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    in Space & Astronomy

    Particles from space provide a new look inside cyclones

    Particles raining down from space offer 3-D views inside swirling tropical storms.

    Muons created from cosmic rays that smash into Earth’s upper atmosphere have revealed the inner workings of cyclones over Japan, researchers report October 6 in Scientific Reports. The new imaging approach could lead to a better understanding of storms, the researchers say, and offer another tool to help meteorologists forecast the weather.

    “Cosmic rays are sustainable natural resources that can be used everywhere on this planet for 24 hours [a day],” says geophysicist Hiroyuki Tanaka of the University of Tokyo, so it’s just a matter of taking advantage of them.

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    Muons offer a glimpse inside storms because variations in air pressure and density change the number of particles that make it through a tempest. By counting how many muons arrived at a detector on the ground in Kagoshima, Japan as cyclones moved past, Tanaka and colleagues produced rough 3-D maps of the density of air inside the storms. The approach gave the team an inside look at the low-pressure regions at the centers rotating storm systems.

    Muons, which are similar to electrons but roughly 200 times as massive, can scatter off molecules in the air. They’re also unstable, which means they break down into electrons and other particles called neutrinos given enough time. As air pressure increases, so does its density. That, in turn, increases the chances that a muon born from a cosmic ray will be bumped off its path on the way toward a detector or get slowed enough that it breaks down before it makes it all the way through the atmosphere.

    For every 1 percent increase in air pressure, Tanaka and colleagues say, the number of muons that survive passage from the upper atmosphere to the ground decreases by about 2 percent.

    Fewer muons make it through the high-pressure portions at the edges of a swirling cyclone (yellow and green in this muograph) than through the low-pressure regions in the center (red), providing a map of conditions inside the storm (illustrated outline). The darkened portion was outside the viewing angle of the muon detector.©2022 H.K.M. Tanaka

    Tanaka has previously used muons from cosmic rays to look inside volcanoes, and he suspects that others have used the particles to study weather (SN: 4/22/22). But, he says, this appears to be the first time that anyone has made 3-D muon scans of the insides of a storm.

    “It is an interesting approach,” says meteorologist Frank Marks of the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory in Miami, who wasn’t involved in the research.

    He doesn’t expect muon imaging to replace conventional meteorological measurements, but it’s another tool that scientists could use. “[It] would be complementary to our existing techniques to provide 3-D mapping of the storms with our other traditional observing systems, like satellites and radar.” More

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    in Humans

    17th-century infant's life and health revealed by 'virtual autopsy'

    A young child found in an unmarked coffin in an Austrian crypt was exceptionally well preserved, and his bones and organs show signs of rickets and pneumonia

    Humans

    26 October 2022

    By Christa Lesté-Lasserre
    A close-up of the mummified child’s handA. G. Nerlich et al/Frontiers
    An infant born into an aristocratic Austrian family in the 17th century died overweight but may have been deficient in vitamin D, according to researchers who conducted a “virtual autopsy” on the mummified body.
    Scans of the surprisingly well-preserved body revealed knobbly extensions on the rib joints typical of rickets, caused by lack of vitamin D, as well as thick layers of fat – which probably helped the tissues mummify. The findings suggest the child was overfed and underexposed to sunlight, leading to his death, says Andreas Nerlich at the Academic Clinic Munich-Bogenhausen in Germany.
    Nerlich and his colleagues examined the infant’s remains after an unmarked wooden coffin was discovered in a crypt near a castle in Upper Austria. The crypt had constant airflow and a stable temperature, which probably helped dry out the child’s body. “We have here one of the very rare cases where such an aristocratic infant spontaneously mummified – and was available for a scientific investigation,” he says.Advertisement
    Radiocarbon dating of the body, combined with records of the crypt’s construction, led the researchers to estimate that the child was buried approximately 400 years ago. Given the infant’s approximate age at death – between 10 and 18 months old – and silk wraps indicative of aristocratic birth, they suspect the child was Reichard Wilhelm, who lived from 1625 to 1626, the first-born son of the Count of Starhemberg.
    Based on computed tomography (CT) scans of the body, the researchers confirmed that the child was male, and his bone measurements and tooth eruption were consistent with a child of about a year old.
    The infant mummy found in the cryptA. G. Nerlich et al/Frontiers
    Scans of his rib bones revealed rachitic rosary, a condition typical of severe cases of rickets. Rickets results primarily from a lack of vitamin D, which the body produces when exposed to ultraviolet sun rays. While his leg bones weren’t bowed – a tell-tale sign of rickets in older children – that may have been because the infant wasn’t walking yet, says Nehrlich. One arm bone, however, appeared slightly bent.
    The infant’s lungs were inflamed, suggesting he may have died of pneumonia – a disease known to occur more frequently in children with rickets, he says.
    “The combination of obesity along with a severe vitamin deficiency can only be explained by a generally ‘good’ nutritional status along with an almost complete lack of sunlight exposure,” says Nerlich.
    It is unclear whether this combination of traits was common, but early infant death rates were generally high compared with today in upper social classes during the Renaissance, says Nerlich.
    Journal reference: Frontiers in Medicine, DOI: 10.3389/fmed.2022.979670

