"There is interest in this source because all other black holes [in the galaxy]have appeared along the Milky Way [plane]," said Ron Remillard, an astronomer at the Massachusetts Institute of Technology. Remillard explained that most of the objects in the Milky Way reside in a single plane, and that the objects within this disk are much younger than those lying just outside. Furthermore, astrophysical theory suggests that black holes in particular should be found at the center of galaxies -- not on their outskirts. XTE J1118+480 seems to reside within the galaxy but outside the plane -- a combination that suggests it may be one of the older objects in our galaxy.

"This source may be related to the ancient population of stars that have random orbits around the center of the galaxy," said Remillard.

On the other hand, it might be that XTE J1118+480 is so close to Earth, it just looks like its outside the Milky Way disk. Scientists still dont have enough data about the object, which was first spotted March 29^th, to know for sure. "Our uncertainty about its nature is enough to convince us to spend some of our time examining it," said Tim McKay, a scientist at the University of Michigan.

XTE J1118+480 was discovered by the Rossi X-ray Timing Explorer, a NASA satellite that scans the sky for X-ray sources. Later analysis of data from ROTSE, an optical telescope run by several astronomical observatories, confirmed that the X-rays detected by Rossi were coming from a strange stellar object in the Big Dipper.

If the object does turn out to be a black hole or neutron star lying outside our galaxy's plane, astronomers will have to rethink theories about the placement of such stellar objects in relation to central galactic planes. If, on the other hand, the object lies within the galaxys disk, astronomers will have to restructure their ideas about just how many black holes reside in the Milky Way. Either way, until further evidence of its nature surfaces, XTE J1118+480 will keep researchers guessing.