An image of Pōwehi, a supermassive black hole in the galaxy Messier 87. This image, which is the most detailed to date taken of a black hole, uses polarized light to reveal relativistic jets (in yellow and red) extending from Pōwehi. Image Credit: the Event Horizon Telescope Collaboration.

You didn't get sucked into a black hole. Now what?

<p>In March, an international network of scientists called the Event Horizon Team delivered the most detailed photograph of a black hole compiled to date. The supermassive black hole it featured, galaxy Messier 87’s Pōwehi, is 6.5 billion times as massive as the Sun and looks like a vibrant, swirling pool of flames being sucked into a dark center.</p><p>That bright ring outside the black hole—its accretion disc—is actually made up of a spiraling vortex of hot, magnetized matter. “This region itself is five times larger than the size of the black hole,” says Jordy Davelaar, a member of the Event Horizon Team and theoretical astrophysicist at Columbia University. “Though in the sky, it [looks] super tiny.”</p>
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<p>“Tiny” to an astrophysicist, of course, is relative. If you were to orbit Pōwehi’s exact center point at a distance relative to Pluto’s orbit of the Sun, Davelaar explains, you would be within the event horizon, your orbit nowhere near its accretion disc. This means our entire solar system would fit inside this supermassive black hole’s event horizon with room to spare.</p><p>Every black hole captures material that gets too close to its event horizon, a boundary in space marking the limit of the black hole and a point of no return from it. All objects—even beams of light—that cross the event horizon will not be able to get back out. If you were to approach a black hole much smaller than Powehi feet-first, you’d feel the gravitational pull on your feet increasing much more severely than you would on your head, causing you to be stretched thin as a noodle in a process called “spaghettification.” But approach the event horizon of a huge black hole, like that of Pōwehi, and you wouldn’t get stretched: Rather, you’d gently cross the event horizon without any particular sensation at all. “You would not feel any spaghettification,” says Rutuparna Das, an astrophysicist at Harvard &amp; Smithsonian’s Center for Astrophysics.</p>
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<img alt="First-ever image of a black hole" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/A-Consensus.width-990_XaMU9lG.jpg"/>
<figcaption><p>Astrophysicists use radio telescopes, which pick up radio waves emitted by black holes and other objects in space that don’t give off optical light, to hunt for black holes, says Rutuparna Das, who conducts research for NASA’s Chandra X-ray Observatory. Telescopes like Chandra can be used to illuminate and observe material orbiting black holes, making a black hole’s spinning accretion disc appear to glow (as seen in this image of Pōwehi from 2019). Image Credit: Event Horizon Telescope collaboration</p>
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<p>Why would a black hole spaghettify objects in the first place? It’s a result of the black hole’s incredibly dense, gravity pit of a center called the singularity. When there is a difference in the gravitational pull of two points relative to each other, it results in what’s called tidal forces. Such forces—which surround all black holes—also affect us here on Earth. “There are tidal forces from the Moon on the Earth that we see in how our water moves,” but are too small to feel, Davelaar says. Tidal forces of black holes cause spaghettification, but because of the overwhelming mass of a supermassive black hole, you wouldn’t be spaghettified until after you crossed its event horizon. If you were to approach a black hole with a smaller mass, however, you would be <a href="https://gizmodo.com/heres-why-small-black-holes-are-more-dangerous-than-big-1681979641">spaghettified well before</a> reaching its event horizon.</p><p>While you might avoid spaghettification due to Pōwehi’s size, you wouldn’t survive the destructive spin of its accretion disc. “The environment is super lethal,” Davelaar says. Material in the accretion disc “accelerates at such velocity it wouldn’t be pleasant for a human being,” adds Maria Charisi, an astrophysicist at Vanderbilt University. As the accretion disc spins, tidal forces shred the stars and gas clouds caught within it down to their atoms.</p><p>No longer intact, you (now broken down to your atoms) may drift toward Pōwehi’s event horizon before entering its center, where intense gravity destroys material. But first you’d visit Pōwehi’s innermost stable orbit, which looms just outside of the event horizon. The innermost stable orbit is the last place any space material has a chance to escape.</p>
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<p>Not all material in the disc falls into a black hole, says Edo Berger, an astrophysicist at Harvard &amp; Smithsonian’s Center for Astrophysics. It’s like “feeding a baby,” Berger says. Much like an infant may spit out mashed potatoes, a supermassive black hole may hurl from its accretion disc the remnants of its cosmic lunch of stars, dust, and other space matter in beams called relativistic jets, which can extend beyond its accretion disc into outer space.</p><p>The deciding factor of what gets consumed and what gets shot out in a relativistic jet is “whichever side is closest to the hole,” Berger says. If you were orbiting Pōwehi clockwise, the right side of you might meet its demise in the singularity while the left side of your body could be sent flying away from Pōwehi in a jet.</p>
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<figcaption><p>This color composite image of Centaurus A reveals the lobes and jets emanating from the galaxy’s central black hole. It was compiled using images taken by three instruments operating at different wavelengths: Data from LABOCA on APEX are shown in orange, X-ray data from the Chandra X-ray Observatory are shown in blue, and visible light data from the MPG/ESO 2.2 m telescope in La Silla, Chile, show background stars and the galaxy’s characteristic dust lane. Image Credit: ESO/WFI; MPIfR/ESO/APEX/A.Weiss et al.; NASA/CXC/CfA/R.Kraft et al. </p>
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<p>The beam of a supermassive black hole’s relativistic jet can reach so far that it may even extend outside of its galaxy, Charisi says. According to a 2012 observation by the Event Horizon Team, Pōwehi’s jet extends a whopping 5,000 light-years outside of Messier 87, and the material within the jet shoots out in “clumps and knots,” <a href="https://www.nasa.gov/mission_pages/chandra/images/famous-black-hole-has-jet-pushing-cosmic-speed-limit.html">NASA wrote</a> in a January 2020 press release. NASA’s Chandra X-ray Observatory, a space telescope that detects X-ray emissions from very hot regions in the universe, discovered that Pōwehi’s jet is moving at a staggering 99% the speed of light. But as a black hole’s relativistic jet tears through the cosmos, the space material it crosses, including gas clouds, slow it down, Charisi says.</p><p>“At some point [the jet] will decelerate,” she says. “If you look at radio galaxies, you see these pencil-thin beams where the jet is accelerating, and then you see these blobs around them, where they have lost velocity.” The blobs at the decelerated ends of a relativistic jet slowly dissipate into space, says Charisi, creating a dumbbell shape around the galaxy, like that seen in images of radio galaxy Centaurus A.</p><p>Once your atoms arrive in the blob of Pōwehi’s relativistic jet, millions of years would have passed since you first ventured into its accretion disc. Though you avoided being swallowed up by the black hole, now, 5,000 light-years away from Pōwehi, your atomic remnants slowly drift apart in space. “Eventually [they] will dissipate,” Charisi says, though astrophysicists are not yet sure how long that may take.</p>
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<p data-block-key="g1lkv">Not everything that crosses a supermassive black hole’s accretion disc gets spaghettified, astrophysicists say.</p>

