(I'm astrophysicist Neil deGrasse Tyson.) Some with billions, others with trilions of stars, these are the fundamental building blocks of visble matter in the universe; they come in many varieties including spiral, irregular & elliptical
... "I need to remind 
these people, hey look, I'm an astrophysicist, did I tell ya ... Tyson: --about five 
billion years and so, we probably have other ....