Philippa Kaur

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    in Space & Astronomy

    ‘Goldilocks’ stars may pose challenges for any nearby habitable planets

    If you’re an aspiring life-form, you might want to steer clear of planets around orange dwarf stars.

    Some astronomers have called these orange suns “Goldilocks stars” (SN: 11/18/09). They are dimmer and age more slowly than yellow sunlike stars, thus offering an orbiting planet a more stable climate. But they are brighter and age faster than red dwarfs, which often spew large flares. However, new observations show that orange dwarfs emit lots of ultraviolet light long after birth, potentially endangering planetary atmospheres, researchers report in a paper submitted March 29 at arXiv.org.

    Using data from the Hubble Space Telescope, astronomer Tyler Richey-Yowell and her colleagues examined 39 orange dwarfs. Most are moving together through the Milky Way in two separate groups, either 40 million or 650 million years old.

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    To Richey-Yowell’s surprise, she and her team found that the ultraviolet flux didn’t drop off from the younger orange stars to the older ones — unlike the case for yellow and red stars. “I was like, `What the heck is going on?’” says Richey-Yowell, of Arizona State University in Tempe.

    In a stroke of luck, another team of researchers supplied part of the answer. As yellow sunlike stars age, they spin more slowly, causing them to be less active and emit less UV radiation. But for orange dwarfs, this steady spin-down stalls when the stars are roughly a billion years old, astronomer Jason Lee Curtis at Columbia University and colleagues reported in 2019.

    “[Orange] stars are just much more active for a longer time than we thought they were,” Richey-Yowell says. That means these possibly not-so-Goldilocks stars probably maintain high levels of UV light for more than a billion years.

    And that puts any potential life-forms inhabiting orbiting planets on notice. Far-ultraviolet light — whose photons, or particles of light, have much more energy than the UV photons that give you vitamin D — tears molecules in a planet’s atmosphere apart. That leaves behind individual atoms and electrically charged atoms and groups of atoms known as ions. Then the star’s wind — its outflow of particles — can carry the ions away, stripping the planet of its air.

    But not all hope is lost for aspiring life-forms that have an orange dwarf sun. Prolonged exposure to far-ultraviolet light can stress planets but doesn’t necessarily doom them to be barren, says Ed Guinan, an astronomer at Villanova University in Pennsylvania who was not involved in the new work. “As long as the planet has a strong magnetic field, you’re more or less OK,” he says.

    Though far-ultraviolet light splits water and other molecules in a planet’s atmosphere, the star’s wind can’t remove the resulting ions if a magnetic field as strong as Earth’s protects them. “That’s why the Earth survived” as a life-bearing world, Guinan says. In contrast, Venus might never have had a magnetic field, and Mars lost its magnetic field early on and most of its air soon after.

    “If the planet doesn’t have a magnetic field or has a weak one,” Guinan says, “the game is over.”

    What’s needed, Richey-Yowell says, is a study of older orange dwarfs to see exactly when their UV output declines. That will be a challenge, though. The easiest way to find stars of known age is to study a cluster of stars, but most star clusters get ripped apart well before their billionth birthday (SN: 7/24/20). As a result, star clusters somewhat older than this age are rare, which means the nearest examples are distant and harder to observe. More

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    in Space & Astronomy

    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).

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    “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.” More

  • 138 Shares139 Views

    in Humans

    People tend to believe populations are more diverse than they are

    In 12 psychological experiments with a total of 942 participants, 82 per cent overestimated the presence of individuals from minority ethnic groups

    Humans

    14 April 2022

    By Jason Arunn Murugesu
    A stock image of a group of people of a range of ethnicitiesShutterstock/Rawpixel.com
    People may subconsciously overestimate the presence of individuals from minority ethnic groups, even if they belong to those groups, which could create illusions of diversity within populations.
    “Individuals from the minority group are by definition less frequent,” says Rasha Kardosh at the Hebrew University of Jerusalem in Israel. “Therefore, we are more likely to notice them and so are more likely to remember their presence, and so we end up overestimating their presence.”
    Previous studies suggest people in … More

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    in Humans

    Earliest evidence for Maya calendar may have been found in Guatemala

    The earliest evidence of calendar use by the Maya may have been found in the remains of an ancient temple in Guatemala

