What we learned about COVID-19 safety from a NYC anime convention

As Kristin Meyer set up her merchandise booth at the Anime NYC convention last November, she was sure she’d be exposed to the coronavirus at some point during the three-day event. “Getting that many people together in one spot, the chance that absolutely no one had COVID was zero,” she says.

Meyer was one of hundreds of artists who paid for a space to sell their art in the convention’s Artist Alley. Many signed up, despite getting a cold or the flu, bronchitis or pneumonia at previous fan conventions. “I used to get everything,” says Daifei, another artist, who asked to be referred to by their online handle. “Just from being around people.”

Anime NYC, first held in 2017, has become a beloved meeting place for fans of Japanese cartoons known as anime and comics called manga. Fans wearing elaborate anime-inspired costumes enter contests and pose for group photos. Actors who voice popular characters speak on panels and meet attendees for autographs. Media companies offer exclusive previews of their upcoming releases.

In the Artist Alley, attendees buy anime-inspired prints, charms, buttons and other custom-made merchandise. At an event like Anime NYC, artists can make as much as $15,000 in a weekend, says Daniela Muino, an artist who traveled from Texas with her partner to the 2021 convention. “People physically seeing your art in front of them” is great for sales, Muino says.
The greatest draw of Anime NYC for many attendees is connecting with other fans. A hobby typically considered niche takes over one of the country’s largest convention centers — the Javits Center — and drives a three-day party in and around the venue. Even in the midst of a pandemic, the 2021 event drew a record 53,000 attendees from around the United States and 30 other countries.

People were clearly drawn to get together. “Self-isolating rules are vital [in a pandemic],” says Robin Wollast, a psychology researcher at Stanford University. But “they also undermine deep-rooted needs for social bonding.” In-person events can be crucial for mental health, he says, despite the health risks they pose.

Attendees aware of those risks were not surprised when news broke in early December that the convention may have been a superspreader event; one of the first U.S. cases of COVID-19 due to the highly contagious omicron variant had been traced back to Anime NYC. The shock came later, in February, when the U.S. Centers for Disease Control and Prevention reported that, in fact, omicron had not spread widely at the convention.

Anime NYC may offer some lessons for making large events safer now and in the post-pandemic future.

What went right?
Peter McGinn, who works in health insurance, felt confident flying to New York City from his Minneapolis home for the convention. The 31-year-old knew the virus spreads easily through the air. But he was fully vaccinated and boosted, as were many of his 30 or so friends coming in from more than 10 states. The group used Anime NYC as a long weekend party; they shared accommodations and socialized at the city’s restaurants, bars and karaoke venues.

“I felt pretty comfortable based off of everything I did to protect myself, and what the people I was with did to protect themselves and everybody around us,” says McGinn, referring to his friends’ vaccination status and their masking in the venue, except when eating or drinking.

Once back in Minneapolis, McGinn didn’t feel great, but he attributed his symptoms to “normal con fatigue.” Plenty of attendees of these and similar events expect to get sick. At the American Geophysical Union’s annual meeting, for example, attendees ruefully refer to “AGU flu,” which spreads among conference-goers every year.

When one of McGinn’s convention friends tested positive for COVID-19, McGinn took a PCR test, which came back positive. A week into his 10-day quarantine, the Minnesota Department of Health called to tell McGinn that he was the first known person in his state to be infected with the omicron variant. Once the health department learned he had been to the crowded convention in New York City, McGinn spent hours helping both Minnesota’s state agency and the CDC with contact tracing.
Once word got out that McGinn had omicron and that several of his convention-going friends had also tested positive, news reports suggested he may have been patient zero for a potential superspreader event at the anime convention.

This news was reminiscent of the February 2020 biotech conference in Boston that had become one of the first superspreader events in the United States. Infections at that conference may have been linked to more than 300,000 cases, researchers reported in Science in December 2020.

In January, McGinn said he hoped the investigation into Anime NYC would push back against the perception that this convention had been a superspreader. “It’s overwhelmingly likely that where I caught COVID was outside of the event at dinner or karaoke,” he says. While at the convention center, he and his friends constantly wore masks.

McGinn felt vindicated when the results of the investigation were published as a pair of reports in the Feb. 18 Morbidity and Mortality Weekly Report. One study focused on McGinn and his friend group, and the other presented a big-picture view of COVID-19 at the convention. The researchers searched state and local health databases for test results from about 34,500 out of the 53,000 convention attendees whose contact information was available from the event organizers. They identified 119 cases among 4,560 people who got tested. Of those 119 cases, 16 were in McGinn’s friend group — and the only cases confirmed as omicron were among those 16.

The CDC characterizes a superspreader event as one infectious person giving the corona­virus to many others at a rate higher than average transmission. This didn’t occur at Anime NYC, the investigation found, because the rate of positive tests among convention attendees was close to the overall rate in New York City two weeks after the convention: about 3 percent.

“It’s nice to confirm that the event wasn’t a spreader event,” McGinn said after receiving news of the reports. “It makes me more comfortable in the future going to these types of events as long as mask and vax requirements are in place.”
Layers of protection
The CDC reports attribute this convention’s success to layers of safety measures put in place, including masks, vaccine checks and good ventilation.

