Philippa Kaur

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    in Space & Astronomy

    Watch this beautiful, high-resolution simulation of how stars are born

    The most realistic computer simulation of star formation yet offers stunning views of what the inside of a stellar nursery might look like.

    In the Star Formation in Gaseous Environments simulation, or STARFORGE, a giant virtual cloud of gas collapses into a nest of new stars. Unlike other simulations, which could render only a small clump of gas within a larger cloud, STARFORGE simulates an entire star-forming cloud. It’s also the first simulation to account for the whole medley of physical phenomena thought to influence star formation, researchers report online May 17 in Monthly Notices of the Royal Astronomical Society.

    “We sort of know the basic story of star formation … but the devil is in the details,” says Mike Grudić, a theoretical astrophysicist at Northwestern University in Evanston, Ill. (SN: 4/21/20). Astronomers still don’t fully understand, for instance, why stars have different masses. “If you really want to get the full picture, then you really have to just simulate the whole thing.”

    [embedded content]
    In the computer simulation STARFORGE, a massive cloud of cosmic gas — roughly 20 parsecs, or 65 light-years, across — collapses to form new stars. White areas indicate denser regions of gas, including baby stars. Orange highlights places where there’s lots of variation in the gas motion, such as in powerful jets launched by new stars. Gas shown in purple is more tranquil. After 4.3 million years (Myr) have passed, the simulation pauses so the virtual camera can swoop around the cloud, revealing its 3-D structure.

    STARFORGE starts with a blob of gas that can be tens to hundreds of light-years across and up to millions of times the mass of the sun. Turbulence inside the cloud creates dense pockets that collapse to forge new stars. Those stars then launch powerful jets, give off radiation, shed stellar winds and explode in supernovas. Eventually, these phenomena blow the last vestiges of the cloud away and leave behind a hive of young stars. The whole process takes millions of years — or months of computing time, even running on supercomputers.

    Using STARFORGE, Grudić and colleagues have confirmed that jets launched by new stars help regulate how much material a star amasses. In simulations without jets, typical stars were about 10 times the mass of the sun — way bigger than the actual average star. “As soon as you add this jet feedback to your simulation,” Grudić says, “stellar masses start coming out more or less right on the dot for what they’re observed to be.”

    The STARFORGE simulation has helped confirm that jets launched by newborn stars (simulated one shown) determine how much mass stars can accrete.Northwestern University, University of Texas at Austin

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    in Humans

    Don't Miss: Netflix original anime Eden is a sci-fantasy with robots

    CBBC Don’t Blame Me, Blame My Brain
    Watch
    Don’t Blame Me, Blame My Brain is a children’s show on CBBC, fuelled by unusual, out-there questions. Is it possible to catapult yourself to the moon? Or talk to dogs? Comedians Ken Cheng and Leila Navabi have answers – maybe.

    Read
    Shape: The hidden geometry of absolutely everything helps explain important ideas and problems, according to its author, maths whizz Jordan Ellenberg. These include everything from the spread of the coronavirus to the rise of machine learning.
    Netflix
    Watch
    Eden is the name of a city built by machines after humanity’s fall in Netflix’s new anime series. When two robots discover a human girl while on a routine assignment, they decide to bring her up in secret. Released on 27 May. More

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    in Humans

    In Silico review: The ambitious project to recreate the human brain

    By Simon Ings

    A virtual model of a mouse neocortex seen in In SilicoCourtesy of Sandbox Films
    In Silico
    Noah Hutton

