Astronomers Discover 'Mega-Earth' Planet
Astronomers discovered a new kind of rocky planet dubbed a 'mega-Earth' that is up to 17 times more massive than Earth. Instead of becoming a gas giant as existing theories predicted, this world remained rocky, challenging current understanding of planetary evolution and offering new possibilities for science fiction world-building.
- The planet is officially named Kepler-10c and is located about 560 light-years from Earth in the constellation Draco. It orbits a Sun-like star that is approximately 11 billion years old, more than twice the age of our sun. - Initial discovery and analysis were conducted by a team at the Harvard-Smithsonian Center for Astrophysics (CfA) led by astronomer Xavier Dumusque. They used the HARPS-North instrument on the Telescopio Nazionale Galileo in the Canary Islands to determine its mass. - With a diameter about 2.3 times that of Earth, its significant mass initially led scientists to believe it had to be a dense, rocky world. Standard planet formation theories suggested a planet of this size would accumulate a massive gas envelope, turning into a gas giant like Jupiter or Neptune. - The planet orbits its star every 45 days, meaning it is too close to its star and therefore too hot to support life as we know it. - The same system also contains Kepler-10b, one of the first confirmed rocky exoplanets. It is a "lava world" that is about three times the mass of Earth and orbits its star in a scorching 20 hours. - The discovery of a massive, apparently rocky planet around such an old star suggested that the heavy elements needed to form terrestrial planets were available earlier in the universe's history than previously thought. - Later analysis in 2017, using more precise data from the HARPS-N and HIRES instruments, revised the mass of Kepler-10c downward to about 7.4 times Earth's mass. This newer data suggests the planet is not a "mega-Earth" but rather a volatile-rich world, composed mainly of water.
