Barry Barish and his team of physicists did something that Albert Einstein doubted could ever be done: They observed gravitational waves.
The discovery of these waves — detected through an elaborate process involving beams of light, state-of-the-art shock absorbers and a little math — lends support to Einstein’s theory of relativity and gives scientists a new tool to investigate the origins of our universe.
It also landed Barish the Nobel Prize in Physics in 2017, a culmination of 20-plus years of work.
“Now, we have a different way to look at our universe than electromagnetic waves,” said Barish, who is visiting UW-La Crosse this week and will give a presentation about his findings at 3:20 p.m. Friday at Centennial Hall.
“It’s like we have a different universe to look at,” he said. “It’s going to open the door, open the window like Galileo did” when he invented the telescope.
It was Einstein who first predicted the existence of gravitational waves, ripples produced when heavenly bodies, such as planets or stars, interact with one another. But Einstein suspected these waves were so small and so weak that they would forever avoid detection.
From 1994 to 2015, Barish and his team at the Laser Interferometer Gravitational Wave Observatories in Washington and Louisiana hunted these invisible ripples.
They would shoot two beams of light in different directions, each aimed at a mirror two and a half miles away, and see if one would beat the other back to the observatory. If there was a winner, and if the team could prove there was no unwanted interference, they could more or less confirm the existence of gravitational waves.
But building an apparatus that could measure results with extreme precision, an apparatus that could cut through interference like the shaking of the Earth, took the better part of two decades. Roughly 1,000 physicists, from nearly every corner of the world, worked on the project.
“People ask how we were able to be so persistent,” Barish said. “Getting better and better at this was a challenge. It was fun, exciting.”
Barish figured that, one day, the team would get a result that hinted at the existence of gravitational waves, something intriguing but inconclusive. That’s not what happened.
“We saw this signal and almost immediately identified it as coming from a collision 1.3 billion years ago, a collision of two black holes,” said Barish, who then set out double- and triple-check that this was, indeed, a gravitational wave.
“My initial reaction was not to say, ‘Eureka!’ — it was to panic,” he said. “I was worried that there were two things that could make it not real: How are we fooling ourselves? And how are we being fooled?”
The team ensured that they hadn’t fooled themselves, hadn’t made any mistakes. They also ruled out malicious interference, a hacker manipulating with the experiment.
Then, in a matter of days, the team observed another wave.
“That clinched it,” Barish said.
It’s difficult to say what these findings imply or represent — other than a big, bright feather in Barish’s cap.
He suggested that scientists might use gravitational waves to develop a picture of how our universe began, since gravitational waves, unlike electromagnetic waves, do not disappear over time.
The years and decades will determine whether there are other scientific or practical applications for gravitational waves. Barish is the first to admit that there might not be.
And to him, that would be just fine.
“We do research like this for the fundamental knowledge — not for the implications that might come out of it,” he said. “I’ve always had that curious nature. It’s just ingrained in me, like when you’re a kid wondering why an ice cube, which is water, floats in your glass of water. You go running and ask your father.”