Roughly 3,000 light-years from Earth sits one of the most complex and least understood nebulae, a whirling landscape of gas and dust left in the wake of a star’s death throes. A new computer visualization reveals the 3-D structure of the Cat’s Eye nebula and hints at how not one, but a pair of dying stars sculpted its complexity.

The digital reconstruction, based on images from the Hubble Space Telescope, reveals two symmetric rings around the nebula’s edges. The rings were probably formed by a spinning jet of charged gas that was launched from two stars in the nebula’s center, Ryan Clairmont and colleagues report in the October Monthly Notices of the Royal Astronomical Society.

“I realized there hasn’t been a comprehensive study of the structure of the nebula since the early ’90s,” says Clairmont, an undergraduate at Stanford University. Last year, while a high school student in San Diego, he reached out to a couple of astrophysicists at a scientific imaging company called Ilumbra who had written software to reconstruct the 3-D structure of astronomical objects.

The team combined Hubble images with ground-based observations of light in several wavelengths, which revealed the motions of the nebula’s gas. Figuring out which parts were moving toward and away from Earth helped reveal its 3-D structure.

The team identified two partial rings to either side of the nebula’s center. The rings’ symmetry and unfinished nature suggest they are the remains of a plasma jet launched from the heart of the nebula, then snuffed out before it could complete a full circle. Such jets are usually formed through an interaction between two stars orbiting one another, says Ilumbra partner Wolfgang Steffen, who is based in Kaiserslautern, Germany.

The work won Clairmont a prize at the 2021 International Science and Engineering Fair, an annual competition run by the Society for Science, which publishes Science News. Steffen was skeptical about the tight deadline — when Clairmont reached out, he had just two months to complete the project.

“I said that’s impossible! Not even Ph.D. students or anybody has tried that before,” Steffen says. “He did it brilliantly. He pulled it all off and more than we expected.”

Body changes at the brink of adulthood can get awkward in humans, but at least our eyes don’t pop out of our heads on stalks longer than our legs.

High-rise eyes, however, give macho pizzazz to the adult male Pelmatops fruit fly. In one of the stalkier species, P. tangliangi, the eyes-up transformation takes only about 50 minutes, a new study reports. Once stretched, the skinny eyestalks darken and harden, keeping the eyes stuck out like selfie sticks for the rest of the fly’s life.
The details of P. tangliangi’s eye lift come from the first published photo sequence of their ocular blossoming, which appears in the September Annals of the Entomological Society of America. Biologists have known that eyestalks evolved in eight different fly families. Yet Pelmatops flies have gotten so little scientific attention that a lot of their basic biology has been a string of question marks.

Video images show the eyestalks curl and rise irregularly. Yet “they are not flopping around while partly inflated,” says Xiaolin Chen, an entomologist and evolutionary biologist at the Chinese Academy of Sciences in Beijing. “They seem slightly stiff, but still flexible enough.”

Females of the species may raise shorter eyestalks too — if Chen and her colleagues have found the right females. Chen suspects that what are now named as two species, based on the few specimens available, may just be two sexes of the same species. The new paper describes a male P. tangliangi mating with a female known by a different species name. Her stalks aren’t as magnificent as his, but she has some.

While the headgear can burden a flying insect, long eyestalks may give flies some swagger. These Pelmatops and other kinds of stalk-eyed flies face off, eyestalk to eyestalk, with uppity intruders. There’s no knocking and locking stalks in fierce fly disputes though. Any pushing and shoving, Chen says, is “done with other body parts.”

Extreme eyes may also have other benefits. In the wild, Chen finds these fruit flies on long stems of Rubus berry brambles. The eyes naturally periscope outward and upward, allowing the flies to spot danger while the body stays hidden in the greenery.

One hundred years ago, archaeologist Howard Carter stumbled across the tomb of ancient Egypt’s King Tutankhamun. Carter’s life was never the same. Neither was the young pharaoh’s afterlife.

Newspapers around the world immediately ran stories about Carter’s discovery of a long-lost pharaoh’s grave and the wonders it might contain, propelling the abrasive Englishman to worldwide acclaim. A boy king once consigned to ancient obscurity became the most famous of pharaohs (SN: 12/18/76).

It all started on November 4, 1922, when excavators led by Carter discovered a step cut into the valley floor of a largely unexplored part of Egypt’s Valley of the Kings. By November 23, the team had uncovered stairs leading down to a door. A hieroglyphic seal on the door identified what lay beyond: King Tutankhamun’s tomb.
Tutankhamun assumed power around 1334 B.C., when he was about 10 years old. His reign lasted nearly a decade until his untimely demise. Although a minor figure among Egyptian pharaohs, Tutankhamun is one of the few whose richly appointed burial place was found largely intact.