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    in Humans

    US Army bullets unexpectedly found at 1918 Mexico border massacre site

    A ballistics analysis has raised new questions about the role of the US Army in the 1918 Porvenir massacre, where Texas Rangers killed 15 unarmed Mexican boys and men

    Humans

    25 October 2022

    By Jeremy Hsu
    The 1918 Porvenir massacre occurred at the US-Mexico borderTexas Historical Commission
    The first archaeological investigation of the site of a century-old massacre at the US-Mexico border has unexpectedly found bullets and cartridge casings for US military weapons.
    On the morning of 28 January 1918, Texas Rangers and local ranchers, escorted by the US Army’s 8th Cavalry, rounded up 15 boys and men of Mexican descent from the town of Porvenir, Texas, and shot them execution-style. None of that is disputed. But new evidence suggesting that both civilian and military weapons were used raises … More

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    in Space & Astronomy

    Most stars may have much more time to form planets than previously thought

    Good news for late bloomers: Planets may have millions of years more time to arise around most stars than previously thought.

    Planet-making disks around young stars typically last for 5 million to 10 million years, researchers report in a study posted October 6 at arXiv.org. That disk lifetime, based on a survey of nearby young star clusters, is a good deal longer than the previous estimate of 1 million to 3 million years.

    “One to three megayears is a really strong constraint for forming planets,” says astrophysicist Susanne Pfalzner of Forschungszentrum Jülich in Germany. “Finding that we have a lot of time just relaxes everything” for building planets around young stars.

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    Planets large and small develop in the disks of gas and dust that swirl around young stars (SN: 5/20/20). Once a disk vanishes, it’s too late to make any more new worlds.

    Past studies have estimated disk lifetimes by looking at the fraction of young stars of different ages that still have disks — in particular, by observing star clusters with known ages. But Pfalzner and her colleagues discovered something odd: The farther a star cluster is from Earth, the shorter the estimated disk lifetime. That made no sense, she says, because why should the lifetime of a protoplanetary disk depend on how far it is from us?

    The answer is quite simple: It doesn’t. But in clusters that are farther away, it’s harder to see most stars. “When you look at larger distances, you see higher-mass stars,” Pfalzner says, because those stars are brighter and easier to see. “You basically don’t see the low-mass stars.” But the lowest-mass stars constitute the vast majority. These stars, orange and red dwarfs, are cooler, smaller and fainter than the sun.

    So Pfalzner and her colleagues examined only the nearest young star clusters, those within 650 light-years of Earth, and found that the fraction of stars with planet-making disks was much higher than that reported in previous studies. This analysis showed that “the low-mass stars have much longer disk lifetimes, between 5 and 10 megayears,” than astronomers realized, she says. In contrast, disks around higher-mass stars are known to disperse faster than this, perhaps because their suns’ brighter light pushes the gas and dust away more quickly.

    “I wouldn’t say that this is definite proof” for such long disk lifetimes around orange and red dwarfs, says Álvaro Ribas, an astronomer at the University of Cambridge who was not involved with the work. “But it’s quite convincing.”

