Using a new automated telescope designed to survey the sky, astronomers have discovered the farthest object ever seen in space.

It is a quasar, an object brighter than a hundred normal galaxies yet not much bigger than our solar system. It is more than 10 billion light years away.

Many aspects of quasars mystify astronomers but they believe the incredible radiation coming from them occurs when material falls onto a super-massive black hole.

Remarkably, the Sloan Sky Survey project has discovered three of the four most distant quasars currently known.

"We could identify these quasars so readily," said discoverer Xiaohui Fan, "because of the Sky Survey's unique characteristics: its superb telescope and camera, the power of the analysis software, and the large amount of sky it can cover."

Record-breaking quasar

Sky Survey astronomer Michael Strauss of Princeton University described the night they found the distant quasar.

"Xiaohui and I were in the basement of Peyton Hall at Princeton, operating the 3.5-meter diameter telescope at Apache Point Observatory over the Internet to follow up on quasar candidates from the Sky Survey data.

"It was 1:30 am on Thanksgiving morning, and we only had about half an hour of observing time left. Xiaohui suggested observing one of our last promising high-redshift quasar candidates before we finished up. As soon as we saw the spectrum, we knew we had a record-breaking quasar."

The automated Sky Survey telescope at Apache Point Observatory in southern New Mexico found the three quasars after examining a narrow slice of the sky

The most distant object has a redshift of 5.0. Redshift is the amount by which light is shifted toward the red end of an object's spectrum by the expansion of the universe. Astronomers use it as a measure of the distance: the higher the redshift, the greater the distance and the younger the universe when the light was emitted.

Wide-field telescope

The newly discovered quasars mark an epoch when the universe was less than a billion years old and a sixth of its current size.

The most distant quasar now surpasses a quasar discovered in 1991 at a redshift of 4.89.

More record breakers are to be expected from the survey. At the current rate of discovery, it should find more than 500 quasars with redshifts greater than 4.75.

Imaging the slender slice of sky, the Sky Survey's new wide-field telescope recorded millions of objects during its trial runs. The images were a broad range of objects - from nearby asteroids between Mars and Jupiter to mysterious hybrid galaxies - and left scientists with an astonishing array of data to analyse.

Alex Szalay, professor of astrophysics at the Johns Hopkins University and a member of the team said: "The real challenge for us now will be recognising objects whose existence we are not even aware of. We'll need to develop new software tools to mine the data."

The ultimate goal of the Sky Survey, an international collaboration of more than 100 scientists and engineers, is to map one quarter of the sky and create a three-dimensional picture of the universe 100 times larger than in previous surveys.

The distant quasars are interesting objects in their own right but they also tell us about the universe in-between them and us.