On Super-Earths, Sub-Neptunes and Some Lessons They Teach

Part 1 of 2 When the first exoplanet was identified and confirmed 20 years ago, there was enormous excitement, a sense of historic breakthrough and, with almost parallel intensity, sheer bewilderment. The planet, 51 Pegasi B, was larger than Jupiter yet orbited its parent star in 4 days. In other words, it was much closer …