Wednesday August 18 3:54 AM ET
Astronomers Baffled by Space Light
By MATTHEW FORDAHL AP Science Writer
LOS ANGELES (AP) - An arsenal of analytic tools used to figure out the makeup and distance of stars and galaxies has failed to unlock the secrets of a mysterious celestial light detected three years ago.
``It's fairly uncommon to stumble on something you don't
have a clue about,'' astronomer S. George Djorgovski said Tuesday. ``It certainly hasn't happened to me, and I've been doing this for many years.''
Djorgovski was part of the team at Caltech's Palomar Observatory that detected the object, a pinpoint of light, during a digital survey of the northern sky.
It remains one of the biggest mysteries uncovered by the Digital Palomar Sky Survey. The survey, which has collected information on more than 50 million galaxies and about 2 billion stars, is about two-thirds complete.
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,'' Djorgovski said. ``That's the closest thing we have found in all the astronomical literature.''
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.
Light also usually holds clues about an object's distance. But because graphs derived from the light do not match anything known, researchers aren't sure whether it is inside or outside the Milky Way galaxy.
Repeated photographs revealed no changes in its appearance, ruling out the possibility that it's an exploding star or supernova.
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.
``But it's very competitive to get time on the Hubble, and
they don't like fishing expeditions,'' he said.