Physicists at the Advanced Laser Interferometer Gravitational Waves Observatory (LIGO) are incredibly excited over the second observation this year of a breakthrough phenomenon: they have confirmed gravitational waves, reports Gizmodo.
Predicted by genius and science icon Albert Einstein over a century ago, gravitational waves are ripples in the fabric of spacetime. The LIGO made scientific history in February when they released the news that a large spacetime ripple had been detected across their Livingston, Louisiana and Hanford, Washington machines on September 14th, 2015. The ripple was a result of two black holes in the final stages of merging located 1.3 billion light years away, weighing 29 and 36 solar masses, respectively.
This second gravitational wave came three months after the first, on December 26th. This was once again the result of two black holes merging at 1.4 billion light years away, although these weighed less at 8 and 14 solar masses. Their coming together made a black hole 21 times more than the mass of the sun, transforming enough mass into a burst of gravitational energy.
David Shoemaker, leader of the Advanced LIGO construction program, says,
Just the fact that we’ve now seen more than one [gravitational wave source] is very exciting. It takes us out of the ‘gee whiz, could it be true?’ mindset to yes, this is a tool that we can use.
Gravitational waves happen when the heaviest objects in the universe crash together in massively powerful collisions, sending shockwaves across spacetime, like ripples in a pond. These waves are incredibly faint when they reach Earth, but they happen all the time and offer insights into the universe completely different from what has been observed using electromagnetic spectrums.
These faint gravitational waves require precise, highly sensitive detectors. The initial LIGO, which appeared in 2002, was reborn as the Advanced LIGO in 2015. It began gathering data and almost immediately, the first gravitational wave was recorded. “The first event was huge—it knocked us off our feet,” Shoemaker said of the September detection.
The team spent five months ruling out everything else that could have made the first gravitational waves, including human error and environmental factors, validating their discovery very carefully before going public. They conducted the same tests for the second waves. Now, science has enough data to officially enter into the “era of gravitational wave astronomy.”
Gravitational waves will offer a unique tool for observing objects in the universe that don’t emit light, and are expected to be a very important tool in gathering new information about the galaxy and make new discoveries about the universe.
Advanced LIGO is currently undergoing improvements after its first observational run ended in January, with its next run scheduled for this fall. It will have better sensitivity and will be able to detect gravitational waves over a broader area of space. The European Gravitational Observatory (EGO), with its gravitational wave detector VIRGO in Italy, is also expected to contribute to this new field in astronomy.
The announcement of this second discovery was given at the American Astronomical Society in San Diego, California. It will be published in Physical Review Letters.