    To bolster the result, he’d like to see observations of more distant star clusters — perhaps with the James Webb Space Telescope — to determine the fraction of the faintest stars that have preserved their planet-making disks between 5 million and 20 million years (SN: 10/11/22).

    If the disks around the lowest mass stars do indeed have long lifetimes, that may explain a difference between our solar system and those of most red dwarfs, Pfalzner says. The latter often lack gas giants like Jupiter and Saturn, which are about 10 times the diameter of Earth. Instead, those stars frequently have numerous ice giants like Uranus and Neptune, about four times the diameter of Earth. Perhaps Neptune-sized planets arise in larger numbers when a planet-making disk lasts longer, Pfalzner says, accounting for why these worlds tend to abound around smaller stars. More

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    in Humans

    The surprising evolutionary history of pumpkins and squashes

    Shops are stocking up on pumpkins for Halloween. While I haven’t always been a fan of squashes, I’ve been charmed by how such unlikely fruits came to spread worldwide, says Penny Sarchet

    Humans

    | Columnist

    19 October 2022

    By Penny Sarchet
    Shutterstock/JamesChen
    IN PARTS of the world where autumn is underway, squashes are now on the menu, and shops are stocking up on pumpkins for Halloween. I haven’t always been a fan of squashes, but the more I have learned about their evolutionary history, the more I have been charmed by how such unlikely and unpromising fruits came to spread worldwide.
    There is a beguiling diversity of squashes and pumpkins, and their range of shapes, sizes and colours gives them much aesthetic appeal. But they all belong to one genus – Cucurbita – and fall broadly into only six main species or subspecies. … More

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    in Humans

    Neanderthal family life revealed by ancient DNA from Siberian cave

    DNA from 11 individuals who lived in Chagyrskaya cave around 51,000 years ago suggests women moved between groups and also shows a high level of inbreeding

    Humans

    19 October 2022

    By Michael Le Page
    Chagyrskaya cave in SiberiaSkov et al.
    Ancient DNA from a group of Neanderthals who lived together has given us an unprecedented glimpse of the social structure of these extinct human relatives. Among other things, it suggests that their women moved between groups while the men stayed put.
    Researchers have previously tried to work out what the social structure of Neanderthal groups was like from evidence such as the layout of caves and footprints, says team member Benjamin Peter at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, but the DNA provides direct evidence. “It’s the first time we’ve been able to do something like this using genetics,” says Peter.
    He and his colleagues managed to extract DNA from 15 out of 17 pieces of bone or teeth recovered from the Chagyrskaya cave in the Altai mountains in Siberia, Russia. The DNA showed that some pieces came from the same individuals, so the findings represent 11 individuals in total, including several teenagers and children.Advertisement
    Dating of sediments and bison bones at the site suggests the Neanderthals lived in the cave between 51,000 and 59,000 years ago, while the DNA shows that many of the individuals were related. “We can say that they very likely lived at the same time,” says Peter.
    For instance, there is a father and daughter among the remains. The father also shares mitochondrial DNA with two other men, meaning they had a common female ancestor, such as the same grandmother.
    Another man and woman are second-degree relatives, meaning the woman might be, say, the grandmother or aunt of the man. The team doesn’t have enough of their DNA to determine the precise relationship.
    Peter thinks it is possible that these individuals all died around the same time, but the team doesn’t know how. There are no signs of burial, he says.
    The DNA also reveals a very high level of inbreeding, much higher than in modern hunter-gatherer groups, suggesting that the Neanderthal population in the area was very small. “It’s very unusual,” says Peter. “The only thing we’ve found that is comparable are species that are critically endangered, like gorillas.”
    However, the team can’t say whether this high level of inbreeding affected the health of these individuals. It may be a result of being an isolated group on the edge of the range of Neanderthals, rather than being true of Neanderthals generally.
    “Other Neanderthal sites like Vindija [in Croatia] indicate larger and more diverse populations,” says Chris Stringer at the Natural History Museum in the UK, who wasn’t part of the team.
    The researchers also compared the diversity of Y chromosomes, inherited from the father, with that of mitochondrial DNA, inherited from the mother. They found an order of magnitude more mitochondrial diversity, says Peter. “I don’t know any human population where we would see that,” he says.
    This suggests that men stayed in the same group where they were born, but that most women moved to different groups.

