Closer View Wrecks Theories on Quasars : Astronomy: The Hubble Space Telescope is aimed at a sample of the bright, distant objects and finds that most are not surrounded by galaxies.


Astronomical theorists are eating their humble pie this week after learning that some of their pet theories about the most brilliant objects in the universe are probably dead wrong.

Widely accepted theory holds that quasars--those distant star-like objects that shine more brightly than a thousand galaxies--are really super-massive black holes devouring nearby stars. So when the Hubble Space Telescope was aimed at a series of quasars over the past few months, scientists expected to see galaxies of millions of stars surrounding each quasar, providing lunch for the beast within.

But the first eight quasars they studied left them stunned. None of the eight was surrounded by a galaxy.

"We wondered what we were doing wrong," John Bahcall of the Institute of Advanced Study at Princeton told the American Astronomical Society's winter meeting in Tucson this week.

The quasars, Bahcall said, were "naked," meaning there appeared to be no nearby stars that could be feeding the quasars and thus supplying their extreme luminosity.

"We couldn't see anything" that supported popular theory, he said. Bahcall's team trained the orbiting telescope on other quasars, and when they reached No. 11 they found pay dirt. It looked pretty much like they had expected, a brilliant object surrounded by a faint galaxy. It was, he recalled, the "smoking gun."

"We were jumping up and down for joy," Bahcall said, even though the phenomenon appeared in only that single quasar.

Unfortunately, they didn't stop with that one. By the time they had finished their allotted time on the scope, they had studied an additional four quasars, all full of surprises.

The quasars were not surrounded by a galaxy, but rather were adjacent to "companion" galaxies that were being stretched out of shape by the immense gravitational tug of the quasar. Bahcall said the galaxies and the quasars would probably collide within the relatively short time of 10 million years.

Scientists had expected the neighborhood of quasars to be violent, but not so violent that even other entire galaxies were in jeopardy. And no one knows what the quasars are feeding on while waiting for the arrival of the companion galaxy.

So what does it all mean?

"I've told you all I know," Bahcall said. "I really don't understand this."

Donald Schneider of Pennsylvania State University made the observations with Bahcall and Sofia Kirhakos of the Institute for Advanced Study, and Schneider was as dumbfounded by the results as Bahcall.

"This is the most enigmatic data I have ever analyzed," Schneider said. "It is much too early to know what the final conclusions will be."

What seems clear, however, is that current theory about the nature of quasars will have to be revised.

"This is a giant leap backward in our understanding of quasars," Bahcall said.

It's an odd twist of fate. Bahcall was one of the most effective lobbyists for construction of the Hubble Space Telescope. Testifying before a congressional committee years ago, he said one of the things the Hubble would be able to do would be to confirm the theories about quasars, which were discovered in 1963.

The Hubble, he said, would be able to look at these enigmatic targets--the most distant objects in the universe--and confirm that they are indeed black holes devouring a surrounding galaxy.

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