“Everyone was always wearing their masks … when speaking to me or walking past my table,” Meyer says. She notes, however, that some costumed attendees took their masks off for photo shoots. And the Artist Alley was also located near the food court, where attendees took off their masks to eat.

Muino was impressed by the safety behaviors she saw at the convention in comparison with her home state of Texas. Still, the spacing of tables in Artist Alley “felt way too close together” for social distancing, she recalls. During busy periods, the area became incredibly crowded.

“There’s only so much control you can exert over a population that large,” Muino says. “People are going to take their masks off for pictures. They’re going to take them off to talk to friends.”
Attendees needed to show proof that they’d received at least one vaccine dose, following the city’s regulations at the time. Among 3,845 attendees whose test results and vaccination status were both available from local health departments, 3.4 percent were partially vaccinated, 84.5 percent were fully vaccinated and 12.1 percent had received a booster dose. Studies have shown that partial vaccination offers significantly less protection against COVID-19 than full vaccination.

However, Anime NYC organizers had too few staff checking proof of vaccination outside the venue, leading to long lines and crowding outside. Some attendees waited outside up to four hours on the first day of the convention.

The Javits Center itself took COVID-19 seriously, partly due to its roles during the pandemic as a field hospital and then a mass vaccination site. Newly installed hospital-grade air filters throughout the building may have helped prevent transmission.

“All the employees at the Javits Center had to go through training,” says Gavin Macgregor-Skinner, senior director of the Global Biorisk Advisory Council, part of the worldwide cleaning industry association that certifies organizations, including the Javits Center, on preparedness for biological threats. This training included cleaning protocols and how to manage traffic through the building.

This venue also worked with event organizers, including the company that runs Anime NYC, to ensure they followed safety protocols. The Javits Center’s attitude was, “if you come into our house, you follow our rules,” Macgregor-Skinner says.
The CDC investigation results do not mention, however, that Anime NYC was also very lucky with its timing. When this event took place, omicron hadn’t yet gotten a foothold in Manhattan. The city’s first wastewater samples containing omicron were collected on November 21, the final day of the event.

If the same event had happened two weeks later — when omicron was raging through the city — organizers would have needed more safety measures, such as a stricter vaccination requirement and rapid testing, to achieve the same low transmission, says Ayman El-Mohandes, an epidemiologist and dean of the school of public health at the City University of New York.

Heroes wear face masks
A successful COVID-19–safe event requires layers of protections that align with the community that the event is serving, says Mark Billik, founder of BeCore, a marketing agency that pivoted to organizing COVID-19–safe events during the pandemic. Billik recommends that his clients tailor their COVID-19 protocols for their events and he offered suggestions for future fan conventions (see Page 25).

Advance communication may be particularly successful when it’s tailored to a community and drives “enthusiasm about creating a safe environment,” El-Mohandes says. For instance, the next Anime NYC could provide masks with the faces of famous anime characters or post signs that show these characters encouraging distancing and frequent handwashing.

Using anime characters to promote safe behaviors is an example of classical conditioning, says Wollast, the Stanford psychology researcher. In classical conditioning, people learn to associate a particular stimulus (like wearing a face mask) with an unrelated stimulus (a favorite character) to drive a particular behavior. “My heroes are wearing face masks so I should wear one too,” Wollast says.
Safety beyond COVID-19
Along with avoiding COVID-19, Anime NYC attendees who spoke to Science News noted that they also avoided other respiratory illnesses. “Less people have been sick that I’ve heard of this year, than any other convention that I’ve ever been to,” Daifei says.

Maybe a cold or flu doesn’t have to be a necessary evil of attending conventions or similar events.

COVID-19 safety measures probably contributed to an unusually low number of flu cases in the 2020–21 season, according to the CDC. Leaders in the events industry are considering safety measures that build on lessons from COVID-19 — such as new technologies to improve ventilation and cleaning protocols — to reduce future outbreaks of flu and other infectious diseases, according to the Global Biorisk Advisory Council.

Some Anime NYC attendees hope to see continued handwashing, mask use and policies that encourage people to stay home when not feeling well, long after this pandemic recedes. All these practices are “very applicable to non-COVID respiratory infections,” El-Mohandes says. Such safety practices may also make large events more inclusive for immunocompromised people, many of whom already had to avoid crowds for their potential to spread infection before the pandemic.

“I feel like this is something that we can actually keep doing,” says Nicole Tan, an artist who shared a booth with Daifei at Anime NYC. The pandemic inspired a widespread realization that “we could have prevented a lot of illness if we just put our minds to it.”

Here’s how NASA’s Ingenuity helicopter has spent 1 year on Mars

One year ago, Ingenuity took its first flight on Mars. And its story since is that of a real-world little helicopter that could.

Ingenuity traveled to the Red Planet attached to the belly of NASA’s Perseverance rover, and both arrived in Jezero crater last February (SN: 2/17/21). About six weeks later, the helicopter began what was meant to be only a 30-day technology demonstration to see if flight is possible in the thin Martian atmosphere.

It proved it could fly — and then some (SN: 4/19/21). Over the next couple weeks, Ingenuity took four more flights, each time going a bit farther, a bit faster and a bit higher. After those first test flights, Ingenuity’s mission morphed from a technology demonstration to operations, helping Perseverance traverse the surface by scouting the terrain ahead (SN: 4/30/21; SN: 12/10/21).
Before the helicopter arrived, scientists had two perspectives of Mars. “We have pictures taken from orbit around Mars, and then we have pictures taken by rovers driving on the ground,” says planetary scientist Kirsten Siebach of Rice University in Houston, who is not part of the Ingenuity team. “But now this has opened up an entirely new perspective on Mars.”

