Physicists Spot Einstein's Gravitational Waves for the First Time

SXS Collaboration, University of Chicago
SXS Collaboration, University of Chicago

Simulation of two merging black holes in front of the Milky Way. Scientists said the Sept. 14 event was so intense that in the moment before the colliding black holes swallowed each other, they emitted more energy than the rest of the universe combined.

After a decades-long search, physicists have managed to detect ethereal ripples in the very fabric of space, known as gravitational waves—triggered in this case by the death-spiral of a pair of merging black holes—and snared by a sophisticated detector known as LIGO, the Laser Interferometer Gravitational-wave Observatory. The discovery is being described as one of the great physics breakthroughs of the decade, on par with the 2012 discovery of the Higgs boson, and very likely Nobel Prize–worthy.

Lawrence Krauss, a physicist at Arizona State University and author of The Physics of Star Trek, told mental_floss that the discovery “monumental.” The new technology will allow astronomers “to peer into parts of the universe that we’d never could have seen otherwise,” Krauss said. More than that, it will pave the way for a new era in astronomy, one in which gravitational waves will be used to study a wide array of all astrophysical phenomena, many of them never before open to scientific scrutiny. “It’s opened up a whole new window on the universe,” he said—a metaphor that’s been echoed by many of the physicists and astronomers who have been weighing in excitedly on the discovery.

The discovery was unveiled Thursday morning at a packed Washington DC press conference organized by the U.S. National Science Foundation (NSF), which funded the research (with simultaneous presentations by partner institutions in at least four other countries).

The gravitational waves recorded by the LIGO detectors were the result of the violent merger of two black holes, located some 1.3 billion light-years from Earth, explained Gabriela González, a physicist at Louisiana State University and a spokesperson for the LIGO collaboration. One of the black holes was determined to have a mass 29 times that of our Sun, the other was even heavier, with a mass equal to 36 Suns. Although LIGO can only roughly pin down the direction of the signal, González said the black hole pair—now a single black hole, following the cataclysmic merger—is located in the southern sky, roughly in the direction of the Magellanic Clouds, the Milky Way’s small companion galaxies (of course, the black holes are far more distant).

The black hole pair had been locked in mutual orbit for hundreds of millions of years, gradually losing energy through the emission of gravitational waves, and then finally emitting one last “death burst” as the two objects merged into a single entity, González said. “What we saw is from only the last fraction of a second before the merger,” she told mental_floss.

The waves created from that final blast then rippled across the cosmos. After more than a billion years, some of those waves washed silently past Earth on September 14 of last year, where they triggered a tiny “blip” at each of the two identical LIGO detectors (one located in Hanford, Washington, the other in Livingston, Louisiana).

Incredibly, the team of researchers managed to keep the discovery relatively secret for almost six months. When the initial signal was recorded, Caltech physicist Kip Thorne received an e-mail from a colleague. “He said, ‘LIGO may have detected gravitational waves; go and look at this,’” referring Thorne to initial data posted on a private LIGO webpage. “I looked at it, and I said, ‘My god—this may be it!’” Thorne told mental_floss. (Thorne played a key role in the early development of LIGO and is known not only for writing some of the most-read books on gravitational physics, but for his collaboration with Carl Sagan on the book Contact, and with the makers of the smash sci-fi film Interstellar.)

Not everyone was quite so tight-lipped—and in fact rumors had been circulating for weeks leading up to Thursday’s announcement (as mental_floss reported last month). A few people got an early look at the results and couldn’t contain their excitement. McMaster University physicist Clifford Burgess emailed some of the details to colleagues in his department, and the news quickly spilled out via social media. (Burgess described the discovery as “off-the-scale huge.”)

And while there have been a somewhat alarming number of super-hyped physics “discoveries” that failed to pan out in recent years—remember the faster-than-light neutrinos?—the LIGO researchers claim to have ruled out any possible non-gravitational-wave explanation for the signal they recorded. The finding is being published in the peer-reviewed journal Physics Review Letters (the “discovery paper” was released yesterday morning, February 11), along with a series of further papers.

