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

Changing Under Pressure, IS ‘Potent’ as Ever

US intel officials describe Ramadi's fall as concerning, but say it isn't emblematic of larger effort to degrade IS capabilities More

Nigeria Fuel Shortage Shows Fragility of Africa’s Oil Giant

Although it is the largest oil producer in Africa, country has nearly ran out of fuel it needs to power its generators, cars and airplanes over the past week More

Arrested Football Officials Come Mainly From the Americas

US Justice Department alleges defendants participated in 24-year scheme to enrich themselves through corruption of international soccer 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.
3D Printer Makes Replica of Iconic Sports Cari
|| 0:00:00
...    
🔇
X
George Putic
May 27, 2015 9:31 PM
Cars with parts made by 3D printers are already on the road, but engineers are still learning about this new technology. While testing the possibility of printing an entire car, researchers at the U.S. Department of Energy recently created an electric-powered replica of an iconic sports roadster. VOA’s George Putic has more.
Video

Video 3D Printer Makes Replica of Iconic Sports Car

Cars with parts made by 3D printers are already on the road, but engineers are still learning about this new technology. While testing the possibility of printing an entire car, researchers at the U.S. Department of Energy recently created an electric-powered replica of an iconic sports roadster. VOA’s George Putic has more.
Video

Video US Voters Seek Answers From Presidential Candidates on IS Gains

The growth of the Islamic State militant group in Iraq and Syria comes as the 2016 U.S. presidential campaign kicks off in the Midwest state of Iowa.   As VOA’s Kane Farabaugh reports, voters want to know how the candidates would handle recent militant gains in the Middle East.
Video

Video A Small Oasis on Kabul's Outskirts Provides Relief From Security Tensions

When people in Kabul want to get away from the city and relax, many choose Qargha Lake, a small resort on the outskirts of Kabul. Ayesha Tanzeem visited and talked with people about the precious oasis.
Video

Video Film Festival Looks at Indigenous Peoples, Culture Conflict

A recent Los Angeles film festival highlighted the plight of people caught between two cultures. Mike O'Sullivan has more on the the Garifuna International Film Festival, a Los Angeles forum created by a woman from Central America who wants the world to know more about her culture.
Video

Video Kenyans Lament Losing Sons to al-Shabab

There is agony, fear and lost hope in the Kenyan town of Isiolo, a key target of a new al-Shabab recruitment drive. VOA's Mohammed Yusuf visits Isiolo to speak with families and at least one man who says he was a recruiter.
Video

Video Scientists Say Plankton More Important Than Previously Thought

Tiny ocean creatures called plankton are mostly thought of as food for whales and other large marine animals, but a four-year global study discovered, among other things, that plankton are a major source of oxygen on our planet. VOA’s George Putic reports.
Video

Video US-led Coalition Gives Some Weapons to Iraqi Troops

In a video released Tuesday from the Iraqi Ministry of Defense, Iraqi forces and U.S.-led coalition troops survey a cache of weapons supplied to help Iraq liberate Mosul from Islamic State group. According to a statement provided with the video, the ministry and the U.S.-led coaltion troops have started ''supplying the 16th army division with medium and light weapons in preparation to liberate Mosul and nearby areas from Da'esh (Arabic acronym for Islamic State group).''
Video

Video Amnesty International: 'Overwhelming Evidence' of War Crimes in Ukraine

Human rights group Amnesty International says there is overwhelming evidence of ongoing war crimes in Ukraine, despite a tentative cease-fire with pro-Russian rebels. Researchers interviewed more than 30 prisoners from both sides of the conflict and all but one said they were tortured. Henry Ridgwell reports for VOA from London.
Video

Video Washington Parade Honors Those Killed Serving in US Military

Every year, on the last Monday in the month of May, millions of Americans honor the memories of those killed while serving in the armed forces. Memorial Day is a tradition that dates back to the 19th Century. While many people celebrate the federal holiday with a barbecue and a day off from work, for those who’ve served in the military, it’s a special day to remember those who made the ultimate sacrifice. Arash Arabasadi reports for VOA from Washington.
Video

Video Kenya’s Capital Sees Rise in Shisha Parlors

In Kenya, the smoking of shisha, a type of flavored tobacco, is the latest craze. Patrons are flocking to shisha parlors to smoke and socialize. But the practice can be addictive and harmful, though many dabblers may not realize the dangers, according to a new review. Lenny Ruvaga has more on the story for VOA from Nairobi, Kenya.
Video

Video Rolling Thunder Run Reveals Changed Attitudes Towards Vietnam War

For many US war veterans, the Memorial Day holiday is an opportunity to look back at a divisive conflict in the nation’s history and to remember those who did not make it home.
Video

Video Female American Soldiers: Healing Through Filmmaking

According to the United States Defense Department, there are more than 200-thousand women serving in the U.S. Armed Forces.  Like their male counterparts, females have experiences that can be very traumatic.  VOA's Bernard Shusman tells us about a program that is helping some American women in the military heal through filmmaking.

VOA Blogs