The scientific discussion forums, publications and newsletters have been booming for two weeks regarding the discovery of gravitational waves. A discovery that was predicted by Albert Einstein nearly a hundred years ago but only experienced, found, tested and verified now. At least, that’s what most of us believe. Days prior to the announcement that gravitational waves had been discovered, scientists all over the world were murmuring hints at its validity.
Twitter and newsletters would occasionally be the host of a cryptic message or two regarding how there was something cooking in regards to gravitational waves. But the real event that triggered everything and set the research in motion had taken place months before, in two different corners of the United States, in the confines of the two Laser Interferometer Gravitational Wave Observatories – one in Hanford and the other in Livingston.
In the morning of September 14th, 2015, a ripple caused by two black holes colliding and travelling from incredibly far away passed through the Earth and recorded by LIGO Livingston, only to be caught on its radar by LIGO Hanford 7 milliseconds later. Though the ‘impact’ manifested itself through a barely noticeable ‘thump’ that stretched and lasted for a mere two milliseconds, it was there, visible on the radar. An easy to miss thing almost.
It took researchers months to be able to study the events that had occurred and be able to confirm with a hundred percent certainty that they were not mistaken in thinking that the signal that the LIGO had picked up was indeed a gravitational wave. And after long and strenuous studies, they were finally able to do so: not only that gravitational waves existed, but this was the direct proof that binary black hole systems exist and that they can, eventually, end up merging into one gigantic black hole, distorting the space-time around it for billions of light years.
It has been calculated that the wave that hit the Earth on the early morning of September 14th, 2015 had originated from a black hole merger nearly 1.3 billion years ago. So long ago, and yet the effect of the impact travelled so far – even if now only a small remainder of it remains.
The LIGO detectors had been built decades ago; a symbol of the arduous search that scientists had embarked on when they chose to chase the gravitational waves on the whims of another, brilliant scientist that lived a century ago. Only decades later, the LIGO project earned results. And now, with this new information on our hands, humanity can look at the universe differently, on the paved path that the gravitational wave discovery has emerged.
You can listen to the sound of two black holes merging 1.3 billion years ago here.
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