Free Astronomy Magazine September-October 2018

20 PLANETOLOGY Planetology has made great strides in the last few decades. Thousands of exo- planets have been discovered and the at- mospheres of distant worlds have been investigated, to the point of our being able to make meteorological forecasts. And yet, in our own solar system, there is the planet Uranus, for which we cannot distinguish the north pole from the south pole, we do not know why its rotation axis is lying horizontal in its orbit, and we do not even know why its atmosphere is much colder than expected. Recent nu- merical simulations provide answers to some of these questions, but a complete understanding of Uranus still alludes us. A solution to the mysteries of Uranus by Michele Ferrara revised by Damian G. Allis NASA Solar System Ambassador SEPTEMBER-OCTOBER 2018