Galaxy Farthest From Earth Is Photographed
Astronomers have photographed a galaxy more distant than any celestial object ever seen.
The galaxy lies more than 13 billion light-years away, said Garth Illingworth, a professor of astronomy at UC Santa Cruz. Light from the stars in it has taken so long to reach Earth that it appears as it did when the universe was less than a billion years old.
It took the combined power of the Hubble Space Telescope, Hawaii’s Keck Telescope and a celestial light trick discovered by Albert Einstein to photograph the distant galaxy.
Einstein’s theory of general relativity allows massive objects to warp space itself, a phenomenon that bends light rays passing nearby. So truly gigantic things, such as black holes and clusters of galaxies, can actually magnify the light traveling from distant objects to Earth.
A galactic cluster about 5 billion light-years from Earth magnifies light coming from the record-breaking galaxy, Illingworth said, making the object appear about 10 times bigger than it otherwise would, and big enough that the Hubble Space Telescope can make it out.
The Keck Telescope, the world’s largest, is required to show that the galaxy really is 13 billion light-years away. Only Keck can gauge how fast the universe’s expansion is carrying the galaxy away from Earth, a number that can be converted into a distance.
The photograph will be published in a September issue of Astrophysical Journal Letters.
The previous record for most distant known celestial object was held by a quasar just a hair closer to Earth than the newly discovered galaxy, Illingworth said. Quasars are extremely bright distant objects thought to be powered by black holes.