The second-ever direct image of a black hole features Sagittarius A*, the supermassive black hole at the center of our galaxy. Image Credit: Event Horizon Telescope collaboration

Scientists capture first-ever image of our galaxy’s supermassive black hole

<p>On Thursday morning, an international team of astrophysicists and other researchers released the world’s first image of the supermassive black hole at the center of our galaxy, 27,000 light-years from Earth. </p><p>The event marks “the dawn of a new era of black hole physics,” the team<a href="https://twitter.com/ehtelescope/status/1524737908892049408"> announced on Twitter</a>.</p><p>More than 4 million times the mass of our sun, the black hole, named Sagittarius A* (or Sgr A*, pronounced “sadge ay star,” for short) is so dense and massive that no light can escape its gravity. The visible light in the new image comes from bright stars, gas, and other space matter swarming around the black hole itself.</p>
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<p>The image is the first visual evidence of Sgr A*’s existence; the black hole was previously only indirectly confirmed by observations of stars in orbit around it. The image comes from the Event Horizon Telescope’s (EHT) international consortium. A group of more than 300 scientists helped with the effort to capture it, “compiling information from radio observatories around the world,” Bill Chappell <a href="https://www.npr.org/2022/05/12/1098472567/image-black-hole-milky-way">reports for NPR</a>. (The EHT, named for the event horizon, or “point of no return” from a black hole, consists of eight radio telescopes scattered across the globe.)</p><p>In 2019, the EHT team compiled an <a href="https://www.pbs.org/wgbh/nova/article/first-black-hole-image/">image of Pōwehi</a>, a supermassive black hole 55 million light-years away in the galaxy Messier 87. Similar in appearance to Sgr A* but much more massive, Pōwehi is 6.5 billion times the mass of our sun.</p><p>The much smaller Sgr A* proved difficult for scientists to visually capture: It’s a “dynamic environment” full of burbling and gurgling, Feryal Özel, a professor of astronomy and physics at the University of Arizona, told NPR. And the necessity to look through both the Earth’s atmosphere, gas clouds, and interstellar dust near the Milky Way’s center added to the challenge, Özel said. “It took several years to refine our image and confirm what we had, but we prevailed," Özel told NPR. And, despite its meager distance from Earth compared to Pōwehi, Sgr A* is far enough away to appear “to us to have about the same size in the sky as a donut on the Moon,” the EHT team stated <a href="https://eventhorizontelescope.org/blog/astronomers-reveal-first-image-black-hole-heart-our-galaxy">in a press release.</a></p><p>Hot gas whirling around Sgr A* at nearly the speed of light made capturing an image of this black hole considerably more difficult than Pōwehi, the EHT team said in the press release. “The brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT was observing it,” EHT scientist Chi-Kwan Chan said in the press release.</p>
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<p>Images of Pōwehi captured by astronomers across the EHT were visually similar to one another, allowing scientists to compile a sharp composite image of Messier 87’s black hole. “That was not the case for Sgr A*,” the EHT team said in the press release. But despite these initial inconsistencies, the scientists were eventually able to compile an image of Sgr A*.</p><p>Now, having images of such differently sized black holes provides a better look into the behavior of swirling gas around supermassive black holes, a phenomenon that’s not yet fully understood, but thought to play a key role in how galaxies, like our own, came to be. "Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works," EHT scientist Keiichi Asada said in the press release. </p>
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<p data-block-key="qta1u">The Event Horizon Telescope team has captured the first image of Sagittarius A*, the black hole at the center of the Milky Way. </p>

A giant pink circle with a bright center and "spokes" out to its outer edges against a black sky

The Cartwheel galaxy (right) was formed as the result of a high-speed collision about 400 million years ago. This composite image brings together observations from JWST's infrared instruments. Image Credit: NASA, ESA, CSA, STScI

