Quasar Eruption Puzzles Scientists : Astronomy: A chance observation of the 1989 event detected an implausibly huge release of X-ray radiation. More studies are planned.

A mysterious quasar in the distant sky erupted so violently in 1989 that it spewed out more radiation in three minutes than the sun will release in nearly a million years, scientists reported Monday.

The brilliant burst was detected by an instrument on a Japanese research satellite called Ginga on Nov. 13, 1989, but the finding was so startling that scientists spent months studying the data before announcing the discovery. Quasars are distant starlike objects that shine brighter than a million suns.

Bruce Grossan, a graduate student at the Massachusetts Institute of Technology who discovered the burst while studying results from the Ginga satellite last summer, said he was so skeptical that he did not even report it for several days. When he determined that the quasar had erupted violently, he sent a single-page message to the Cambridge campus.

“It said, ‘flare, flare, flare,’ ” said Grossan’s adviser, MIT astrophysicist Ronald Remillard.

The discovery was announced Monday during the winter convention of the American Astronomical Society.

At first, no one was ready to believe the finding because there are mathematical limits to the amount of energy a quasar can release without blowing itself apart, Remillard said. The burst detected by Ginga exceeded those limits by about 20 times.

After determining that the figures were real, scientists decided to announce it, even though they are not certain how the quasar could have erupted with such brilliance.

The quasar that erupted is called PKS 0558-504 and is located about 2 billion light-years from Earth. Scientists were studying it because it is a high emitter of X-rays, and during the 11-hour observation, it increased its emissions of X-rays by 67% over a three-minute period.

The observation has not been confirmed, possibly because no one else was known to be studying the quasar at the time of the eruption. Other studies are planned, but for now, scientists are left trying to explain something that would seem to defy explanation.

It is widely believed that the energy output of a quasar comes from hot gases that are falling into a super-massive black hole at its center. As matter falls toward the black hole, it is ripped apart and becomes a cloud of charged gas particles. That process releases the X-rays that Ginga detected.

Remillard said the most plausible explanation is that some of the hot gas was somehow ejected violently in the direction of the Earth, causing the rapid rise in emissions.