Fourth Gravitational Wave Detected – Now By Two Groups of Scientists

The LIGO Livingston control room as it was during Advanced LIGO’s first observing run (O1). This panoramic was sewn together from several images. Photo: Amber Stuver, Wikimedia Commons
The detection of gravitational waves, a phenomenon predicted by Albert Einstein a century ago, confirmed some of the humanity’s most advanced theories about the universe early last year.

Now the fourth such collision of two black holes – impossibly far off, a long, long time ago – has been detected by multiple agencies.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors in Louisiana and Washington State (supported by the National Science Foundation reported the detection on Aug. 14, 2017. At the same time, in Pisa, Italy, the new Virgo detector detected the same ripple in space-time.

The Virgo detector has been in operation just two weeks, according to the collaboration, involving Italy, France, the Netherlands, Poland, and Hungary.

“It is wonderful to see a first gravitational-wave signal in our brand new Advanced Virgo detector only two weeks after it officially started taking data,” said jo van den Brand, Virgo spokesman, of Nikhef and VU University Amsterdam.

The Advanced LIGO started operations in September 2015, and made its first detection just weeks later.

This fourth detection involved an enormous event 1.8 billion light years away: the crash of two black holes with masses 31 and 25 times the mass of our sun. The two created an even bigger spinning black hole with 53 times the mass of our sun, the scientists said.

In the massive merger, mass of approximately three of our suns was converted into energy.

That burst rippled through space-time until it reached Earth – and the three new detectors.

Supernovae, collisions of black holes, and the creation of neutron stars through thermonuclear conflagrations are so disruptive that they cause the fabric of the universe to vibrate like a drum. But by the time the ripples reach the Earth, they are diminished to just a billionth of the diameter of an atom, according to scientists.

The arrival times of the signals – different in Louisiana and Washington by about a millisecond – allow scientists to determine the rough position of the source of the wave, they have said.

The new detector gives humanity another ear to space. The gravitational wave detections could come even more frequently, and mean even more to science, they said.

“This is just the beginning of observations with the network enabled by Virgo and LIGO working together,” said David Shoemaker, the LIGO Scientific Collaboration spokesman, also an MIT scientist. “With the next observing run planned for Fall 2018 we can expect such detections weekly or ever more often.”

Virgo, which was revamped and upgraded over a six-year project, is less sensitive than LIGO. But the addition of the third detector helps better triangulate the location of the waves – and potentially allow follow-up observation and interpretation, the two groups said in a joint statement.

“The increased precision will allow the entire astrophysical community to eventually make even more exciting discoveries, including multi-messenger observations,” said Laura Cadonati, of Georgia Tech. “A smaller search area enables follow-up observations with telescopes and satellites for cosmic events that produce gravitational waves and emissions of light, such as the collision of neutron stars.”

Original article here.

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