Black Holes

They are menacing features of deep space, monstrous devourers of everything around them. They are black holes.

Black holes are regions in space that are impossible to see because the gravity within them is so strong that not even light can escape. What is visible is matter being decimated as it is sucked in by the gravitational force of these cosmic vacuum cleaners.

As material is dragged into a black hole, it is torn apart and its bits are flattened into rotating discs. The debris speeds up as it gets closer to the mouth of the hole and the bits start to smash together, creating friction the heats up the matter. This leads to x-rays being given off, which can be detected by astronomers equipment.

The core of a black hole is known as a singularity, while the mouth is called the event horizon, the radius of referred to as the Schwarzschild radius. This measurement is named after Karl Schwarzschild, an astronomer whose work led to the theory of black holes.

Once matter passes the event horizon, it is gone for ever. The only way to escape a black hole is to build up energy within the distorted area of space around the event horizon, called the ergosphere, and be ejected.

Only rotating black holes, or Kerr black holes, have ergospheres. A hole rotates because the star from which it was formed was rotating as it collapsed. Non-rotating black holes are less common and are known as Schwarzschild holes.

Black holes come in two awesome sizes: stellar and supermassive. Stellar holes, of which there are millions in our galaxy, are the remains of dead stars that have imploded.

A supermassive black hole can have the mass of millions of stars. One is thought to lurk in the centre of every large galaxy. There is some disagreement over how they are formed. One theory suggests they are stellar black holes that over the course of millions of years have swallowed inestimable amounts of matter. Another conjecture is that supermassive black holes are clusters of star-like black holes that have merged. It also could be that a single gigantic gas cloud collapsed to form a supermassive black hole.

Mini black holes may also exist and be smaller in size than an atom, but larger in mass than a mountain. It is also possible that white holes might be a phenomenon of deep space, spewing out matter and energy into the universe.