Ingenuity has surpassed all expectations. It has shown not only that flight is possible but also what is possible with flight. Science News discussed the helicopter’s big moments, collaboration with the rover and upcoming flights with Håvard Fjær Grip. He’s Ingenuity’s chief pilot and an engineer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. His answers were edited for length and clarity.

SN: What does the “chief pilot” for a helicopter on another planet do?

Grip: The biggest part of the job is planning the flights. Ingenuity doesn’t know where it is or where it wants to go when it wakes up, so all of those decisions are made here [on Earth]. Every maneuver that the helicopter makes during the flight is planned here on the ground first, and then we uplink the instructions to Ingenuity. When it comes time to fly, it uses its onboard software to follow our instructions as precisely as possible.
SN: Ingenuity has completed 25 flights. Can you talk about how it’s exceeded expectations?

Grip: It is pretty great. We came there expecting to perform at most five flights within the 30-day window. And all of that was going to happen within in a small area that we carefully selected. We spent weeks figuring out exactly where to place the helicopter, studying these tiny little rocks. Everything was mapped out. And then things went so well when we started flying that almost immediately people started thinking, “Wow, let’s try to make use of this beyond those five flights.”

We started this next phase where, to be useful at all, we had to fly away from this carefully selected area. I’m really proud of that. We’ve been able to take this technology that was designed for this very limited mission and extend it to go and land different places on Mars and to travel across terrain that, originally, we had never planned on traveling across.

It’s lasted now for over a year since we deployed it to the surface. I don’t think any of us had imagined that that would be possible.

SN: Have there been any specific flights that have stood out to you?

Grip: Obviously, the first flight. That was the most important flight; it still is. We had a more challenging [time on] flight six. It became exciting, because we had an anomaly during the flight. [A glitch led to navigation images being marked with the wrong time stamps, which caused Ingenuity to sway back and forth during its flight.] Ingenuity had to power through that and survive and get down on the ground in one piece.

We’ve had some flights that have been dedicated to scouting activities. We went to an area where the rover was going to spend several months, and we went ahead of the rover and scouted [it] out so the rover drivers could be more efficient in finding safe ways to drive. Those were flights 12 and 13. Then some of these longer flights have been exciting. Flight No. 9, until a few days ago, was the biggest thing we’d ever done, at [a distance of] 625 meters. And with flight 25, we just beat that and flew more than 700 meters.

SN: There was a flight recently that had to be postponed because of a dust storm, right?

Grip: That’s correct. That was flight No. 19. With flying, whether it’s on Mars or here on Earth, you’re worried about weather. We always look at the weather before flying. And every time we’ve done that [on Mars], it had been more or less the same. Then the afternoon before we were about to open flight 19, we were notified that we had a dust storm. That delayed us by quite a bit. When we woke up from that, we had dust on our navigation camera lens, and sand covered our legs partially. We had to fly out of that, and it was a new challenge for the helicopter, but again, it tackled that perfectly.
SN: Ingenuity has flown through two seasons on Mars. As seasons change, so does air pressure. Does that affect the helicopter?

Grip: Yeah, that’s a pretty big deal. We knew, for several years before launch, exactly when we were going to land and where we were going to land. Our design was geared towards the first few months after landing, and that coincided with a particular season [spring] in Jezero crater on Mars. We could [ahead of launch] predict reasonably well what the air density would be. And when we extended [the mission] beyond that, the air density started dropping. To be able to keep flying, we had to increase our rotor speed. In fact, we increased it above anything we tested on Earth. Now we’ve come out of summer, the density has started climbing again, and we’ve been able to go back to our original rotor speed and also extend our flight time.

SN: What comes next? Are there any big flights planned soon?

Grip: We’re going to make our way over to the river delta that Perseverance is headed toward. We’ve just completed the biggest obstacle to doing that, flight 25, which was getting across this region called Séítah, which has a lot of sand and varied terrain. And when we get to the river delta, there are a few different options on the table: to help the rover drivers, to scout out targets, or even potentially to do some scouting on behalf of the next Mars mission. Perseverance is the first part of a sample return campaign. It’s sampling right now. And those samples will be left on the surface and will be eventually picked up — that’s the plan anyway — and sent back to Earth.

SN: What does Ingenuity mean for future exploration?

Grip: This is a new era. Aviation in space is now a thing. We can’t think about Mars exploration without aerial assets as part of that. I think that’s the most exciting thing.

A new nuclear imaging prototype detects tumors’ faint glow

A type of light commonly observed in astrophysics experiments and nuclear reactors can help detect cancer. In a clinical trial, a prototype of an imaging machine that relies on this usually bluish light, called Cerenkov radiation, successfully captured the presence and location of cancer patients’ tumors, researchers report April 11 in Nature Biomedical Engineering.

When compared with standard scans of the tumors, the Cerenkov light images were classified as “acceptable” or higher for 90 percent of patients, says Magdalena Skubal, a cancer researcher at Memorial Sloan Kettering Cancer Center in New York City.