The top science stories of 2022

<p>As of 2022, you share this planet with 8 billion people (and about <a href="https://www.wgbh.org/news/science-and-technology/2022/09/21/the-number-of-ants-on-earth-has-a-mass-greater-than-all-birds-and-mammals-combined">20 quadrillion ants</a>). </p><p>It’s not just population growth that made this year remarkable. From January to December, scientists have launched revolutionary space missions, wrangled new viral outbreaks, discovered old DNA, and even taken a step towards <a href="https://www.pbs.org/wgbh/nova/video/scientists-make-breakthrough-in-nuclear-fusion/">harnessing nuclear fusion</a>. Explore the science that made headlines throughout 2022.</p>
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<h3><b>Tonga volcano eruption</b></h3><p>Just off the island nation of Tonga in the South Pacific, a mostly underwater volcano called Hunga Tonga-Hunga Ha'apai quite literally rocked the world when it erupted on January 15.</p><p>Hunga Tonga-Hunga Ha'apai’s eruption was one of the <a href="https://www.quantamagazine.org/scientists-unravel-how-the-tonga-volcano-caused-worldwide-tsunamis-20220413/">most powerful on record</a>—hundreds of times more powerful than the atomic bomb dropped on Hiroshima, <a href="https://earthobservatory.nasa.gov/images/149367/dramatic-changes-at-hunga-tonga-hunga-haapai">NASA reported</a>, and the largest explosion of any kind in the <a href="https://www.cnn.com/2022/05/12/asia/tonga-eruption-biggest-in-more-a-century-scn/index.html">last 140 years</a>. Its roar was heard nearly 6,000 miles away in Alaska, and the eruption triggered tsunamis that reached Tonga, nearby Fiji, and far-off locations like Japan, Russia, Peru, and the United States. The volcano’s <a href="https://www.pbs.org/wgbh/nova/article/hunga-tonga-volcano-eruption-education/">unique position</a> may help explain why this particular eruption created such a violent shockwave. But the full implications of the explosion for future volcanic events <a href="https://www.jpl.nasa.gov/news/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere">are still being studied.</a></p>
<h3><b>Ernest Shackleton's ship Endurance is found after 106 years</b></h3><p>In December 1914, British explorer Ernest Shackleton led a crew of 27 men aboard two ships, Endurance and Aurora, on an expedition to Antarctica. The goal was to complete the first land crossing of the Antarctic continent. But in January 1915, the Endurance became trapped in the ice of the Weddell Sea before reaching land.</p><p>For nine months, Shackleton and his crew tried to break the ship free. But their efforts were unsuccessful, and Endurance was gradually crushed by the shifting ice. In October 1915, Shackleton ordered his crew to abandon the ship, and a month later Endurance slipped beneath the surface, not to be seen again. Until this year.</p>
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<img alt="Black and white photo of a three-masted ship trapped in ice, with huge ice chunks in foreground" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/Shackeltons_Endurance.width-990.jpg"/>
<figcaption><p>A distant view of the Endurance trapped in an ice floe. Image Credit: James Francis Hurley via National Maritime Museum, Wikimedia Commons</p>
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<p>On February 5, an expedition called Endurance22 set off from Cape Town, South Africa, in search of Shackleton’s long-lost ship. And on March 5, some 106 years after it was lost, Endurance was found. Using sonar, the team spotted the sunken ship just four miles south of where the original captain, Frank Worsley, had said it was in 1915, <a href="https://www.npr.org/2022/03/09/1085432575/endurance-ship-found-ernest-shackleton">NPR reported</a>. Shockingly well-preserved, Endurance had “hardly anything living on it,” and some of its original paint still intact, Endurance22 expedition leader John Shears told NPR. “It’s as if it sank only yesterday,” Shears said. The Endurance will stay in the Weddell Sea, protected as a historical site under the Antarctic Treaty.</p>
<h3><b>First images from James Webb Space Telescope</b></h3><p>Of NASA's many successful endeavors this year, the images taken by the agency's <a href="https://www.pbs.org/wgbh/nova/video/ultimate-space-telescope/">James Webb Space Telescope</a> (JWST) are perhaps the most awe-inspiring (Have you seen JWST's image of <a href="https://www.nasa.gov/feature/goddard/2022/new-webb-image-captures-clearest-view-of-neptune-s-rings-in-decades">Neptune's rings</a>? Tell me that doesn’t leave you awestruck.) </p><p>JWST launched at the end of 2021 and gradually unfolded, <a href="https://www.pbs.org/wgbh/nova/video/how-scientists-created-the-james-webb-telescopes-first-test-image/">aligning 18 segments</a> of its massive, gilded mirror before getting to work. A month after its launch, the telescope was already a million miles from Earth. And in July, NASA began to unveil <a href="https://www.pbs.org/wgbh/nova/article/james-webb-space-telescope-first-images-nasa/">stunning images</a> of stars and faraway nebulas in greater clarity than its predecessor, Hubble. JWST has also managed to capture galaxies <a href="https://blogs.nasa.gov/webb/2022/12/09/nasas-webb-reaches-new-milestone-in-quest-for-distant-galaxies/">never before seen</a> by scientists, breaking the record for the most distant galaxy ever detected.</p>
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<figcaption><p>"Cosmic Cliffs" in the Carina Nebula, as captured by the James Webb Space Telescope. Image Credit: NASA, ESA, CSA, STScI </p>
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<p>In the coming years, the telescope's data will help scientists understand the evolution of stars and planets, since its infrared instruments can peer through dense dust clouds where star and planet formation begins. "The great thing, really, is that this is just the beginning," Stefanie Milam, deputy project scientist on JWST, <a href="https://www.youtube.com/watch?v=kOiGZZ9LU0I&amp;t=143s">told NOVA</a>. "We'll be able to go much, much deeper, and this telescope is going to do what we designed it to do."</p>
<h3><b>Mpox (monkeypox) outbreak</b></h3><p>Mpox, previously referred to as monkeypox, emerged in the U.S. and several other countries where it is not endemic in May. Although the disease—which presents as a painful rash, followed by flu-like symptoms—was first identified in humans in 1970, mpox was fairly unknown to the American public before this year's outbreak. Mpox spread quickly and peaked in early August, with hundreds of cases being reported per day. Around that time, the Department of Health and Human Services declared the disease a public health emergency and authorized the emergency use of mpox vaccines. </p><p>Data suggest that mpox transmission most often occurs through sexual activity or contact with open wounds or mucous membranes, like the eyes and mouth. While anyone can transmit the disease, there was a prevalence in cases among men who have sex with men (MSM). Many public health campaigns encouraged MSM in particular to get vaccinated, and as of this month, 1.1 million people have been vaccinated against mpox in the U.S.</p><p>By late September 2022, <a href="https://www.npr.org/sections/health-shots/2022/08/26/1119659681/early-signs-suggest-monkeypox-may-be-slowing-in-the-u-s">NPR reported</a> that New York City, San Francisco, Houston, and Chicago—all cities with high rates of infection—had begun to see a decline in cases, though not particularly correlated with vaccination rates. The CDC announced in a November report a highly confident assessment that “the overall incidence of monkeypox in the United States is declining.” And in December, the Department of Health and Human Services announced mpox will not be renewed as a public health emergency in 2023.</p>
