Astronomers baffled over mysterious space light

LOS ANGELES - A mysterious celestial object detected three years ago in the northern sky is baffling scientists who have so far been unable to figure out its makeup or how far it is from Earth.

It's rare for astronomers to find an unexplainable object, but it's even more unusual for it to remain undefined for more than a week, said S. George Djorgovski, a California Institute of Technology astronomer who helped discover the object.

"It's fairly uncommon to stumble on something you don't have a clue about," he said Tuesday. "It certainly hasn't happened to me, and I've been doing this for many years."

Djorgovski and his team at Caltech's Palomar Observatory in San Diego County detected the object during a digital survey of the northern sky. It's one of the biggest mysteries uncovered to date.

Usually, astronomers are able to determine an object's composition and distance by breaking down and analyzing its light. But the mystery object's spectrum does not fit any of the known patterns, Djorgovski said.

And since scientists rely on a shift in the light of the spectrum to determine distance, they are unsure whether the object is inside the Milky Way or at the edge of the universe.

Repeated photographs of the pinpoint of light revealed no changes in its appearance. That ruled out the possibility that it's an exploding star or supernova.

Some astronomers believe the object may be a new class of quasar, sources of energy found in the center of galaxies and believed to be powered by matter falling into massive black holes.

"This sort of looks a little like them, but not quite. The similarity may be superficial," he said. "That's closest thing we have found in all the astronomical literature."

Djorgovski challenged fellow astronomers to help explain his discovery at the June meeting of the American Astronomical Society in Chicago. So far, nobody has produced an adequate explanation.

"We probably have looked at the spectra of several thousand quasars, and this just doesn't seem to fit," said David Crampton, an astronomer with the National Research Council of Canada. "It didn't ring any bells."

The next step will be to analyze the object's infrared spectrum, something Djorgovski hopes to do next month at the Keck Observatory in Hawaii.

Researchers also hope that the Hubble Space Telescope might someday be pointed at the object, which is located in the constellation Serpens, or snake.

"But it's very competitive to get time on the Hubble, and they don't like fishing expeditions," he said.

The Digital Palomar Sky Survey, which has collected information on more than 50 million galaxies and about 2 billion stars, is about two-thirds complete. The DPSS and other sweeping surveys in progress are likely to create more mysteries.

"We now have the advent of a new way of doing astronomy, data mining the sky using these digital surveys," he said. "It's virtually guaranteed that we will be discovering things we never heard of before. This is maybe the first example of one of those things."

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