Scientists have made a breakthrough announcement confirming the existence of gravitational waves, in a landmark finding for physics that opens a new window for studying the cosmos.
Researchers at the $620M Advanced Laser Interferometer Gravitational-Wave Observatory in the United States said on Thursday that they had detected minute ripples in the structure of space-time for the first time.
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The researchers said they detected gravitational waves coming from two black holes – extraordinarily dense objects whose existence also was foreseen by Einstein – that orbited one another, spiralled inward and smashed together.
They said the waves were the product of a collision between two black holes 30 times as big as the sun, located 1.3 billion light years from earth.
The scientific milestone, announced at a news conference in Washington on Thursday, was achieved using a pair of giant laser detectors in the US, located in Louisiana and Washington state, capping a long quest to confirm the existence of these waves.
Einstein first predicted the existence of gravitational waves 100 years ago in his theory of general relativity, suggesting that some of the most powerful processes in the universe, such as colliding black holes or exploding stars, would cause disruption to the fabric of the universe.
He thought their extraordinary energy would radiate out in waves at the speed of light, causing ripples and distortions in what he called space-time.
The problem was these gravitational waves were thought to be very weak and almost impossible to detect, until now.
“It just takes such incredible sensitivity,” said Andrew Pontzen, a fellow at University College London.
“It’s a really subtle effect both from the theoretical side and also just from the magnitude of the effect you are looking at.”
A new window on the Universe
Scientists say the detection of gravitational waves will open a new window on the universe.
In the same way that radio waves and X-ray telescopes have vastly increased what we are able to see, they say gravitational waves could do the same, revealing new details about the formation and structure of galaxies, the behaviour of black holes and the evolution of the universe.
“At the moment we look at the universe using telescopes that collect light,” says Pontzen.
“Now we are going to be able to change mode, look out into the universe in a completely different way and find very different objects to what you’d actually be able to see directly with a normal telescope.”
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Scientists are also testing technology in space that could be used to detect gravitational waves free from the interference and noise on Earth.
The European Space Agency’s LISA Pathfinder mission was launched late last year and is able to detect movements as small as one millionth of a millimetre.
It hoped that these readings will eventually add to those from observatories on earth.
“There are plans to develop this technology and in particular to open new detectors at new places on the earth,” says Pontzen.
“That slowly allows you to start triangulating where these waves are coming from, and start pinpointing individual objects.”