<h3><b>DART Mission deflects an asteroid</b></h3><p>In 2021, <a href="https://www.pbs.org/wgbh/nova/article/nasa-dart-deflect-hazardous-asteroid-didymos/">NASA launched</a> its Double Asteroid Redirection Test (DART) spacecraft on a mission to test whether scientists could possibly deflect asteroids at risk of colliding with Earth.</p>
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<p>In the first-ever “full scale planetary defense test,” the DART spacecraft set out to knock Dimorphos—a 525-foot asteroid “moonlet” that circles a larger asteroid called Didymos—off track. The spacecraft <a href="https://www.pbs.org/wgbh/nova/article/nasa-dart-asteroid-impact/">slammed into its target</a> in September 2022, but it wasn’t until October that scientists determined that the DART mission was, in fact, a smashing success. <a href="https://www.pbs.org/wgbh/nova/video/watch-dart-spacecraft-smash-into-asteroid/">The spacecraft’s impact</a> nudged the moon closer to Didymos, shortening its nearly 12-hour orbital period by 32 minutes, <a href="https://www.science.org/content/article/nasa-test-mission-successfully-deflects-asteroid">Science reported</a>. While neither Didymos nor Dimorphos pose any risk to Earth, DART is proof that if Earth were to be threatened by an asteroid, humans may actually be able to something about it.</p>
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<h3><b>Dropping water levels reveal dinosaur tracks, Nazi warships, human remains and more</b></h3><p>The blistering summer of 2022 saw drought from Asia to Europe to North America. And while people may have anticipated a water shortage, few could predict what would be revealed when water levels dropped. </p><p>Spotting dinosaur tracks in Texas’ Dinosaur State Valley Park may not seem surprising. But scientists and park rangers were fascinated to find sets of tracks usually obscured by water suddenly exposed when the park’s Paluxy River dried up <a href="https://www.smithsonianmag.com/smart-news/drought-exposes-dinosaur-tracks-in-texas-180980647/">in August</a>. The footprints, estimated to be 113 million years old, were left deep in the sediment by the carnivorous <i>Acrocanthosaurus,</i> a two-legged dinosaur that weighed up to 7 tons and stood around 15 feet tall. </p><p>Just 1,200 miles away in Nevada, Lake Mead revealed its own <a href="https://www.cnn.com/interactive/2022/12/us/lake-mead-drought-shoreline-discoveries-climate-ctpr/">hidden secrets</a>. Along with long-sunken boats, a total of six sets of human remains—one of which was discovered <a href="https://www.npr.org/2022/05/02/1096049180/a-barrel-containing-a-body-was-exposed-as-the-level-of-nevadas-lake-mead-drops">inside a barrel</a>—were found as the lake’s levels dropped. This year, Lake Mead hit its lowest levels since 1937, continuing a 22-year long downward trend, <a href="https://earthobservatory.nasa.gov/images/150111/lake-mead-keeps-dropping">NASA reports</a>. “There’s no telling what we’ll find in Lake Mead,” former Las Vegas mayor and defense attorney Oscar Goodman said in May. “It’s not a bad place to dump a body,” he added, <a href="https://www.pbs.org/newshour/nation/officials-prep-for-gruesome-surprises-as-las-vegas-lake-slowly-dries-up">according to PBS NewsHour</a>.</p>
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<figcaption><p>A once-submerged speedboat juts out from the dry lakebed of Lake Mead in June 2022. Image Credit: James Marvin Phelps, Flickr</p>
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<p>Regional drought and a heatwave in southwestern China led to a rapid water level drop in the country’s massive Yangtze River, revealing a small island and three previously submerged Buddhist statues. The statues are thought to be 600 years old. While the artifacts are exciting, this historic drought—and those expected in summers to come—threatens the livelihood of some 400 million people who depend on the Yangtze River for water.</p><p>But the largest, and perhaps the most dangerous, of these drought discoveries was in Europe. This summer, the Danube River was at its lowest levels in almost a century. Out from the shrinking waters along eastern Serbia emerged dozens of sunken German WWII ships, each covered in tons of ammunition and explosives. The explosives on the ships pose a major ecological and safety risk to the fishing and coal shipping industries operating within the Danube, <a href="https://www.reuters.com/world/europe/low-water-levels-danube-reveal-sunken-ww2-german-warships-2022-08-19/">Reuters reported</a>.<br/><br/>This summer’s drought, and the strange items it brought to light, foreshadow a larger problem to come with climate change. And in colder climes, melting permafrost is also revealing long-unseen entities, though <a href="https://www.smithsonianmag.com/smart-news/scientists-revive-48500-year-old-virus-setting-world-record-180981208/">not all of them</a> are as exciting as dinosaur tracks.</p>
<h3><b>Artemis 1 kicks off a new lunar program </b></h3><p>This year, NASA's much-anticipated <a href="https://www.pbs.org/wgbh/nova/article/artemis-launch-nasa-sls-orion-moon/">Artemis I mission finally took off</a>. Following months of postponements, fuel leaks, and hurricanes, NASA launched the world's most powerful rocket from the Kennedy Space Center on November 16. Artemis I is the first mission in the Artemis program, which aims to put a crew on the Moon. The inaugural mission, which was uncrewed, was intended to test the massive SLS rocket and the Orion crew capsule. </p><p>Once launched, Orion spent 25.5 days zooming well past the Moon and looping back to Earth. The spacecraft <a href="https://www.pbs.org/wgbh/nova/article/artemis-launch-nasa-sls-orion-moon/">splashed down</a> in the Pacific Ocean on December 11. Now begins NASA's post-flight analysis, which will help reveal just what’s possible in <a href="https://www.pbs.org/wgbh/nova/video/why-nasa-is-going-back-to-the-moon/">this new chapter</a> of space exploration.</p>
<h3><b>Oldest DNA ever found</b></h3><p>Last but not least came a breakthrough just before the end of year. On December 7, scientists announced the remarkable discovery of <a href="https://youtu.be/JS0Cn-bDuKs">the oldest DNA to date</a>. The DNA, retrieved from the sediment cores at the northern edge of Greenland, is a whopping 2 million years old. It reveals stunning information about the plants and animals that once inhabited the Arctic, which was once a lush, green landscape. </p><p>The finding, experts say, could not only <a href="https://www.pbs.org/wgbh/nova/article/oldest-dna-study-nature/">revolutionize paleontology</a>, opening new windows onto ancient worlds, but also help us better understand how species adapted to a warming world in the past. “It's as though we really do have a time machine in a way that we never expected,” said Ross MacPhee, senior curator at the American Museum of Natural History.</p><h4>OLDEST DNA EVER FOUND REVEALS SECRETS OF THE ANCIENT ARCTIC:</h4>
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<p data-block-key="ie61a">NASA nudges an asteroid, weird things emerge from water, and scientists tackle a new epidemic.</p>

