Milky Way could hold hundreds of rogue black holes: study
Wed Jan 9, 3:09 PM ET



CHICAGO (AFP) - Hundreds of rogue black holes may be roaming around the Milky Way waiting to engulf stars and planets that cross their path, US astronomers said Wednesday.
The astronomers believe these "intermediate mass" black holes are invisible except in rare circumstances and have been spawned by mergers of black holes within globular clusters -- swarms of stars held together by their mutual gravity.
These black holes are unlikely to pose a threat to Earth, but may engulf nebulae, stars and planets that stray into their paths, the researchers said.
"These rogue black holes are extremely unlikely to do any damage to us in the lifetime of the universe," said Kelly Holley-Bockelmann, an assistant professor of physics and astronomy at Vanderbilt University in Nashville, Tennessee.
"Their danger zone, the Schwarzschild radius, (or gravitational radius) is really tiny, only a few hundred kilometers. There are far more dangerous things in our neighbourhood."
The evidence for "intermediate mass" black holes, as opposed to supermassive or stellar-mass black holes, is still largely theoretical and therefore controversial. Only two tentative observations of objects of this sort have been made to date.
But the theoretical case for them is strong, and X-ray observations in recent years suggestive of their existence encouraged Holley-Bockelmann and colleagues at the University of Michigan and Penn State University to simulate what would happen if intermediate mass black holes combined with stellar-sized black holes, which are plentiful in globular clusters.
Using sophisticated computer modeling, they calculated that these mergers would generate hundreds of mid-size black holes, and that the force of their combinations would catapult them out of the globular cluster at speeds of up to 4,000 kilometers per second.
That would leave these black holes, each weighing several times the mass of the sun, to careen around interstellar space, unattached to any stellar system, at high speeds. Hence the term rogue.
Bockelmann presented her findings Wednesday at the 211th American Astronomical Society meeting in Austin, Texas.
Separately, researchers reported that they have discovered a new X-ray source in the galaxy of Centarus A.
The X-ray appeared in new observations of the galaxy taken in 2007, but was not visible in a survey taken in 2003. The new ray is much smaller than the X-ray jets that have long been a feature of the galaxy, but it still glows brightly.
The new object is most likely a binary star system, the researchers from Ohio State University said. The two stars probably formed at the same time, with one much more massive than the other.
The more massive star evolved more quickly, and collapsed to form a black hole. It is now slowly devouring its companion. Such binary systems are thought to be rare.

i think maybe there something in that:shrug:

Our Galaxy sure is a dangerous place and more so the more we look at it....but it sure is beautiful...