Entries in Planets (4)


Earth-Like Planets May Be Next Door in Milky Way

iStockphoto/Thinkstock(NEW YORK) -- You may look out on a starry night and get a lonely feeling, but astronomers now say our Milky Way galaxy may be thick with planets much like Earth -- perhaps 4.5 billion of them, according to the Harvard-Smithsonian Center for Astrophysics.

Astronomers looked at data from NASA's Kepler space telescope in orbit and concluded that 6 percent of the red dwarf stars in the Milky Way probably have Earth-like, habitable planets.  That's a lot by space standards, and since red dwarfs are very common -- they make up three out of four stars in our part of the galaxy -- we may have a lot more neighbors than we thought.

The nearest of them, astronomers said on Wednesday, could be 13 light-years away -- not exactly commuting distance, since a light-year is six trillion miles, but a lot closer than most yellow stars like Earth's sun.

"We thought we would have to search vast distances to find an Earth-like planet.  Now we realize another Earth is probably in our own backyard, waiting to be spotted," said Courtney Dressing, an astronomer at the Harvard-Smithsonian Center, in announcing the findings on Wednesday.  The results will be published in The Astrophysical Journal.

David Charbonneau, a co-author, said, "We now know the rate of occurrence of habitable planets around the most common stars in our galaxy.  That rate implies that it will be significantly easier to search for life beyond the solar system than we previously thought."

Red dwarfs are older, smaller and dimmer than our sun, but a planet orbiting close to one could be sufficiently warmed to have liquid water.  Dressing and her colleagues cited three possible planets that were spotted by Kepler, which was launched in 2009.  One is 90 percent as large as Earth, and orbits its red sun in just 20 of our days.

There is no saying what such a world would actually be like; the Kepler probe can only show whether distant stars have objects periodically passing in front of them.  But based on that, scientists can do some math and estimate the mass and orbit of these possible planets.  So far, Kepler has spotted more than 2,700 of them in the small patch of sky it has been watching.

There are estimated to be 200 to 400 billion stars in the Milky Way.  So the new estimate implies a universe with tremendous numbers of Earth-like planets, far beyond our ability to count.

Could they be friendly to life?  There's no way to know yet, but space scientists say that if you have the right ingredients -- a planet the right size, temperatures that allow for liquid water, organic molecules and so forth -- and the chances may be good, even on a planet that is very different from ours.

"You don't need an Earth clone to have life," said Dressing.

Copyright 2013 ABC News Radio


Scientists Say 1 in 6 Stars May Have Own Earth-Size Planet

M. Kornmesser /ESA/NASA(NEW YORK) -- The Kepler Space Telescope, an observatory launched by NASA in 2009 to find Earth-like planets, has provided data that suggests there are billions of them -- enough that one in six stars may have at least one orbiting it.

Out of roughly 100 billion stars in the Milky Way galaxy, a new analysis of Kepler data shows that around 17 percent of them have Earth-sized planets orbiting them, meaning there could be as many as 17 billion Earth-sized worlds.

Such planets, trillions of miles or more away, are too small for current technology to see, so Kepler watches thousands of stars -- and if one dims by a tiny amount regularly, that's a sign that perhaps a planet has crossed its face, blocking a little of its light. Researchers at the Harvard-Smithsonian Center for Astrophysics analyzed the entire data set from Kepler and concluded that virtually all sun-like stars have at least one planet.

"This is the first time we've been able to say with any certainty how many stars out there have Earth-like planets," Christine Pulliam of with the Harvard-Smithsonian Center for Astrophysics told ABC News.

Francois Fression of the Harvard-Smithsonian Center presented the statistical study Monday at a meeting of the American Astronomical Society in Long Beach, Calif. A paper detailing the research has been accepted for publication in The Astrophysical Journal.

Contradicting previous findings, researchers also found that the type of star does not make certain sizes of planets more or less common. The team grouped planets into five different sizes and 17 percent of them, roughly 1 in 6, have a planet 0.8-1.25 times the size of Earth in an orbit of 85 days or less.