An unusually meticulous excavator for his time, Carter organized a 10-year project to document, conserve and remove more than 6,000 items from Tutankhamun’s four-chambered tomb. While some objects, like Tut’s gold burial mask, are now iconic, many have been in storage and out of sight for decades. But that’s about to change. About 5,400 of Tutankhamun’s well-preserved tomb furnishings are slated to soon go on display when the new Grand Egyptian Museum, near the Pyramids of Giza, opens.

“The [Tut] burial hoard is something very unique,” Shirin Frangoul-Brückner, managing director of Atelier Brückner in Stuttgart, Germany, the firm that designed the museum’s Tutankhamun Gallery, said in an interview released by her company. Among other items, the exhibit will include the gold burial mask, musical instruments, hunting equipment, jewelry and six chariots.

Even as more of Tut’s story is poised to come to light, here are four things to know on the 100th anniversary of his tomb’s discovery.

1. Tut may not have been frail.
   Tutankhamun has a reputation as a fragile young man who limped on a clubfoot. Some researchers suspect a weakened immune system set him up for an early death.

But “recent research suggests it’s wrong to portray Tut as a fragile pharaoh,” says Egyptologist and mummy researcher Bob Brier, who is an expert on King Tut. His new book Tutankhamun and the Tomb That Changed the World chronicles how 100 years of research have shaped both Tut’s story and archaeology itself.

Clues from Tutankhamun’s mummy and tomb items boost his physical standing, says Brier, of Long Island University in Brookville, N.Y. The young pharaoh might even have participated in warfare.

Military chariots, leather armor and archery equipment buried with Tutankhamun show that he wanted to be viewed as a hunter and a warrior, Brier says. Inscribed blocks from Tutankhamun’s temple, which were reused in later building projects before researchers identified them, portray the pharaoh leading charioteers in undated battles.

If more blocks turn up showing battle scenes marked with dates, it would suggest Tutankhamun probably participated in those conflicts, Brier says. Pharaohs typically recorded dates of actual battles depicted in their temples, though inscribed scenes may have exaggerated their heroism.

The frail story line has been built in part on the potential discovery of a deformity in Tut’s left foot, along with 130 walking sticks found in his tomb. But ancient Egyptian officials were often depicted with walking sticks as signs of authority, not infirmity, Brier says. And researchers’ opinions vary about whether images of Tut’s bones reveal serious deformities.

X-rays of the recovered mummy from the 1960s show no signs of a misshapen ankle that would have caused a limp. Neither did CT images examined in 2005 by the Egyptian Mummy Project, headed by Egyptologist and former Egyptian Minister of Antiquities Zahi Hawass.

Then a 2009 reexamination of the CT images by the same researchers indicated that Tutankhamun had a left-foot deformity generally associated with walking on the ankle or the side of the foot, the team reported. The team’s radiologist, Sahar Saleem of Egypt’s Cairo University, says the CT images show that Tutankhamun experienced a mild left clubfoot, bone tissue death at the ends of two long bones that connect to the second and third left toes and a missing bone in the second left toe.
Those foot problems would have “caused the king pain when he walked or pressed his weight on his foot, and the clubfoot must have caused limping,” Saleem says. So a labored gait, rather than an appeal to royal authority, could explain the many walking sticks placed in Tutankhamun’s tomb, she says.

Brier, however, doubts that scenario. Tutankhamun’s legs appear to be symmetrical in the CT images, he says, indicating that any left foot deformity was too mild to cause the pharaoh regularly to put excess weight on his right side while walking.

Whether or not the boy king limped through life, the discovery and study of his mummy made it clear that he died around age 19, on the cusp of adulthood. Yet Tut’s cause of death still proves elusive.

In a 2010 analysis of DNA extracted from the pharaoh’s mummy, Hawass and colleagues contended that malaria, as well as the tissue-destroying bone disorder cited by Saleem from the CT images, hastened Tutankhamun’s death. But other researchers, including Brier, disagree with that conclusion. Further ancient DNA studies using powerful new tools for extracting and testing genetic material from the mummy could help solve that mystery.

2. Tut’s initial obscurity led to his fame.
   After Tutankhamun’s death, ancient Egyptian officials did their best to erase historical references to him. His reign was rubbed out because his father, Akhenaten, was a “heretic king” who alienated his own people by banishing the worship of all Egyptian gods save for one.

“Akhenaten is the first monotheist recorded in history,” Brier says. Ordinary Egyptians who had prayed to hundreds of gods suddenly could worship only Aten, a sun god formerly regarded as a minor deity.

