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.

A Dracula Ant's Jaws Snap at 200 Mph—Making It the Fastest Animal Appendage on the Planet

Ant Lab, YouTube
Ant Lab, YouTube

As if Florida’s “skull-collecting” ants weren’t terrifying enough, we’re now going to be having nightmares about Dracula ants. A new study in the journal Royal Society Open Science reveals that a species of Dracula ant (Mystrium camillae), which is found in Australia and Southeast Asia, can snap its jaws shut at speeds of 90 meters per second—or the rough equivalent of 200 mph. This makes their jaws the fastest part of any animal on the planet, researchers said in a statement.

These findings come from a team of three researchers that includes Adrian Smith, who has also studied the gruesome ways that the skull-collecting ants (Formica archboldi) dismember trap-jaw ants, which were previously considered to be the fastest ants on record. But with jaw speeds of just over 100 miles per hour, they’re no match for this Dracula ant. (Fun fact: The Dracula ant subfamily is named after their habit of drinking the blood of their young through a process called "nondestructive cannibalism." Yikes.)

Senior author Andrew Suarez, of the University of Illinois, said the anatomy of this Dracula ant’s jaw is unusual. Instead of closing their jaws from an open position, which is what trap-jaw ants do, they use a spring-loading technique. The ants “press the tips of their mandibles together to build potential energy that is released when one mandible slides across the other, similar to a human finger snap,” researchers write.

They use this maneuver to smack other arthropods or push them away. Once they’re stunned, they can be dragged back to the Dracula ant’s nest, where the unlucky victims will be fed to Dracula ant larvae, Suarez said.

Researchers used X-ray imaging to observe the ants’ anatomy in three dimensions. High-speed cameras were also used to record their jaws snapping at remarkable speeds, which measure 5000 times faster than the blink of a human eye. Check out the ants in slow-motion in the video below.

14 Facts About Celiac Disease

Going gluten-free may be a modern diet trend, but people have been suffering from celiac disease—a chronic condition characterized by gluten intolerance—for centuries. Patients with celiac are ill-equipped to digest products made from certain grains containing gluten; wheat is the most common. In the short-term this can cause gastrointestinal distress, and in the long-term it can foster symptoms associated with early death.

Celiac diagnoses are more common than ever, which also means awareness of how to live with the condition is at an all-time high. Here are some things you might not know about celiac disease symptoms and treatments.

1. Celiac an autoimmune disease.

The bodies of people with celiac have a hostile reaction to gluten. When the protein moves through the digestive tract, the immune system responds by attacking the small intestine, causing inflammation that damages the lining of the organ. As this continues over time, the small intestine has trouble absorbing nutrients from other foods, which can lead to additional complications like anemia and osteoporosis.

2. You can get celiac disease from your parents.

Nearly all cases of celiac disease arise from certain variants of the genes HLA-DQA1 and HLA-DQB1. These genes help produce proteins in the body that allow the immune system to identify potentially dangerous foreign substances. Normally the immune system wouldn't label gliadin, a segment of the gluten protein, a threat, but due to mutations in these genes, the bodies of people with celiac treat gliadin as a hostile invader.

Because it's a genetic disorder, people with a first-degree relative (a sibling, parent, or child) with celiac have a 4 to 15 percent chance of having it themselves. And while almost all patients with celiac have these specific HLA-DQA1 and HLA-DQB1 variations, not everyone with the mutations will develop celiac. About 30 percent of the population has these gene variants, and only 3 percent of that group goes on to develop celiac disease.

3. Makeup might contribute to celiac disease symptoms.

People with celiac disease can’t properly process gluten, the protein naturally found in the grains like wheat, rye, and barley. Patients have to follow strict dietary guidelines and avoid most bread, pasta, and cereal, in order to manage their symptoms. But gluten isn’t limited to food products: It can also be found in some cosmetics. While makeup containing gluten causes no issues for many people with celiac, it can provoke rashes in others or lead to more problems if ingested. For those folks, gluten-free makeup is an option.

4. The name comes from 1st-century Greece.

A 1st-century Greek physician named Aretaeus of Cappadocia may have been the first person to describe celiac disease symptoms in writing [PDF]. He named it koiliakos after the Greek word koelia for abdomen, and he referred to people with the condition as coeliacs. In his description he wrote, “If the stomach be irretentive of the food and if it pass through undigested and crude, and nothing ascends into the body, we call such persons coeliacs.”

