Astronomers find a new type of planet: The 'mega-Earth'
Typically, planets much larger than Earth would be gas giants. That’s what we thought, anyway. But now astronomers have discovered an exoplanet seventeen times heavier than Earth, made up of rock and solids, some 560 light-years away. Not only is the planet exceptionally large for its composition, it’s also surprisingly old. Its parent solar system is 11 billion years old. In order to make the heavier elements needed to create an earthy planet, you require stellar nucleosynthesis—stars merging atomic nuclei into successively heavier elements until they explode, dispersing the mass, which can then form planets. There weren’t a whole lot of heavy elements present in the universe less than three billion years after the Big Bang, but apparently, there was enough to create Kepler-10c. Fascinating.
Think of the implications for life elsewhere in the universe. Although we have yet to confirm its existence, the conditions conducive to it could have appeared much earlier than one would have thought.