The most common “sized” world in the galaxy is a super-Earth, between 2 and 10 Earth masses, like Kepler 452b, right. Where is ours? (Image credit: NASA/Ames/JPL-Caltech/T. Pyle)

Is Earth our Solar System’s missing ‘Super-Earth’?

The reports that our Solar System is missing the galaxy’s most common type of planet are greatly exaggerated.

“To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.” -Albert Einstein

It wasn’t that long ago that we thought our Solar System was the prototype for how planetary systems ought to be configured. We thought that there were two classes of planets: the rocky worlds, that we’d find clustered in the inner regions, and the gas giants, located farther out. Starting in the 1990s, we finally began discovering planets around stars other than our own, and we were in for not just one but two rude awakenings, and we discovered our Solar System was not normal. In a new paper just accepted for publication this week, two Columbia University astrophysicists might have just explained why.

An illustration of the full suite of planets discovered by Kepler. (Image credit: NASA /W. Stenzel)

Having small, rocky worlds in the inner solar system and large, gas giants in the outer solar system isn’t the norm, as we might have expected. Gas giants and rocky planets, it turned out, could be…