Free Astronomy Magazine January-February 2022

51 JANUARY-FEBRUARY 2022 ASTRO PUBLISHING R ocky debris, the pieces of a for- mer rocky planet that has bro- ken up, spiral inward toward a white dwarf in this illustration. Studying the atmospheres of white dwarfs that have been “polluted” by such debris, a NOIRLab as- tronomer and a geologist have iden- tified exotic rock types that do not exist in our Solar System. The results suggest that nearby rocky exoplan- ets must be even stranger and more diverse than previously thought. [NOIRLab/NSF/AURA/J. da Silva]