Red hot chili peppers, and other hot peppers within the Capsicum genus, get their heat from the chemical capsaicin. Image credit: Austin Kirk, Flickr

From jumping horses to jalapeños: the science of spicy peppers

<p>A few months after competing in the 2008 Summer Olympics in Beijing, Norweigian horseback rider Tony André Hansen was stripped of his bronze medal. His horse Camiro had failed a drug test during the Games, testing positive for capsaicin. The International Equestrian Federation <a href="https://www.nytimes.com/2008/08/22/sports/olympics/22doping.html">dismissed the pair</a>, along with three other showjumping riders and horses, from the competition. </p><p>Hansen has not competed in the show ring since.</p><p>Capsaicin is the chemical responsible for the “heat” in chile peppers. Like many over-the-counter muscle rubs—think “IcyHot”—capsaicin can bring on both tingling sensitivity and numbness.</p>
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<p>When applied as a <a href="https://www.reuters.com/article/us-olympics-equestrian-doping/norway-bronze-medalist-suspended-idUSPEK303420080821">paste or lotion to horses’ forelegs</a>, capsaicin can cause a burning sensation that would be exacerbated by knocking against the rails of a jump. If a showjumping horse lifts its legs higher, it avoids the potentially irritating touch of a fence—and its rider avoids incurring penalties. But capsaicin can also soothe aches and pains by temporarily <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6006555/">deactivating the nerve endings</a> where it’s applied. An exhausted horse with numbed nerves will perform better than an equally tired one that can feel the full pain of its aching muscles, according to the <a href="https://aaep.org/horsehealth/lameness-and-poor-performance-sport-horse-eventing">American Association of Equine Practitioners</a>, which is why capsaicin is banned from equestrian competitions to this day. </p><p>“Capsaicin binds to the TRPV-1 receptor—a pain receptor present all over our bodies,” says Ivette Guzmán, a horticulturist and member of the Chile Pepper Institute of New Mexico State University. If a horse is sore, “applying capsaicin binds up those pain receptors,” she says. A horse may feel a little bit of heat from topical capsaicin, but “they won’t feel the pain,” Guzmán explains. “It works on us, too.”</p><p>Just as horses experience a numbing feeling from a topical application of capsaicin, your tongue will tingle when you chew a hot pepper. This numbing sensation is often coupled with a burning one that’s enjoyed by spicy food-lovers around the world: Whether eating centuries-old cuisines like <a href="https://www.theatlantic.com/health/archive/2019/04/why-we-call-indian-dishes-curry-colonial-history/586828/">Indian curry</a> or saucy chicken wings on the popular YouTube series “Hot Ones,” human beings have subjected themselves to the uncomfortable chemistry of capsaicin <a href="http://sitn.hms.harvard.edu/flash/2012/issue131b/">for millennia</a>.</p><h3>The need for heat</h3><p>Pepper species native to the Americas fall within the genus <i>Capsicum</i>. Some <i>Capsicum</i> peppers, like the mild bell pepper, have no capsaicin at all. Others, like the jalapeño and habanero pepper—popular additions to dishes requiring some extra “heat”—do have the chemical. (A few <i>Capsicum</i> peppers, including the incredibly-hot ghost pepper, were developed in South Asia by hybridizing varieties from the Americas.)</p><p>“A lot of people mistakenly think the seeds are what hold the spice,” Guzmán says. But “capsaicin is found in the part of the fruit called the placenta: the membrane that holds onto the seeds.”</p><p>But spicy food doesn’t have to be hot to convey heat. In fact, capsaicin doesn’t physically burn your tongue and innards at all. When your body processes capsaicin, your nervous system sends out a response that activates your senses for touch and temperature. The same receptors responsible for blocking topical pain send signals to your brain that you’re being burned when you eat something spicy. And here’s the kick: Capsaicin alters the sensitivity of the pain receptors in your mouth, effectively lowering the temperature at which you feel burning pain. This is why jalapeño sauce feels burning hot even after being refrigerated.</p><p>“These [receptors] work really well when they detect the correct stimulus,” says Joanna Buckley, a chemist at the University of Sheffield in England. “They respond to anything over 43 C (109 F). So if you have a hot cup of tea, this receptor will work correctly and tell you, ‘Oh, your tea’s a bit hot.’” </p><p>The problem is, Buckley adds, these heat-sensing receptors are also triggered by a class of compounds called vanilloids. Capsaicin is one of them.</p>
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<p></p><p>Chemically, capsaicin is corrosive (like hydrogen peroxide), acutely toxic (like chlorine), and irritating (like ammonia). And its irritant qualities won’t just fire up your mouth: Capsaicin can have a similar effect on other mucous membranes. If you’ve ever chopped peppers and then accidentally touched your eye, you understand how irritating this compound can be. </p><p>So why do some people enjoy—and even get a thrill out of—eating a fruit with such a kick?</p><p>“We get interviewed often by chiliheads,” Guzmán says. “I’m Mexican. I grew up eating jalapeños, I grew up eating really spicy food, and I understand that there are other chemicals in [peppers] that are medicinal. But when it comes to chiliheads, I think they’re fascinated by the chemistry of capsaicin and how it makes you feel something you’ve never felt before. It gives you a euphoria.” </p><p>Measuring that euphoria depends on the Scoville scale.</p><h3>Let’s talk Scovilles</h3><p>Named for American pharmacist Wilbur Scoville, <a href="https://www.vox.com/2016/1/22/10810564/wilbur-scoville-google-doodle">the Scoville scale</a> ranks the pungency of chile peppers based on the concentration of capsaicin in the pepper. It’s this concentration that determines how our bodies will react to peppers; while small amounts of capsaicin fall within the “spicy chicken dinner” category, stronger concentrations spell out “weapon-grade pepper spray.” </p><p>In the early 1900s, Scoville, who was working as a chemist at the time, attempted to test out people’s relative capsaicin tolerance. He recruited five human subjects to taste-test mixtures of dried pepper and sugar water and had them report how hot they found each mixture to be. The basis of his heat scale is the amount of sugar water needed to dilute the mixture enough for the majority of his subjects to no longer feel the heat. </p><p>These days, a technique called high-performance liquid chromatography is used to determine exactly how much capsaicin a pepper contains in parts per million, and multiplying the result by 16 converts it to <a href="https://www.smithsonianmag.com/arts-culture/how-hot-is-that-pepper-how-scientists-measure-spiciness-884380/">Scoville Heat Units (SHUs)</a>.</p>
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<p>The highest level of naturally occuring capsaicin is in the Carolina Reaper, the hottest pepper in the world. Its creator, chile pepper grower Ed Currie, bred the pepper by taking one uniquely spicy <a href="https://www.palmettobluff.com/discover/fear-the-reaper">habanero</a> grown on the La Soufrière volcano on Saint Vincent in the Caribbean and crossing it with a Naga Viper pepper, which was developed in the United Kingdom from peppers hailing from the Caribbean and South Asia. The hottest single Carolina Reaper ever to be harvested rang in at 2.2 million SHU, meaning that more than a tenth of the pepper was pure capsaicin.</p><p>High amounts of capsaicin, like those found in the Carolina Reaper, can cause injury. “Capsaicin is a really potent chemical. If you have too much of it, it can be toxic,” Buckley says. “It’s the thing that’s used in pepper spray. We’ve all seen images of people who have been pepper sprayed. Their eyes are swollen up, they’re crying, they can’t see…so it’s incredibly important to know how to handle capsaicin” safely, she says.</p><h3>Your body’s battle against spice</h3><p>If you don’t welcome spicy burns, there’s a way to neutralize the compound’s effects: dairy. “Capsaicin is an oil and it is insoluble in cold water,” Buckley says. Though it’s somewhat soluble in alcohol, like beer, Buckley explains, capsaicin is best dissolved by another oil. “You need to find something that’s fatty to dissolve the capsaicin,” she says. “That’s why the best thing to drink is milk.” </p><p>Although spicy food is sometimes associated with stomach problems—Currie, who not only created the Carolina Reaper but also eats one every day, still <a href="https://www.latimes.com/nation/la-na-reaper-pepper-20141127-story.html#">experiences severe stomach cramps</a>—there is no direct evidence that spicy food causes belly cramps or nausea. The perceived pain, Guzmán explains, may just be a side effect of your gut membranes being irritated. While a 2016 study showed capsaicin can cause those with abdominal disorders to experience <a href="https://pubmed.ncbi.nlm.nih.gov/27094759/">flare-ups in their symptoms,</a> the same can be said for <a href="https://www.pbs.org/wgbh/nova/article/unless-you-have-celiac-disease-gluten-sensitivity-is-probably-just-in-your-head/">too much bread</a>, a famously unspicy food.</p><p>But there are always worst-case scenarios.</p>
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<figcaption><p>A Trinidad moruga scorpion pepper, which is currently the second hottest pepper in the world to the Carolina reaper. Image credit: John Vonderlin, Flickr</p>
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<p>More than 150 different varieties of chile grow in a garden at New Mexico State University’s Chile Pepper Institute. “One year we had a group of students we were doing a tour with in the garden. And one student thought it would be funny if he bit a tiny piece off a Trinidad Scorpion pepper,” Guzmán says. “He did that, and he threw up in the garden, and he passed out, and we had to carry him to a shaded area under some trees.” </p><p>Because capsaicin is a toxin, Guzmán explains, the human body’s first response to an excess of it is to flush it out. (In the student’s case, by vomiting.) </p><p>In 2018, the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893965/">National Institutes of Health reported</a> that a previously healthy 34-year-old man was admitted to the hospital with “thunderclap headaches”—sudden, severe head pain accompanied by fever, blurred vision, and even seizures—after eating a Carolina Reaper whole. Doctors treated him by flushing the capsaicin out of his body, which, like many chemical compounds in large amounts, can be dangerous. </p><p>Of course, Olympic equestrian Tony André Hansen’s story shows that even a small amount of this complex compound can be damaging (and in some cases, even career-ruining). It just depends on where—or upon whom—the capsaicin ends up.</p>
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<p>Discover capsaicin, the active ingredient in chile peppers. (If you can take the heat.)</p>

