Fossil clams found in southwestern Florida contain ancient microtektites, tiny (about 200 μm in diameter) glass beads that form when the explosive impact of an extraterrestrial object sends molten debris hurtling into the atmosphere where it cools and recrystallizes before falling back to Earth. A microtektite from the shell bed of southwestern Florida. Image credit: Meyer et al, doi: 10.1111/maps.13299. Dr. Mike Meyer, a researcher at Harrisburg...
