Researchers have discovered new type of rocky planet that is about 17 times larger than Earth.
In the past researchers did not think a world like this could exist because it would "grab" hydrogen gas as it grew, a Harvard-Smithsonian Center for Astrophysics news release reported.
"We were very surprised when we realized what we had found," astronomer Xavier Dumusque of the Harvard-Smithsonian Center for Astrophysics (CfA), said in the news release.
"This is the Godzilla of Earths!" CfA researcher Dimitar Sasselov, director of the Harvard Origins of Life Initiative, said in the news release. "But unlike the movie monster, Kepler-10c has positive implications for life."
The planet, dubbed Kepler-10c, orbits its host star once every 45 days. It's located 560 light-years from Earth in the constellation Draco.
The planet was discovered by NASA's Kepler spacecraft; the craft looked for changes in light that occur when a planet passes in front of its star. Researchers can estimate the size of the planet by looked at the amount of dimming.
Kepler-10c is believed to have a diameter of 18,000 miles, which is 2.3 larger than Earth. At first the team thought the planet was a gaseous mini-Neptune. Using the HARPS-North instrument on the Telescopio Nazionale Galileo (TNG) the researchers determined the planet must be made up of rock and other heavy materials.
"Kepler-10c didn't lose its atmosphere over time. It's massive enough to have held onto one if it ever had it," Dumusque said. "It must have formed the way we see it now."
There could be more planets like Kepler-10c out there. There is believed to be a connection between how long a planet takes to orbit its star and its size, suggesting more of these types of super-Earths will be seen in the future.
"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.