Shivering triggers the release of a hormone called irisin, which jump-starts a lesser-known cold weather response: the activation and buildup of brown fat. Image Credit: tomasso79, iStock

How 'brown fat' helps you cope with cold weather

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<p>Have you ever wondered why the first cold day of fall feels so much colder than a day the exact same temperature at the end of the winter? It’s not just a matter of perspective: Your body really is more prepared for cold conditions at certain times of the year—thanks to a mysterious form of fat.</p><p>When you experience cold, your body responds in a few noticeable ways. Your blood vessels constrict—a process called vasoconstriction—taking blood away from your extremities and keeping it near your core. And you shiver, meaning certain muscles start shaking to produce heat. But shivering also triggers the release of a hormone called irisin, which jump-starts a lesser-known cold weather response: the activation and buildup of brown fat.</p><p>Brown adipose tissue, or brown fat, is different from the white fat we might think of when discussing diet or weight loss. White fat lines our skin and muscles, cushioning our organs and bones. But brown fat appears only in specific areas around the neck, spine, aorta, and kidneys. It builds up in clumps around major blood vessels, warming the blood as it passes through the body. “If vasoconstriction is closing the window, brown fat is turning on the heater,” says Yossi Rathner, a physiologist at the University of Melbourne.</p><p>We don’t create enough brown fat to cause noticeable weight gain, but the small deposits are still powerful thanks to their high concentration of energy-creating mitochondria. Instead of burning calories to produce energy to power the body, the mitochondria in brown fat burn calories to produce heat. By acting like little heating stations for blood vessels, these soft clumps of insulation help us deal with the cold more efficiently than shivering, which expends a lot of energy, and vasoconstriction, which puts us at risk of frostbite.</p>
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<p>“Your body goes from a rickety radiator to a smooth central heating system by the end of the winter,” says Francesco S. Celi, a professor of medicine at Virginia Commonwealth University.</p><p>But the effect only lasts for as long as we need it. When the temperature warms up, brown fat fades away. “If we are not exposed to the cold, the brown fat will atrophy,” says Barbara Cannon, a physiologist at Stockholm University. “There may be a few stem cells left in the area for later regeneration, but it will nearly disappear,” Cannon says.</p><p>Even a one-month tropical vacation is enough to deplete one’s brown fat reserves, Celi says, creating that “extra cold” sensation a traveler might feel upon returning to a cold climate.</p><p>You could say brown fat is winter's undercover hero, dropping in when we need it most, and disappearing once the job is done. So, the next time a chilly day leaves you shivering, just remember help is on the way.</p>
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<p data-block-key="m57w9">Shivering can activate a series of “heating stations” for your blood vessels—but they take a little while to get up and running.</p>

Katherine Julian, physician and associate dean of graduate medical education at the University of California, San Francisco (UCSF). Image courtesy of UCSF

A physician on her grandfather’s experience as a minority in STEM—and the state of progress today