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    SHORTLY after gaining a neuroscience degree, young film-maker Noah Hutton fell into the orbit of Henry Markram, a neuroscientist based at the Swiss Federal Institute of Technology in Lausanne.
    Markram models brains in all their complexity. His working assumption is that since the brain is an organ, a sufficiently good computer model ought to reveal its workings, just as “in-silico” models of kidneys, livers and hearts enrich our under standing.
    The world is filled with people who seem to think in different ways. Much as we might want to understand this full diversity, no one is going to dig about in a living human. Markram hopes that a computer model will offer an ethically acceptable route.
    So far, so reasonable. Except that, in 2009, Markram said he would build a working computer model of the brain in 10 years. This was during a TED talk about his Blue Brain Project (BBP), set up in 2005 to model the mouse brain.
    Every year for well over a decade, Hutton interviewed Markram, his colleagues and his critics as the project expanded and the deadline shifted. Hutton’s film, In Silico, is the result.
    Markram’s vision transfixed purseholders across the European Union: in 2013, he won €1 billion of public cash to set up the Human Brain Project (HBP).
    “It is within our power to model some organs. But the brain isn’t an organ in the usual sense”
    Although his tenure at its Geneva headquarters didn’t last long, Markram is hardly the first founder to be wrested from the controls of their institute. His BBP endures: its in-silico model of the mouse neocortex is visually astounding.
    Perhaps that is the problem. In a voice-over, Hutton says the HBP has become a special-effects house, a shrine to touchscreens and VR headsets, but lacks meaning “outside this glass and steel building in Geneva”.
    We have heard such criticisms before. What about how the CERN particle physics lab sucks funds from the rest of physics? There is no shortage of disgruntled junior researchers blaming it for failed grant applications. CERN, however, gets results; HBP, not so much.
    The problem runs deep. It is within our power to model some organs, but the brain isn’t an organ in the usual sense. By any engineering measure, it looks inefficient. A spike in the neurons can trigger the release of this neurotransmitter, except when it releases another one – or does nothing. There is bound to be some commonality in brain anatomy, but so far research shows that every brain is like a beautiful, unique snowflake.
    The HBP’s models generate noise, just like real brains. In the film, there is a vague mention of “emergent properties”. Yet linking that noise to brain activity is an intellectual Get Out of Jail Free card if ever there was one: no one knows what this noise means, so there is no way to tell if the model is making the right noise.
    Deep learning guru Terrence Sejnowski, who is based at the Salk Institute for Biological Studies in California, tells Hutton that the whole caper is a bad joke – if successful, Markram will only generate a simulation “every bit as mysterious as the brain itself”.
    Hutton accompanies us into the yawning gap between Markram’s reasonable ambitions and the promises he makes to attract funds. It is a film made on a budget of nothing, and it isn’t pretty. But Hutton makes up for all that with the sharpest of scripts.

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    Inception
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    Cobb (Leonardo DiCaprio) is out to steal from your mind in a groundbreaking sci-fi flick that gave Freudian psychoanalytic theory a jaw-dropping CGI makeover.

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    in Humans

    How the way you move can change the way you think and feel

    New research suggests the connection between exercise and the brain goes deeper than you might think. These six kinds of movement can help make you more creative, boost your self-esteem and reach altered states of consciousness

    Health

    19 May 2021

    By Caroline Williams

    Sergio Membrillas
    FILTER-FEEDERS aside, humans are the only creatures that can get away with sitting around all day. As a species, we have been remarkably successful at devising ways to feed, entertain ourselves and even find mates, all while barely lifting a finger.
    True, this is a sign of just how clever and adaptable we are. But there is a huge cost to our sedentary ways, not only to our bodies, but also our minds. Falling IQs and the rise in mental health conditions have both been linked to our lack of physical movement.
    But the connection between movement and the brain goes deeper than you might think. A revolutionary new understanding of the mind-body connection is revealing how our thoughts and emotions don’t just happen inside our heads, and that the way we move has a profound influence on how our minds operate. This opens up the possibility of using our bodies as tools to change the way we think and feel.
    Evidence is starting to stack up that this is indeed the case, and it isn’t all about doing more exercise. In my new book, Move! The new science of body over mind, I explore emerging research in evolutionary biology, physiology, neuroscience and cell biology to find out which body movements affect the mind and why.
    Whatever it is that you want from your mind – more creativity, improved resilience or higher self-esteem – the evidence shows that there is a way of moving the body that can help. Here is my pick of the best ways to use your body to achieve a healthier, better-functioning mind.
    Get on your … More

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    in Humans

    Did you know? Laughing gas may have ended the last glacial period

    By Alexander McNamara
    and Matt Hambly

    Monica Bertolazzi/Getty Images
    Laughing gas, otherwise known as nitrous oxide, has been used as an anaesthetic since the 19th century. These days, it is most commonly found in small, steel cartridges sold to the catering industry for making whipped cream. However, nitrous oxide is also a potent greenhouse gas and ozone-depleting chemical. Although it is present in the atmosphere at much lower concentrations than carbon dioxide – just 330 parts per billion – it has 300 times the heat-trapping capability. Indeed, a pulse of nitrous oxide released from plants 14,500 years ago may have hastened the end of the last glaciation.
    We don’t necessarily yawn because we are tired
    Gints Ivuskans / Alamy
    We tend to think of yawning as a sign of being tired or bored. That probably explains the popular perception that it is a way to get more oxygen into the blood to increase alertness. However, psychologist Robert Provine at the University of Maryland tested this idea and found people were just as likely to yawn when breathing air high in oxygen. A closer look at when people yawn suggests another explanation. It turns out that most spontaneous yawning actually happens when we are limbering up for activity such as a workout, performance or exam, or simply when we wake up. That has led to the idea that yawning helps us gear up by increasing blood flow to the brain.

