(January 13, 2026)
Coining the term ânear-Earth astrophysics,â Fasel has devoted much of his career to investigating solar-terrestrial interactions between the Sun and Earth, using the aurora borealis to obtain clues regarding the coupling mechanisms between the solar wind and the Earthâs terrestrial magnetic field.
âStars have winds,â says Fasel. âAnd this includes our Sun. While solar wind is a relatively continuous stream of particles that interact with the Earthâs magnetic field, the Sun can also produce powerful solar storms. These storms expel billions of charged particles [plasma] coupled to magnetic fields, called coronal mass ejections, which bang up into the Earthâs magnetic field.â
The Earthâs magnetic field lines, Fasel explains, âact like wiresâ on which these particles travel down into the Earthâs upper atmosphere, specifically the ionosphere. The aurora is an end result of this interaction, where high-energy electrons collide with oxygen to produce green light, while those of lower energy produce a raspberry-red color.