EVERYDAY SCIENCE

Detailed explanation-1: -If its mass collapses into an infinitely small point, a black hole is born. Packing all of that bulk-many times the mass of our own sun-into such a tiny point gives black holes their powerful gravitational pull. Thousands of these stellar-mass black holes may lurk within our own Milky Way galaxy.

Detailed explanation-2: -Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.)

Detailed explanation-3: -Black Holes If the collapsed stellar core is larger than three solar masses, it collapses completely to form a black hole: an infinitely dense object whose gravity is so strong that nothing can escape its immediate proximity, not even light.

Detailed explanation-4: -About 75% of the mass of the star is ejected into space in the supernova. The fate of the left-over core depends on its mass. If the left-over core is about 1.4 to 5 times the mass of our Sun, it will collapse into a neutron star. If the core is larger, it will collapse into a black hole.

Detailed explanation-5: -Stellar black holes form when the center of a very massive star collapses in upon itself. This collapse also causes a supernova, or an exploding star, that blasts part of the star into space. Scientists think supermassive black holes formed at the same time as the galaxy they are in.