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

    Syrian Torture Victim Recounts Horrors

    'You make them think you have surrendered' says Jalal Nofal, a doctor who was jailed and survived repeated interrogations in Syria

    Mandela’s Millions Paid to Heirs, But Who Gets His Country Home?

    Saga around $3 million estate of country's first democratic president is far from over as Winnie Mandela’s fight for home overshadows payouts

    Guess Which Beach is 'Best in the US'?

    Hawaii’s Hanauma Bay tops an annual "top 10" list compiled by a coastal scientist, also known as Doctor Beach

    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.
    Chinese-Americans Heart Trump, Bucking National Trendi
    X
    May 27, 2016 5:57 AM
    A new study conducted by three Asian-American organizations shows there are three times as many Democrats as there are Republicans among Asian-American voters, and they favor Hillary Clinton over Donald Trump. But one group, called Chinese-Americans For Trump, is going against the tide and strongly supports the business tycoon. VOA’s Elizabeth Lee caught up with them at a Trump rally and reports from Anaheim, California.
    Video

    Video Chinese-Americans Heart Trump, Bucking National Trend

    A new study conducted by three Asian-American organizations shows there are three times as many Democrats as there are Republicans among Asian-American voters, and they favor Hillary Clinton over Donald Trump. But one group, called Chinese-Americans For Trump, is going against the tide and strongly supports the business tycoon. VOA’s Elizabeth Lee caught up with them at a Trump rally and reports from Anaheim, California.
    Video

    Video Reactions to Trump's Success Polarized Abroad

    What seemed impossible less than a year ago is now almost a certainty. New York real estate mogul Donald Trump has won the number of delegates needed to secure the Republican presidential nomination. The prospect has sparked as much controversy abroad as it has in the United States. Zlatica Hoke has more.
    Video

    Video Drawings by Children in Hiroshima Show Hope and Peace

    On Friday, President Barack Obama will visit Hiroshima, Japan, the first American president to do so while in office. In August 1945, the United States dropped an atomic bomb on the city to force Japan's surrender in World War II. Although their city lay in ruins, some Hiroshima schoolchildren drew pictures of hope and peace. The former students and their drawings are now part of a documentary called “Pictures from a Hiroshima Schoolyard.” VOA's Deborah Block has the story.
    Video

    Video Vietnamese Rapper Performs for Obama

    A prominent young Vietnamese artist told President Obama said she faced roadblocks as a woman rapper, and asked the president about government support for the arts. He asked her to rap, and he even offered to provide a base beat for her. Watch what happened.
    Video

    Video Roots Run Deep for Tunisia's Dwindling Jewish Community

    This week, hundreds of Jewish pilgrims are defying terrorist threats to celebrate an ancient religious festival on the Tunisian island of Djerba. The festivities cast a spotlight on North Africa's once-vibrant Jewish population that has all but died out in recent decades. Despite rising threats of militant Islam and the country's battered economy, one of the Arab world's last Jewish communities is staying put and nurturing a new generation. VOA’s Lisa Bryant reports.
    Video

    Video Meet Your New Co-Worker: The Robot

    Increasing numbers of robots are joining the workforce, as companies scale back and more processes become automated. The latest robots are flexible and collaborative, built to work alongside humans as opposed to replacing them. VOA’s Tina Trinh looks at the next generation of automated employees helping out their human colleagues.
    Video

    Video Wheelchair Technology in Tune With Times

    Technologies for the disabled, including wheelchair technology, are advancing just as quickly as everything else in the digital age. Two new advances in wheelchairs offer improved control and a more comfortable fit. VOA's George Putic reports.
    Video

    Video Baby Boxes Offer Safe Haven for Unwanted Children

    No one knows exactly how many babies are abandoned worldwide each year. The statistic is a difficult one to determine because it is illegal in most places. Therefore unwanted babies are often hidden and left to die. But as Erika Celeste reports from Woodburn, Indiana, a new program hopes to make surrendering infants safer for everyone.
    Video

    Video California Celebration Showcases Local Wines, Balloons

    Communities in the U.S. often hold festivals to show what makes them special. In California, for example, farmers near Fresno celebrate their figs and those around Gilmore showcase their garlic. Mike O'Sullivan reports that the wine-producing region of Temecula offers local vintages in an annual festival where rides on hot-air balloons add to the excitement.
    Video

    Video US Elementary School Offers Living Science Lessons

    Zero is not a good score on a test at school. But Discovery Elementary is proud of its “net zero” rating. Net zero describes a building in which the amount of energy provided by on-site renewable sources equals the amount of energy the building uses. As Faiza Elmasry tells us, the innovative features in the building turn the school into a teaching tool, where kids can't help but learn about science and sustainability. Faith Lapidus narrates.

    Special Report

    Adrift The Invisible African Diaspora