They are the first to determine how much haze can form in water planets beyond the solar system, Hörst said. Haze consists of solid particles suspended in gas, and it alters the way light interacts with that gas. "This haze really complicates our observations, as it clouds our view of an exoplanet's atmospheric chemistry and molecular features." They beamed those concoctions with ultraviolet light to simulate how light from a star would start the chemical reactions that produce haze particles. This research was supported by the NASA Exoplanets Research Program 80NSSC20K0271 and the NASA Astrophysics Research and Analysis Program NNX17AI87G.