Quasar discovery blasts old theories on universe Astronomers find objects are older than expected

August 26, 1991|By Doug Birch

A team of astronomers say they have located the oldest and most distant object yet discovered, a quasar that may be a trifling 900 million years younger than the universe itself.

Donald P. Schneider of the Institute for Advanced Study in Princeton, N.J., said Friday the discovery of that object, which is perhaps 40 million light-years farther away than any previously discovered quasar, suggests that stars and galaxies formed much earlier than once thought. That delivers another blow to most current theories of how the early universe swirled out of the chaos following the so-called "big bang."

"These quasars mean you have to make large-scale structures [such as galaxies] very rapidly, more rapidly than most theories say you can make them," he said. "It means nature is much cleverer than we are about making galaxies."

Mr. Schneider, Professor Maarten Schmidt of the California Institute of Technology and Professor James E. Gunn of Princeton University made the discovery April 6 using the 200-inch Hale telescope located on top of Mount Palomar, Calif. Their findings, disclosed Friday, will be published in next month's issue of the Astronomical Journal.

The astronomers were watching a computer screen displaying infrared light data gathered from the quasar, now designated PC 1247+3406, when they recognized it as the most distant object yet discovered.

"We knew within 10 seconds," Mr. Schneider said.

Those 10 seconds were preceded by about two years of planning and research, including the design of a new method of surveying huge sections of the heavens using a supersensitive digital camera, called a "4-Shooter," first developed by Mr. Gunn for the Hubble telescope.

The Schneider-Schmidt-Gunn team began their survey in March 1990 by fixing Palomar's Hale telescope in a single position to watch the sky as it swept past overhead. They attached to the telescope a digital camera with four special filters designed to help spot the oldest objects.

Earlier this century, it was discovered that the older and more distant a celestial object, the farther its light is shifted into the infrared part of the spectrum. The camera's filters helped it spot those objects with the largest red shift.

The camera, linked to a computer, scoured an area of the sky that is enormous by astronomical standards: about 15 to 20 times the size of the moon. It eventually found about 40,000 likely suspects, Mr. Schneider said. At Princeton in January, the scientists winnowed that list to about 100 finalists.

The team took the list of 100 back to Palomar and used the telescope to look more closely at each one. Eventually, the astronomers aimed the telescope at PC 1247+3406, which appears about 600,000 times less visible than the faintest star visible to the naked eye.

Mr. Schneider said so far the team has analyzed only about one-seventh of the data, so it seems likely that other distant quasars will appear. One may be found that is older than the PC 1247+3406, he said, "but that's up to the quasars."

Assuming the universe is 13 billion years old, PC 1247+3406 is about 12.1 billion years old, according to a spokeswoman for the Institute for Advanced Study. Under the prevailing theory, the universe was born in a huge explosion of matter called the "big bang."

Quasars, which generate between 10 and 1,000 times more light as our Milky Way, are thought to be massive black holes in the process of swallowing entire galaxies. (A black hole is an object in which matter is so densely compacted that nothing -- not even light -- can escape its gravitational pull).

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