Meeting intense resistance to his banning of cherished religious practices, Akhenaten — who named himself after Aten — moved to an isolated city, Amarna, where he lived with his wife Nefertiti, six girls, one boy and around 20,000 followers. After Akhenaten died, residents of the desert outpost returned to their former homes. Egyptians reclaimed their old-time religion. Akhenaten’s son, Tutankhaten — also originally named after Aten — became king, and his name was changed to Tutankhamun in honor of Amun, the most powerful of the Egyptian gods at the time.

Later pharaohs omitted from written records any mentions of Akhenaten and Tutankhamun. Tut’s tomb was treated just as dismissively. Huts of craftsmen working on the tomb of King Ramses VI nearly 200 years after Tut’s death were built over the stairway leading down to Tutankhamun’s nearby, far smaller tomb. Limestone chips from the construction littered the site.
The huts remained in place until Carter showed up. While Carter found evidence that the boy king’s tomb had been entered twice after it was sealed, whoever had broken in took no major objects.

“Tutankhamun’s ignominy and insignificance saved him” from tomb robbers, says UCLA Egyptologist Kara Cooney.

3. Tut’s tomb was a rushed job.
   Pharaohs usually prepared their tombs over decades, building many rooms to hold treasures and extravagant coffins. Egyptian traditions required the placement of a mummified body in a tomb about 70 days after death. That amount of time may have allowed a mummy to dry out sufficiently while retaining enough moisture to fold the arms across the body inside a coffin, Brier suspects.

Because Tutankhamun died prematurely, he had no time for extended tomb preparations. And the 70-day burial tradition gave craftsmen little time to finish crucial tomb items, many of which required a year or more to make. Those objects include a carved stone sarcophagus that encased three nested coffins, four shrines, hundreds of servant statues, a gold mask, chariots, jewelry, beds, chairs and an alabaster chest that contained four miniature gold coffins for Tutankhamun’s internal organs removed during mummification.

Evidence points to workers repurposing many objects from other people’s tombs for Tutankhamun. Even then, time ran out.

Consider the sarcophagus. Two of four goddesses on the stone container lack fully carved jewelry. Workers painted missing jewelry parts. Carved pillars on the sarcophagus are also unfinished.

Tutankhamun’s granite sarcophagus lid, a mismatch for the quartzite bottom, provides another clue to workers’ frenzied efforts. Something must have happened to the original quartzite lid, so workers carved a new lid from available granite and painted it to look like quartzite, Brier says.

Repairs on the new lid indicate that it broke in half during the carving process. “Tutankhamun was buried with a cracked, mismatched sarcophagus lid,” Brier says.

Tutankhamun’s sarcophagus may originally have been made for Smenkare, a mysterious individual who some researchers identify as the boy king’s half brother. Little is known about Smenkare, who possibly reigned for about a year after Akhenaten’s death, just before Tutankhamun, Brier says. But Smenkare’s tomb has not been found, leaving the sarcophagus puzzle unsolved.

Objects including the young king’s throne, three nested coffins and the shrine and tiny coffins for his internal organs also contain evidence of having originally belonged to someone else before being modified for reuse, says Harvard University archaeologist Peter Der Manuelian.
Even Tutankhamun’s tomb may not be what it appears. Egyptologist Nicholas Reeves of the University of Arizona Egyptian Expedition in Tucson has argued since 2015 that the boy king’s burial place was intended for Nefertiti. He argues that Nefertiti briefly succeeded Akhenaten as Egypt’s ruler and was the one given the title Smenkare.

No one has found Nefertiti’s tomb yet. But Reeves predicts that one wall of Tutankhamun’s burial chamber blocks access to a larger tomb where Nefertiti lies. Painted scenes and writing on that wall depict Tutankhamun performing a ritual on Nefertiti’s mummy, he asserts. And the gridded structure of those paintings was used by Egyptian artists years before Tutankhamun’s burial but not at the time of his interment.

But four of five remote sensing studies conducted inside Tutankhamun’s tomb have found no evidence of a hidden tomb. Nefertiti, like Smenkare, remains a mystery.

4. Tut’s tomb changed archaeology and the antiquities trade.
   Carter’s stunning discovery occurred as Egyptians were protesting British colonial rule and helped fuel that movement. Among the actions that enraged Egyptian officials: Carter and his financial backer, a wealthy British aristocrat named Lord Carnarvon, sold exclusive newspaper coverage of the excavation to The Times of London. Things got so bad that Egypt’s government locked Carter out of the tomb for nearly a year, starting in early 1924.

Egyptian nationalists wanted political independence — and an end to decades of foreign adventurers bringing ancient Egyptian finds back to their home countries. Tutankhamun’s resurrected tomb pushed Egyptian authorities toward enacting laws and policies that helped to end the British colonial state and reduce the flow of antiquities out of Egypt, Brier says, though it took decades. Egypt became a nation totally independent of England in 1953. A 1983 law decreed that antiquities could no longer be taken out of Egypt (though those removed before 1983 are still legal to own and can be sold through auction houses).