    Humans

    13 April 2022

    By Carissa Wong
    An ancient fragment of a Maya calendarHeather Hurst/Skidmore College/Saratoga Springs
    Two pieces of an ancient wall may preserve the earliest evidence of the Maya calendar. The fragments are decorated with a dot and line above a deer head – representing one of the dates from the 260-day calendar – and they are from a temple built between 2300 and 2200 years ago in what is now Guatemala in central America.
    Several ancient communities living across the Americas – including the Aztecs, Maya, Mixtecs and Zapotecs – tracked the time using cycles of 13 days denoted by numbers, alongside cycles of 20 days named after gods. In this calendar, a specific day is assigned both a number and a name, producing 260 unique days before the cycle repeats. It is thought that people used the calendar to decide when to hold ceremonies, to mark important dates or to attempt to predict future events.
    Until now, most previous early evidence for calendar use by these ancient people had been found on stone monuments dating to around 100 BC. David Stuart at the University of Texas at Austin and his colleagues have now found evidence that the Maya people may have used this calendar over a century earlier.Advertisement
    The team previously discovered the San Bartolo archaeological site, which includes a pyramid called Las Pinturas – meaning “the paintings” – back in 2001. Excavations then revealed that the Maya completed several phases of construction, with earlier structures eventually knocked down to form the foundations of the pyramid.
    When the researchers were sorting through pieces of plaster collected from the pyramid’s foundations, they realised that two pieces fit perfectly together to form a date symbol.
    “That was a stunner – we believe that this is the earliest example of the use of the Maya calendar, showing the day seven Deer,” says Stuart.

    The fragments came from the remains of a long platform that was probably built to track astronomical events as well as the time. “This platform may have acted as an observatory for looking at the rising sun or other astronomical bodies in the sky, or for just keeping track of time. Like a kind of architectural clock,” says Stuart.
    By radiocarbon dating charcoal found alongside the fragments, the team dated the symbols to between 300 and 200 BC. Stuart believes the symbols may have been used to denote the date of a new year, but they may also have been used to reference a person or deity.
    However, some archaeologists question whether this is really the earliest evidence of the 260-day calendar. Mary Pohl at Florida State University believes that a previously discovered roller stamp from Tabasco in Mexico shows this date notation was used in 500 BC. But Stuart thinks the symbols on the stamp from 500 BC aren’t necessarily a form of date notation comparable to the Maya system.
    “Early evidence of the… calendar has been debated, but in this study they present clear evidence of the 260-day calendar use. This is very important work,” says Takeshi Inomata at the University of Arizona.
    Journal reference: Science Advances, DOI: 10.1126/sciadv.abl9290
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    in Humans

    Women in a 19th-century Dutch farming village didn't breastfeed

    An analysis of bones from about 500 individuals who died between 1830 and 1867 in Middenbeemster suggests women in the dairy farming community did not breastfeed

    Health

    13 April 2022

    By Jason Arunn Murugesu
    Engraving from From The Five Senses by Fredrick Bloemaert, after Abraham Bloemaert, 1632-1670F. Bloemaert/A. Bloemaert/N. Visscherimage/Rijks Museum/Public Domain
    Women from a 19th-century farming community in the Netherlands probably didn’t breastfeed their babies because they were too busy working. It is the first time that widespread artificial feeding has been discovered in a farming community from this period.
    Andrea Waters-Rist at Western University in Canada and her colleagues analysed the bones of about 500 individuals who died between 1830 and 1867 in Middenbeemster, a rural village in the north of the Netherlands.
    The remains were dug up because a church was expanding into the cemetery, and Waters-Rist and her team were offered the chance to analyse them. They also had death certificates for about half the people. “It’s really rare to have such a large sample size and to have all this amazing archival information,” she says.Advertisement
    The researchers wanted to find out more about the diets of the women and children in this village, which mainly consisted of dairy farmers at this time. “One of the main reasons behind this type of research is to rectify the historical record about the lives of women and children,” says Waters-Rist. “Traditional archaeology has focused on what adult males were doing and women were just seen as passive actors.”
    The team was able to determine whether the children were breastfed by analysing the chemical isotopes in their bones. Children who are breastfed have different carbon and nitrogen isotope ratios to their mothers.

    Out of 20 children who had died before the age of 1, 15 showed no evidence of breastfeeding. “Even the five who did show some sign – it did not seem like they were breastfed for long,” says Waters-Rist.
    And out of 35 children aged between 1 and 6, 29 showed no signs of breastfeeding in their bones. The team believes this was probably due to the fact that women predominantly worked the farms in this community, milking and raising the cows.
    “We think it’s a sign of how hard the women were working and that they were just really busy,” she says. “Also, there was always fresh cow’s milk.”
    Waters-Rist says this has never been seen among farmers from this period before. “We’ve only seen this behaviour in really large cities where women were working in factories and couldn’t take their babies with them,” she says.
    “The findings of this study are intriguing for an agricultural community where mothers and infants would not have spent long periods apart,” says Ellen Kendall at Durham University in the UK. But she says the results may be skewed by only looking at children who died before the age of six – it could be that children who weren’t breastfed were more likely to die early.
    Journal reference: PLOS One, DOI: https://dx.doi.org/10.1371/journal.pone.0265821

