Earth is Dr. Jekyll, men are from mars, and Venus is Mrs. Hyde,100 billion Venus-like planets in our galaxy. Hopefully astronomers will be able to find more difficult to detect Earth-size planets in Earth-like orbits so that they can come up with an estimate on the prevalence of habitable planets soon.you can't distinguish between the two based only on size," lead author Stephen Kane, of San Francisco State University, said in a statement. "So the question then is, how do you define those differences, and how many 'Venuses' is Kepler actually finding?"
The results could also lead to a better understanding of Earth's history, Kane added.
We believe the Earth and Venus had similar starts in terms of their atmospheric evolution," he said. "Something changed at one point, and the obvious difference between the two is proximity to the sun."
Kane and his team defined the Venus Zone based on solar flux — the amount of stellar energy that orbiting planets receive. The outer edge of the zone is the point at which a runaway greenhouse effect would take hold, with a planet's temperature soaring thanks to heat-trapping gases in its atmosphere. The inner boundary, meanwhile, is the distance at which stellar radiation would completely strip away a planet's air.
The thinking is similar to that behind the "habitable zone" — the just-right range of distances from a star at which liquid water, and perhaps life as we know it, may be able to exist.
The dimensions of these astronomical zones vary from star to star, since some stars are hotter than others. In our own solar system, the Venus Zone's outer boundary lies just inside the orbit of Earth, researchers said.
Future space-based instruments — such as NASA's $8.8 billion James Webb Space Telescope, scheduled to launch in 2018 — will be able to analyze some exoplanets' atmospheres, helping scientists refine the Venus Zone concept, researchers said.
"If we find all of these planets in the Venus Zone have a runaway greenhouse-gas effect, then we know that the distance a planet is from its star is a major determining factor. That's helpful to understanding the history between Venus and Earth," Kane said.
"This is ultimately about putting our solar system in context," he added. "We want to know if various aspects of our solar system are rare or common." Kepler spacecraft launched in March 2009 on a mission to determine how commonly Earth-like planets occur around the Milky Way galaxy. To date, Kepler has detected more than 4,200 exoplanet candidates, 978 of which have been confirmed by follow-up observations or analysis. Mission team members think about 90 percent of the candidates will eventually turn out to be the real deal.
The telescope suffered a glitch in May 2013 that ended its original exoplanet hunt, but Kepler has embarked upon a new mission called K2, which calls for it to observe a range of cosmic objects and phenomena.
Thursday, September 18, 2014
EARTH IS DR. JEKYLL AND VENUS IS MRS HYDE
Earth is Dr. Jekyll, men are from mars, and Venus is Mrs. Hyde,100 billion Venus-like planets in our galaxy. Hopefully astronomers will be able to find more difficult to detect Earth-size planets in Earth-like orbits so that they can come up with an estimate on the prevalence of habitable planets soon.you can't distinguish between the two based only on size," lead author Stephen Kane, of San Francisco State University, said in a statement. "So the question then is, how do you define those differences, and how many 'Venuses' is Kepler actually finding?"
The results could also lead to a better understanding of Earth's history, Kane added.
We believe the Earth and Venus had similar starts in terms of their atmospheric evolution," he said. "Something changed at one point, and the obvious difference between the two is proximity to the sun."
Kane and his team defined the Venus Zone based on solar flux — the amount of stellar energy that orbiting planets receive. The outer edge of the zone is the point at which a runaway greenhouse effect would take hold, with a planet's temperature soaring thanks to heat-trapping gases in its atmosphere. The inner boundary, meanwhile, is the distance at which stellar radiation would completely strip away a planet's air.
The thinking is similar to that behind the "habitable zone" — the just-right range of distances from a star at which liquid water, and perhaps life as we know it, may be able to exist.
The dimensions of these astronomical zones vary from star to star, since some stars are hotter than others. In our own solar system, the Venus Zone's outer boundary lies just inside the orbit of Earth, researchers said.
Future space-based instruments — such as NASA's $8.8 billion James Webb Space Telescope, scheduled to launch in 2018 — will be able to analyze some exoplanets' atmospheres, helping scientists refine the Venus Zone concept, researchers said.
"If we find all of these planets in the Venus Zone have a runaway greenhouse-gas effect, then we know that the distance a planet is from its star is a major determining factor. That's helpful to understanding the history between Venus and Earth," Kane said.
"This is ultimately about putting our solar system in context," he added. "We want to know if various aspects of our solar system are rare or common." Kepler spacecraft launched in March 2009 on a mission to determine how commonly Earth-like planets occur around the Milky Way galaxy. To date, Kepler has detected more than 4,200 exoplanet candidates, 978 of which have been confirmed by follow-up observations or analysis. Mission team members think about 90 percent of the candidates will eventually turn out to be the real deal.
The telescope suffered a glitch in May 2013 that ended its original exoplanet hunt, but Kepler has embarked upon a new mission called K2, which calls for it to observe a range of cosmic objects and phenomena.
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