Blast From Empty Space Poses Mystery

The researchers also collected the visible light from the burst's afterglow with the Gemini North 8-meter telescope in Hawaii, then split the light into its spectrum of colors to look for telltale "absorption" lines. These dark lines are sure signs of material in the burst's home galaxy filtering the light of the burst.

"We usually see very deep absorption features," said Caltech astronomer Brad Cenko, lead author of the report. "In this case we didn't see any. That in and of itself is pretty unique."

Nor did any other researchers have any luck.

"There are quite a few groups that have looked at this place," confirmed Gehrels. "You can really tell for sure that there's nothing going on there."

The next step, says Cenko, is to win some time using the Hubble Space Telescope to look for the missing galaxy. If it's not there, it's possible they could see some signs that two nearby galaxies, already observed with the Keck I telescope, have been colliding and leaving a string of lonely stars of all ages and sizes between them, he said.

"That's the leading hypothesis," Cenko said.

Then again, they could find something else entirely unexpected. As Cenko added, "There are still lots of surprises in this field."

Related Links:

Larry O'Hanlon's blog: Earth Impacts

NASA: Gamma Ray Bursts

NASA's Swift telescope

The Hubble Space Telescope