Cerenkov radiation is generated by high-speed particles traveling faster than light through a material, such as bodily tissue (SN: 8/5/21). Nothing can travel faster than the speed of light in a vacuum, but light travels more slowly through a material, allowing particles to overtake it. In Cerenkov luminescence imaging, or CLI, particles released by radiotracers cause the target tissue to vibrate and relax in a way that emits light, which is then captured by a camera.

Between May 2018 and March 2020, in the largest clinical trial of its kind to date, 96 participants underwent both CLI and standard imaging, such as positron emission tomography/computed tomography, or PET/CT. Participants with a variety of diagnoses, including lymphoma, thyroid cancer and metastatic prostate cancer, received one of five radiotracers and were then imaged by the prototype — a camera in a light-proof enclosure.
Skubal and colleagues found that CLI detected all radiotracers, suggesting that the technology is more versatile than PET/CT scans, which work with only some radiotracers.

CLI images aren’t as precise as those from PET/CT scans. But CLI could be used as an initial diagnostic test or to assess the general size of a tumor undergoing treatment, says study coauthor Edwin Pratt, also of Memorial Sloan Kettering Cancer Center. “It would be a quick and easy way to see if there’s something off … [that warrants] further investigation,” Pratt says.

The findings strengthen the case for the technology as a promising low-cost alternative that could expand access to nuclear imaging in hospitals, says Antonello Spinelli, a preclinical imaging scientist at Experimental Imaging Centre in Milan, Italy, who was not involved in the research.

Crumbling planets might trigger repeating fast radio bursts

Fragmenting planets sweeping extremely close to their stars might be the cause of mysterious cosmic blasts of radio waves.

Milliseconds-long fast radio bursts, or FRBs, erupt from distant cosmic locales. Some of these bursts blast only once and others repeat. A new computer calculation suggests the repetitive kind could be due to a planet interacting with its magnetic host star, researchers report in the March 20 Astrophysical Journal.

FRBs are relative newcomers to astronomical research. Ever since the first was discovered in 2007, researchers have added hundreds to the tally. Scientists have theorized dozens of ways the two different types of FRBs can occur, and nearly all theories include compact, magnetic stellar remnants known as neutron stars. Some ideas include powerful radio flares from magnetars, the most magnetic neutron stars imaginable (SN: 6/4/20). Others suggest a fast-spinning neutron star, or even asteroids interacting with magnetars (SN: 2/23/22).
“How fast radio bursts are produced is still up for debate,” says astronomer Yong-Feng Huang of Nanjing University in China.

Huang and his colleagues considered a new way to make the repeating flares: interactions between a neutron star and an orbiting planet (SN: 3/5/94). Such planets can get exceedingly close to these stars, so the team calculated what might happen to a planet in a highly elliptical orbit around a neutron star. When the planet swings very close to its star, the star’s gravity pulls more on the planet than when the planet is at its farthest orbital point, elongating and distorting it. This “tidal pull,” Huang says, will rip some small clumps off the planet. Each clump in the team’s calculation is just a few kilometers wide and maybe one-millionth the mass of the planet, he adds.

Then the fireworks start. Neutron stars spew a wind of radiation and particles, much like our own sun but more extreme. When one of these clumps passes through that stellar wind, the interaction “can produce really strong radio emissions,” Huang says. If that happens when the clump appears to pass in front of the star from Earth’s perspective, we might see it as a fast radio burst. Each burst in a repeating FRB signal could be caused by one of these clumps interacting with the neutron star’s wind during each close planet pass, he says. After that interaction, what remains of the clump drifts in orbit around the star, but away from Earth’s perspective, so we never see it again.

Comparing the calculated bursts to two known repeaters — the first ever discovered, which repeats roughly every 160 days, and a more recent discovery that repeats every 16 days, the team found the fragmenting planet scenario could explain how often the bursts happened and how bright they were (SN: 3/2/16).

The star’s strong gravitational “tidal” pull on the planet during each close pass might change the planet’s orbit over time, says astrophysicist Wenbin Lu of Princeton University, who was not involved in this study but who investigates possible FRB scenarios. “Every orbit, there is some energy loss from the system,” he says. “Due to tidal interactions between the planet and the star, the orbit very quickly shrinks.” So it’s possible that the orbit could shrink so fast that FRB signals wouldn’t last long enough for a chance detection, he says.

But the orbit change could also give astronomers a way to check this scenario as an FRB source. Observing repeating FRBs over several years to track any changes in the time between bursts could narrow down whether this hypothesis could explain the observations, Lu says. “That may be a good clue.”

Glowing spider fossils may exist thanks to tiny algae’s goo 

The secret ingredient for fossil preservation at a famous French site wouldn’t be found in a Julia Child cookbook. It was a sticky goo made by microalgae, researchers suggest.

An analysis of roughly 22-million-year-old spider fossils from a fossil-rich rock formation in Aix-en-Provence, France, reveals that the arachnids’ bodies were coated with a tarry black substance. That substance, a kind of biopolymer, was probably secreted by tiny algae called diatoms that lived in the lake or lagoon waters at the ancient site, scientists report April 21 in Communications Earth & Environment.

