Free Astronomy Magazine May-June 2016

PLANETOLOGY 5 I n recent months, Pluto, gravita- tional waves and Martian missions seems to have relegated to the background the constant and increas- ingly interesting discoveries of exo- planets, which follow one another in quick succession and that progres- sively bring us closer to the identi- fication of worlds similar to our own. In this article we will focus on those discoveries that more than others have surprised researchers. THE LARGEST ROCKY PLANET For some years, the varied world of extrasolar planets has put to a hard test the theories and models at- tempting to interpret their chemical, physical and dynamic properties. The basic problem lies in the fact that, historically, our knowledge on the birth and evolution of the plan- etary system in which we live is only partly directly applicable to other systems. It follows that what was for us was the norm, i.e., the typical architecture of the solar system and char- acteristics of the planets in it, now it appears more and more as one of the many and diverse possible real- ities. Indeed, for certain aspects it is our system that does not seem to fall within the norm. We do not have, for example, that class of planets called super-Earths, which may be the most common in the Milky Way. Based on seemingly solid the- oretical arguments, these plan- ets should have a mass of up to 10 Earth masses, but even this certainty has fallen apart, as a re- sult of a study conducted by a group of astrophysicists of the Pon- tificia Universidad Católica de Chile, coordinated by Néstor Espinoza. The researchers, thanks to observations made with the Kepler space tele- MAY-JUNE 2016 d more le