Interstellar space refers to the areas between star systems within a galaxy. It varies hugely in composition, and contains atomic and subatomic particles, molecular and ionic particles as well as cosmic radiation. Cardelli used spectroscopy and the scattered-light characteristics to identify the elements in interstellar space.
56300login-checkJuly 8th- Astrophysicist Jason Cardelli announced that he had detected thallium (Tl) and lead (Pb) in interstellar gas on this day in 1994