The biopolymer didn’t just coat the spiders’ bodies — it pickled them. By chemically reacting with the spiders’ carbon-rich exoskeletons, the goo helped preserve the bodies from decomposition, allowing them to more easily become fossils, the team hypothesizes.
A clue that this coating might play a role in fossilization came when the researchers, on a whim, placed a spider fossil under a fluorescence microscope. To their surprise, the substance glowed a bright yellow-orange. “It was amazing!” says geologist Alison Olcott of the University of Kansas in Lawrence.

The fluorescent imaging painted a bright, colorful palette onto what was otherwise a fairly faint spider fossil, Olcott says. In the original, she could barely tell the spider apart from the background rock. But under fluorescence, she says, the spider fossil glowed in one color, the background in another and the biopolymer in a third.

That discovery — along with an abrupt halt in early 2020 to any additional fossil-collecting plans due to the COVID-19 pandemic — swiftly shifted the focus of the team’s work. “Had it been normal times, this would have been a side note in a taxonomy study” classifying ancient spiders, Olcott says. Instead, “I really had to explore what I had,” she adds. “It was me and these images.”

The researchers next sought to identify the chemical makeup of the mysterious substance. The orange-yellow glow, the team found, comes from abundant carbon and sulfur in the coating. “That got me thinking about sulfurization,” Olcott says.
Sulfurization is the reaction of organic carbon with sulfur, which forms sturdy chemical bonds with the carbon, making it more resistant to degradation and breakdown — similar to how tire manufacturers harden rubber to make it more durable. The process requires a ready supply of sulfur available for bonding.

In modern times, such a supply comes from the sulfur-rich gooey secretions of diatoms, microalgae found floating in many waters around the world. When these secretions meet carbon-laden marine particles headed for the bottom of the ocean, this sulfurization process helps lock the carbon in place and possibly keep it buried in the seafloor.

Similarly, sulfurization might help to preserve delicate carbon-rich fossils, helping them to withstand the test of millions of years of geologic time, Olcott says. Scientists have often noted diatoms in the fossil-bearing rock formations of Aix-en-Provence, as well as at many similar fossil-rich sites, she adds. “Everyone’s seeing diatoms everywhere. Thinking about that and the chemistry, I was like, ‘Wait a minute. All the pieces are here to make this chemistry happen.’”

The arachnids’ preservation might have gone like this: A dead spider, floating in the water column, became covered in the diatoms’ sticky goo. The goo chemically reacted with the spider’s chitin exoskeleton, more or less pickling it and keeping the exoskeleton largely intact and ready for fossilization.

That scenario “makes sense based on what we know about organic sulfur cycling in modern environments so far,” says Morgan Raven, an organic geochemist at the University of California, Santa Barbara. Scientists still have a lot to learn about the conditions that allow materials like chitin to sulfurize, Raven says. “But this study highlights why that matters.”

For example, if sulfurization selectively helps preserve some types of organic matter — such as soft-bodied fossils — that “could be a crucial filter on our fossil record, influencing what we do and don’t know about plant and animal evolution,” she adds.

This process of diatom-assisted sulfurization may have been at work in other fossil-rich sites during the Cenozoic Era, Olcott says. That span of time began 66 million years ago, after an asteroid ended the Age of Dinosaurs, and continues to the present day. Before that era, diatoms were not widespread. That didn’t happen until silica-bearing grasses sprouted around the world during the Cenozoic, offering a ready source of silica for the tiny creatures to build their delicate bodies (SN: 5/1/19).

It’s unknown if other biopolymer-producing algae might have helped fossilize soft-bodied creatures from even earlier, such as during the flourishing of Cambrian Period life-forms beginning around 541 million years ago, Olcott says (SN: 4/24/19). “But it would be really interesting to expand this further out.”

Muons spill secrets about Earth’s hidden structures

Inside Egypt’s Great Pyramid of Giza lies a mysterious cavity, its void unseen by any living human, its surface untouched by modern hands. But luckily, scientists are no longer limited by human senses.

To feel out the contours of the pyramid’s unexplored interior, scientists followed the paths of tiny subatomic particles called muons. Those particles, born high in Earth’s atmosphere, hurtled toward the surface and burrowed through the pyramid. Some of the particles imprinted hints of what they encountered on sensitive detectors in and around the pyramid. The particles’ paths revealed the surprising presence of the hidden chamber, announced in 2017 (SN: 11/25/17, p. 6).

That stunning discovery sparked plans among physicists to use muons to explore other archaeological structures. And some researchers are using the technique, called muography, to map out volcanoes’ plumbing. “You can see inside the volcano, really,” says geophysicist Giovanni Leone of Universidad de Atacama in Copiapó, Chile. That internal view could give scientists more information about how and when a volcano is likely to erupt.
Muons are everywhere on Earth’s surface. They’re produced when high-energy particles from space, known as cosmic rays, crash into Earth’s atmosphere. Muons continuously shower down through the atmosphere at various angles. When they reach Earth’s surface, the particles tickle the insides of large structures like pyramids. They penetrate smaller stuff too: Your thumbnail is pierced by a muon about once a minute. Measuring how many of the particles are absorbed as they pass through a structure can reveal the density of an object, and expose any hidden gaps within.

The technique is reminiscent of taking an enormous X-ray image, says Mariaelena D’Errico, a particle physicist at the National Institute for Nuclear Physics in Naples, Italy, who studies Mount Vesuvius with muons. But “instead of X-rays, we use … a natural source of particles,” the Earth’s very own, never-ending supply of muons.