In 1922, however, Carter and Lord Carnarvon regarded many objects in Tutankhamun’s tomb as theirs for the taking, Brier says. That was the way that Valley of the Kings excavations had worked for the previous 50 years, in a system that divided finds equally between Cairo’s Egyptian Museum and an expedition’s home institution. Taking personal mementos was also common.

Evidence of Carter’s casual pocketing of various artifacts while painstakingly clearing the boy king’s tomb continues to emerge. “Carter didn’t sell what he took,” Brier says. “But he felt he had a right to take certain items as the tomb’s excavator.”
Recently recovered letters of English Egyptologist Alan Gardiner from the 1930s, described by Brier in his book, recount how Carter gave Gardiner several items from Tutankhamun’s tomb, including an ornament used as a food offering for the dead. French Egyptologist Marc Gabolde of Paul-Valéry Montpellier 3 University has tracked down beads, jewelry, a headdress fragment and other items taken from Tutankhamun’s tomb by Carter and Carnarvon.

Yet it is undeniable that one of Tutankhamun’s greatest legacies, thanks to Carter, is the benchmark the excavation of his tomb set for future excavations, Brier says. Carter started his career as an artist who copied painted images on the walls of Egyptian tombs for excavators. He later learned excavation techniques in the field working with an eminent English Egyptologist, Flinders Petrie. Carter took tomb documentation to a new level, rounding up a crack team consisting of a photographer, a conservator, two draftsmen, an engineer and an authority on ancient Egyptian writing.

Their decade-long effort also made possible the new Tutankhamun exhibition at the Grand Egyptian Museum. Now, not only museum visitors but also a new generation of researchers will have unprecedented access to the pharaoh’s tomb trove.

“Most of Tutankhamun’s [tomb] objects have been given little if any study beyond what Carter was able to do,” says UCLA’s Cooney.

That won’t be true for much longer, as the most famous tomb in the Valley of the Kings enters the next stage of its public and scientific afterlife.

Tiny “fingers” can help polar bears get a grip.

Like the rubbery nubs on the bottom of baby socks, microstructures on the bears’ paw pads offer some extra friction, scientists report November 1 in the Journal of the Royal Society Interface. The pad protrusions may keep polar bears from slipping on snow, says Ali Dhinojwala, a polymer scientist at the University of Akron in Ohio who has also studied the sticking power of gecko feet (SN: 8/9/05).
Nathaniel Orndorf, a materials scientist at Akron who focuses on ice, adhesion and friction, was interested in the work Dhinojwala’s lab did on geckos, but “we can’t really put geckos on the ice,” he says. So he turned to polar bears.

Orndorf teamed up with Dhinojwala and Austin Garner, an animal biologist now at Syracuse University in New York, and compared the paws of polar bears, brown bears, American black bears and a sun bear. All but the sun bear had paw pad bumps. But the polar bears’ bumps looked a little different. For a given diameter, their bumps tend to be taller, the team found. That extra height translates to more traction on lab-made snow, experiments with 3-D printed models of the bumps suggest.

Until now, scientists didn’t know that bump shape could make the difference between gripping and slipping, Dhinojwala says.
Polar bear paw pads are also ringed with fur and are smaller than those of other bears, the team reports, adaptations that might let the Arctic animals conserve body heat as they trod upon ice. Smaller pads generally mean less real estate for grabbing the ground. So extra-grippy pads could help polar bears make the most of what they’ve got, Orndorf says.

Along with bumpy pads, the team hopes to study polar bears’ fuzzy paws and short claws, which might also give the animals a nonslip grip.

The closest black hole yet found is just 1,560 light-years from Earth, a new study reports. The black hole, dubbed Gaia BH1, is about 10 times the mass of the sun and orbits a sunlike star.

Most known black holes steal and eat gas from massive companion stars. That gas forms a disk around the black hole and glows brightly in X-rays. But hungry black holes are not the most common ones in our galaxy. Far more numerous are the tranquil black holes that are not mid-meal, which astronomers have dreamed of finding for decades. Previous claims of finding such black holes have so far not held up (SN: 5/6/20; SN: 3/11/22).
So astrophysicist Kareem El-Badry and colleagues turned to newly released data from the Gaia spacecraft, which precisely maps the positions of billions of stars (SN: 6/13/22). A star orbiting a black hole at a safe distance won’t get eaten, but it will be pulled back and forth by the black hole’s gravity. Astronomers can detect the star’s motion and deduce the black hole’s presence.

Out of hundreds of thousands of stars that looked like they were tugged by an unseen object, just one seemed like a good black hole candidate. Follow-up observations with other telescopes support the black hole idea, the team reports November 2 in Monthly Notices of the Royal Astronomical Society.