It’s a discovery nearly a quarter-century in the making: LIGO was spearheaded by Caltech and MIT in 1992, and now involves nearly 1000 researchers from the UK, Germany, Australia, and beyond. With a total cost of more than $600 million, LIGO is the largest project ever funded by NSF.

Einstein predicted the existence of gravitational waves, based on his newly developed theory of gravity, known as general relativity, in 1915. Gravitational waves are literally ripples in spacetime, created whenever massive objects throw their weight around—for example, when ultra-dense stars, known as neutron stars, collide, or when a star blows up in a supernova. In fact, any time masses accelerate, gravitational waves are produced—even doing dumbbell-lifts at the gym would produce them—but such waves would be infinitesimally weak, and quite impossible to measure. Even the waves from the black hole merger were so faint that they required the massive LIGO detectors to finally pick them up.

“It’s just really, tremendously exciting,” physicist Clifford Will of the University of Florida, one of the world’s leading authorities on general relativity, told mental_floss. “We’ve just finished celebrating the 100th anniversary of GR [general relativity], so this is icing on the cake.”

David Spergel, a physicist at Princeton, tweeted: “Up to now, we have only seen the universe. Now, for the first time, we can hear," adding, "The universe is playing a beautiful tune and LIGO just heard it.”

Gravitational waves alternately stretch and shrink space, by a tiny amount, as they pass by. Inside each of the LIGO detectors, laser beams bounce back and forth between mirrors attached to weights. A passing gravitational wave causes a slight change in the distance the laser beam travels, which leaves a telltale pattern (known as an interference pattern) in the recorded laser light. (Having two detectors located more than 2000 miles apart helps rule out false-alarm signals that might register at only one site.)

“We saw the same waveform—the same signal—in the two detectors,” González told mental_floss. Recording such signals by chance might happen “once in every 200,000 years,” she said.

LIGO went online in 2002, but with only a fraction of its current sensitivity. The detectors were upgraded last fall in an effort known as “Advanced LIGO.” The actual stretching caused by the passing gravitational wave is mind-bogglingly small, causing the detectors to grow or shrink in length by a distance equivalent to just 1/1000th of the width of a proton.

The success of the LIGO detectors is “a wonderful testament to the perseverance and ingenuity of the scientists,” Krauss said. “I never thought I’d see this in my lifetime.”

Astronomers and physicists expect the new technique to reveal the universe in a new light, as the first optical telescopes did when Galileo first used them to study the night sky 400 years ago, and as the first radio telescopes did in the mid-20th century.

Editor's note: This story has been significantly updated to include input from a main LIGO researcher and additional outside experts, as well as with more comprehensive details about the extraordinary find.

11 Things You Might Not Know About Neil Armstrong

NASA/Hulton Archive/Getty Images
NASA/Hulton Archive/Getty Images

No matter where private or government space travel may take us in the future, NASA astronaut Neil Armstrong (1930-2012) will forever have a place as the first human to ever set foot on solid ground outside of our atmosphere. Taking “one small step” onto the Moon on July 20, 1969, he inspired generations of ambitious people to reach for the stars in their own lives. On the 50th anniversary of Apollo 11, we're taking a look back at the life of this American hero.

1. Neil Armstrong knew how to fly before he got a driver's license.

Neil Armstrong poses for a portrait 10 years before the 1969 Apollo mission
NASA/Hulton Archive/Getty Images

Born August 5, 1930 in Wapakoneta, Ohio, Armstrong became preoccupied with aviation early on. At around age 6, his father took him on a ride in a Ford Trimotor airplane, one of the most popular airplanes in the world. By age 15, he had accumulated enough flying lessons to command a cockpit, reportedly before he ever earned his driver’s license. During the Korean War, Armstrong flew 78 combat missions before moving on to the National Advisory Committee for Aeronautics (NACA), the precursor to NASA.