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    The placebo effect can depend on whether a pill is colourful
    Derek Croucher / Alamy
    The placebo effect is the mysterious reduction in a patient’s medical symptoms via the power of suggestion or expectation, the cause of which remains unexplained. However, what we do know is that a number of different factors can affect the power of the placebo effect. It can be triggered by administering pills, injections or surgery, or even just an authority figure assuring a patient that a treatment will be effective. In fact, experiments have shown that the power of the placebo effect depends on surprising factors like the appearance of tablets. For example, colourful pills work better as a placebo than white ones.
    Some people can taste music
    Anna Bizon / Alamy
    Forget feeling the music, some of us can actually taste it. Around one in 20 of us have synaesthesia, a condition that creates a strange connection between our senses. For these people, words may take on certain colours and music may have a particular taste or texture.
    Although we aren’t certain of the causes of this unusual condition, studies have given us some idea of what is happening. As infants, our brains’ cells have millions of connections that are pruned away as we get older. Some studies suggest that people with synaesthesia have genetic variations that prevent this pruning from happening normally in certain brain regions, giving them unusual connections between sensory areas.
    Being stronger reduces your risk of death
    Javier Sanchez Mingorance / Alam
    Here’s the motivation you need for your next trip to the gym: having stronger muscles reduces the risk of dying of any cause, and is especially important in preventing type-2 diabetes, cardiovascular disease and cancer. Broadly speaking, exercise of any kind is good for you, but unlike aerobic fitness regimes, strength training also helps to build bone, which can decrease your risk of osteoporosis. It can even help to prevent cognitive decline and memory loss in old age. Maintaining and improving your strength throughout life has become such an important, yet forgotten, aspect of general fitness that the UK government recently placed it above aerobic exercise in its new guidelines.
    We have 19 different smiles but only one is ‘genuine’
    Superb Images/Getty Images
    The 42 facial muscles it takes to break out into a grin are capable of producing 19 different types of smile, but, according to French anatomist Duchenne de Boulogne, only one is ‘genuine’. In 1862 Duchenne identified that the difference between a genuine smile and a fake one lay in the eyes — the orbicularis oculi — to be precise. All smiling involves contraction of the zygomatic major muscles, which lifts the corners of the mouth. But a Duchenne smile is characterised by the additional contraction of the orbicularis oculi, crumpling the skin around the eyes into crows’ feet. Largely overlooked at the time, the Duchenne smile’s reputation has grown. In the 1950s a study found that Duchenne smilers had a 70 per cent chance of living until age 80 compared with 50 per cent for non-smilers. However, more recent findings have suggested that smiles don’t necessarily indicate that we are happy, but instead signal collaboration or bonding.

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    in Space & Astronomy

    The Milky Way may have grown up faster than astronomers suspected

    The Milky Way as we know it today was shaped by a collision with a dwarf galaxy about 10 billion years ago. But most of the modern galaxy was already in place even at that early date, new research shows.

    Ages of stars left behind by the galactic interloper are a bit younger or on par with stars in the Milky Way’s main disk, researchers report May 17 in Nature Astronomy. And that could mean that the Milky Way grew up faster than astronomers expected, says study author Ted Mackereth, an astrophysicist at the University of Toronto.

    “The Milky Way had already built up a lot of itself before this big merger happened,” he says.

    Our galaxy’s history is one of violent conquest. Like other giant spiral galaxies in the universe, the Milky Way probably built up its bulk by colliding and merging with smaller galaxies over time. Stars from the unfortunate devoured galaxies got mixed into the Milky Way like cream into coffee, making it difficult to figure out what the galaxies were like before they merged.