Gaia BH1 is the nearest black hole to Earth ever discovered — the next closest is around 3,200 light-years away. But it’s probably not the closest that exists, or even the closest we’ll ever find. Astronomers think there are about 100 million black holes in the Milky Way, but almost all of them are invisible. “They’re just isolated, so we can’t see them,” says El-Badry, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

The next data release from Gaia is due out in 2025, and El-Badry expects it to bring more black hole bounty. “We think there are probably a lot that are closer,” he says. “Just finding one … suggests there are a bunch more to be found.”

There’s a new way to rip apart harmful “forever chemicals,” scientists say.

Perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS, are found in nonstick pans, water-repellent fabrics and food packaging and they are pervasive throughout the environment. They’re nicknamed forever chemicals for their ability to stick around and not break down. In part, that’s because PFAS have a super strong bond between their carbon and fluorine atoms (SN: 6/4/19). Now, using a bit of heat and two relatively common compounds, researchers have degraded one major type of forever chemical in the lab, the team reports in the Aug. 19 Science. The work could help pave the way for a process for breaking down certain forever chemicals commercially, for instance by treating wastewater.
“The fundamental knowledge of how the materials degrade is the single most important thing coming out of this study,” organic chemist William Dichtel said in an August 16 news conference.

While some scientists have found relatively simple ways of breaking down select PFAS, most degradation methods require harsh, energy-intensive processes using intense pressure — in some cases over 22 megapascals — or extremely high temperatures — sometimes upwards of 1000⁰ Celsius — to break the chemical bonds (SN: 6/3/22).

Dichtel, of Northwestern University in Evanston, Ill., and his team experimented with two substances found in nearly every chemistry lab cabinet: sodium hydroxide, also known as lye, and a solvent called dimethyl sulfoxide, or DMSO. The team worked specifically with a group of forever chemicals called PFCAs, which contain carboxylic acid and constitute a large percentage of all PFAS. Some of these kinds of forever chemicals are found in water-resistant clothes.

When the team combined PFCAs with the lye and DMSO at 120⁰ C and with no extra pressure needed, the carboxylic acid fell off the chemical and became carbon dioxide in a process called decarboxylation. What happened next was unexpected, Dichtel said. Loss of the acid led to a process causing “the entire molecule to fall apart in a cascade of complex reactions.” This cascade involved steps that degraded the rest of the chemical into fluoride ions and smaller carbon-containing products, leaving behind virtually no harmful by-products. .

“It’s a neat method, it’s different from other ones that have been tried,” says Chris Sales, an environmental engineer at Drexel University in Philadelphia who was not involved in the study. “The biggest question is, how could this be adapted and scaled up?” Northwestern has filed a provisional patent on behalf of the researchers.

Understanding this mechanism is just one step in undoing forever chemicals, Dichtel’s team said. And more research is needed: There are other classes of PFAS that require their own solutions. This process wouldn’t work to tackle PFAS out in the environment, because it requires a concentrated amount of the chemicals. But it could one day be used in wastewater treatment plants, where the pollutants could be filtered out of the water, concentrated and then broken down.

Some mosquitoes have a near-foolproof thirst for human blood. Previous attempts to prevent the insects from tracking people down by blocking part of mosquitoes’ ability to smell have failed. A new study hints it’s because the bloodsuckers have built-in workarounds to ensure they can always smell us.

For most animals, individual nerve cells in the olfactory system can detect just one type of odor. But Aedes aegypti mosquitoes’ nerve cells can each detect many smells, researchers report August 18 in Cell. That means if a cell were to lose the ability to detect one human odor, it still can pick up on other scents.
The study provides the most detailed map yet of a mosquito’s sense of smell and suggests that concealing human aromas from the insects could be more complicated than researchers thought.

Repellents that block mosquitoes from detecting human-associated scents could be especially tricky to make. “Maybe instead of trying to mask them from finding us, it would be better to find odorants that mosquitoes don’t like to smell,” says Anandasankar Ray, a neuroscientist at the University of California, Riverside who was not involved in the work. Such repellents may confuse or irritate the bloodsuckers and send them flying away (SN: 9/21/11; SN: 3/4/21).

Effective repellents are a key tool to prevent mosquitoes from transmitting disease-causing viruses such as dengue and Zika (SN: 7/11/22). “Mosquitoes are responsible for more human deaths than any other creature,” says Olivia Goldman, a neurobiologist at Rockefeller University in New York City. “The better we understand them, the better that we can have these interventions.”

Mosquitoes that feed on people home in on a variety of cues when hunting, including body heat and body odor. The insects smell using their antennae and small appendages close to the mouth. Using three types of sensors in olfactory nerve cells, they can detect chemicals such as carbon dioxide from exhaled breath or components of body odor (SN: 7/16/15).

