Exploding star is the brightest supernova ever seen

A galaxy 3 billion light years away (left, seen in 2014) blazes with the light (right, seen in 2015) from the brightest known supernova, dubbed ASASSN-15lh.
The Dark Energy Survey, B. Shappee and the ASAS-SN team
The brightest known supernova shines with the light of about 550 billion suns. This stellar explosion is more than two times as bright as the previous record holder, Subo Dong, an astrophysicist at Peking University in Beijing, and colleagues report in the Jan. 15 Science.
Researchers first reported in June the discovery of supernova ASASSN-15lh, which sits about 3 billion light-years away in the constellation Indus. Further observations have confirmed and refined the nature of ASASSN-15lh, a cosmic cataclysm known as a superluminous supernova. Astronomers aren’t sure what triggers such powerful eruptions.