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article imageEinstein was right: U.S. researchers detect gravitational waves

By Brett Wilkins     Feb 11, 2016 in Science
Washington - After decades of effort, scientists in the United States have opened a new era of discovery by detecting gravitational waves 100 years after famed theoretical physicist Albert Einstein first predicted their existence in his general theory of relativity.
Researchers from the Laser Interferometer Gravitational-Wave Observatory (LIGO)—two observing stations located near Hanford, Washington and Livingston, Louisiana—announced the exciting breakthrough at the National Press Club in Washington, DC on Thursday, the Washington Post reports.
"Ladies and gentlemen, we have detected gravitational waves. We did it!" exclaimed LIGO executive director David Reitze to rousing applause. Gravitational waves are tiny ripples in the fabric of space-time generated by the colossal collision of two black holes dozens the mass of our sun at half the speed of light some 1.3 billion years ago. As Scientific American reports:
About 1.3 billion years ago two black holes swirled closer and closer together until they crashed in a furious bang. Each black hole packed roughly 30 times the mass of our sun into a minute volume, and their head-on impact came as the two were approaching the speed of light. The staggering strength of the merger gave rise to a new black hole and created a gravitational field so strong that it distorted spacetime in waves that spread throughout space with a power about 50 times stronger than that of all the shining stars and galaxies in the observable universe.
The discovery was unequivocal. Not only was the collision of the two black holes detected, a distinctive "chirp" was recorded as they hurtled toward each other. The signal closely matched what scientists had predicted working from Einstein's relatively equations.
Although such cosmic events are believed to be common, LIGO researchers were the first to ever detect gravitational waves resulting from the collisions. It was an incredibly difficult task to achieve. Gravitational waves compress and stretch space on such an infinitesimal scale by the time they are detectable on Earth that researchers had to find a way to measure such subatomic fluctuations in distance.
CBS News reports they used vacuum tubes stretching 2.5 miles (4 km) arranged in an L-shape through which finely-tuned lasers were fired between mirrors. This effectively increased the distance the laser beams could travel to nearly 1,000 miles (1,600 km). The beams were then recombined and directed into a sensor. The researchers also went to great lengths to reduce vibrations, using large mirrors to blunt Earth vibrations and reducing the pressure in the vacuum tubes to 1/1,000,000,000,000th of Earth's atmosphere at sea level to minimize sound vibrations.
The LIGO team celebrated their monumental achievement.
“We are all over the moon and back,” spokeswoman Gabriela González said at Thursday's press conference. “Einstein would be very happy, I think.”
“I think this will be one of the major breakthroughs in physics for a long time,” said Columbia University professor Szabolcs Marka, who added that the discovery will enable a deeper understanding of our universe. "Everything else in astronomy is like the eye. Finally, astronomy grew ears. We never had ears before.”
"It's the first time the universe has spoken to us through gravitational waves," marveled Reitze. "This is remarkable. Up to now, we have been deaf to gravitational waves but today we are able to hear them. That's just amazing to me."
LIGO co-founder Kip Thorne of the California Institute of Technology, who along with Rainer Weiss of the Massachusetts Institute of Technology and retired Caltech researcher Ronald Drever dedicated their careers to proving Einstein right, said that until now astronomers have viewed the universe as if it were a calm sea.
“The colliding black holes that produced these gravitational waves created a violent storm in the fabric of space and time, a storm in which time speeded up and slowed down, and speeded up again, a storm in which the shape of space was bent in this way and that way,” Thorne told the Guardian.
Leading astronomers, physicists and scientists of all stripes hailed the great discovery. Foremost among them was British theoretical physicist and cosmologist Stephen Hawking, who congratulated LIGO in a Facebook post 'liked' more than 100,000 times:
Theoretical physicist and futurist Michio Kaku tweeted that "Einstein would be proud" of the discovery:
Albert Einstein's estate reacted with a humorous tweet:
The National Science Foundation had spent around $1.1 billion over the course of more than 40 years on the project, vindicating researchers who have fought hard against scientific naysayers and Republican-inspired cuts to the nation's science budgets.
"I remember when LIGO was being discussed and debated in Congress and it was not clear that it would get funded," noted astronomer Neil deGrasse Tyson said during a speech at Columbia University in New York. "It took people with great foresight to say, 'this is something we should begin even though the technology is not ready for it,' because the science was. That's the kind of decision-making that... invents a future."
"What's really exciting is what comes next," said LIGO director Reitze while announcing the discovery. "Four hundred years ago, Galileo turned a telescope to the sky and opened the era of modern observational astronomy. I think we're doing something equally important here today... opening a window on a new universe of gravitational wave astronomy."
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