In previous work, researchers thought that blocking some sensors might hide human scents from mosquitoes by disrupting the smell messages sent to the brain (SN: 12/5/13). But even those sensor-deprived mosquitoes can still smell and bite people, says neurobiologist Margo Herre also of Rockefeller University.

So Goldman, Herre and colleagues added fluorescent labels to A. aegypti nerve cells, or neurons, to learn new details about how the mosquito brain deciphers human odors. Surprisingly, rather than finding the typical single type of sensor per nerve cell, the team found that individual mosquito neurons appear more like sensory hubs.

Genetic analyses confirmed that some of the olfactory nerve cells had more than one type of sensor. Some cells produced electrical signals in response to several mosquito-attracting chemicals found in humans such as octenol and triethyl amine — a sign the neurons could detect more than one type of odor molecule. A separate study published in April in eLife found similar results in fruit flies, which suggests such a system may be common among insects.

It’s unclear why having redundant ways of detecting people’s odors might be useful to mosquitoes. “Different people can smell very different from one another,” says study coauthor Meg Younger, a neurobiologist at Boston University. “Maybe this is a setup to find a human regardless of what variety of human body odor that human is emitting.”

Comets from the solar system’s deep freezer often don’t survive their first encounter with the sun. Now one scientist thinks he knows why: Solar warmth makes some of the cosmic snowballs spin so fast, they fall apart.

This suggestion could help solve a decades-old mystery about what destroys many “long-period” comets, astronomer David Jewitt reports in a study submitted August 8 to arXiv.org. Long-period comets originate in the Oort cloud, a sphere of icy objects at the solar system’s fringe (SN: 8/18/08). Those that survive their first trip around the sun tend to swing by our star only once every 200 years.
“These things are stable out there in the Oort cloud where nothing ever happens. When they come toward the sun, they heat up, all hell breaks loose, and they fall apart,” Jewitt says.

The Dutch astronomer Jan Oort first proposed the Oort cloud as a cometary reservoir in 1950. He realized that many of its comets that came near Earth were first-time visitors, not return travelers. Something was taking the comets out, but no one knew what.

One possibility was that the comets die by sublimating all of their water away as they near the heat of the sun until there’s nothing left. But that didn’t fit with observations of comets that seemed to physically break up into smaller pieces. The trouble was, those breakups are hard to watch in real time.

“The disintegrations are really hard to observe because they’re unpredictable, and they happen quickly,” Jewitt says.

He ran into that difficulty when he tried to observe Comet Leonard, a bright comet that put on a spectacular show in winter 2021–2022. Jewitt had applied for time to observe the comet with the Hubble Space Telescope in April and June 2022. But by February, the comet had already disintegrated. “That was a wake-up call,” Jewitt says.

So Jewitt turned to historical observations of long-period comets that came close to the sun since the year 2000. He selected those whose water vapor production had been indirectly measured via an instrument called SWAN on NASA’s SOHO spacecraft, to see how quickly the comets were losing mass. He also picked out comets whose movements deviating from their orbits around the sun had been measured. Those motions are a result of water vapor jets pushing the comet around, like a spraying hose flopping around a garden.

That left him with 27 comets, seven of which did not survive their closest approach to the sun.

Jewitt expected that the most active comets would disintegrate the fastest, by puffing away all their water. But he found the opposite: It turns out that the least active comets with the smallest dirty snowball cores were the most at risk of falling apart.

“Basically, being a small nucleus near the sun causes you to die,” Jewitt says. “The question is, why?”

It wasn’t that the comets were torn apart by the sun’s gravity — they didn’t get close enough for that. And simply sublimating until they went poof would have been too slow a death to match the observations. The comets are also unlikely to collide with anything else in the vastness of space and break apart that way. And a previous suggestion that pressure builds up inside the comets until they explode like a hand grenade doesn’t make sense to Jewitt. Comets’ upper few centimeters of material would absorb most of the sun’s heat, he says, so it would be difficult to heat the center of the comet enough for that to work.

The best remaining explanation, Jewitt says, is rotational breakup. As the comet nears the sun and its water heats up enough to sublimate, jets of water vapor form and make the core start to spin like a catherine wheel firework. Smaller cores are easier to push around than a larger one, so they spin more easily.

“It just spins faster and faster, until it doesn’t have enough tensile strength to hold together,” Jewitt says. “I’m pretty sure that’s what’s happening.”

That deadly spin speed is actually quite slow. Spinning at about half a meter per second could spell curtains for a kilometer-sized comet, he calculates. “You can walk faster.”

But comets are fragile. If you held a fist-sized comet in front of your face, a sneeze would destroy it, says planetary astronomer Nalin Samarasinha of the Planetary Science Institute in Tucson, who was not involved in the study.

