Today, three researchers have been awarded the Nobel Prize in physics for their work in detecting gravitational waves — ripples in space and time that travel throughout our Universe. The recipients are Rainer Weiss, a physics professor at MIT, and Kip Thorne and Barry Barish, who are both physics professors at Caltech.
The trio are key members of LIGO, or the Laser Interferometer Gravitational-Wave Observatory — a scientific collaboration that made history when it announced last year the first ever detection of gravitational waves. Over a century ago, Albert Einstein predicted the existence of these waves in his theory of general relativity. He argued that every object in the Universe warps the space and time around it, and when an object moves, it creates ripples in this space-time — gravitational waves — a bit like ripples in a pond.
LIGO boasts two specialized detectors in Washington and Louisiana, designed to pick up these ripples. Specifically, the observatories look for the gravitational waves stemming from violent mergers of super dense faraway objects, such as black holes or leftover stellar remnants known as neutron stars. When these bodies come together, they spin around each other rapidly, several times per second, before joining to make one incredibly dense object. It’s like a cosmic dance that creates gargantuan ripples in the fabric of space-time, which travel outward at the speed of light, and eventually reach Earth. By the time they reach our planet, the waves have greatly diminished, needing extremely sensitive instruments, like LIGO’s detectors, to pick them up.
In February 2016, LIGO announced that its two observatories had detected the waves from black holes merging 1.3 billion light-years away for the first time ever. The discovery revolutionized the field of astronomy, giving scientists a new way to study the mysterious, dark objects that lurk in the distant Universe. LIGO has since detected three additional black hole mergers — and more announcements may come soon. A third European observatory, Virgo, has also detected one of the mergers, allowing researchers to locate the source of these waves more accurately than ever before. “We have unlocked this new window of the Universe, and we’re just starting to peek in,” says Laura Cadonati, a LIGO collaborator and professor of physics at Georgia Institute of Technology. “This discovery has been groundbreaking because it’s not the end of the path; we’ve really opened the door to new discovery.”
The Royal Swedish Academy of Sciences, which awards the Nobel Prizes, said that Weiss, Thorne, and Barish deserved the award specifically “for decisive contributions to the LIGO detector and the observation of gravitational waves.” Cadonati says that many within the collaboration “look up to them as the founders who started it all.” Weiss championed the idea of using miles-long lasers as the best way to detect gravitational waves on Earth, and the technology is a fundamental tool used in the LIGO detectors today. He also helped identify sources of background noise that might muck up detections. “He’s really been on the forefront of all the construction,” Cadonati tells The Verge. “He really was the one who made it happen.”
Meanwhile, Thorne is the reason why LIGO looks for mergers in the first place. Many scientists thought the explosions of stars would create the best waves for detection, but Thorne said that black holes or neutron stars rotating around one another would make the best sources for study.
As for Barish, he’s the one who really brought the LIGO collaboration together. He became the principal investigator of LIGO in 1994, and then spearheaded the funding and construction of its two observatories through the National Science Foundation. Ultimately, he’s responsible for making the collaboration the vibrant operation that it is, made up of over a thousand scientists, Cadonati says. “He had the vision of recognizing that kind of endeavor could not be done by a small group but a huge effort,” she says.
While only three men are receiving the award today, Cadonati says many within LIGO feel as though they are being awarded with the prize as well. She says many have been crying this morning in light of the news. “We really are happy to celebrate Ray, Barry, and Kip,” she says. “We also feel very honored; we feel like we’re part of this as well.”