Its arrival may have gone unnoticed by the naked eye, but astronomers are giving the newly discovered light of a quasar a hero's welcome.
Surveying a small bit of sky -- the size of a dime held at arm's length -- astronomers spotted a point of light, generated some 13 billion years ago, that they say is the most distant quasar ever found. Thousands of closer quasars have been catalogued.
By studying the quasar's light, scientists hope to learn about the matter in the intervening space between Earth and the oldest parts of the universe. This in turn would help explain how the universe evolved into its current structure, which consists of clumps of galaxies instead of a smooth distribution of matter.
"Finding a quasar at this distance is like turning on a flashlight at the edge of the universe," said Daniel Stern of NASA's Jet Propulsion Laboratory, part of a team that announced the finding February 18. "Because quasars are more luminous than distant galaxies at the same redshift, they act as the brightest flashlights, allowing us to study everything that has ever developed between us and the quasar," he said.
Redshift measures how fast an object is moving away from us as the universe expands? The faster it moves away, the more an object's light shifts to the red part of the spectrum, toward longer wavelengths. The faster an object appears to move, the farther away it is thought to be.
At a redshift of 5.5, light traveling from the newly found quasar has journeyed about 13 billion years, meaning that it existed at a time when the universe was probably less than 8 percent of its current age, researchers said.
The quasar was found by combining studies from the Hale Telescope at Palomar Observatory in California and the Mayall Telescope at Kitt Peak, Arizona. The object's light was further analyzed at the Keck Observatory in Hawaii.
The findings will be presented in an upcoming issue of the Astrophysical Journal Letters.
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