BLACK HOLES Black holes were once thought to be the monsters of the Universe, devouring everything around them in a frenzied cosmic feast. But now astronomers think that rather than being a space menace, black holes may be fundamental to the creation of galaxies. Black holes are regions of space where gravity is so strong that not even light can escape, making them impossible to see. But we can see the stuff that is being sucked in to these massive cosmic vacuum cleaners. Anything that approaches a black hole is first torn apart by its immense gravitational force and then forms a flat rotating disc that spirals into the hole. As this debris gets closer and closer to the mouth of the black hole it speeds up and the bits start to smash together. The material heats up due to this friction [this is the same effect as when you rub your hands together to warm them up]. When this happens around a black hole, X-rays are given off which we can detect. If the black hole is really large and has lots of debris in its disc, then it can reveal itself as one of the brightest objects in the Universe - a quasar.

WORMHOLES As any science fiction fan knows, one of the most menacing and mysterious things in space is a wormhole. Wormholes are a possible consequence of Einstein's Theory of General Relativity. Einstein came up with the remarkable idea that mass warps space, and the bigger the mass, the more space will be bent. This strange conjecture was proved by Arthur Eddington in 1919, when he journeyed to the island of Principe, off the coast of Africa, for the solar eclipse. There he proved that the Sun bent light from the stars as it passed in front of them. Theoretically, a wormhole could be formed when two or more massive bodies warp space and the fabric of space collides, forming a tunnel between distant places. The easiest way to think about this is in two dimensions rather than three.
Information provided by http://www.bbc.co.uk/

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