Detection of gravitational waves opens "new window" on universe

It was a gathering of elite scientists like no other in recent memory at the National Press Club in Washington.

Professors of theoretical physics, nearly all PhDs and at least one Nobel Prize winner, mingled with dozens of reporters.

When the announcement came there was applause and a few cheers. Even though it had been leaked days before and speculated about in the scientific community for months there was more than just a "ripple" of excitement.

The detection of gravitational waves, sometimes described as ripples in the fabric of spacetime, was a "monumental" event, the scientists said with visible excitement.

And the work they described, carried out by hundreds of people all over the world, amounts to something most people said was worthy of a Nobel Prize in Physics.

The details of the announcement were straightforward: two listening facilities in the United States detected the gravitational waves on September 14, each confirming what the other had heard.

The duration was just a fraction of a second and the cause was the coalescence of two black holes about 1.3 billion years ago.

The result is that the scientific community has an entirely new way of studying the universe.

"Four hundred years ago Galileo turned a telescope to the sky and opened the era of modern observatory astronomy," said David Reitze, executive director of the Laser Interferometer Gravitational-Wave Observatory (LIGO) laboratory at Caltech, southern California, where part of the experiment was based.

"I think we are doing something equally important here today. I think we are opening a window on the universe, the window of gravitational wave astronomy."

They didn't parse their enthusiasm. "It's monumental," said Gabriela Gonzalez, a spokeswoman for LIGO. "It's mind-boggling," Reitze said, adding it is "truly a scientific moonshot, and we did it. We landed on the moon."

There were a lot of reasons for their excitement.

Gravitational waves are among the most spectacular predictions of Albert Einstein's general theory of relativity: that every accelerated body emits gravitational waves that are greater the more mass the body has.

But they are so tiny that Einstein did not believe that they could ever be measured. Physicists have been looking for direct evidence of them for more than 50 years. Until Thursday's announcement, all reports of success in measuring them have turned out to be untenable.

But their existence has not been in doubt.

Russell Hulse and Joseph Taylor Alan received the 1993 Nobel Prize in Physics for their work that provided indirect evidence of the existence of gravitational waves.

The LIGO programme was founded 10 years later and construction began in 1994 on the two listening facilities on opposite sides of the US.

After enhancements last year the LIGO sytem detected the waves on the first test run following the upgrade.

The scientists referred to the LIGO system as the most precise measuring devise ever built and said such precision was needed because it had to detect something one-thousandth the diameter of a proton.

Reitze said another amazing thing about the signal was that it is "exactly what Einstein's theory of general relativity would predict for two big massive objects like black holes spiraling and merging together."

The existence of binary black holes was an added bonus in the detection of the waves, said Bruce Allen, the director of the Max Planck Institute for Gravitational Physics in Germany. When LIGO set out the experiment, the expectation was that the first waves detected would come from two neutron stars interacting.

The scientists knew LIGO would be sensitive to two spiraling black holes if they existed, he said, and in a way they got lucky.

Many more surprises are expected in the years ahead. The LIGO system soon will expand to include a detector in Italy and another in Japan further down the road.

There will be much more news from the universe because each new method of observation has revealed surprises, the scientists said.

But they warned the breakthrough would not directly transform the human experience.

Kip Thorne, a professor at Caltech and one of the presenters at the news conference, said while the detection "brings us a much deeper understanding of how warped space time behaves when it’s extremely warped, I don’t think it’s going to [bring us] any closer to being able to do time travel."

Gonzalez called it "inspirational science," but said it was worth spending money on because it "pushes" other industries to making improvements. And beyond that it will "keep all of us looking into the sky."

Last update: Tue, 28/06/2016 - 17:25

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