BOZEMAN — A century ago Albert Einstein predicted the existence of gravitational waves rippling through the universe, and on Thursday a team of 1,000 scientists worldwide — including Montana State University astrophysicist Neil Cornish — announced they found proof in the echo of a billion-year-old collision between two massive black holes.
“It’s great to finally be able to tell everybody,” said Cornish, 47, speaking in his native Australian accent, standing in line at The Daily coffee shop.
As the story broke on NPR and the New York Times’ front page, his cellphone was buzzing with friends texting congratulations and a USA Today reporter calling.
The discovery, originally made last September, is so exciting because “we’ve never seen ripples in this force (gravity) before,” Cornish explained. It’s part of “our quest to understand the fundamentals of the universe.”
“One of the things we find most exciting is that we’ve gained a new sense. It’s like we were deaf, and now we can hear the universe,” he told the Bozeman Daily Chronicle (http://bit.ly/1Tgm0ny ). “Before, all information came from different forms of light. Now we can listen to objects that don’t emit light, like black holes.
“It’s inaugurating an entirely new branch of astronomy. It’s akin to Galileo turning his telescope to the heavens.”
Cornish, co-director of MSU’s eXtreme Gravity Institute, said he, his graduate student Margaret Millhouse and five MSU Ph.D. graduates will be named on scientific papers on the discovery, among more than 1,000 scientists in 16 countries, from Germany, Japan, France, Italy and Australia to the United States.
“This absolutely is a Nobel Prize-worthy discovery,” Cornish said, for the three “visionaries” who have been working on it for decades — Kip Thorne and Ronald Drever of Caltech in Los Angeles and Ray Weiss of MIT in Boston. Weiss, in his 80s, is still out tinkering and trouble-shooting on the giant detectors, built in Hanford, Washington, and Livingston, Louisiana.
“They’ve worked on this for 50 years,” Cornish said. “I think this is one of the most significant scientific discoveries in history.”
The technology developed to build the detecting instruments by itself is worthy of a top prize, Cornish said. These are the most sensitive instruments human beings have ever made.
Called LIGO, for Laser Interferometer Gravitational-Wave Observatory, the L-shaped instruments consist of two arms, each 2 miles long, housing lasers that shoot beams to mirrors. After years with no results, the detectors were recently upgraded to detect a change one ten-thousandth of the width of an atom nucleus. It’s like detecting the width of a strand of hair in the 4 light years distance between Earth and the nearest star.
If, as Einstein predicted, gravitational waves squish and stretch the fabric of space-time, then the length of the L arms should stretch and contract slightly when gravitational waves pass through.
It was 3 a.m. in Montana on Sept. 14, when computers detected a pretty big blip in the LIGO instruments – first in Louisiana, and then in Washington.
“We thought, wow, this looks amazing,” Cornish said. That Monday, MSU ran one of five computer analyses of the data, using algorithms developed by past MSU students. By Tuesday they could see that the signal fit the exact pattern predicted in computer simulations of two black holes colliding.
“It was just perfect,” Cornish said. “It was so loud and the signal was so clear.”
But Cornish and Millhouse weren’t supposed to discuss it with anyone outside the project. And it took time to double check and make sure there wasn’t some mistake. It was like seeing your team score, he said, but then waiting to see if a flag was thrown.
While other teams had worked on perfecting lasers, mirror coatings, Einstein’s calculations and quantum computers, the MSU group worked on developing ways to analyze the data. The other MSU-trained scientists listed on the discovery papers, Cornish said, are Tyson Littenberg, Paul Baker, Laura Sampson, Joey Shapiro Key and Shane Larson. Their work contributed to the first figure in the discovery paper, published in the journal Physical Review Letters.
Scientists concluded from the LIGO data that 1.3 billion years ago “in a galaxy far, far away,” Cornish said, two black holes, collapsed stars, each about 30 times more massive that our Sun, smashed into each other at half the speed of light. The black holes merged into an even bigger black hole, releasing energy equivalent to three Suns, which went rippling through the universe as gravitational waves.
“It is the most energetic event ever observed,” he said.
The National Science Foundation provided financial support “through thick and thin,” he said, which meant that U.S. taxpayers had made a bet of more than $650 million that gravitational waves existed.
There’s no way of knowing if the discovery will have practical impacts, but the technology developed to detect them will, Cornish said. He added no one expected that basic discoveries in quantum mechanics would someday help make cellphones possible.
For scientists, Cornish said, this new technology is like having a sonogram to look into the birth of the universe.
“We can peer back to the very moment of creation using gravitational waves,” he said.
His own son, James, 9, has been asking him regularly for five years, as they walk to Irving School in the morning, “‘Daddy, have you found those waves yet?'”
Finally Cornish could tell his son, “‘We found those waves.’ . He gave me a big hug.”
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