Artist depiction of a starsystem with exo-planets. Credit: NASA/JPL-Caltech, NASA/JPL-Caltech, ESO
Artist depiction of a starsystem with exo-planets. Credit: NASA/JPL-Caltech, NASA/JPL-Caltech, ESO

SETI Talks presents Jonathan Fortney who talks about how the NASA’s Kepler Mission has revealed that the most common size of a planet in our galaxy may be those from 2-3 Earth radii. Such medium-sized planets are significantly more common on close-in orbits than Neptune and Jupiter-class giant planets. We have no analog for these planets in our solar system. What are they made of?