News / Science & Technology

Study Finds Billions of Earth-like Planets

Illustration of planets that are habitable based on their proximity to the sun. (Photo credit: Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley)
Illustration of planets that are habitable based on their proximity to the sun. (Photo credit: Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley)
Rick Pantaleo
Astronomers from the University of California, Berkeley, and the University of Hawaii, Manoa say that based on new analysis of Kepler spacecraft data, one in five stars similar to our own sun are orbited by planets about the size of Earth, with a surface temperature that would be favorable to support life.

 

"What this means is, when you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye," said UC Berkeley graduate student Erik Petigura, who led the analysis of the Kepler data. "That is amazing,"

 

Petigura, along with his colleagues Geoffrey Marcy from UC Berkeley and Andrew Howard from the University of Hawaii, have had their analysis published online in the journal Proceedings of the National Academy of Sciences.
 

The researchers point out that just because an exoplanet is Earth-sized or is in an Earth-sized orbit does not automatically mean that it can to support life, even if their orbits are within a star’s habitable zone, where temperatures are not too hot or too cold.


"Some may have thick atmospheres, making it so hot at the surface that DNA-like molecules would not survive," Marcy said. "Others may have rocky surfaces that could harbor liquid water suitable for living organisms. We don't know what range of planet types and their environments are suitable for life."

Artist's impression of the planet Kepler-78b and its host star. (Karen Teramura/UHIfA)Artist's impression of the planet Kepler-78b and its host star. (Karen Teramura/UHIfA)
x
Artist's impression of the planet Kepler-78b and its host star. (Karen Teramura/UHIfA)
Artist's impression of the planet Kepler-78b and its host star. (Karen Teramura/UHIfA)
Last week Marcy, Howard and their colleagues made news when they announced that they found Kepler-78b, an Earth-sized exoplanet with the same density and a core made up of the same mixture of rock and iron as our own planet.

But since it orbits so close to its star, this newly-discovered rocky planet has a blazing surface temperature of about 2,200 degrees Kelvin, which is far too hot to support life as we know it.

The team focused on 42,000 stars that are like the sun or slightly cooler and smaller. Among those stars, the researchers said they found 603 candidate planets orbiting them. Of these candidate exoplanets, only 10 were Earth-sized, meaning that they were about one to two times the diameter of Earth and orbiting their star at a distance that would provide life supporting temperatures.

To find how many other Earth-sized planets residing in habitable zones they missed in their search, the researchers put planet-finding algorithms devised by Petigura through a number of tests. In these tests, Petigura actually threw in some fake planets into the actual Kepler data to find out which planets his software could detect and which it couldn't.

"What we're doing is taking a census of extrasolar planets, but we can't knock on every door. Only after injecting these fake planets and measuring how many we actually found, could we really pin down the number of real planets that we missed," Petigura said.

NASA's Kepler spacecraft observed 150,000 stars within a field in the constellation Cygnus. (NASA)NASA's Kepler spacecraft observed 150,000 stars within a field in the constellation Cygnus. (NASA)
x
NASA's Kepler spacecraft observed 150,000 stars within a field in the constellation Cygnus. (NASA)
NASA's Kepler spacecraft observed 150,000 stars within a field in the constellation Cygnus. (NASA)
Taking several factors into consideration, such these missing planets, and that only a small number of Earth-like exoplanets are situated in such way that they can be seen transiting in front of their host stars from Earth, the team estimated that 22 percent of all sun-like stars in the galaxy have Earth-size planets in their habitable zones.

"Until now, no one knew exactly how common potentially habitable planets were around Sun-like stars in the galaxy," said Marcy.

Although they found all of the possibly habitable planets circling around cooler K stars, or Orange Dwarfs, which are somewhat smaller than our sun, the researchers said that the results of their analysis could also be inferred to G stars like the sun.

The researchers speculated that if the Kepler spacecraft hadn’t been crippled by technical malfunctions this past spring and was able to fully continue its research mission, it would have been able to gather enough data to directly detect some Earth-size planets in the habitable zones of G-type stars.

This new, more thorough analysis of Kepler data made by the researchers shows that "nature makes about as many planets in hospitable orbits as in close-in orbits," said Howard.

