Astronomy

Black Hole Terra Twister

Luckily for astronomers wanting to investigate black holes, which by definition are black and therefore virtually invisible, the ‘twisted spacetime carpet’ effect allows them to study black holes indirectly by looking at the effect they have on the space around them.

Black holes and particularly the supermassive kind, which can be found strutting their stuff at the centre of most galaxies, are of great interest to astronomers because they hold clues to how those galaxies evolved in the first place.

Now a team from Durham University has made a ‘supermassive’ breakthrough by finding a new way to measure how fast they spin.

Armed with the European Space Agency’s XMM-Newton satellite, the team, led by Professor Chris Done, took a look at a supermassive black hole with the mass of ten million Suns that lies at the heart of a galaxy 500million light years away.

This black hole, like many of its ilk, is surrounded by a spinning disk of gas and dust that sits like a glowing picnic, spread out across the spacetime rug waiting to dragged in and devoured. By looking at the gaseous picnic (also known as an accretion disk) in a variety of wavelengths, the team could determine how far the inner edge of the disc was from the black hole.

This distance can tell astronomers how fast the black hole is spinning because, like the unfortunate cat, material in the disk is drawn closer as the black hole’s spin increases.

The disk was found to be some distance from the edge of the black hole, which means that, for the moment at least (bearing in mind it is 500million light-years away so they are studying it as it appeared half a billion years ago), it is spinning at the relatively slow speed of ‘only’ half the speed of light.

But who cares how fast a black hole spins? Well, if you thought a pair of rubber-soled socks can make a mess of a carpet, just take a look at what a spinning black hole can do…