Physicists have typically studied cosmic rays to better understand the universe from whence they came. But muography turns this tradition on its head, using these cosmic particles to learn more about previously unknowable parts of our world. For the most part, says particle physicist Hiroyuki Tanaka of the University of Tokyo, “particles arriving from the universe have not been applied to our regular lives.” Tanaka and others are trying to change that.
No particle like it
Awkward cousins of electrons, muons may seem like an unnecessary oddity of physics. When the particle’s identity was first revealed, physicists wondered why the strange particle existed at all. While electrons play a crucial role in atoms, the heavier muons serve no such purpose.

But muons turn out to be ideal for making images of the interiors of large objects. A muon’s mass is about 207 times as large as an electron’s. That extra bulk means muons can traverse hundreds of meters of rock or more. The difference between an electron and a muon passing through matter is like the difference between a bullet and a cannonball, says particle physicist Cristina Cârloganu. A wall may stop a bullet, while a cannonball passes through.

Muons are plentiful, so there’s no need to create artificial beams of radiation, as required for taking X-ray images of broken bones in the doctor’s office, for example. Muons “are for free,” says Cârloganu, of CNRS and the National Institute of Nuclear and Particle Physics in Aubière, France.
Another crucial upside of muons: “They’re also very easy to detect,” says nuclear physicist Richard Kouzes of the Pacific Northwest National Laboratory in Richland, Wash. A simple detector made of strips of plastic and light sensors will do the trick. Other muon detectors require little more than a specialized version of photographic film. There’s no other particle like it, Kouzes says.

Muons have a negative electric charge, like an electron. Their antiparticles, antimuons, which also shower down on Earth, have a positive charge. Muon detectors capture tracks of both negatively and positively charged varieties. When these particles pass through material, they lose energy in various ways, for example, by colliding with electrons and knocking them loose from their atoms.

With that energy loss, muons slow down, sometimes enough to stop. The denser the material, the fewer muons will make it through to a detector placed underneath or to the side of the material. So large, dense objects such as volcanoes or pyramids cast a muon shadow. And any gaps within those structures will appear as bright spots within that shadow, because more muons can slip through. Interpreting such dappled shadows can open a vista into hidden worlds.

Probing pyramids
Muography proved itself in a pyramid. One of the first uses of the technique was in the 1960s, when physicist Luis Alvarez and colleagues looked for hidden chambers in Khafre’s pyramid in Giza, a slightly smaller neighbor of the Great Pyramid. Detectors found no hint of unexpected rooms, but proved that the technique worked.

Still, the idea took time to take off, because muon detectors of the era tended to be bulky and worked best in well-controlled laboratory conditions. To spot the muons, Alvarez’s team used detectors called spark chambers. Spark chambers are filled with gas and metal plates under high voltage, so that charged particles passing through create trails of sparks.

Now, thanks to advances in particle physics technologies, spark chambers have largely been replaced. “We can make very compact, very sturdy detectors,” says nuclear physicist Edmundo Garcia-Solis of Chicago State University. Those detectors can be designed to work outside a carefully controlled lab.

One type of resilient detector is built with plastic containing a chemical called scintillator, which releases light when a muon or other charged particle passes through (SN Online: 8/5/21). The light is then captured and measured by electronics. Later this year, physicists will use these detectors to take another look at Khafre’s pyramid, Kouzes and colleagues reported February 23 in the Journal for Advanced Instrumentation in Science. Compact enough to fit within two large carrying cases, the detector “can be carried into the pyramid and then operated with a laptop and that’s all,” Kouzes says.
A different but particularly low-maintenance type of detector, called a nuclear emulsion film, was crucial to uncovering the Great Pyramid’s hidden void in 2017. Nuclear emulsions record particle tracks in a special type of photographic film. The detectors are left in place for a period of time, then brought back to a lab for analysis of the tracks imprinted in them.

Particle physicist Kunihiro Morishima of Nagoya University in Japan helped discover the secret chamber through work on an international project called ScanPyramids. “Nuclear emulsions are lightweight, compact and do not require a power supply,” he explains. That meant that multiple detectors could be placed in prime viewing locations in one of the pyramid’s rooms, the Queen’s Chamber, and a small niche next to it. The detectors’ measurements were supplemented with plastic scintillator detectors inside the Queen’s Chamber, and gas-based detectors outside the pyramid.
Since the discovery of the void, Morishima and colleagues have been taking additional measurements to better sketch out its properties. The team placed emulsion detectors in 20 locations in the pyramid, as well as gas detectors in several different spots. Using their new array of instruments, the researchers determined that the void is over 40 meters long. Its purpose is still unknown.

A more extensive survey of the Great Pyramid, placing much larger detectors outside the pyramid, is being planned by another team of researchers. The detectors will be periodically moved to measure muons from multiple angles, the team reported March 6 in the Journal for Advanced Instrumentation in Science. The result, says co­author and particle physicist Alan Bross of Fermilab in Batavia, Ill., will offer a 3-D view of what’s inside (SN: 12/18/21 & 1/1/22, p. 44).

Pyramids in other parts of the world are also getting closer scrutiny. Garcia-Solis and colleagues are now planning muography of the Maya pyramid known as El Castillo at Chichén Itzá in Mexico. Morishima and colleagues, as well, are planning work on Maya pyramids.

