BLACK HOLES  

Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.

THREE TYPES OF BLACK HOLES

STELLAR BLACK HOLES- SMALL BUT DEADLY

When a star burns through the last of its fuel, it may collapse, or fall into itself. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to compress and creates a stellar black hole.

Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-size range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.

SUPER BLACK HOLES- THE BIRTH OF GIANT

Super massive black holes may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accrediting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together.

INTERMEDIATE BLACK HOLES- STUCK IN THE MIDDLE

Scientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of mid-size, or intermediate, black holes (IMBHs). Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole.

In 2014, astronomers found what appeared to be an intermediate-mass black hole in the arm of a spiral galaxy.

"Astronomers have been looking very hard for these medium-sized black holes," co-author Tim Roberts, of the University of Durham in the United Kingdom, said in a statement.

"There have been hints that they exist, but IMBH's have been acting like a long-lost relative that isn't interested in being found."

Black hole theory 

Black holes are incredibly massive, but cover only a small region. Because of the relationship between mass and gravity, this means they have an extremely powerful gravitational force. Virtually nothing can escape from them — under classical physics, even light is trapped by a black hole.

Such a strong pull creates an observational problem when it comes to black holes — scientists can't "see" them the way they can see stars and other objects in space. Instead, scientists must rely on the radiation that is emitted as dust and gas are drawn into the dense creatures. Super massive black holes, lying in the center of a galaxy, may find themselves shrouded by the dust and gas thick around them, which can block the tell-tale emissions