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    In 2018, astronomers realized that they could identify stars from the last major merger using detailed maps of several million stars from the European Space Agency’s Gaia spacecraft (SN: 5/9/18). Streams of stars orbit the galactic center at an angle to the main disk of stars. Those stars’ motions and chemistries suggest they once belonged to a separate galaxy that plunged into the Milky Way about 10 billion years ago (SN: 11/1/2018).

    “Those stars are left there like fossil remnants of the galaxy,” Mackereth says.

    Two groups discovered evidence of the ancient galaxy at around the same time. One called the galaxy Gaia-Enceladus; the other group called it the Sausage. The name that stuck was Gaia-Enceladus/Sausage.

    Mackereth and his colleagues wondered if they could figure out how well developed the Milky Way was when Gaia-Enceladus/Sausage came crashing in. If the oldest stars in the Milky Way’s disk formed after this merger, then they probably formed as a result of this collision, suggesting that Gaia-Enceladus/Sausage met a proto–Milky Way that still had a lot of growing up to do. On the other hand, if the oldest stars are about the same age or older than the stars from the galactic interloper, then our galaxy was probably pretty well developed at the time of the run-in. 

    Previous researchers had made estimates. But Mackereth and his colleagues used a precise tool called asteroseismology to figure out the ages of individual stars from both the Milky Way and from Gaia-Enceladus/Sausage (SN: 8/2/19). Just like seismologists on Earth use earthquakes to probe the interior of our planet, asteroseismologists use variations in brightness caused by starquakes and other oscillations to probe the innards of stars.

    “Asteroseismology is the only way we have to access the internal part of the stars,” says physicist and study coauthor Josefina Montalbán of the University of Birmingham in England. From intel on the star’s interior structures, researchers can deduce the stars’ ages.

    The team selected about 95 stars that had been observed by NASA’s exoplanet-hunting Kepler space telescope, which ended its mission in 2018 (SN: 10/30/18). Six of those stars were from Gaia-Enceladus/Sausage, and the rest were from the Milky Way’s thick disk. By measuring how the brightnesses of those stars fluttered over time, Mackereth and colleagues deduced ages with about 11 percent precision.

    The Gaia-Enceladus/Sausage stars are slightly younger than the Milky Way stars, but all were pretty close to 10 billion years old, the team found. That suggests that a large chunk of the Milky Way’s disk was already in place when Gaia-Enceladus/Sausage came crashing through. It’s still possible that the incoming galaxy sparked the formation of some new stars, though, Mackereth says. To tell how much, they’ll need to get ages of a lot more stars.

    Measuring ages for individual stars represents a step forward for galactic astronomy, says astrophysicist Tomás Ruiz-Lara of the University of Groningen, the Netherlands, who studies galactic evolution but was not involved in the new work.

    “If you cannot tell the difference between a kid and a teenager and an adult, then we cannot say anything” about a population of people, Ruiz-Lara says. “But if I can distinguish between someone in his 40s or her 50s, you have a better graph of society. With the stars, it’s the same. If we are able to distinguish the age properly, then we can distinguish individual events in the history of the galaxy. In the end, that’s the goal.” More

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    in Space & Astronomy

    A study of Earth’s crust hints that supernovas aren’t gold mines

    A smattering of plutonium atoms embedded in Earth’s crust are helping to resolve the origins of nature’s heaviest elements.

    Scientists had long suspected that elements such as gold, silver and plutonium are born during supernovas, when stars explode. But typical supernovas can’t explain the quantity of heavy elements in our cosmic neighborhood, a new study suggests. That means other cataclysmic events must have been major contributors, physicist Anton Wallner and colleagues report in the May 14 Science.

    The result bolsters a recent change of heart among astrophysicists. Standard supernovas have fallen out of favor. Instead, researchers think that heavy elements are more likely forged in collisions of two dense, dead stars called neutron stars, or in certain rare types of supernovas, such as those that form from fast-spinning stars (SN: 5/8/19).

    Heavy elements can be produced via a series of reactions in which atomic nuclei swell larger and larger as they rapidly gobble up neutrons. This series of reactions is known as the r-process, where “r” stands for rapid. But, says Wallner, of Australian National University in Canberra, “we do not know for sure where the site for the r-process is.” It’s like having the invite list for a gathering, but not its location, so you know who’s there without knowing where the party’s at.

