What Are Black Holes? : Introduction

What Are Black Holes ?

Black holes are some of the strangest and most fascinating objects found in outer space. A black hole is a region of Space-Time exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it.

Albert Einstein first predicted black holes in 1916 with his general theory of relativity. The term "black hole" was coined in 1967 by American astronomer John Wheeler, and the first one was discovered in 1971. 

Types Of Black Holes:   

 

1. Stellar Black Holes

2. Super-massive Black Holes 

3. Intermediate Black Holes.

  

1. - 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.According the Harvard-Smithsonian Center for
   Astrophysics,"the Milky Way contains a few hundred million" stellar black holes.
   
   

   2- Super-massive Black Holes: (The birth of giants)

   

   Small black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.
   
   Scientists aren't certain how such large black holes spawn. Once they've formed, they gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes.
   
   
   
   
   
   
   
   
   Supermassive 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 accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together.
   
   

   3- 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 super-massive 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."