Last week, some exciting new science made its way to the public stage. Exoplanet hunters (astronomers who search out planets outside of our own solar system) confirmed that they had found a planet, Kepler-10c.
Yeah, yeah, another planet to add to the record books. What's so special about this one planet that sets it apart from the 1000 confirmed and 4000 planet candidates found so far with Kepler? After all, it gets a little tedious to see a new planet confirmation published every couple of days.
This planet is different. It is a rocky planet, dubbed the 'Godzilla' of Earths by the Harvard team who confirmed its properties. But it is 2.3 times the size of Earth?!?! Weighing in at 17 times the mass of Earth, this planet is baffling theorists. It was previously thought that a planet this massive couldn't possibly be made of rock. Instead, only gassy planets could theoretically grow to be this massive; they gravitationally attract gases and balloon in size.
So here we have an excellent example of how theory and observation work together in the scientific community! Observational astronomy (what I do) often completely obliterates (sticking with the Godzilla metaphor) the previous theories. This doesn't mean that the previous science is inherently wrong. This just demonstrates that the scientific process is an evolving one, open to re-invention and innovation.
Humbling, isn't it?
The theorists are getting back to work...It's now thought that the critical mass of a planet above which the planet MUST be made of gas to be stable might depend on how far the planet is from its star. Kepler-10c just happens to span the gap between what we dub "normal" terrestrial planets and "normal" gas giants.
Not only is Kepler-10c a new type of "mega-Earth", but it also orbits a star older than our own. Astronomers now know that rocky planets can exist at a time much earlier than our own solar system's birth. This planet was born around 11 billion years ago (around 5 billion years older than Earth!).
In the mad search for life on exoplanets, this planet represents a whole new type of planet that could host life - because rocky planets are the best for this. And after all, it would be so sad to be all alone in this universe.