New picture of galaxy shows turbulent core
After a year of scanning radiowaves from the Milky Way, a group of astronomers has just charted the center of our galaxy with unprecedented clarity.
Resulting images show three curving streams of gas apparently converging on the center of our galaxy' and, perhaps, into a black hole -- theoretically a collapsed star of such gravitational pull that even light cannot escape its clutches.
If such an object is actually there, then these images are the first that show matter "falling" into a black hole.
The images, reconstructed by a California Institute of Technology team from observations at New Mexico's Very Large Array (VLA) radio telescope, depict a hot, explosive area that may be responsible for the turbulence at the core of the galaxy. Earlier attempts to probe this area in recent years have led some scientists to speculate that the hot area may have been created by a black hole.
"What we've done," says Kwokyung Lo, the California Institute of Technology astronomer who led this effort, "is to give a clearer picture of what the motion of gases are near the core of the galaxy."
Previous studies by scientists at the University of California at Berkeley noted extremely rapid motions of these gases -- remnants of disintegrating stars -- as they neared the core. That led many to speculate that the gases were under the control of an extremely powerful gravity field, perhaps a black hole or some other extraordinarily dense object.
Such a phenomenon would also explain the cause of an intense energy source that recent studies have determined is creating turbulence in the galactic center. As matter falls into a spinning black hole, it becomes enormously compressed and heated, thus releasing great amounts of energy.
The energy being released at the center of our galaxy does not compare to the enormous amounts pouring out of some distant galaxies. But if the mechanism that produces the energy is the same, then the VLA images could provide a critical clue in understanding the behavior and evolution of galaxies.
And if it turns out that a black hole is actually in the galactic core, then these images could provide scientists theorizing on the existence of black-holes with their first glance of one.
At the current state of the art, however, scientists cannot be completely sure. Black holes' peculiar characteristics make them particularly elusive.None has ever been observed.
Because of this, the debate over the very existence of black holes is rekindled in some quarters with each new "discovery."
"It could be something we haven't dreamed of," Dr. Lo admits. Yet he adds that the black hole theory seems to be the best explanation of the behavior of the gas streams.
"There is certainly something funny going on out there, and there is no reason not to think a black hole would form under the conditions we've observed, " he says.
"They're a natural consequence of physics."