Hubble finds oldest type Ia supernova yet

Ars Technica : A type Ia supernova occurs when a white dwarf star being orbited by a secondary star pulls enough material from the secondary star to cause a thermonuclear explosion. So bright are the supernovae that their light vies with that of the system’s parent galaxy. While the Hubble Space Telescope was being used for the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS), it detected a sudden increase in the brightness of one of the galaxies in its field of view. An analysis of the light indicated that it was a type Ia supernova. At 10 billion light-years away, the supernova was 350 million light-years farther than the previous distance record holder. That made it only the eighth type Ia supernova found farther than 9 billion light-years away. Because white dwarfs are the end stages of some stars’ life cycles, the earliest type Ia supernovae had to wait until the first generation of white dwarf precursors had lived and died.