NASA has found thousands of exoplanets in the past 20 years, since it was first discovered that other suns have orbiting planets, much like ours. But they’ve never found one as similar to Earth as Kepler-452b. As reported by Scientific American July 27, the planet is like an “older bigger cousin” to Earth but, at 1,400 light-years away, it’s a distant cousin.
NASA has been looking for planets that are similar in size to Earth and orbit a star at just the right distance: this is what NASA calls the “habitable zone”, or “Goldilocks zone”. If the planet is too close it gets cooked; if it’s too far, it freezes. Planets like Kepler-452b that are right in the middle may have liquid water on their surface, making them just right for conditions that could spawn life.
Only a dozen or so planets that are close in size to Earth have been discovered in this Goldilocks zone. Of those, Kepler 452b is the only planet orbiting a G Star, the same stellar classification as our sun, making it an even more interesting find for planet hunters. According to NASA, Kepler-452b is 60 percent larger than Earth, making it a super-Earth-size planet. The planet’s orbit is five percent farther from its parent star, making one revolution every 385 days, which is only 20 days longer than a solar year on Earth.
At six billion years old, Kepler-452b has had a billion and a half more years than Earth to orbit its sun, which is the same temperature as our own. The mass and the composition of the planet have yet to be determined but the surface of the planet is thought to rocky like ours. According to Jon Jenkins, Kepler data analysis lead at NASA’s Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b, the planet could provide insight into conditions here on Earth, and more.
“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment,” Jenkins said. “It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”
According to the Los Angeles Times the larger planet would likely have a stronger gravitational pull, making conditions for humans more challenging, should we ever reach it. Pending the development of some new technology like “impossible” electromagnetic propulsion drive, it isn’t likely we will be traveling there anytime soon.
“You and I probably won’t be traveling to any of these planets without some unexpected breakthrough, but our children’s children’s children may,” said Jeffrey Coughlin, a Kepler research scientist at the SETI Institute in Mountain View California. “So I think this really gives you something to aim for. Kepler is the first step. We’re finding out if planets like Earth are common – and the answer seems, so far, to be yes.”