Black holes, one of the more frightening and fascinating forces in space, may be much more numerous than previously thought.

Scientists analyzing a patch of sky have come across a kind of "stealth" black hole, called VLA J2130+12, that was previously mistaken for a distant galaxy. Unlike standard black holes, which pull in a tremendous amount of material and emit detectable X-rays, this clandestine version gobbles up matter and light at a much slower rate.

"Usually, we find black holes when they are pulling in lots of material. Before falling into the black hole this material gets very hot and emits brightly in X-rays," said Bailey Tetarenko of the University of Alberta, Canada, who led the study. "This one is so quiet that it's practically a stealth black hole."

The good news is VLA J2130+12 is a safe 7,200 light years from Earth. The bad news is, now that we know they exist, there may be many more stealth black holes that are lurking closer.

"Some of these undiscovered black holes could be closer to the Earth than we previously thought," said Robin Arnason, a co-author from Western University, Canada. "However there's no need to worry as even these black holes would still be many light years away from Earth."

Astronomers estimate our Milky Way may contain as many as 100 million stellar-mass black holes. Thanks to this recent discovery, there may be an additional 25,000 to 150 million low-mass black hole binaries hiding in our neighborhood, as well.

Sleep well.