Samarasinha thinks Jewitt’s proposal is convincing. “Even though the sample size is small, I think it is something really happening.” But other things might be destroying these comets too, he says, and Jewitt agrees.

Samarasinha is holding out for more comet observations, which could come when the Vera Rubin Observatory begins surveying the sky in 2023. Jewitt’s idea “is something which can be observationally tested in a decade or two.”

Revamped COVID-19 vaccines are poised to do battle with the super-contagious omicron variant.

On September 1, U.S. health officials greenlit the first major update of the mRNA-based shots, reformulated to recognize both the original version of SARS-CoV-2 and the recently circulating versions of omicron. Those mRNA vaccine boosters could start going into arms within days.

“They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants,” Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention, said in a statement after endorsing a vaccine advisory committee’s approval of the shots.
Both Moderna and Pfizer and its German partner BioNTech created boosters that contain instructions for making the BA.4 and BA.5 omicron subvariants’ spike protein as well as the original virus’ spike protein (SN: 6/30/22). Those two variants now account for nearly all the new cases in the United States. The U.S. Food and Drug Administration granted emergency use authorization for the shots August 31. The CDC action means the Pfizer booster is now OK’d for those 12 and older; Moderna’s shot is for those 18 and older.

The European Medicines Agency and Health Canada also authorized use of an updated booster vaccine on September 1. That one, made by Moderna, contains mRNA instructions for building the original coronavirus spike protein and the spike protein from the omicron BA.1 subvariant. The United Kingdom, Switzerland and Australia have already given the nod for use of that dual, or bivalent, booster.

Here’s what to know about the new shots:

Should I get a booster shot?
Probably. The CDC now recommends that all fully vaccinated people 12 and older get the bivalent shot, provided it has been at least two months since their last vaccine dose. “If you are eligible, there is no bad time to get your COVID-19 booster and I strongly encourage you to receive it,” Walensky said.

That recommendation comes regardless of how many boosters people have already had.

“If you perceive this as big change … you’re right,” Evelyn Twentyman, who leads CDC’s vaccine policy unit, said September 1 during the vaccine advisory committee meeting. “We want to emphasize we’re no longer looking at total number of doses,” she said. From now on, the agency hopes to transition into a more regular schedule for COVID-19 vaccines, similar to getting annual flu shots.

The original vaccines will still be used for the first two doses, but bivalent vaccines will replace the old boosters for all but 5- to 11-year-olds. Pfizer’s original vaccine booster is still available for that age group but bivalent vaccines may come later this year for children as young as 6 months old.

There was another big difference this time around: The decision to move forward with the BA.4/5 boosters was made without data from human trials. Such trials are under way, but results won’t be known until the end of the year.
In authorizing the new boosters without clinical trial data, the agencies are treating COVID-19 vaccines more like annual flu vaccines.

Data collected from people immunized with the BA.1 boosters and data from studies of mice inoculated with the BA.4/5 vaccine were used as evidence of the new boosters’ likely safety and effectiveness. The European Medicines Agency said in a Sept. 2 press briefing that it would also use the BA.1 booster to evaluate the new shots.

Why do the shots target the BA.4 and BA.5 omicron subvariants?
“We very deliberately picked BA.4/5,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, which oversees vaccines, said in a news briefing August 31.

Both companies have tested vaccines based on the omicron BA.1 variant in humans. But BA.1, which caused the massive surge earlier in the year, is no longer circulating in the United States. As of the week of August 21 through 27, BA.5 was projected to cause about 89 percent of COVID-19 cases, with BA.4 variants responsible for about 11 percent of cases.

“This gives us a variant that is most up-to-date, and most likely looks closer to something that may evolve further in the fall,” Marks said. “The more up-to-date you are, the better chance we have of [the vaccine] working for what comes afterward.”

All omicron subvariants share common mutations. But the shape of BA.4/5’s spike protein looks much different to the immune system than other omicron subvariants do, the CDC’s Natalie Thornburg said at the advisory committee meeting. Those differences may train immune cells to build a wider variety of antibodies that can latch onto a broad array of variants.

Mice inoculated with a BA.4/5 containing booster had fewer viruses in their lungs than mice given a BA.1 boosters, Moderna’s Jacqueline Miller said at the CDC meeting. The mice make a human version of ACE2, the protein on the surface of cells that the coronavirus uses to gain entry. Mouse studies of earlier variant boosters corresponded well to levels of protection seen in human clinical trials, Miller said, so the company is hopeful that the BA.4/5 booster will provide good protection, too.

