June 29, 2011 - Scientific American
Peering far across space and time, astronomers have located a luminous beacon aglow when the universe was still in its infancy. That beacon, a bright astrophysical object known as a quasar, shines with the luminosity of 63 trillion suns as gas falling into a supermassive black holes compresses, heats up and radiates brightly. It is farther from Earth than any other known quasar—so distant that its light, emitted 13 billion years ago, is only now reaching Earth. Because of its extreme luminosity and record-setting distance, the quasar offers a unique opportunity to study the conditions of the universe as it underwent an important transition early in cosmic history.
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