ENP Newswire -
Release date- 28102013 - IMPERIAL COLLEGE
Imperial scientists are working on a space mission that will listen to violent cosmic events that send out ripples in the very fabric of the universe.
Probably one of the first real bits of physics we learn at school is how the force of gravity keeps us all from floating off into space - a lesson helped to stick by a certain apocryphal tale about a scientist and a falling apple.
But gravity is actually rather more complex and profound than this - certainly more complex than
In 1916 Einstein came up with his famous general theory of relativity, which completely redefined gravity. No longer was it thought of as simply a mutually attractive force between objects - but rather a deformation in the underlying fabric of the universe, known as space-time. Objects with mass distort space-time, essentially stretching it in all directions, and in doing so 'tugging' at other nearby objects, affecting their motion.
One feature of Einstein's theory was that when massive bodies moveA binary star system asymmetrically, they will create gravitational waves that ripple out through the fabric of spacetime at the speed of light. Prime candidates for the creation of gravitational waves are binary systems, where two stars orbit each other around their common centre of gravity (see image above). But gravitational waves are also likely to be given off by violet cosmic events such as the merging of black holes and even the big bang itself.
Yet, no one has ever observed a gravitational wave directly. We can infer their presence based on the energy that binary stars lose when creating gravitational waves. But definitive confirmation is proving rather elusive.
And if there's one thing we know about physicists, it's a dogged determination to fill gaps in theory - as shown by the confirmation of the existence of the Higgs Boson at CERN, 60 years after it was first postulated in theory.
But with gravitational waves it's so much more than balancing the books, as
'It opens up a whole new way of doing astronomy,' he says. 'Over the centuries astronomy has grown to cover more and more of the electromagnetic spectrum, seeing more colours if you like, whether visible light, infrared, X-rays or submillimetre. We've come to the realisation that the more ways you look at things, the more you learn. But it is always just looking, it's always visual. With gravitation waves, some people have said it's analogous to adding a sound channel; it's a totally different way of collecting information.'
Tim and his colleagues have been investigating the possibility of observing gravitational waves since the early 1990s, and in 2015 they will finally get that chance with a
But how does one look for something that's never been seen before and does not give off any light or an electromagnetic signature?
All types of waves, whether sound waves or ocean waves, create a periodic squashing and stretching effect in the medium in which they are travelling. That also applies to gravitational waves; but because the medium they are travelling in - spacetime - is three-dimensional (really four-dimensional, but we can ignore time in this case) it's slightly different.
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