    Female-based migration is the predominant pattern in modern hunter-gatherers, says Stringer, and there is some evidence for it among Neanderthals from the El Sidrón site in northern Spain. “So finding this at another site, with more data, does suggest that this was a common pattern in Neanderthals,” says Stringer.
    Peter and his colleagues also tried extracting DNA from 10 specimens from the nearby Okladnikov cave, but only got DNA from two individuals. These weren’t related to each other or to the Chagyrskaya group.
    The research team included Svante Pääbo, who won the 2022 Nobel prize in physiology or medicine for his discoveries concerning human evolution and the genomes of our extinct human relatives.
    Journal reference: Nature, DOI: 10.1038/s41586-022-05283-y
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    in Space & Astronomy

    For the first time, astronomers saw dust in space being pushed by starlight

    A pair of stars in our galaxy is revealing how light pushes around matter. It’s the first time anyone has directly seen how the pressure of light from stars changes the flow of dust in space.

    Such radiation pressure influences how dust clears from the regions near young stars and guides the formation of gas clouds around dying stars (SN: 9/22/20). The dust pattern surrounding a stellar pair 5,600 light-years away in the Cygnus constellation is providing a rare laboratory to observe the effect in action, astronomer Yinuo Han and colleagues report in the Oct. 13 Nature. 

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    Astronomers have long known that the dust emerging from the star WR 140 and its companion is formed by gas from these two stars colliding and condensing into soot. But images of the pair taken over the course of 16 years show that the dust is accelerating as it travels away from the stars.

    Dust initially departs the stars at about 6.5 million kilometers per hour, the researchers report, and over the course of a year accelerates to nearly 10 million km/h. At that speed, the dust could make the trip from our sun to Earth in a mere 15 hours.

    The revelation came from comparing the positions of concentric dust shells year to year and deducing a speed. The researchers’ calculations show that the force accelerating the dust is the pressure exerted by light radiated from the stars, says Han, of the University of Cambridge. “Radiation pressure [becomes apparent] only when we put all the images next to each other.”  

    Not only are those layers of dust feeling light’s push, they also extend out farther than any telescope could see — until this year. Images from the James Webb Space Telescope, or JWST, depict more of the dusty layers around WR 140 and its companion than ever seen before, Han and another team report October 12 in Nature Astronomy.

    At first glance, the intricate patterns surrounding the stars resemble a gigantic spiderweb. But the researchers’ analysis reveals that they are actually enormous, expanding, cone-shaped dust shells. They’re nested inside each other, with a new one forming every eight years as the stars complete another journey around their orbits. In the new images, the shells look like sections of rings because we observe them from the side, Han says.  

    A computer simulation that takes radiation pressure from starlight into account shows how a dust plume (expanding arc and line) emerges from a pair of orbiting stars (not visible).Y. Han/Univ. of Cambridge

    The patterns don’t completely surround the stars because the distance between the stars changes as they orbit one another. When the stars are far apart, the density of the colliding gas is too low to condense to dust — an effect the researchers expected. 

    What surprised them is that the gas doesn’t condense well when the stars are closest together either. That suggests there’s a “Goldilocks zone” for dust formation: Dust forms only when the separation between the stars is just right, creating a series of concentric dust shells rippling away from the duo.

    “Their Goldilocks zone is a new idea,” says astrophysicist Andy Pollock of the University of Sheffield in England, who was not part of either study. “A similar sort of thing happens in my field of X-rays.”

    In his work, Pollock has observed that WR 140 and its partner emit more X-rays as the stars approach each other, but then fewer as they get very close together, suggesting there’s a Goldilocks zone for X-rays coming from the stars as well. “It would be interesting to see if there’s any connection” between the two types of Goldilocks zones, he says. “All of this must somehow fit together.” More