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    in Humans

    Tremors in the Blood review: The intriguing origins of the polygraph

    Amit Katwala’s thorough history of the lie detector test looks at its inventors and some of its earliest cases, placing it, warts and all, in its historical and scientific context

    Humans

    13 April 2022

    By Chris Stokel-Walker
    The polygraph test looked scientific because it was based on physiological readingsPeter Dazeley/Getty Images
    Tremors in the Blood
    Amit Katwala
    MudlarkAdvertisement
    THE polygraph test has been used in criminal prosecutions for decades – a silver bullet for police and prosecutors alike. Measuring heart rate, breathing speed and the conductivity of skin, it is supposedly infallible and given the respectable veneer of science in a courtroom. Someone who flunks the test must be lying, their body’s tell-tale signs betraying their deepest secrets.
    Yet that is far from reality. “There is no single tell-tale sign of deception that holds true for everyone – no Pinocchio’s nose,” writes Amit Katwala in Tremors in the Blood. A misfiring test has real ramifications: the US-based National Registry of Exonerations holds records of more than 200 people who failed a polygraph test, were convicted of a crime and imprisoned, but were later found to be innocent.
    Katwala’s book traces the test’s history, looking at the early adopters of the technology and some of its earliest cases. The book goes back a century, telling the story of John Larson and Leonarde Keeler, co-inventors of the polygraph (called the emotograph by Keeler), and August Vollmer – all three key to its adoption by US police forces and later worldwide.
    Larson was a complex character, breathed back to life by Katwala’s meticulous research. A bookish, morally driven individual, Larson joined the Californian police force in the early 1920s. Unlike the high school dropouts and extortionists who filled the force’s ranks then, Larson was the only police officer in the US with a PhD, in physiology. He would work in university labs by day and police the streets at night.
    Larson’s master’s thesis had been on the relatively new technology of fingerprint identification, which had recently become admissible in court. He thought there were still more ways of catching criminals. He was lucky to work under a police chief, Vollmer, who was more bookish than he liked to let on.
    Vollmer was equally driven to do the right thing, and was constantly trying to improve policing. In 1921, after reading an academic paper by a psychologist and lawyer who had tested whether his friends were lying based on their blood pressure readings, Vollmer asked Larson to develop a machine that could do the same. The result was mocked by fellow officers, and described in newspapers as looking like a combination of radio, gas stove, stethoscope, dentist’s drill, barometer, wind gauge, time ball (an old form of clock) and watch – but it appeared to work.
    Katwala vividly portrays those heady early days when the polygraph seemed to catch out liars. Then, he deftly delivers the twist in the tale: 40-odd years after cobbling together the first machine, Larson forswore his invention because of the way it was used. It was “nothing more than a psychological third degree aimed at extorting confessions, as the old physical beatings were”, he said in an interview – far removed from his meticulous scientific approach.
    The book captures the wonder of scientific breakthrough – and what happens as the story becomes more complex. In 1965, the year Larson died, the US House Committee on Government Operations warned that the world had been hoodwinked by “a myth that a metal box in the hands of an investigator can detect truth or falsehood”.
    Yet the polygraph is still being used. In 2021, the UK began polygraph testing people convicted of terrorism offences and, later that year, convicted domestic abusers, despite the fact there are serious doubts about whether it works.
    Why has the polygraph remained on its pedestal? Perhaps because no one, until now, has placed it, warts and all, in its historical and scientific context.

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    in Humans

    Don’t Miss: Russian Doll returns to Netflix for more time loop fun

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

    Humans

    13 April 2022

    Visit
    Don’t Adjust Your Mindset by artist Pete McKee welcomes you to a futuristic Great(ish) Britain of lockdown, climate change and digital dependence. Running from 22 April at London’s Hoxton Arches.
    COURTESY OF NETFLIX
    Watch
    Russian Doll returns to Netflix on 20 April for a second season. The highly successful series stars co-creator Natasha Lyonne as Nadia, a woman facing an unusual existential crisis: she is trapped in a time loop on a subway train in Manhattan.Advertisement

    Read
    The Sloth Lemur’s Song haunts Alison Richards’s account, fuelled by more than 50 years of research, of Madagascar’s deep past and uncertain present. This island microcosm is a bellwether for the whole planet. More

