Astronomers have detected gravitational waves from two merging black holes located more than a billion light years from Earth. Stephen Hawking has called it a key moment of scientific history.
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The US-based Laser Interferometer Gravitational-wave Observatory (LIGO) announced its ground-breaking discovery of gravitational waves on Thursday (Feb 11), which fulfilled the prediction of Albert Einstein’s general theory of relativity a century ago. When a gravitational wave comes through, it stretches space in one direction and squeezes it in another, causing the lasers to change ever so slightly. Now, the detection of these undulations has changed how we see the universe.
The researchers said they identified gravitational waves coming from two distant black holes – extraordinarily dense objects whose existence also was foreseen by Einstein – that orbited one another, spiraled inward and smashed together at high speed to form a single, larger black hole. “Observing the two black holes is fantastic – but there are probably all kinds of things out there we can observe with this technology”.
Just a little refresher – what is a black hole again?
For India, this discovery is also a matter of pride given the role of Indian scientists in the Ligo project.
“This discovery is a very big achievement for science, it basically opens up newer horizons for us to look at the universe”. “They released the same amount of energy as 8.5 billion trillion trillion Hiroshima nuclear bombs”, explains Dr. Alan Duffy, a professor of astronomy at Swinburne University.
The violent event created “gravitational waves” – a ripple in space-time. “We are really witnessing the opening of a new tool for doing astronomy”, MIT astrophysicist Nergis Mavalvala said in an interview. This discovery has the potential to revolutionise our understanding of the forces of gravity, time and space the most basic of elements that impact our everyday lives.
He continued, “It’s the first time the Universe has spoken to us through gravitational waves”. At the end of previous year the European Space Agency (ESA) launched the LISA Pathfinder to test the technologies for detecting gravitational waves in space. The Hanford LIGO detected them seven milliseconds after they traveled past a twin LIGO in Louisiana.
Gravitational waves experience no such barriers, meaning they can offer a wealth of additional information. “That totally revolutionizes our expectations of what we can see”.
The waves have already shown that they travel at the speed of light and that black holes do exist. The gravitational waves described by Reitze is made of one black hole with the mass of 29 suns while the other was the equivalent of 36 suns. Like the best data visualizations, it breaks down gravitational waves, and the method by which LIGO detected them, in a clear, visually compelling and digestible way.
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In order to build a more advanced interferometer, Gonzalez said they used special mirrors that, “essentially make the light go back and forth about a hundred times, essentially making it about 100 times more sensitive than it would be”.
