Stunning: Scientists say billions of Earth-like planets reside in Milky Way

January 07, 2013

Stunning: Scientists say billions of Earth-like planets reside in Milky Way

A lot of Earth-life planets reside in the Milky Way.

New findings have been released that estimate there are billions of planets in the Milky Way galaxy, each of which are the size of Earth.

In fact, the studies revealed that there are no less than 17 billion of these similarly sized planets, providing an enormous amount of potential future research for astronomers interested in discovering planets that could harbor life.

The 17 billion planet estimate was made by two separate research groups, both of which released their findings late Monday. Astronomers calculated the figure after using new data released from NASA’s Kepler Space Telescope.

Before using the data from the Kepler spacecraft, Francois Fressin and his team at the Harvard-Smithsonian Center for Astrophysics wanted to make sure its findings were reliable. In the end, they found that approximately 90 percent of Kepler’s planet detections were accurate.

“There is a list of astrophysical configurations that can mimic planet signals, but altogether, they can only account for one-tenth of the huge number of Kepler candidates,” Fressin said in a statement. “All the other signals are bona-fide planets.”

“We found that the occurrence of small planets around large stars was underestimated,” Fressin added. “Every time you look up on a starry night, [nearly] each star you’re looking at has a planetary system.”

The two research teams who utilized the Kepler data to determine the number of Earth sized planets use the findings in different ways. First, the team from the Harvard-Smithsonian Center for Astrophysics, which was led by Fressin, used the data from the Kepler spacecraft to find that approximately one in six stars in the Milky Way galaxy has a planet the size of Earth orbiting around it.

Using a different method, a team from the University of California, Berkeley and the University of Hawaii separately came up with a similar estimate. According to Berkeley and Hawaii astronomers,  they discovered 17 percent of the stars in the Milky Way have planets that are one to two times the diameter of the Earth orbiting them —  a figure that matches that provided by Fressin.

Though it is unlikely that all 17 billion of these Earth-sized planets are able to host life, the finding is a welcomed one for astronomers seeking a starting point in a bid to discover the next Earth.

So far, no planet like Earth has been discovered. This is mostly due to the crucial criteria involved in finding a twin Earth. First, the planet must be the same size as our planet. Second, it must be located in what is referred to as the Goldilocks zone, an area that contains liquid water and is not too hot or too cold for life.

NASA’s Kepler mission looks out at a vast field of more than 150,000 stars, scanning for the periodic dimming in their light that might indicate orbiting planets are crossing in front of them, also known as transiting. According to the NASA team, Kepler has detected 2,740 candidate planets orbiting 2,036 stars. Thus far, 105 of the candidates have been confirmed to be planets, they noted.

The groups revealed their findings at the American Astronomical Society in Long Beach, California.


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