"As far as planets go, Earth-sized planets are very small," Pulliam said. "Jupiter-like planets are easier to find; however, our study finds that the smaller planets are more common."

Using Kepler data, Christopher Burke, a scientist at the SETI Institute, said that 58 planets found so far are believed to be in their host stars' habitable zones -- where any water on them has a chance of being liquid. Planets orbiting close to their suns are likely to be infernos; planets in distant orbits will probably be too icy.

Kepler's mission is to find and document Earth-sized planets at greater distances. The more planets discovered with Earth-like orbits in the habitable zone, the greater the chances of extraterrestrial life.

Copyright 2013 ABC News Radio


Explosion Spotted on Jupiter a Comet or Asteroid?

Hemera/Thinkstock(NEW YORK) -- A bright flash was spotted on Jupiter early Monday morning, and astronomers are trying to figure out exactly what hit it.

The flash was first spotted by Dan Peterson, an amateur astronomer from Racine, Wisc., who saw the flash through a telescope. He posted about his sighting on the Association of Lunar & Planetary Observers message board with the subject line, “I observed an explosion on Jupiter this morning!”  He reported that the explosion occurred inside the southern edge of Jupiter’s northern equatorial belt of clouds.

“My best guess is that it was a small undetected comet that is now history, hopefully it will sign its name on Jupiter’s cloud tops,” he wrote.

Astrophotographer George Hall of Dallas was shooting video of Jupiter at the time and caught the flash on camera at 6:35 a.m. Monday.

Glenn Orton, a senior research scientist at the Jet Propulsion Laboratory in Pasadena, Calif. said he believes a frozen comet may be the culprit.

“Most things in that part of the solar system are called Jupiter-family comets,” Orton said. “They’re ice balls that move in and have started co-orbiting around Jupiter. ”

The explosion doesn’t appear to have left any trace, Orton said. It was quickly swallowed up by Jupiter’s thick atmosphere.  Orton said he and other researchers will publish a paper about their observations in the next few months.

In August 2009, a space rock hit the planet leaving a giant black mark and sending debris into Jupiter’s clouds. In June 2010, another explosion caused an Earth-sized fireball to emerge from Jupiter, much like Monday’s sighting. Orton believes Monday’s impact was about the same size as that in 2010.

“It’s the big gravitational vacuum cleaner of the solar system,” Orton said.

Copyright 2012 ABC News Radio


New Super-Earth Found Near Distant Star

File photo. Ingram Publishing/Thinkstock(WASHINGTON) -- Scientists have found a planet orbiting another star -- 22 light years away -- and of all the hundreds of so-called exoplanets so far discovered, this one is, lead researcher Guillem Anglada-Escude said, "the new best candidate to support liquid water and, perhaps, life as we know it."

The planet is labeled GJ 667Cc, found in the constellation Scorpio. It is about five times more massive than Earth. It orbits its host star in only 28 of our days -- as opposed to earth's 365.

But that star is smaller and dimmer than our sun, and most of the light it emits is infrared. Anglada-Escude says it would provide just the right amount of warmth for the planet to be temperate like ours.

"Other proposed candidates [to be watery worlds] would require very special conditions to support liquid water," Anglada-Escude said in an email to ABC News.

The temperature, he said, is probably right regardless of the planet's atmosphere or cloud cover: "This one lies within the zone where no further assumptions (or fine tuning) are required."

Water is common in the universe -- but as ice or vapor, not flowing water that scientists say would probably be necessary for life as we know it. Comets, for instance, have been called "dirty snowballs," and when they get close to the sun they develop gaseous tails. But the temperature range for flowing water -- the liquid you would find in the cells of a living organism -- is very small. Earth is the only planet we know of with the right temperature and atmospheric pressure.

Anglada-Escude and Paul Butler led the research at the Carnegie Institution for Science in Washington. They and a dozen colleagues are publishing their work in Astrophysical Journal Letters.

They report they found the planet by looking through telescope data collected by HARPS, a rival group of planet hunters in Europe. Anglada-Escude said the HARPS group had observed the star three years ago -- but missed the planet.

Copyright 2012 ABC News Radio

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