After studying the chemical composition of "polluted" white dwarfs, astronomers have concluded that most rocky planets orbiting nearby stars are more diverse and exotic than previously thought, with types of rocks not found anywhere in our Solar System.
Potentially Habitable Exoplanets: How To Find Hidden Oceans on Distant Worlds With Chemistry
Need for Giant Space Telescope To Discover Exoplanets Inspires Lightweight Flexible Holographic Lens