2. Neil Armstrong's famous quote was misheard back on Earth.

When Armstrong and Buzz Aldrin touched down on the Moon, hundreds of millions of television viewers were riveted. Armstrong could be heard saying, “That’s one small step for man, one giant leap for mankind.” But that’s not exactly what he said. According to the astronaut, he was fairly sure he stated, “That’s one small step for a man, one giant leap for mankind.” The “a” may have broken up on transmission or it may have been obscured as a result of his speaking patterns. (According to First Man: The Life of Neil A. Armstrong, Armstrong said, “I’m not particularly articulate. Perhaps it was a suppressed sound that didn’t get picked up by the voice mike. As I have listened to it, it doesn’t sound like there was time for the word to be there. On the other hand, I think that reasonable people will realize that I didn’t intentionally make an inane statement, and certainly the ‘a’ was intended, because that’s the only way the statement makes any sense. So I would hope that history would grant me leeway for dropping the syllable and understand that it was certainly intended, even if it wasn’t said—although it actually might have been.”) Armstrong claimed the statement was spontaneous, but his brother and others have claimed he had written it down prior to the mission.

3. We don't have a really good picture of Neil Armstrong on the Moon.

Buzz Aldrin is seen walking on the moon
NASA/Hulton Archive/Getty Images

One of the most celebrated human achievements of the 20th century came at a time when video and still cameras were readily available—yet there are precious few images of Armstrong actually walking on the surface of the Moon. (One of the most iconic shots, above, is Aldrin; Armstrong only appears as a reflection in his helmet.) The reason, according to Armstrong, is that he really didn’t care and didn’t think to ask Aldrin to snap some photos. “I don't think Buzz had any reason to take my picture, and it never occurred to me that he should,” Armstrong told his biographer, James R. Hansen. “I have always said that Buzz was the far more photogenic of the crew."

4. A door hinge may have made all the difference to the Apollo 11 mission.

Theories abound as to why it was Armstrong and not Buzz Aldrin who first set foot on the Moon. (On the Gemini missions, the co-pilot did the spacewalks, while the commander stayed in the craft. For Apollo 11, Armstrong was the commander.) The answer may have been the simple logistics of getting out of their lunar module. The exit had a right hinge that opened inwardly, with the man sitting on the left (Armstrong) having the most unobstructed path to the outside. Aldrin would have essentially had to climb over Armstrong to get out first.

5. Neil Armstrong was more concerned about landing on the Moon than he was walking on it.

The lunar module that took NASA astronauts to the moon
NASA/Hulton Archive/Getty Images

The romantic notion of a human stepping foot on space soil captured imaginations, but for Armstrong, it was getting there in one piece that was the real accomplishment. The lunar module Armstrong controlled had to be brought down on the Moon’s surface from 50,000 feet up, avoiding rocks, craters, and other obstacles as it jockeyed into a position for landing. Because there is no air resistance, nothing could slow their descent, and they used thrusters to guide the craft down. That meant there was only enough fuel to attempt it once. The “business” of getting down the ladder was, in Armstrong’s view, less significant.

6. Neil Armstrong was carrying a bag worth $1.8 million.

When Armstrong surveyed the surface of the Moon, he collected a bag of dust for NASA scientists to examine. Apollo moon samples are illegal to buy or sell, but that apparently wasn't the case with the “lunar collection bag” Armstrong used to hold the samples. In 2015, the bag was purchased by Chicago resident Nancy Lee Carlson from a government auction site for $995. But its sale was, apparently, an accident: When Carlson sent the bag to NASA to confirm its authenticity, NASA said it was their property and refused to send it back—so Carlson took the agency to court. A judge ruled it belonged to Carlson, and in 2017, she sold the bag for a whopping $1.8 million at a Sotheby’s auction.

7. Neil Armstrong and his fellow Apollo 11 astronauts had to spend three weeks in quarantine.

Richard Nixon greets the returning Apollo 11 astronauts
NASA/Hulton Archive/Getty Images

When Armstrong, Aldrin, and Michael Collins (who remained behind in the command module while the other two touched down on the Moon) returned to Earth and were fetched by the USS Hornet, they got a king’s welcome. The only asterisk: They had to bask in their newfound fame from inside a sealed chamber. All three men were quarantined for three weeks in the event they had picked up any strange space virus. When President Richard Nixon visited, he greeted them through the chamber’s glass window.