Bivalent vaccines perform better — raising antibody levels higher in people and animals — than ones that contain just the original spike protein or only a variant spike protein, Miller said. The spike protein that grabs onto human cells is a three-pronged claw. With the bivalent vaccine, each prong could be either an original or an omicron version. The mixed claw may expose parts of the spike to the immune system that are normally hidden, Miller suggested.
Why now?
Though the mouse data suggest the BA.4/5 booster will work, some of the CDC advisers said they’d be more comfortable having data from the ongoing human clinical trials before recommending the new shots. That data could be available in a couple of months, so why not wait?

The wait could cost lives and money, computer projections suggest. The COVID-19 scenario modeling hub, a consortium of pandemic forecasters who predict COVID-19 patterns over the next six months under varying conditions, considered what would happen in the United States if the boosters were given in September or not until November. Waiting would lead to 137,000 more hospitalizations and 9,700 more deaths, the researchers projected.

An early fall booster campaign could save more than $62 billion in direct medical costs, an analysis from the Commonwealth Fund projects.

Is it safe?
Based on studies with the BA.1 bivalent booster, yes. That shot produced similar side effects to the original shots.

And it’s also safe to get flu shots and other vaccines, including ones used against monkeypox, at the same time as the COVID-19 booster. In fact, doctors should offer all vaccines for which a person is eligible at the same visit, Elisha Hall of the CDC said.

Some data indicate that the chance of serious side effects, like heart inflammation called myocarditis, happen at similar or lower rates with boosters than with the second doses of the mRNA vaccines. The side effect is rare; CDC has verified 131 myocarditis cases out of more than 126 million booster doses given, Tom Shimabukuro of the CDC COVID-19 Vaccine Safety Unit reported. The rate of myocarditis is 1.8 to 5.6 times higher after a COVID-19 infection than after vaccination for 12- to 17-year-old males — the group for which the condition has the highest risk, the CDC’s Sara Oliver said. Spacing the booster at least two months after the last dose of vaccine may help to head off any increase in myocarditis, Marks said in the FDA press briefing.

“We have a tremendous amount of experience with the monovalent, original vaccine,” the FDA’s Doran Fink said during the CDC advisory meeting. That experience made the FDA comfortable extrapolating data from the BA.1 booster trials to decide that the new shots are also safe.

“We don’t usually have too much clinical information … when we are thinking about changing influenza vaccines,” said Sarah Long, an infectious diseases pediatrician at Drexel University College of Medicine in Philadelphia. Much like the flu vaccine remodels last season’s version, the updated COVID-19 booster is built on the same scaffolding as the original version. “It’s part of the same roof. We’re just putting in some dormers and windows.”

Pablo Sanchez, a pediatric infectious diseases doctor at The Ohio State University and Nationwide Children’s Hospital in Columbus, cast the sole dissenting vote against recommending the BA.4/5 boosters. Other committee members voted to recommend the boosters, but they voiced reservations about those votes.

“I really don’t want to establish a precedent of recommending a vaccine that we don’t have clinical data on,” Sanchez said. He added, “I’m comfortable that the vaccine will likely be safe like the others,” but having the human data may help counter vaccine hesitancy.

A laser blast produces miniature diamonds from plain-old plastic. That’s right, the same kind used in soda bottles.

When squeezed to about a million times Earth’s atmospheric pressure and heated to thousands of degrees Celsius, polyethylene terephthalate, or PET, forms nanodiamonds, physicist Dominik Kraus and colleagues report September 2 in Science Advances.

Ice giant planets, such as Neptune and Uranus, have similar temperatures, pressures and combinations of chemical elements as the materials in the study, suggesting that diamonds may rain down in those planets’ interiors. What’s more, the researchers say, the new technique could be used to manufacture nanodiamonds for use in quantum devices and other applications.
In the new study, researchers trained lasers on samples of plastic. Each laser blast sent a shock wave careening through the plastic, amping up the pressure and temperature within. Probing the material with bursts of X-rays revealed that nanodiamonds had formed.

Previous studies had created diamonds by compressing compounds of hydrogen and carbon. But PET, which is commonly used in food and drink packaging, contains not just hydrogen and carbon but also oxygen. That makes it a better match to the composition of ice giant planets like Neptune and Uranus. The oxygen seems to assist the diamond formation, says Kraus, of the University of Rostock in Germany. “The oxygen sucks out the hydrogen,” he says, leaving behind carbon which can then form diamond.

Nanodiamonds are commonly produced using explosives, Kraus says, a process not easy to control. The new technique could create nanodiamonds that are more easily tailored for particular uses, such as quantum devices made using diamond with defects where, for example, nitrogen atoms replace some of the carbon atoms (SN: 7/6/18).

“The idea is quite cool. You take water bottle plastic; you zap it with a laser to make diamond. How practical it is, I don’t know,” says physicist Marius Millot of Lawrence Livermore National Laboratory in California, who was not involved with the new study. How easily the diamonds could be recovered is unclear, he says. But, “it’s pretty neat to think about the idea.”