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    in Humans

    Crucial research update on ‘exopets’ unveiled

    Josie Ford
    Hunt the exopet
    ‘Twas the season to be jolly’, by which we mean April Fool’s Day has been and gone again, before you get too feisty with your falalalalas. Particularly jolly, Feedback found, was a paper posted to the arXiv preprint server by members of the Astrobites collaboration, “First detections of exop(lan)ets: Observations and follow-ups of the floofiest transits on Zoom”.
    “For more than two years, humanity has been examining new methods of adjusting to work-from-home due to the COVID-19 pandemic. Scientists have tried everything: whipped coffee, sourdough bread, and even questioning whether everything is made out of cake,” the astronomers write. They have possibly also spent too long on video-conferencing platforms, as they continue, “Over two years of casual observation, we noted occasional drops in the brightness of a Zoom image of our far-flung collaborators.”
    But systematic observation brings its own challenges, not least that these transits are less regular than those of exoplanets over the face of their parent star, and – the bane of physicists’ lives everywhere – caused not by conveniently spherical objects, but entities irregular in both shape and colour.Advertisement
    At this point, we should say that these are follow-up observations to those made last year of similar objects found rolling around in the local environment by Laura Mayorga and her colleagues at Johns Hopkins University in their paper “Detection of rotational variability in floofy objects at optical wavelengths”.
    This new analysis of “exopets” inhabiting other homes brings us further, not least in pinning down difficulties observing rarer types, such as Sub-Neptunian Animal Keplerian Extended bodies (SNAKEs) and Dynamically Unstable Coplanar Kepler objects (DUCKs). We salute the creative impetus of lockdown ennui, while fearing this might continue as long as astronomers are trapped on Zoom.
    Absolutely roasting
    As Isaac Asimov wrote – not apropos April, but Shakespeare – the secret of the successful fool is that he is no fool at all. This must be why the US National Weather Service chose 1 April to announce on Twitter: “Big changes to our forecast pages! To avoid any confusion between °F and °C, we’ve converted all of our temperatures to Kelvin. Enjoy!”
    Feedback is a fan of absolutism, at least in the scientific sense, and certainly the daily high and low quoted by the NWS at Indianapolis International Airport, 281 K and 273 K, provide a fairer reflection of the relative benignity of Earth’s surface temperature fluctuations. But we fear this won’t catch on. We ourselves remain fans of what we call the Standard British Mixed Temperature system, in which low temperatures are quoted in Celsius and high temperatures in Fahrenheit, resulting in a handy scale ranging from 0 for cold to 100 for hot. What this loses in logic, it gains in user-friendliness, as long as you don’t worry too much about what happens in the middle. Take an umbrella anyway.
    News from the future
    Feedback joins the world – or everyone in the UK of a certain age or under – in saluting Newsround, the BBC news programme for children that recently celebrated its 50th anniversary and remains for many of us the prime source of trusted news that tells it like it is.
    Richard Glover has the grumps, however, about a story on the Newsround web page claiming that “quantum technology” could be used to charge electric car batteries “in seconds”. “I would have thought that this would be more likely to involve extra wiring and some clever switching, than anything quantum mechanical,” he says.
    Delving into the paper trail so you don’t have to, we discover some enthusiastic press releases and a paper from Juyeon Kim and his colleagues at the Institute for Basic Science in Daejeon, South Korea. The good news is that, whereas the charging time of dull old classical batteries shrinks with the number of battery cells, the charging time of whizzo batteries in an entangled quantum state could decrease with the square of the number of cells. The bad news is that no one yet knows how to put a battery in an entangled quantum state.
    We fear this might not have changed by 2030, when the UK government plans to ban the sale of new petrol and diesel cars. Still, hats off to Newsround for knowing its audience and highlighting a technology that, a bit like nuclear fusion, could well be ready by the time we all grow up.
    Lost and found
    One area where we can already rely on whizzo quantum speed-ups is in algorithms for searching for things. We are put in mind of this by the happy story of the return to Cambridge University Library of two priceless manuscripts written by Charles Darwin, one containing his famous “tree of life” sketch, in a pink gift bag accompanied by a typed note: Librarian, Happy Easter, X.
    Discovered to be missing in 2001, and with various searches of the library’s 10-million-odd items turning up nothing, the books were finally reported as stolen in 2020. This exceeds even the time periods we have spent fruitlessly searching for our keys. Sadly, a practical quantum computer that can ask “Well, where did you last have it?” is probably a good few years away too. Still, won’t the future be marvellous when it comes? And with that: Reader, Happy Easter, X.
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    You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week’s and past Feedbacks can be seen on our website. More