Philippa Kaur

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    in Humans

    Large cities lead to more segregation between rich and poor

    Smartphone data from more than 9 million people in the US reveals that big cities lead to greater socioeconomic segregation despite claims they reduce it

    Humans

    28 October 2022

    By Alex Wilkins
    The size and design of cities affect social segregationImage Craft/Shutterstock
    People living in large cities are more segregated, and mix less with those from different socioeconomic backgrounds, than people in small towns, according to an analysis of anonymous phone data from more than 9 million people in the US.
    A longstanding premise of urban design is that cities encourage interactions between different economic groups, and so lead to less segregation. One of the most common ways to measure this segregation is to look at where people live and their corresponding economic status. … More

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    in Space & Astronomy

    Meet the BOAT, the brightest gamma-ray burst of all time

    The brightest gamma-ray burst ever recorded recently lit up a distant galaxy — and astronomers have nicknamed it the BOAT, for Brightest of All Time.

    “We use the boat emoji a lot when we’re talking about it” on the messaging app Slack, says astronomer Jillian Rastinejad of Northwestern University in Evanston, Ill.

    Gamma-ray bursts are energetic explosions that go off when a massive star dies and leaves behind a black hole or neutron star (SN: 11/20/19; SN: 8/2/21). The collapse sets off jets of gamma rays zipping away from the poles of the former star. If those jets happen to be pointed right at Earth, astronomers can see them as a gamma-ray burst.

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    This new burst, officially named GRB 221009A, was probably triggered by a supernova giving birth to a black hole in a galaxy about 2 billion light-years from Earth, researchers announced October 13. Astronomers think it released as much energy as roughly three suns converting all of their mass to pure energy.

    NASA’s Neil Gehrels Swift Observatory, a gamma-ray telescope in space, automatically detected the blast October 9 around 10:15 a.m. EDT, and promptly alerted astronomers that something strange was happening.

    “At the time, when it went off, it looked kind of weird to us,” says Penn State astrophysicist Jamie Kennea, who is the head of science operations for Swift. The blast’s position in the sky seemed to line up with the plane of the Milky Way. So at first Kennea and colleagues thought it was within our own galaxy, and so unlikely to be something as dramatically energetic as a gamma-ray burst. If a burst like this went off inside the Milky Way, it would be visible to the naked eye, which wasn’t the case.

    But soon Kennea learned that NASA’s Fermi Gamma-ray Space Telescope had also seen the flash — and it was one of the brightest things the telescope had ever seen. A fresh look at the Swift data convinced Kennea and colleagues that the flash was the brightest gamma-ray burst seen in the 50 years of observing these rare explosions.

    “It’s quite exceptional,” Kennea says. “It stands head and shoulders above the rest.”

    This series of visible-light images from NASA’s Swift telescope’s ultraviolet/optical instrument shows that the bright glow of the gamma-ray burst GRB 221009A (yellow circle) faded over about 10 hours.Swift/NASA, B. Cenko

    After confirmation of the burst’s BOAT bonafides — a term coined by Rastinejad’s adviser, Northwestern astronomer Wen-fai Fong — other astronomers rushed to get a look. Within days, scientists around the world got a glimpse of the blast with telescopes in space and on the ground, in nearly every type of light. Even some radio telescopes typically used as lightning detectors saw a sudden disturbance associated with GRB 221009A, suggesting that the burst stripped electrons from atoms in Earth’s atmosphere.

    In the hours and days after the initial explosion, the burst subsided and gave way to a still relatively bright afterglow. Eventually, astronomers expect to see it fade even more, replaced by glowing ripples of material in the supernova remnant.

    The extreme brightness was probably at least partially due to GRB 221009A’s relative proximity, Kennea says. A couple billion light-years might seem far, but the average gamma-ray burst is more like 10 billion light-years away. It probably was also just intrinsically bright, though there hasn’t been time to figure out why.

    Studying the blast as it changes is “probably going to challenge some of our assumptions of how gamma-ray bursts work,” Kennea says. “I think people who are gamma-ray burst theorists are going to be inundated with so much data that this is going to change theories that they thought were pretty solid.”

    GRB 221009A will move behind the sun from Earth’s perspective starting in late November, shielding it temporarily from view. But because its glow is still so bright now, astronomers are hopeful that they’ll still be able to see it when it becomes visible again in February.

    “I’m so excited for a few months from now when we have all the beautiful data,” Rastinejad says. More

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    in Humans

    Don't Miss: Read about how the milky way smells of rum and raspberries

    New Scientist’s weekly round-up of the best books, films, TV series, games and more that you shouldn’t miss

    Humans

    26 October 2022

    Read
    The Milky Way Smells of Rum and Raspberries writes astrophysicist Jillian Scudder. Her offbeat tour of the universe, with its weird and wonderful facts, will have us looking at the night sky afresh. On sale 3 November.
    PETER KRAMER/NETFLIX
    Watch
    Manifest‘s fourth season continues the uncanny story of airline passengers who landed five years too late. It stars Josh Dallas and Melissa Roxburgh as Ben and Michaela Stone (pictured above). The first half of the season comes to Netflix on 4 November.
    NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
    Visit
    The Pluto Story is astronomer Ian Robson’s tale of … More

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    in Humans

    How to make a sweet potato even sweeter: freeze it before baking

    Studies show it is always best to bake your sweet potatoes, rather than boil or microwave them, and there is another trick to take the tubers to the next level of deliciousness, says Sam Wong

    Humans

    26 October 2022

    By Sam Wong
    Shutterstock/Piyaset
    DELICIOUS meals don’t get much simpler than a baked sweet potato. But a little science can tell us how to maximise this dish’s sweetness and deepen its flavour.
    Sweet potatoes are between 1 and 2.5 per cent sugar when raw, but they get sweeter as they cook thanks to the work of amylase enzymes that break down starch into simple sugars. These enzymes are most active at 75°C (167°F).
    A study from 2012 found that the sugar content of one type of sweet potato was almost five times higher after baking for 90 minutes, mainly due … More

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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

    More on these topics: More

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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