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Astronomers have cracked the Milky Way like a piñata, and planets are now pouring out so fast that they do not know what to do with them all.
In a long-awaited announcement, scientists operating NASA’s Kepler planet-hunting satellite reported on Wednesday that they had identified 1,235 possible planets orbiting other stars, potentially tripling the number of known planets.
Of the new candidates, 68 are one and a quarter times the size of the Earth or smaller — smaller, that is, than any previously discovered planets outside the solar system, which are known as exoplanets. Fifty-four of the possible exoplanets are in the so-called habitable zones of stars dimmer and cooler than the Sun, where temperatures should be moderate enough for liquid water.
Astronomers said that it would take years to confirm that all of these candidates were really planets — by using ground-based telescopes to measure their masses, for example, or inspecting them to see if background stars are causing optical mischief. Many of them might never be vetted because of the dimness of their stars and the lack of telescope time and astronomers to do it all. But statistical tests of a sample suggest that 80 to 95 percent of the objects on it are real, as opposed to blips in the data.
“It boggles the mind,” said the Kepler team’s leader, William Borucki, of the Ames Research Center in Northern California.
At first glance, not one of them appears to be another Earth, the kind of cosmic Eden fit for life as we know it, but the new results represent only four months’ worth of data on a three-and-a-half-year project, and have left astronomers optimistic that they will eventually find Earth-like planets.
“For the first time in human history, we have a pool of potentially rocky habitable-zone planets,” said Sara Seager of the Massachusetts Institute of Technology, who works with Kepler. “This is the first big step forward to answering the ancient question, ‘How common are other Earths?’ ”
At a news conference at NASA headquarters in Washington on Wednesday, Mr. Borucki noted that the Kepler telescope surveys only one four-hundredth of the sky. If it could see the whole sky, he said, “we would see 400,000 candidates.” He is the lead author of a paper describing the new results that has been submitted to The Astrophysical Journal.
In a separate announcement, to be published in the journal Nature on Thursday, a group of Kepler astronomers led by Jack Lissauer of Ames said it had found a star with six planets — the most Kepler has yet discovered around one star — orbiting in close ranks in the same plane, no farther from their star than Mercury is from the Sun.
This dense packing, Dr. Lissauer said, seems to violate all the rules astronomers have begun to discern about how planetary systems form and evolve.
“This is sending me back to the drawing board,” he said.
Summarizing the news from the cosmos, Geoffrey W. Marcy of the University of California, Berkeley, a veteran exoplanet hunter and a mainstay of the Kepler work, said, “There are so many messages here that it’s hard to know where to begin.”
He called the Borucki team’s announcement “an extraordinary planet windfall, a moment that will be written in textbooks. It will be thought of as watershed.”
Debra Fischer, an astronomer at Yale who is not part of the Kepler team, said, “This is an amazing era of discovery for astronomy.” Kepler, she added, had “blown the lid off everything we thought we knew about exoplanets.”
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Mr. Borucki said the growing number of small planets revealed by Kepler was a welcome change from the early days of exoplanet research, when most of the planets discovered were Jupiter-size giants hugging their stars in close orbits, leading theorists to speculate that smaller planets might be thrown outward from their stars by gravitational forces or dragged right into those suns.
Due to technological limitations, we spun a theory that we were truly unique, the only planet in the Universe capable of life. Wow, that's what I call Hubble Hubris ....
In a long-awaited announcement, scientists operating NASA’s Kepler planet-hunting satellite reported on Wednesday that they had identified 1,235 possible planets orbiting other stars, potentially tripling the number of known planets.
Of the new candidates, 68 are one and a quarter times the size of the Earth or smaller — smaller, that is, than any previously discovered planets outside the solar system, which are known as exoplanets. Fifty-four of the possible exoplanets are in the so-called habitable zones of stars dimmer and cooler than the Sun, where temperatures should be moderate enough for liquid water.
Astronomers said that it would take years to confirm that all of these candidates were really planets — by using ground-based telescopes to measure their masses, for example, or inspecting them to see if background stars are causing optical mischief. Many of them might never be vetted because of the dimness of their stars and the lack of telescope time and astronomers to do it all. But statistical tests of a sample suggest that 80 to 95 percent of the objects on it are real, as opposed to blips in the data.
“It boggles the mind,” said the Kepler team’s leader, William Borucki, of the Ames Research Center in Northern California.
At first glance, not one of them appears to be another Earth, the kind of cosmic Eden fit for life as we know it, but the new results represent only four months’ worth of data on a three-and-a-half-year project, and have left astronomers optimistic that they will eventually find Earth-like planets.
“For the first time in human history, we have a pool of potentially rocky habitable-zone planets,” said Sara Seager of the Massachusetts Institute of Technology, who works with Kepler. “This is the first big step forward to answering the ancient question, ‘How common are other Earths?’ ”
At a news conference at NASA headquarters in Washington on Wednesday, Mr. Borucki noted that the Kepler telescope surveys only one four-hundredth of the sky. If it could see the whole sky, he said, “we would see 400,000 candidates.” He is the lead author of a paper describing the new results that has been submitted to The Astrophysical Journal.
In a separate announcement, to be published in the journal Nature on Thursday, a group of Kepler astronomers led by Jack Lissauer of Ames said it had found a star with six planets — the most Kepler has yet discovered around one star — orbiting in close ranks in the same plane, no farther from their star than Mercury is from the Sun.
This dense packing, Dr. Lissauer said, seems to violate all the rules astronomers have begun to discern about how planetary systems form and evolve.
“This is sending me back to the drawing board,” he said.
Summarizing the news from the cosmos, Geoffrey W. Marcy of the University of California, Berkeley, a veteran exoplanet hunter and a mainstay of the Kepler work, said, “There are so many messages here that it’s hard to know where to begin.”
He called the Borucki team’s announcement “an extraordinary planet windfall, a moment that will be written in textbooks. It will be thought of as watershed.”
Debra Fischer, an astronomer at Yale who is not part of the Kepler team, said, “This is an amazing era of discovery for astronomy.” Kepler, she added, had “blown the lid off everything we thought we knew about exoplanets.”
Favorite line:
Mr. Borucki said the growing number of small planets revealed by Kepler was a welcome change from the early days of exoplanet research, when most of the planets discovered were Jupiter-size giants hugging their stars in close orbits, leading theorists to speculate that smaller planets might be thrown outward from their stars by gravitational forces or dragged right into those suns.
Due to technological limitations, we spun a theory that we were truly unique, the only planet in the Universe capable of life. Wow, that's what I call Hubble Hubris ....
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