What we know about airborne coronavirus

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By Victoria Jaggard, SCIENCE Executive Editor

As any fan of musical theater will tell you, front-row seats might as well be labeled as the splash zone. Between projecting, enunciating, and breathing hard through a big song-and-dance routine, stage performers generate a lot of spit. That’s kinda gross under normal circumstances, but it’s downright unsafe during the coronavirus pandemic.

COVID-19 is a respiratory disease, and it travels in drops of saliva and mucus known as respiratory droplets. Someone speaks, sneezes, or sings, and virus-laden drops spew forth, landing on surfaces or in other people’s faces. That’s why we have the now common practices of wearing masks, washing hands, and social distancing. But evidence is emerging that the coronavirus might also move about in much smaller droplets suspended in the air, which has scientists and public health experts debating whether to officially consider it airborne.

It may seem like a question of semantics, but figuring out when and where coronavirus might linger raises a host of questions about best practices, especially as people consider going back inside restaurants and reopening schools, Maya Wei-Haas reports for Nat Geo. If tiny drops carrying the virus can float, they might then build up inside confined spaces, including buses and classrooms. Last month, more than 200 scientists put out a call for additional health guidance based on the current evidence for airborne transmission, including improving ventilation in public buildings. Jose-Luis Jimenez at the University of Colorado, Boulder, even led creation of a model that can help people figure out their relative risk from airborne exposure in offices, schools, public transit, and other settings.

The flip side is that while coronavirus may loft in the air in select circumstances, it does not appear to be as contagious that way as definitively airborne diseases such as the measles. As such, the label may create more fear than is strictly necessary. “The connotation to people is that, Well, if I simply walk by a person on the street who is exhaling, I’m going to get sick,” says Michael Klompas, a hospital epidemiologist at Brigham and Women's Hospital in Boston. “That, I think, is both an inaccurate and unduly fearsome kind of message.”

The bottom line for now is that people should definitely still use masks to avoid spitting all over the place, and that potentially stuffy rooms should be better ventilated whenever possible. Of course, Broadway has been shut down since mid-March, and it will remain that way until January 2021, NPR reports. But I dearly look forward to getting back to the theater—and hopefully by then, we’ll know far more about the best ways of keeping everyone inside safe and healthy.

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Today in a minute

Microplastics are absolutely everywhere: Plastic pollution is far more pervasive than bottle-strewn beaches or garbage patches floating in the world’s oceans. It’s in the air we breathe and the soil we cultivate. Nat Geo’s Laura Parker reports on a collection of new research that reveals how microplastics “have spread into virtually every crevice on Earth, from the deepest sea trenches to the highest alpine mountains.” Scientists are studying how these fragments—which may survive for centuries—harm human health. Pictured above, a sample of trash collected off the coast of Hawaii contains plastic particles.

Dino diagnosis
: An interdisciplinary group of scientists and doctors found advanced cancer in a bone of a dinosaur that lived 76 million years ago. Scientists say it’s the first confirmed detection of fossilized cancer on a cellular level. The tumor was spotted on the partial fibula—in the lower leg—that belonged to a horned, plant-eating Centrosaurus. The dino suffered from osteosarcoma, which causes tumors of immature bone tissue, frequently in the leg, Science reported.

Earthquake boomerangs: Earthquakes are all weird in their own way. But the boomerang earthquake is one oddity that seismic evidence has never been able to verify—until now. As Nat Geo’s Maya Wei-Haas explains, a team of researchers has finally caught one of these temblors in action as it ripped across the surface of the Atlantic seafloor before unexpectedly turning back toward its starting point. These findings offer insight into why these quakes happen and their potential for destruction.

Derecho destruction: On Monday, a rare storm called a derecho swept across the Midwest, traveling 770 miles in 14 hours and knocking out power for more than a million people. Primarily seen in the late spring and summer, a derecho (pronounced deh-REY-cho) produces a wall of wind that can be just as dangerous as a hurricane or tornado. Nat Geo’s Amy McKeever explains how these storms form and why they’re so destructive.

Deforestation drives malaria surge: Widespread deforestation and gold mining have been linked to the rise of mosquito-borne diseases in Brazil’s Amazon—and the situation is only getting worse. As Jill Langlois reports for Nat Geo, malaria and dengue cases are on the rise in the region as deforestation rates surged in the first half of 2020. This connection alarms experts who worry about the threat this poses to Indigenous communities as well as the looming possibility of yet another public health crisis.

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Not signaling aliens: Photographer Navid Baraty could see the shining tower gleaming in the Nevada desert for miles. Standing 640 feet high, the shaft’s top is filled with molten salt. Temperatures inside it rise as 10,000 billboard-size mirrors track the desert sun and focus their rays onto the storage tank. Baraty says the heated salt produces steam and generates electricity. “Driving along the endless expanse of nothingness in the Nevada desert, I could see this tower ... looking like some sort of advanced alien communication device.”

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This week in the night sky

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Shooting stars galore: The Perseid meteor shower peaks tonight and early Thursday, with 20 to 70 stars shooting by each hour. With the glare of the quarter moon to contend with, you’ll get the most out of the Perseids if you keep your back to the moon or if you time your observation at mid to late evenings before moonrise. Early birds get a chance to witness a pairing of the whisker-thin waning crescent moon and brilliant Venus low in the eastern sky at dawn Saturday. And then on Monday night look for the peak of the minor κ-Cygnid meteor shower. With hourly rates of about three shooting stars per hour, this shower is more like a trickle, but with the moon out of the sky and a few straggler Perseid meteors streaking by, this could be fun to watch from a blanket or a reclining lawn chair. — Andrew Fazekas

The big takeaway

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The explosive behind Beirut’s catastrophe: Since 1916, ammonium nitrate has been responsible for at least 30 disasters, some accidental and some intentional. Used in fertilizing and in demolition, “a lot has to go wrong” for explosions of this magnitude, Nat Geo’s Sarah Gibbens finds. Yet the substance was behind the accidental explosions that killed 600 people in Texas in 1947 and 173 people in Tianjian, China, in 2015. The slow-heating compound has been used purposefully to kill, also, most notably in 1995 by American terrorists. They used it in a truck-bomb attack on the Oklahoma City federal building; 168 people were killed. Pictured above, Beirut amid the deadly explosion on August 4, which wrecked its port and severely damaged residential and commercial buildings in parts of the Lebanese capital.

In a few words

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On Thursday, Rachael Bale covers the latest in animal news. If you’re not a subscriber, sign up here to also get Whitney Johnson on photography, Debra Adams Simmons on history, and George Stone on travel.

The last glimpse

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Earth’s suddenly active neighbor: The dwarf planet closest to Earth is geologically alive, Nat Geo’s Michael Greshko reports. For years, scientists have puzzled over how these bright pockets of briny liquid formed on the floor of a crater on Ceres, a small world tucked into the asteroid belt between Mars and Jupiter. New data collected by NASA’s Dawn spacecraft suggests that these salty spots are relics of an ancient ocean—and that the asteroid impact that created the crater some 20 million years ago “likely kickstarted the icy volcanism that brought briny material to the surface.” And, just like that, Ceres joins the list of worlds that have once had all the required ingredients for life: liquid water, energy, and carbon-bearing organic molecules. While we still don’t know if the dwarf planet has ever been inhabited, it may have at least been habitable.

This newsletter has been curated and edited by David Beard, with photo selections by Jen Tse. Have an idea or a link? Send it our way at . Thanks for reading, and have a good week ahead.