It seems the phrase “hell on Earth” was off… by about 400 light years.
Researchers announced on Wednesday, in the journal Nature, the discovery of an Earth-like planet called Kepler-78B in the constellation Cygnus.
It’s unique because it is the first known Earth-sized planet with an Earth-like density, the researchers say. Because it has a density similar to Earth, it likely shares an iron and rock composition with the Earth.
But it’s also a “scorching lava world” that orbits the star Kepler-78 every eight and a half hours at a distance of less than one million miles.
It is 2,000 degrees Celsius hotter than Earth’s hottest day, Discovery reported. The surface would be molten rock and the atmosphere would be almost non-existent.
“It’s certainly not a habitable planet,” University of Geneva professor Francesco Pepe told The New York Times.
What has astronomers more confused, however, is the planet’s origin.
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According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there.
“This planet is a complete mystery,” said David Latham, a Harvard-Smithsonian Center for Astrophysics astronomer. “We don’t know how it formed or how it got to where it is today. What we do know is that it’s not going to last forever.”
Gravitational tides will draw it even closer to its star. Eventually, it will move so close that the star’s gravity will rip the world apart.
“Kepler-78B is going to end up in the star very soon, astronomically speaking,” fellow CfA astronomer Dimitar Sasselov said.
That would be about three billion years. Tops.
According to Latham, Kepler-78B is a member of a new class of planets recently identified in data from NASA’s Kepler spacecraft. These newfound worlds all orbit their stars with periods of less than 12 hours. They’re also small, about the size of Earth. Kepler-78B is the first planet in the new class to have its mass measured.
“Kepler-78B is the poster child for this new class of planets,” Latham said.
Let’s just hope the rest aren’t so darn hot.
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