A supernova remnant in the Milky Way galaxy
Chandra X-ray Observatory
After a star explodes in a supernova, the remnants can reform into more stars again and again. These subsequent generations could be full of elements heavier than helium that astronomers refer to as metals, which could explain why the cosmos is littered with puzzlingly metal-rich stars.
Supernovae are often thought of as explosions, but in the later stages of their evolution, they slam into particles in the surrounding interstellar medium and begin to implode instead. This creates a dense cloud of gas and dust, enriched with all of the…