<p>The grandson of Alabama slaves, Percy Julian worked tirelessly—transitioning from university classrooms to private laboratories; from the U.S. to Austria and back—to find a place that would allow him to work in chemistry. After one year as a department head at Howard University—a stint <a href="https://www.pbs.org/wgbh/nova/video/forgotten-genius/">that ended in his resignation</a>—Julian would go on to work at DePauw University, where he became the first to ever totally synthesize physostigmine, an alkaloid used to treat glaucoma.</p><p>His other successes, which include synthesizing cortisone (used to treat arthritis) and progesterone (used to prevent miscarriages) improved society. They also helped pave the way for Black, Indigenous, and other people of color in STEM, and <a href="https://www.pbs.org/wgbh/nova/article/percy-julian/">inspire the next generation of scientists</a>.</p>
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<p>One of those scientists is Percy Julian’s granddaughter, Katherine Julian. A physician and associate dean of graduate medical education at the University of California, San Francisco, Katherine trains medical residents and fellows, and researches medical education. Her work of practicing science and educating others mirrors—and honors—her grandfather’s legacy, and she sees Percy Julian’s sacrifices reflected in the work she and other Black scientists do today. </p><p>A lot of Black people “have to work three times as hard” to be taken seriously, Katherine says. “I think that kind of work ethic is something that I have to continue to uphold—certainly in my professional world. That has been instilled in me in a lasting manner.” </p><p>Katherine spoke with NOVA about her memories of Percy, her career, and the effect his life and work has had on the way she perceives progress in STEM today.</p><p><b>Hanna Ali:</b> <a href="https://www.pbs.org/wgbh/nova/article/blackinnature-tropical-paleontology/"><b>Black scientists</b></a><b> and</b> <a href="https://www.pbs.org/wgbh/nova/video/joys-challenges-birding-while-black-christian-cooper/"><b>hobbyists</b></a><b> still face discrimination in the lab and in public, much like Percy Julian did himself. More often than not, the onus is on Black, Indigenous, and other people of color to push their way into STEM environments and educate their peers on what it means to treat them with humanity.</b></p><p><b>Do you often find that your cohort of students is fairly diverse, and have you seen more strides being made at UCSF to make more opportunities for students of color?</b></p><p><b>Katherine Julian:</b> In my almost 25-year career—and I think this is not just at UCSF, this is on a larger scale—we’ve made great strides to become more diverse in science. Do I think we are where we need to be? No, of course not. And I still feel like we have a ways to go. </p><p>We are not perfect. We have many things to learn and change. But I do feel like we are at a unique point—particularly now—because, unfortunately, of many current events. There is more consciousness-raising presently than I have seen in the last 20 years. I feel like that’s an incredible opportunity to be able to continue to make change.</p><p><b>HA: In the time that your lives overlapped, did you witness your grandfather working as a chemist? If so, what impression did this leave on you?</b></p><p><b>KJ:</b> Well, he passed away when I was pretty young. The side that I saw of him was not necessarily the scientist side. I saw a side that was super passionate about gardening: the garden he had, around his house [in Chicago] and on the grounds of his home. He loved tulips—and planted thousands and thousands and thousands of tulip bulbs in the ground. [He’d] go out and garden every morning before going to work. </p><p>I think it does reflect that he was someone who worked so incredibly hard. I think he was someone that put himself fully into many, many things. Obviously he had science. And moving that forward and to do the things that he did, I think required such incredible fortitude.</p><p><b>HA: Did your grandfather use gardening as a way to educate the younger children in your family?</b></p><p><b>KJ:</b> I definitely remember being out there with him. I was probably too young for there to be any sort of education aspect. But I do think after he passed away, there has been an education aspect: from my grandmother and my father and my aunt, in terms of his legacy and what that meant, and almost a responsibility for that legacy. And that goes a little bit toward having to work twice as hard and how important education is. I think that there was very much a feeling that he had worked so hard to be able to advance Black and African Americans and to be able to provide for his family. </p><p><b>HA: It seems like, instead of a hands-on teaching approach, there was more of a legacy of learning.</b></p><p><b>KJ:</b> That’s exactly right. </p>
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<p><b>HA: “Forgotten Genius” offers a perspective of Percy Julian’s career and also suggests that he made lots of friends along the way, including some overseas in Austria, that came to do research with him in the States later on. Are you in touch with any of them?</b></p><p><b>KJ:</b> You know, I actually am in touch with a family friend—she's now of advanced age. Her family worked with my grandfather. She now lives in Israel. </p><p>She travels to the U.S. once a year—well, not in COVID times—usually for competitions. She's a scientist herself, and we get together every year when she comes. So there is some of that connection, obviously, because my grandfather now would be very old, and a lot of those connections have now passed. Staying in touch with her [has] really been terrific. And [being] able to hear old stories has been great. </p>
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<p><b>HA:</b> <b>It’s interesting to think about how Percy Julian had to go out of the country just to get more research and work experience. </b></p><p><b>KJ:</b> And to encounter all of the racism and barriers there—just even to try and live in the community of what he was trying to live—I think required incredible fortitude. </p><p><b>HA: My family members are immigrants, and we don’t have that sort of long story of a family legacy in America. It’s more like, “Your parents came here to go to school and they made a life for themselves. Any sort of family history is back in Somalia.” </b></p><p><b>KJ:</b> I see an immigrant's story in a way very similar to the way you think back to fortitude. How hard it is to leave everything behind, to go someplace new to try and make a better life—whether it's for you or often really for your kids—right? So I see it as very, very similar. I can't speak for children of immigrants, but having spoken to several of my friends, I do think they also feel a big responsibility. It's like, “Wow, my parents went through all of this for me…I have a responsibility to pay that forward in a way.” </p><p><b>HA: We’ve been highlighting</b> <a href="https://www.pbs.org/wgbh/nova/article/inaugural-black-x-weeks-foster-inclusivity-and-empowerment-stem/"><b>"Black in X" weeks at NOVA</b></a><b>, talking about what it means to be a Black scientist. Being a physician, do you find yourself having to explain the most basic inequities in health care or STEM to your peers, where you say something like, “I shouldn’t have to tell you this, but I do?”</b></p><p><b>KJ:</b> You know, not so much now. Some of that is a function of the stage I'm at in my career, [and] where I'm at, being at UCSF, where I do think people are really looking at <a href="https://www.pbs.org/wgbh/nova/video/covid-19-vaccine/">health equity</a> in a real way and thinking deeply about it. I do feel fortunate that I am not having those conversations in my workplace, at least presently. I have, years and years ago, [but] I do feel that that's a marker where I am in terms of change. Because I also recognize that's not the case for many, many other people and where they are. </p><p>The current pandemic has just uncovered so much <a href="https://www.pbs.org/wgbh/nova/article/racism-stress-covid-allostatic-load/">health inequity.</a> And I think people—at least the folks I’m working with—realize that. I do think folks are really looking and thinking about “How can we, as a medical community, make a difference in terms of really trying to eliminate those disparities and help?” </p><p></p><p><i>This interview has been edited for length and clarity.</i></p>
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<p>Dr. Katherine Julian, the granddaughter of famed chemist Percy Julian, discusses her grandfather’s legacy—and how barriers for people of color in science still exist.</p>

Water flowing from a Weatherford, Texas resident's well ignites when he puts a flame to the well spigot. The U.S. Environmental Protection Agency had evidence a gas company's drilling operation contaminated his drinking water with explosive methane, but withdrew its enforcement action, leaving the family with no useable water supply, according to a report obtained by The Associated Press. Image Credit: Lm Otero/AP/Shutterstock

Could tiny sensors keep methane out of our atmosphere—and homes?

