Question: what is a black hole

David Freeborn answered on 20 Jun 2013:

Hi frogatelli,

Good question! A black hole is an object with a mass that is so dense, that nothing, not even light, can escape its gravity.

The heavier an object is, the stronger its gravitational pull towards other objects becomes. The gravitational pull also gets stronger the closer objects get. What this means is that if an object becomes very, very dense, there is a region around it where nothing is able to escape, the gravity is just too strong.

Light is the fastest object in the Universe- nothing can travel faster. So if not even light can escape a black hole, then nothing can escape it.

Black holes usually form from massive stars. When the star becomes heavy enough, its gravitational pull is so strong that it collapses in on itself and forms a black hole. In fact, we think there is a black hole at the centre of our galaxy, the Milky Way. One day, the whole galaxy will be sucked into this black hole, billions of years into the future.

At the LHC where I work, we might also be able to make tiny, microscopic black holes, by colliding particles into each other at very, very high energies.

The gravity of a black hole is so strong, it distorts the space and time around it. You can watch what it would look like to fall into a black hole here:

(but I don’t recommend it- you’d be burned alive by the intense radiation, then stretched infinitely thin, and then trapped, unable to escape ever again)