A long time ago, in a galaxy far, far away, a star detonated with enough energy to briefly shine with an intrinsic brightness of one billion of our suns. The beacon of radiation arrived at Earth 10 billion years later and was captured in a Hubble Space Telescope deep survey of the universe. It is the farthest, and earliest, supernova of its type detected to date. More than simply an example of the ancient fireworks in the young and effervescent universe, the supernova belongs to a special class of stellar detonations that are so reliably bright, they can be used as intergalactic milepost markers.
Supernovae like this one provided the first observational evidence that the universe is expanding at an ever-faster rate. Our understanding of the accelerating universe, however, is only as solid as the reliability of supernovae as solid yardsticks for measuring cosmic distances. This record-breaker is so ancient it can be used to test competing theories about how such supernovae exploded in the universe's early days and compare them with nearby supernovae seen today. Its discovery is part of an ongoing program, where different teams of astronomers are using Hubble to push ever farther back into the early epoch of star formation.
http://hubblesite.org/news_release/news/2013-11