<p>You’ve seen the images: floating islands of plastic in the ocean, marine life entangled in nets and lines. Whether in the ocean or on land, <a href="https://www.pbs.org/wgbh/nova/article/bacteria-plastic-biodegradable-pha-recycling/">plastic pollutants</a>—and their effects—are often visible.</p><p>But not all pollutants are.</p><p>“What most people don’t realize is that there has been pollution for a long time,” says Desiree Plata, an environmental engineer and chemist at the Massachusetts Institute of Technology (MIT). “Most of it we just can’t see.”</p><p>Enter methane, a colorless, odorless chemical that, like carbon dioxide and other greenhouse gases, contributes to climate change by collecting in our atmosphere and trapping radiation from the sun. Methane is emitted into the air by many sources, including <a href="https://www.nature.com/articles/d41586-021-00659-y">melting permafrost</a>, gassy cows, and oil and gas drilling sites. And it’s about <a href="https://www.scientificamerican.com/article/how-bad-of-a-greenhouse-gas-is-methane/">86 times more potent</a> than carbon dioxide, according to the Intergovernmental Panel on Climate Change.</p>
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<p>Methane is the main ingredient in natural gas, which powers 48% of homes in the United States. Commercial natural gas is scented with odorants to make a potential gas leak detectable, alerting a resident to shut off their stove or track down the leak.</p><p>“I like to call methane ‘the elephant in the atmosphere,’” Plata says. “It’s the gas everyone should be talking about, but few people know about.”</p><p>But now, a team at MIT is producing sensors to allow people to “see” methane, and ultimately track down its sources and mitigate its harmful effects.</p><h3>Sensor technology: by chemicals, for chemicals</h3><p>These methane sensors, developed by chemist Tim Swager <a href="https://www.c2sense.com/gas-sensors">and his team</a> at MIT, vary in size depending on how large of an area a user would like to monitor. The sensors could be big, shaped like a laptop briefcase for easy carrying. Or they could be small, about the size of a sticker, and shaped like the flat chip in your credit card.</p><p>The sensors are inexpensive, low-power devices that can detect methane emissions in nature and at industrial sites, Swager said in an email. The company C2Sense is working with his team’s technology, which could be on the market within a few years.</p><p>Though they’re not yet licensed for commercial use, Swager’s methane sensors have the potential to be as widely used as the carbon monoxide detectors we have in our homes. Methane is present in natural, industrial, and agricultural environments, and sometimes leaches into drinking water through the ground <a href="https://www.health.state.mn.us/communities/environment/water/wells/waterquality/methane.html">in the form of tiny gas bubbles</a>, meaning that anyone—from a farmer to an engineer to a homeowner—could use a sensor to get a better idea of the chemical’s presence in their air or water.</p><p>All of Swager’s team’s sensors are powered by the same thing: chemical elements. Platinum and oxygen naturally react with methane, so they can be used in the sensors to detect methane in an environment, Swager explains.</p>
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<figcaption><p>Ice-rich permafrost thaws in Alaska. The carbon stored in the formerly frozen ground is consumed by microbes, which release methane gas. Image credit: USGS</p>
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<p>Here’s how: The platinum in the sensor reacts with oxygen in the atmosphere, bonding to create a chemical compound. This compound then reacts with any methane present in the surrounding environment. “Basically, you’re oxidizing the methane,” Swager says. This reaction between the platinum-oxygen compound and methane sets off the sensor, which sends a notification to a specialized device (for an industrial-use sensor) or a cell phone (for a personal-use sensor).</p><p>The sensor’s platinum and electrode sensing component “is very tiny—and that means that you could put it into lots of different structures,” says Plata, who’s not involved in Swager’s work. Unlike some other machinery that’s weighed down by the bulky essential technology within it, C2Sense’s sensors rely on very little to work, so they can be easily integrated into homes, barns, drilling sites, and other environments where methane is present.</p><p>Gas sensors that can detect volatile organic compounds, including methane, already exist. But they’re not tailored to detect methane alone, Swager said in an email, and require temperatures higher than 570 F to operate. This makes them both costly and potentially dangerous around high concentrations of methane, a flammable gas.</p><p>Conversely, Swager's sensors can operate in ambient conditions and have low power requirements—they can run at <i>submicrowatts</i>—making them inexpensive to operate. And unlike existing sensors on the market, which generally need a battery pack or wiring to work, Swager's sensors can be powered wirelessly and read by a smartphone.</p><p>Some of the smaller prototype methane sensors are 0.08 inch (2mm) cubes, approximately as thick as a nickel. They can potentially help pinpoint leaks in homes or wells, attaching physically to an area where methane may spew from. The sensors can also attach to a cell phone for on-the-go sensing, reporting the changes in air or water quality right to a “mobile-friendly sensor platform” on the phone, Swager explains.</p><p>That said, personal-use sensors may be a ways off, Swager cautions. Currently, odorants added to methane-containing gas serve as the main indicator for gas leaks in homes. Unfortunately, scent is only useful if you’re present and able to smell it. “Houses can blow up if there’s too much natural gas,” Swager says. When someone is away from their home or is unable to smell a leak, it’s harder to protect against a possible gas fire—<a href="https://www.nytimes.com/2020/02/26/us/columbia-gas-massachusetts.html">or worse, explosion</a>.</p>
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<p>Another possible application for the sensors, Swager says, is to test well water, which <a href="https://www.usgs.gov/mission-areas/water-resources/science/domestic-private-supply-wells?qt-science_center_objects=0#qt-science_center_objects">millions of people</a> in the U.S. rely on. When methane is drilled underground, the gas sometimes escapes from the pipe it’s being pumped into, travels through the porous earth, and rises from the ground. “In the process of drilling down, you've created another pathway for the methane to reach the surface. It could come up 100 yards from the well pad depending on the location, even get into the groundwater,” Swager says. Because the gas is considered nontoxic by several state departments of public health, methane doesn’t have a <a href="https://www.rcap.org/resource/natural-gas-and-your-drinking-water-system/">Safe Drinking Water Act maximum contaminant level</a>. (Although the U.S. Department of the Interior suggests a <a href="https://extension.psu.edu/methane-gas-and-its-removal-from-water-wells">specific methane level</a> at which homeowners should vent their wells.)</p><p>Larger sensors can sense transient leaks (leaks that start and stop) over large swaths of land. Intended for use by engineers, park rangers, and other professionals, industrial-use sensors could identify methane leaks at natural gas drilling sites, where methane comes up from the earth; forests, where <a href="https://www.nationalgeographic.com/environment/article/trees-release-methane-what-it-means-climate-change">raging fires can emit</a> the chemical; or large farms, where <a href="https://www.smithsonianmag.com/smart-news/seaweed-fed-cows-burp-less-planet-warming-methane-180977296/">methane-emitting livestock</a> live.</p><p>Cattle farming is the <a href="https://www.epa.gov/ghgemissions/overview-greenhouse-gases#methane">leading cause of methane emissions</a> in the U.S., with nearly <a href="https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions#agriculture">2% of total greenhouse gas</a> emissions annually coming from the methane cows burp and fart (and the U.S. is the <a href="https://www.usda.gov/topics/animals/animal-production">world’s largest producer of beef</a>). Scientists have looked for ways to lower methane emissions from cattle farming, going so far as to put <a href="https://www.wired.co.uk/article/cows-climate-change-methane-stop">masks on cows to catch their burps</a>.</p><h3>Addressing the elephant in the room</h3><p>As methane and other greenhouse gases collect in the atmosphere, they “work as a blanket,” says Andra Garner, a climate scientist at Rowan University in New Jersey. “Methane is a much thicker and heavier blanket than carbon dioxide and if you add too many blankets, we start to get way too warm,” she explains.</p><p>Beyond climate change and immediate safety risks of methane, the health effects of being exposed to high levels of methane over a prolonged period of time are also a concern, but haven’t been thoroughly investigated. Communities that have dealt with large amounts of methane leaking into their air—like the residents of Belmont County, Ohio, where one of the <a href="https://www.nytimes.com/2019/12/16/climate/methane-leak-satellite.html">biggest methane leaks ever recorded</a> in the U.S. happened in 2018—have reported respiratory problems and dizziness after being exposed to methane gas. In-home methane sensors could notify residents of leaks when their noses can’t, just like carbon monoxide and smoke detectors do.</p><p>“You probably hear headlines all the time, ‘Everywhere we look for plastics in the environment, we find them,’” Plata says. “The same is true of most industrial chemicals, but the problem is I can’t pull out my cell phone and take a picture of [them]. Tim’s sensors are helping to close that gap.”</p><p>Being able to see where methane comes from is the first step to controlling its effects on our planet. “Any time we have more data, that’s better; we get a better handle on where these emissions are coming from,” Garner says. After all, Plata says, “Getting chemicals out of the environmental system is a bigger challenge than trying to keep them from getting there in the first place.”</p>
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<p>Methane is a greenhouse gas 86 times as potent as carbon dioxide. What if we could see methane emissions in real time?</p>

Hanna Ali

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