse gas power, we don’t really know what the surface temperatures are like.”