There are 300 million habitable planets in our Milky Way galaxy

There are at least 300 million habitable planets in the Milky Way, new research from NASA has shown – suggesting that humanity is less likely to be alone in the universe.

Research based on scans from NASA’s retired Kepler planet-hunting telescope suggests that about half of stars with a temperature similar to our sun may have a rocky planet capable of having liquid water on its surface .

This means that the planets could potentially harbor life, scientists believe.

Some of these potential planets are also very close to Earth (relatively speaking), with the closest likely to be only 20 light years away.

Four are within 30 light years of Earth, the researchers say.

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“Kepler once told us that there are billions of planets, but now we know a good chunk of those planets could be rocky and habitable,” said lead author Steve Bryson, researcher at Ames Research Center from NASA in Silicon Valley, California.

“Although this result is far from a final value and the water on a planet’s surface is only one of the many factors that support life, it is extremely exciting that we have calculated that these worlds are also common with such confidence and precision. “

Researchers say there could be many, many more than 300 million habitable planets, according to research published in the Astronomical Journal.

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This is the minimum number of such planets based on the most conservative estimate that 7% of sun-like stars host such worlds.

However, at the expected average rate of 50%, there could be many more.

For the purpose of calculating this rate of occurrence, the team looked at exoplanets between a radius of 0.5 to 1.5 times that of Earth, narrowing to planets that are likely rocky.

This new discovery is a significant step forward in Kepler’s original mission to understand how many potentially habitable worlds exist in our galaxy.

Previous estimates of the frequency, also known as the rate of occurrence, of these planets ignored the relationship between the star’s temperature and the types of light emitted by the star and absorbed by the planet.

The new analysis accounts for these relationships and provides a more complete understanding of a given planet’s ability to support liquid water and potentially life.

This approach is made possible by combining Kepler’s final dataset of planetary signals with data on the energy production of each star from a vast data trove of the European Space Agency’s Gaia mission. .

“We have always known how to define habitability simply in terms of the physical distance of a planet from a star, so that it is neither too hot nor too cold, left us to make a lot of assumptions,” said Ravi Kopparapu, journalist and NASA scientist. Goddard Space Flight Center in Greenbelt, Maryland.

“Gaia’s star data has allowed us to look at these planets and their stars in an entirely new way.”

“Not all stars are the same,” Kopparapu said. “And neither does every planet.

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