Scientists hope such studies might reveal new chambers, or features not visible with other techniques for peering inside of objects. Ultrasound, ground-penetrating radar or X-rays, for example, can only penetrate a short distance from the surface, Bross explains. Muons, on the other hand, give an in-depth picture. For studying pyramids, Bross says, “muons really are ideal.”

Peering inside a volcano
Vesuvius is a known menace in Naples and the surrounding municipalities that snuggle up against the volcano’s flanks. Infamous for destroying the ancient city of Pompeii in A.D. 79, the volcano has been quiescent since 1944, when a major eruption destroyed several nearby villages (SN: 2/29/20, p. 5). But if it erupted, it would endanger the lives of roughly 600,000 people who live closest to it, and many others in the vicinity.

“Vesuvius always scared me,” D’Errico says. “I was born and I live under this volcano.” Now, as part of the Muon Radiography of Vesuvius experiment, or MURAVES, she seeks to better understand the volcano and its dangers.
Using muon detectors 1.5 kilometers from the volcano’s crater, the team is mapping out muon densities — and thus rock densities — at the top of Vesuvius’ cone. In a paper posted February 24 at arXiv.org, the researchers presented preliminary hints of density differences between the volcano’s northwestern and southeastern halves. MURAVES is still collecting data; future observations should help scientists understand finer details of the volcano’s internal structure, which is thought to be layered due to repeated eruptions.

Information about a volcano’s structure can help scientists predict what hazards to expect in an eventual eruption, such as where landslides might occur. And that could help scientists know what steps to take to reduce risks to people living nearby, says Cârloganu, who studied the dormant volcano Puy de Dôme near Clermont-Ferrand, France, with muography and is now working to image the aptly named island of Vulcano in Italy.

When Mount St. Helens in Washington erupted in 1980, for example, an entire flank of the volcano collapsed. The disaster killed 57 people and caused widespread damage. Knowing where a volcano’s structural weaknesses lie could help scientists better predict how an eruption might play out, and what areas sit inside the danger zone, Cârloganu says.

Cârloganu thinks muons will be useful for pointing out structural weaknesses, but not for giving a warning when the volcano is going to blow. Other researchers are more optimistic about muons’ capability for giving timely forewarnings.

Muography is ripe for inclusion in volcano early-warning systems, Leone, Tanaka and colleagues wrote last November in Proceedings of the Royal Society A. But more work needs to be done to integrate muography with other established methods that help warn of an upcoming eruption, Leone says. These methods include seismic measurements, as well as observations of ground deformation and volcanic gas emissions.

Tanaka and colleagues are studying Sakurajima, one of the most active volcanoes in the world, near Kagoshima, Japan. One of the volcano’s craters, the Showa crater, erupted frequently until 2017 when the activity abruptly shifted to another crater, Minamidake. Comparing muography data taken before and after this shift revealed that a new, dense region had formed below the Showa crater, Tanaka and colleagues reported in 2019 in Geophysical Research Letters. That hints at the reason Showa’s eruptions stopped: It was clogged with a dense plug of solidified magma, Tanaka says.
These results suggest that scientists can use muography to help predict volcanic eruptions, Tanaka says. In fact, using deep learning techniques on the muography data from Sakurajima, Tanaka and colleagues reported in Scientific Reports in 2020 that they were able to predict whether the volcano would erupt the next day, by analyzing the previous week’s data. The technique correctly predicted eruption days of the volcano more than 72 percent of the time, and correctly predicted non-eruption days more than 85 percent of the time.

Just as the discovery of X-rays unveiled a whole new way of seeing the world, harnessing muons could change our perspective on our surroundings. Attitudes toward a particle once thought to be unnecessary — unwanted and unloved by physicists — have been transformed. One day, perhaps, muons could save lives.

Missing COVID-19 data leave us in the dark about the current surge

As science journalists, we’re accustomed to data. We sift through it and talk it over with experts. We pay close attention to the stories that numbers can tell. But at this point in the pandemic, many of us are having a hard time finding the story. That’s because the numbers aren’t there.

Data on coronavirus infections in the United States have become less reliable, many experts say. Fewer people are getting tested, local governments have stopped reporting results, and home test results rarely make it into official counts (SN: 4/22/22).
To be sure, there are still official numbers to be found. They don’t look great. Hospitalizations are low compared with earlier in the pandemic, but they’re rising again, and the case counts that do exist are ticking up, too. After dipping in March, the tally in the United States is back up to more than 100,000 known cases a day. A third of Americans now live in places with “medium to high” levels of virus spread.

With these not-so-great numbers in mind, it’s not a stretch to assume that the missing data probably wouldn’t tell us a cheery story either. We are almost certainly undercounting cases in the United States. And we’re not alone. Amid worldwide declines in testing and sequencing to see where coronavirus is spreading and how it’s changing, “we are blinding ourselves to the evolution of the virus,” Tedros Adhanom Ghebreyesus, the head of the World Health Organization, said May 22.

We’ve never had a perfect count of COVID-19 cases, of course. Early on in the pandemic, before testing ramped up in some places, scientists found clues about COVID-19’s transmission in odd places. Wastewater testing, for instance, spotted signs of the virus getting flushed down the toilet (SN: 5/28/20). That dirty water continues to be an indirect, but helpful, measure of viral loads in a community. Here in Oregon, where I live, some wastewater spots again show increases in coronavirus, suggesting a surge.

