The Milky Way is a spiral galaxy made of hundreds of billions of stars and planets and also this galaxy is a home to our own solar system which is located in the Orion Spur region of the galaxy. The Milky Way galaxy measures a mind boggling 120,000 light years across and is estimated to be about 13.6 billion years old, the galactic center can be found in the constellation Sagittarius and like any other large galaxies in the universe the Milky Way galaxy too harbors a cosmic terror at it’s heart which is a super massive black hole.
Black holes are cosmic objects that are extremely dense and exhibit immense gravitational forces, they are formed as a result of matter collapsing in on itself, creating regions with huge amounts of mass concentrated into an incredibly small area. The gravitational pull of a black hole is so strong that nothing can escape it not even light once the event horizon has been crossed, currently there are three different types of black holes namely The Stellar Mass which are the smallest, The Intermediate Mass which are somewhere in the middle and the third which is the largest The Super-massive. A Super-massive black hole contains between a million and billion times more mass than a typical Stellar Mass black hole and can be found at the center of large galaxies.
Scientists know that the center of the Milky Way contains a Super-massive black hole because they have observed a group of stars near the center of our galaxy zipping past an invisible object which indicates whatever lurks at the center holds a colossal amount of power and the only known object discovered so far within the universe that has this much density and gravity is a Super-massive black hole.
There are many theories on how Super-massive black holes form and although black holes cannot currently be directly observed the environment that they exist and interact with can be observed, one idea is that during early stages of the universe these black holes were lot smaller in size then over time they absorbed massive amounts of gases and dust, merging with other black holes growing larger and larger until they ended up the colossal monsters they are today, however the agreed reason for why these Super-massive black holes grow so big is still been researched.