By the gravitational collapse of a star of sufficient mass. Once the star stops producing energy, the radiation pressure decreases, and it can't maintain itself against its own gravity.
Its called a Super Black-hole and scientists believe it is what holds all galaxies together.
Black holes do exist - they are just VERY difficult to detect.
No one knows till now but scientists believe that there can be a black hole in the centre of the Universe.
No rubbish has been sent into a black hole.
If you go into a black hole you will be stretch out into two and then you will be crushed.
Scientists can determine the mass of a black hole through various methods, including observing the orbits of objects around the black hole, analyzing the gravitational lensing effects of the black hole on light, and studying the X-ray emissions from material falling into the black hole. These observations help scientists calculate the mass of the black hole based on the influence it has on its surroundings.
The very center is believed to contain a very powerful black hole.
Scientists think that quasars emit a large amount of energy because they believe each quasar has an incredibly large black hole in the center of it. They believe a torus, or disk of dust and gas, has material that falls near the black hole causing it to hear to millions of degrees that accelerates the reaction outward.
When a black hole spits something out, it is called a "black hole jet." This event happens when matter and energy are ejected from the black hole at high speeds, creating powerful jets of particles and radiation.
No - at least not intentionally.
Our galaxy contains a supermassive black hole at the center and probably several million stellar mass black holes scattered throughout.
I believe the closest black hole is in the center of the Milky Way galaxy... But is a black hole a dark hole? Hmm.