Even more indirect measurements can give us additional hints. Early on in the pandemic, “smart” thermometers connected to the internet generated fever data used to map risk of getting sick by region. Internet searches for words and phrases, such as “chills,” “fever” and “I can’t smell,” also pointed to virus hot spots.

My favorite digital sign of illness comes from online reviews of Yankee Candles. One-star reviews (“No scent.” “Embarrassed as this was a gift.”) tracked neatly with a rise in COVID-19 cases in 2020 and the subsequent loss of smell. Just last week, more one-star reviews showed up, notes Twitter user @drewtoothpaste, who compiled the latest complaints. “No smell.” “Absolutely no scent.” “Very disappointing!!!”
These one-star reviews are not airtight evidence of COVID-19 rates — not by any stretch. But they add to the broader picture that we are not yet done with this pandemic, as much as we would all love to be. We are still experiencing disruptions to our lives, illness, suffering and sadness. Very disappointing indeed.

To better understand this particular moment in the pandemic, I talked with data expert Beth Blauer of Johns Hopkins University. She’s been tracking metrics of the pandemic since it started. In the earliest days, she helped build databases, including a widely used COVID-19 tracker, that ultimately became the Coronavirus Resource Center at Hopkins. Those tools get data out to other scientists, health experts, government leaders, journalists and people who want to keep up with the latest numbers. The interview has been edited for length and clarity.

SN: How solid is the testing data right now in the United States?

Blauer: The testing data in this country is crumbling…. We’re barely getting data out of the application-based resources that come with home tests. And the home tests are running 10 bucks apiece. That’s cost prohibitive for people who live below the poverty line. Even middle-income people are not spending $20 for a pack of two. [Free tests are available in the United States, but it’s not known how many of those tests are reaching people who need them.]

We are flying blind. Completely. We are in a surge right now, but we don’t even appreciate fully how big of a surge this is.

SN: Any guesses?

Blauer: I have no idea. Anecdotally, I’m sure you and I both know a ton of people who have COVID-19 or who just got over it. All the mitigation strategies are not being spun up to meet the rising demand that a surge, like we’re in right now, calls for, which means we’re just going to be getting a lot more COVID-19. People are going on vacations, they’re traveling, graduations, all of these things are just going forward. So yes, we’re seeing some increase in hospitalization, but I don’t think we have any idea how much disease there is in the community.
SN: I’ve had trouble gauging my risk from COVID-19 in everyday life. Is that typical?

Blauer: It’s a mess. I think a lot of people are sensing that. And it dilutes our capacity to have faith in science and in all the things that have happened over time. It is confusing. It’s like, “Oh, we have just as much COVID, but we can go to parties? And school is in?” Everything all of a sudden gets called into question.

[That uncertainty highlights a] need to really think critically about our public health infrastructure in this country.

SN: How should we be living with this virus right now?

Blauer: We all acknowledge that we need social anchoring in our communities. We need to see people. We can’t hide away in our houses forever. But that means we have to think about what it means to live with a pathogen like COVID-19 out there. And we’re not giving ourselves all the best tools to be able to do that.

I work in a building where right down the hall, people are getting chemotherapy. I feel a responsibility to the community that I’m not giving them a disease that could potentially kill them. That’s not happening in a lot of places. For me, it’s sad. It’s like a loss of collective empathy, and I don’t think we should not talk about that.

I think I would feel the very same way even if I wasn’t leading this effort here at Hopkins. But I don’t know. Maybe it’s because I feel the toll of a million Americans who have died. I’ve experienced loss in my life. I do have a lot of empathy. But I don’t think I’m overdoing it.

SN: But you’re not saying we should all hunker down and stay away from people.

Blauer: No. We’re done with that. But we have to start integrating and really putting into place these habits [masking, testing and adjusting behavior when needed]. Because I think it’s the only way we get out of this.

Scientists made a Möbius strip out of a tiny carbon nanobelt

From cylindrical nanotubes to the hollow spheres known as buckyballs, carbon is famous for forming tiny, complex nanostructures (SN: 8/15/19). Now, scientists have added a new geometry to the list: a twisted strip called a Möbius carbon nanobelt.

Möbius strips are twisted bands that are famous in mathematics for their weird properties. A rubber band, for example, has an inside and an outside. But if you cut the rubber band crosswise, twist one end and glue it back together, you get a Möbius strip, which has only one face (SN: 7/24/07).

In 2017, researchers created carbon nanobelts, thin loops of carbon that are like tiny slices of a carbon nanotube. That feat suggested it might be possible to create a nanobelt with a twist, a Möbius carbon nanobelt. To make the itsy-bitsy twisty carbon, some of the same researchers stitched together individual smaller molecules using a series of 14 chemical reactions, chemist Yasutomo Segawa of the Institute for Molecular Science in Okazaki, Japan, and colleagues report May 19 in Nature Synthesis.

While carbon nanotubes can be used to make new types of computer chips and added to textiles to create fabric with unusual properties, scientists don’t yet know of any practical applications for the twisty nanobelts (SN: 8/28/19; SN: 2/8/19). But, Segawa says, the work improves scientists’ ability to make tiny carbon structures, especially complicated ones.