if you’re fed up with the drama of climate change, the presidential election and the ever-present threat of nuclear warfare, there may be approximately 300 million other options to set up a home, according to new data scraped by the National Aeronautics and Space Administration’s Kepler Space Telescope.
Between 2009 and 2018, Kepler explored the far reaches of our galaxy in search of exoplanets. In particular, rock-based, Earth-size planets that orbit a star like our sun and orbit at nearly the same distance. Kepler’s tour revealed potentially billions of planets in the Milky Way outside of the nine in our solar system. It also delivered images of other blue-green planets with the potential to support life.
Now, an updated analysis of the retired telescope’s findings, published in the Astronomical Journal, provides a more accurate snapshot of habitable worlds. In a “conservative” estimate, NASA researchers believe that at least 50% of all sun-like stars have terrestrial planets with the potential for water. More optimistic models guess up to 75%.
“Kepler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable,” said lead study author Steve Bryson in a statement on the NASA site. “Though this result is far from a final value, and water on a planet’s surface is only one of many factors to support life, it’s extremely exciting that we calculated [that] these worlds are this common with such high confidence and precision.”
Their aim in this study was to establish a more thorough equation to determine habitability, by examining the relationship between an exoplanet’s distance from and the temperature of its parent star, as well as the amount of light energy, which that star emits.
Data from the European Space Agency’s Gaia mission was key.
“We always knew defining habitability simply in terms of a planet’s physical distance from a star, so that it’s not too hot or cold, left us making a lot of assumptions,” said co-author Ravi Kopparapu. “Gaia’s data on stars allowed us to look at these planets and their stars in an entirely new way.”
“Not every star is alike,” said Kopparapu. “And neither is every planet.”
The new calculations suggest that there are at least four livable planets at a relatively close distance from Earth, between 20 and 30 light-years away — an inconceivable number for a human, sure, but meaningful to a scientist.
“Knowing how common different kinds of planets are is extremely valuable for the design of upcoming exoplanet-finding missions,” said co-author Michelle Kunimoto.
The more accurately that they can pinpoint these highly eligible worlds, the more successful exploration of exoplanets can be. And we’ll need that data if we ever hope to get out.
“Surveys aimed at small, potentially habitable planets around sun-like stars will depend on results like these to maximize their chance of success,” said Kunimoto.