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Are there 300 million more Earths out there?

(Nanowerk News) From philosophers and astronomers to the child gazing up at the cosmos in wonder, the question remains unanswered: How many planets beyond our solar system known as exoplanets could host life? We抮e getting closer to the answer.

How big is space?

According to a paper accepted for publication in The Astronomical Journal (), worlds with similar conditions to Earth could have a rocky planet able to support liquid water on its surface.
In collaboration with colleagues from around the world, NASA scientists examined data gathered from the Kepler Mission抯 space telescope that monitored about 150 000 stars. NASA抯 planet-hunting mission successfully identified more than 4 000 exoplanets that could be candidates. They also used valuable data from the European Space Agency抯 Gaia mission whose satellite has measured the position and brightness of 1 billion stars.
NASA that there are about 100 to 400 billion stars in our Milky Way. A recent study (The Astronomical Journal, ) estimates there may be up to 6 billion Earth-like planets in our galaxy.
揟his is the science result we抳e all been waiting for,?co-author Natalie M. Batalha, an astronomer at the University of California, Santa Cruz, told 慛ational Geographic? Early estimates indicated that 7 % of Sun-like stars hosted a world similar to Earth抯. That number is now closer to 50 %, and possibly even more. 揑t抯 higher than I thought. I was always saying to the public, one in four, one in five梩his result is quite a pleasant surprise,?Prof. Batalha added. 揈very other sunlike star is likely, on average, to have a potentially habitable planet.?
The researchers searched for stars similar to the Sun in age and temperature. They also searched for exoplanets with a similar radius to Earth抯 and chose those that were most likely rocky. They also considered each planet抯 distance from its star. Thanks to Gaia data, the team was able to take temperature into consideration for the very first time when calculating all these factors.

Can we end interstellar loneliness?

Some of these exoplanets could be fairly close to us. At least 4 are potentially within 30 light years of the Sun, with the closest probably about 20 light years at most from Earth.
揔epler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable,?lead author Steve Bryson, a researcher at NASA抯 Ames Research Center in California抯 Silicon Valley, commented. 揟hough this result is far from a final value, and water on a planet抯 surface is only one of many factors to support life, it抯 extremely exciting that we calculated these worlds are this common with such high confidence and precision.?
揟o me, this result is an example of how much we抳e been able to discover just with that small glimpse beyond our solar system,?noted Bryson. 揥hat we see is that our galaxy is a fascinating one, with fascinating worlds, and some that may not be too different from our own.?
Source: Cordis
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