Scientists on the hunt for extraterrestrial life have discovered “the closest twin to Earth” outside the solar system, NASA announced on Thursday.
Working off four years’ worth of data from the Kepler space telescope, researchers from NASA, the Seti Institute and several universities announced the new exoplanet along with 12 possible “habitable” other exoplanets and 500 new candidates in total.
The new planet, named Kepler 452b, is “the closest twin to Earth, or the Earth 2.0 that we’ve found so far in the dataset”, said John Grunsfeld, associate administrator for NASA’s mission directorate.
“This is the first possibly rocky, habitable planet around a solar-type star,” said Jeff Coughlin, a Seti scientist.
All 11 previously discovered exoplanets of a similar size and orbit travel around stars are smaller and cooler than the sun.
“It is the closest thing that we have to another place that somebody might call home,” said Jon Jenkins, a NASA scientist. The planet is like Earth’s “older, bigger first cousin”, he added.
The research suggests 452b has five times the mass of Earth, is about 1.5 billion years older, and has a gravity about twice as powerful as our own.
About 1,400 light years away, Kepler 452b orbits a star similar to our sun, and at about the same distances as Earth orbits the sun, meaning it has a similar length year and exists in the “habitable zone” where liquid water can exist on a planet.
Jenkins said they suspect the planet is rocky, likely with active volcanoes, and has a thicker atmosphere with greater cloud cover than the Earth.
But although 452b has more in common with Earth than any exoplanet yet discovered, its star is 4% more massive and 20% brighter than our own. As stars age they grow in mass and energy, casting more heat at the objects in their orbit.
Jenkins compared them to people. “When they’re young they’re small and dim,” he said, and millennia later “they grow and they get brighter”.
The new planet consequently receives 10% more energy than the Earth, meaning it could provide a glimpse into a burning, waterless future on Earth, the scientists said.