8. Neil Armstrong's space suit was made by Playtex.

Yes, the undergarment people. In the early 1960s, NASA doled out contract work for their space suits to government suppliers, but it was Playtex (or more properly the International Latex Corporation) and their understanding of fabrics and seams that led to NASA awarding them responsibility for the Apollo mission suits. Their A7L suit was what Armstrong wore to insulate himself against the harsh void of space when he made his famous touchdown. The astronaut called it “reliable” and even “cuddly.”

9. Neil Armstrong became a university professor.

Newil Armstrong sits behind a desk in 1970
AFP/Getty Images

Following his retirement from NASA in 1971, Armstrong was reticent to remain in the public eye. Demands for his time were everywhere, and he had little ambition to become a walking oral history of his singular achievement. Instead, he accepted a job as a professor of engineering at the University of Cincinnati and remained on the faculty for eight years.

10. Neil Armstrong once sued Hallmark.

Hallmark was forced to defend itself when Armstrong took issue with the company using his name and likeness without permission for a 1994 Christmas ornament. The bulb depicted Armstrong and came with a sound chip that said phrases like, “The Eagle has landed.” The two parties came to an undisclosed but “substantial” settlement in 1995, which was, according to First Man, donated to Purdue University (minus legal fees).

11. Neil Armstrong was a Chrysler pitchman.

Armstrong’s preference to lead a private life continued over the decades, but he did make one notable exception. For a 1979 Super Bowl commercial spot, Armstrong agreed to appear on camera endorsing Chrysler automobiles. Armstrong said he did it because he wanted the struggling U.S. car maker to improve their sales and continue contributing to the domestic economy. The ads never mentioned Armstrong was an astronaut.

Pioneering Heart Surgeon René Favaloro Is Being Honored With a Google Doodle

Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
The Cleveland Clinic Center for Medical Art & Photography, Wikimedia Commons // CC BY 4.0

Argentinian heart surgeon René Favaloro is the subject of today’s Google Doodle, which features a sketched portrait of the doctor along with an anatomical heart and several medical tools, The Independent reports.

The renowned doctor was born on this day in 1923 in La Plata, the capital of Argentina’s Buenos Aires province, and pursued a degree in medicine at La Plata University. After 12 years as a doctor in La Pampa, where he established the area’s first mobile blood bank, trained nurses, and built his own operating room, Favaloro relocated to the U.S. to specialize in thoracic surgery at the Cleveland Clinic.

In 1967, Favaloro performed coronary bypass surgery on a 51-year-old woman whose right coronary artery was blocked, restricting blood flow to her heart. Coronary bypass surgery involves taking a healthy vein from elsewhere in the body (in this case, Favaloro borrowed from the patient’s leg, but you can also use a vein from the arm or chest), and using it to channel the blood from the artery to the heart, bypassing the blockage. According to the Mayo Clinic, it doesn’t cure whatever heart disease that caused the blocked artery, but it can relieve symptoms like chest pain and shortness of breath, and it gives patients time to make other lifestyle changes to further manage their disease.

Favaloro wasn’t keen on being called the “father” of coronary bypass surgery, but his work brought the procedure to the forefront of the clinical field. He moved back to Argentina in 1971 and launched the Favaloro Foundation to train surgeons and treat a variety of patients from diverse economic backgrounds.

Favaloro died by suicide on July 29, 2000, at the age of 77, by a gunshot wound to the chest. His wife had died several years prior, and his foundation had fallen deeply into debt, which Argentinian hospitals and medical centers declined to help pay, The New York Times reported at the time.

“As a surgeon, Dr. Favaloro will be remembered for his ingenuity and imagination,” his colleague Dr. Denton A. Cooley wrote in a tribute shortly after Favaloro’s death. “But as a man ... he will be remembered for his compassion and selflessness.” Today would have been his 96th birthday.

[h/t The Independent]

SECTIONS

arrow
LIVE SMARTER