Wed, Jun 04, 2014 - Page 7 News List

Scientists find ‘Godzilla’ earth

SURPRISING:The discovery of the 11 billion-year-old planet shows that the early universe was able to form massive rocks even when heavy elements were scarce

AFP, WASHINGTON

Newly discovered “mega-earth” Kepler-10c dominates the foreground in an artist’s conception released by the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, on Monday. Its sibling, the lava world Kepler-10b, is in the background and both orbit a sun-like star.

Photo: Reuters

Astronomers have spotted the “Godzilla” of all earths, a huge rocky planet orbiting a star 560 light years away that is changing scientists’ understanding of the origins of the universe.

This new mega-earth weighs 17 times as much as our planet and was found by NASA’s Kepler mission, experts said at a meeting in Boston of the American Astronomical Society.

The discovery, named Kepler-10c, is 29,000km wide, or 2.3 times the size of the Earth.

“We were very surprised when we realized what we had found,” said astronomer Xavier Dumusque of the Harvard-Smithsonian Center for Astrophysics.

Until now, astronomers did not think a rocky planet could get so large, because its growing girth would make it collect more hydrogen gas and turn it into a gas-giant, like Jupiter.

“This is the Godzilla of earths, but unlike the movie monster, Kepler-10c has positive implications for life,” said researcher Dimitar Sasselov, director of the Harvard Origins of Life Initiative.

The US space agency’s planet-hunting Kepler mission can only spot planets and classify them based on the number of times they pass in front of their star. It cannot reveal much about whether they are rocky or gassy.

What lifted Kepler-10c out of the category of super-earths and mini-neptunes — planets outside our solar system that are larger than Earth and smaller than dense, gassy Neptune — was a special telescope in the Canary Islands which measured its mass.

“Kepler-10c didn’t lose its atmosphere over time. It’s massive enough to have held on to one if it ever had it,” Dumusque said. “It must have formed the way we see it now.”

Since Kepler-10c is far denser than expected, that puts it in a new class, which more planets are likely to join once discovered, experts said.

Kepler-10c circles its sun-like star once every 45 days, suggesting it is likely too hot for life to survive.

It is located in a planetary system that is also home to Kepler-10b, a lava-world that spins around in a fast 20-hour orbit.

The Kepler-10 system is about 11 billion years old and it formed less than 3 billion years after the Big Bang, scientists said.

That means that somehow the universe was able to form massive rocks even when heavy elements like silicon and iron were scarce. The early universe was made of only hydrogen and helium.

“Finding Kepler-10c tells us that rocky planets could form much earlier than we thought, and if you can make rocks, you can make life,” Sasselov said.

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