What is a black hole?

Black holes ignite the imagination of the scientific community and are often a source of fascination for story writers as well. They are often characterized as immensely powerful interstellar vacuum cleaners which consume everything in sight. But do they expand exponentially and can they consume the earth in an instant? Not Really.
A black hole is formed when huge stars exhaust all of their energy and internally collapse in a process known as supernovae. Yet, the hole created in the aftermath is not particularly large, and does not expand as it ‘consumes’. Rather than consuming outright, it pulls matter towards it and traps it in an orbit of its own. This is because it can only draw in material of a similar mass and black holes are relatively small, compared to the stars they replace. The theoretical collapse of the sun would produce a hole with a radius of just 2 miles. A sun sized black hole would permit the Earth to orbit it in the same manner and position it currently orbits the sun. The misperception stems from its immense density and its invisibility.
All light in the orbit of a black hole immediately falls victim to it. Yet, while they have never and cannot be ‘observed’, their existence ‘came to light’ while scientists in the 1960s where able to detect the gravitational disturbances in a constellation which disturbed the orbits of planets and moons. Stephen Hawking is one of the most celebrated proponents of black hole theories. Hawking developed paradoxical theories regarding black holes, suggesting that they can shrink, dissipate and that particles and information trapped in its gravitational pull are not lost forever.