Supernovas are already the brightest lights in the sky, but then there's ASASSN-15lh — the brightest ever. (Video via NASA)
It's 570 billion times brighter than our sun, and 20 times brighter than our entire galaxy combined — although it's way too far to see with the naked eye. (Video via NASA)
ASASSN-15lh is one of a new class of supernova. They're called "hypernovas," and scientists still aren't sure what makes them so bright.
ASASSN-15lh was found by the All Sky Automated Survey for Supernovae.