5. There are nearly 300 celiac disease symptoms.

Celiac disease may start in the gut, but it can be felt throughout the whole body. In children, the condition usually manifests as bloating, diarrhea, and abdominal discomfort, but as patients get older they start to experience more “non-classical” symptoms like anemia, arthritis, and fatigue. There are at least 281 symptoms associated with celiac disease, many of which overlap with other conditions and make celiac hard to diagnose. Other common symptoms of the disease include tooth discoloration, anxiety and depression, loss of fertility, and liver disorders. Celiac patients also have a greater chance of developing an additional autoimmune disorder, with the risk increasing the later in life the initial condition is diagnosed.

6. Some patients show no symptoms at all.

It’s not uncommon for celiac disease to be wrecking a patient’s digestive tract while showing no apparent symptoms. This form of the condition, sometimes called asymptomatic or “silent celiac disease,” likely contributes to part of the large number of people with celiac who are undiagnosed. People who are at high risk for the disease (the children of celiac sufferers, for example), or who have related conditions like type 1 diabetes and Down syndrome (both conditions that put patients at a greater risk for developing new autoimmune diseases) are encouraged to get tested for it even if they aren’t showing any signs.

7. It’s not the same as wheat sensitivity.

Celiac is often confused with wheat sensitivity, a separate condition that shares many symptoms with celiac, including gastrointestinal issues, depression, and fatigue. It’s often called gluten sensitivity or gluten intolerance, but because doctors still aren’t sure if gluten is the cause, many refer to it as non-celiac wheat sensitivity. There’s no test for it, but patients are often treated with the same gluten-free diet that’s prescribed to celiac patients.

8. It's not a wheat allergy either.

Celiac disease is often associated with wheat because it's one of the more common products containing gluten. While it's true that people with celiac can't eat wheat, the condition isn't a wheat allergy. Rather than reacting to the wheat, patients react to a specific protein that's found in the grain as well as others.

9. It can develop at any age.

Just because you don’t have celiac now doesn’t mean you’re in the clear for life: The disease can develop at any age, even in people who have tested negative for it previously. There are, however, two stages of life when symptoms are most likely to appear: early childhood (8 to 12 months) and middle adulthood (ages 40 to 60). People already genetically predisposed to celiac become more susceptible to it when the composition of their intestinal bacteria changes as they get older, either as a result of infection, surgery, antibiotics, or stress.

10. Not all grains are off-limits.

A gluten-free diet isn’t necessarily a grain-free diet. While it’s true that the popular grains wheat, barley, and rye contain gluten, there are plenty of grains and seeds that don’t and are safe for people with celiac to eat. These include quinoa, millet, amaranth, buckwheat, sorghum, and rice. Oats are also naturally gluten-free, but they're often contaminated with gluten during processing, so consumers with celiac should be cautious when buying them.

11. Celiac disease can be detected with a blood test.

Screenings for celiac disease used to be an involved process, with doctors monitoring patients’ reactions to their gluten-free diet over time. Today all it takes is a simple test to determine whether someone has celiac. People with the condition will have anti-tissue transglutaminase antibodies in their bloodstream. If a blood test confirms the presence of these proteins in a patient, doctors will then take a biopsy of their intestine to confirm the root cause.

12. The gluten-free diet doesn’t work for all patients.

Avoiding gluten is the most effective way to manage celiac disease, but the treatment doesn’t work 100 percent of the time. In up to a fifth of patients, the damaged intestinal lining does not recover even a year after switching to a gluten-free diet. Most cases of non-responsive celiac disease can be explained by people not following the diet closely enough, or by having other conditions like irritable bowel syndrome, lactose intolerance, or small intestine bacterial overgrowth that impede recovery. Just a small fraction of celiac disease sufferers don’t respond to a strict gluten-free diet and have no related conditions. These patients are usually prescribed steroids and immunosuppressants as alternative treatments.

13. If you don’t have celiac, gluten probably won’t hurt you.

The gluten-free diet trend has exploded in popularity in recent years, and most people who follow it have no medical reason to do so. Going gluten-free has been purported to do everything from help you lose weight to treat autism—but according to doctors, there’s no science behind these claims. Avoiding gluten may help some people feel better and more energetic because it forces them to cut heavily processed junk foods out of their diet. In such cases it’s the sugar and carbs that are making people feel sluggish—not the gluten protein. If you don’t have celiac or a gluten sensitivity, most experts recommend saving yourself the trouble by eating healthier in general rather than abstaining from gluten.

14. The numbers are growing.

A 2009 study found that four times as many people have celiac today than in the 1950s, and the spike can’t be explained by increased awareness alone. Researchers tested blood collected at the Warren Air Force Base between 1948 and 1954 and compared them to fresh samples from candidates living in one Minnesota county. The results supported the theory that celiac has become more prevalent in the last half-century. While experts aren’t exactly sure why the condition is more common today, it may have something to do with changes in how wheat is handled or the spread of gluten into medications and processed foods.