You May Like

Philippines, Muslim Rebels Try to Salvage Peace Pact

Peace process faces major setback after botched military operation to find terrorists results in bloody gunbattle between government forces, Moro Islamic Liberation Front fighters More

Republicans Expect Long, Expensive Presidential Battle

Political strategist says eventual winner will be one who can put together strongest coalition of various conservative groups that make up Republican Party More

Video New Wheelchair Is Easier to Use, Increases Mobility

Engineers have come up with a lever-operated design that makes use of easily accessible bicycle technology More

This forum has been closed.
Comment Sorting
Comments
     
by: Steve Hopkins from: New York
November 06, 2013 2:23 PM
That means there's probably somebody, somewhere on one or more of these billions of planets watching Brady Bunch reruns on a protoplasmic TV, thanking their lucky stars that they don't live here. Still, it's beyond obvious that the cosmos is teeming with life, intelligent and otherwise, some of it benevolent and syrupy-sweet and some of it bent on conquest and destruction, like us. Sometimes you just have to open your mind to see the possibilities. Here's a song to help you do that ...

by: Jim from: Philly
November 05, 2013 7:22 PM
Amazing stuff. Every year they have more information thats exciting . Can't wait til they actually discover life on another planet intelligent or not though intelligent would be awesome. Unless they are already here and NASA is just trying to get us more comfortable with the idea before the big announcement that we are not alone. ;)

by: Rb from: WW
November 05, 2013 4:57 PM
Amos 8: Seek him that makes the seven stars and Orion, and turns the shadow of death into the morning, and makes the day dark with night: that calls for the waters of the sea, and pours them out on the face of the earth: The LORD is his name
In Response

by: fimani from: botswana
November 10, 2013 11:42 AM
try harder guys may be u shall find us planet haven,and stop living in confusion

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Islamic State Prisoners Talk of Curiosity, God, Regreti
X
Zana Omer
March 28, 2015 1:19 AM
Islamic State fighter, a prisoner of Kurdish YPG forces, asked his family asking for forgiveness: "I destroyed myself and I destroyed them along with me." The Syrian youth was one of two detainees who spoke to VOA’s Kurdish Service about the path they chose; their names have been changed and identifying details obscured. VOA's Zana Omer reports.
Video

Video Islamic State Prisoners Talk of Curiosity, God, Regret

Islamic State fighter, a prisoner of Kurdish YPG forces, asked his family asking for forgiveness: "I destroyed myself and I destroyed them along with me." The Syrian youth was one of two detainees who spoke to VOA’s Kurdish Service about the path they chose; their names have been changed and identifying details obscured. VOA's Zana Omer reports.
Video

Video Germanwings Findings Raise Issue of Psychological Testing for Pilots

More is being discovered about the co-pilot in the crash of Germanwings Flight 9525 in the French Alps. Investigators say he was hiding a medical condition, raising questions about the mental qualifications of pilots. VOA's Carolyn Presutti reports.
Video

Video Hi-tech Motorbike Helmet's Goal: Improve Road Safety

In cities with heavily congested traffic, people can get around much faster on a motorcycle than in a car. But a rider who is not sure of his route may have to stop to look at the map or consult a GPS. A Russian start-up company is working to make navigation easier for motorcyclists. Designers at Moscow-based LiveMap are developing a smart helmet with a built-in navigation system, head-mounted display and voice recognition. Zlatica Hoke has more.
Video

Video New Wheelchair Is Easier to Use, Increases Mobility

Traditional push-rim wheelchairs create a lot of stress for arm, shoulder and neck muscles and joints. A redesigned chair, based on readily available bicycle technology, radically increases mobility while reducing the physical effort. VOA’s George Putic reports.
Video

Video Liberia's Almost Last Ebola Patient Grateful but Still Grieving

Beatrice Yardolo was to make history as Liberia’s last Ebola patient. Liberians recently started counting down 42 days, the period that has to go by without a single new infection until the World Health Organization can declare a country Ebola-free. That countdown stopped on March 20 when there was another new case of Ebola, making Yardolo’s story a reminder that Ebola is far from over. Benno Muchler reports from Monrovia.
Video

Video Cambodian Land Grabs Threaten Traditional Communities

Indigenous communities in Cambodia's Ratanakiri province say the government’s economic land concession policy is taking away their land and traditional way of life, making many fear that their identity will soon be lost. Local authorities, though, have denied this is the case. VOA's Say Mony went to investigate and filed this report, narrated by Colin Lovett.
Video

Video Virginia Tavern Takes Patrons Back to Medieval Times

European martial arts are not widely practiced and are unknown by most people. A tavern in Old Town Alexandria, outside Washington, wants to change this by promoting these fighting techniques from medieval times. Through combining visual arts, martial arts and culinary arts, this tavern brings medieval history back to life. VOA's Yang Lin and Helen Wu report.
Video

Video Space Program Status Disappoints 'Last Man on the Moon'

One of the films that drew big crowds last week at the annual South by Southwest festival in Austin, Texas, tells the story of the last human being to stand on the moon, U.S. astronaut Eugene Cernan. It has been 42 years since Cernan returned from the moon and he laments that no one else has gone there since. VOA’s Greg Flakus reports.

VOA Blogs

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More