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    Scientists thought they had their answer after a neutron star collision was caught producing heavy elements in 2017 (SN: 10/16/17). But heavy elements show up in very old stars, which formed too early for neutron stars to have had time to collide. “We know that there has to be something else,” says theoretical astrophysicist Almudena Arcones of the Technical University of Darmstadt, Germany, who was not involved with the new study.

    If an r-process event had recently happened nearby, ­some of the elements created could have landed on Earth, leaving fingerprints in Earth’s crust. Starting with a 410-gram sample of Pacific Ocean crust, Wallner and colleagues used a particle accelerator to separate and count atoms. Within one piece of the sample, the scientists searched for a variety of plutonium called plutonium-244, which is produced by the r-process. Since heavy elements are always produced together in particular proportions in the r-process, plutonium-244 can serve as a proxy for other heavy elements. The team found about 180 plutonium-244 atoms, deposited into the crust within the last 9 million years.

    Scientists analyzed a sample of Earth’s deep-sea crust (shown) to search for atoms of plutonium and iron with cosmic origins.Norikazu Kinoshita

    Researchers compared the plutonium count to atoms that had a known source. Iron-60 is released by supernovas, but it is formed by fusion reactions in the star, not as part of the r-process. In another, smaller piece of the sample, the team detected about 415 atoms of iron-60.

    Plutonium-244 is radioactive, decaying with a half-life of 80.6 million years. And iron-60 has an even shorter half-life of 2.6 million years. So the elements could not have been present when the Earth formed, 4.5 billion years ago. That suggests their source is a relatively recent event. When the iron-60 atoms were counted up according to their depth in the crust, and therefore how long ago they’d been deposited, the scientists saw two peaks at about 2.5 million years ago and at about 6.5 million years ago, suggesting two or more supernovas had occurred in the recent past.

    The scientists can’t say if the plutonium they detected also came from those supernovas. But if it did, the amount of plutonium produced in those supernovas would be too small to explain the abundance of heavy elements in our cosmic vicinity, the researchers calculated. That suggests regular supernovas can’t be the main source of heavy elements, at least nearby.  

    That means other sources for the r-process are still needed, says astrophysicist Anna Frebel of MIT, who was not involved with the research. “The supernovae are just not cutting it.”

    The measurement gives a snapshot of the r-process in our corner of the universe, says astrophysicist Alexander Ji of Carnegie Observatories in Pasadena, Calif. “It’s actually the first detection of something like this, so that’s really, really neat.” More

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    in Humans

    Isotope study hints ancient Greeks used foreign fighters in key battle

    By Krista Charles

    The Temple of Victory at Himera, Sicily, constructed after the first Battle of Himera in 480 BCKatherine Reinberger
    The ancient Greeks relied on help from non-Greek mercenaries when it came to fighting their enemies, suggests an analysis of bodies in 2500-year-old mass graves.
    The western Mediterranean witnessed several conflicts between about 2600 and 2300 years ago as a number of Greek-led city-states – including Syracuse on the island of Sicily – fought against the Carthaginians, whose base of power lay in what is now Tunisia. The Sicilian wars were documented by contemporary writers, including Herodotus in his book The Histories. But given that Herodotus was Greek, it is possible that his accounts of the conflicts may have been biased to paint the Greek fighters in a favourable light.

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    In particular, Herodotus suggests that in 480 BC, during the first Battle of Himera, local soldiers received aid from other Greek allies and successfully defeated the Carthaginians. But during a second battle in 409 BC, the local soldiers went unaided and the city of Himera fell to the Carthaginians.
    Following the recent discovery of eight mass graves associated with the Battles of Himera, it is now possible to explore whether Herodotus’s account was faithful or not.
    Katherine Reinberger at the University of Georgia and her colleagues analysed strontium and oxygen isotopes from the tooth enamel of 62 individuals from the mass graves, which can reveal whether someone was born and raised locally or not.

    The team’s analysis revealed that some historical claims could be validated – there were two battles, about two thirds of the Himeran forces in the first conflict weren’t local while only a quarter in the second battle weren’t from there, and Greek soldiers from outside of the city did fight alongside local Himerans. But the contemporary accounts weren’t entirely accurate: the isotope evidence suggests that many of the non-local soldiers weren’t actually Greek, but came from across the Mediterranean.
    “Finding evidence of people who were foreign and maybe not even Greek is unusual and interesting and sort of indicates that maybe ancient communities, and definitely ancient armies, could have been more diverse than we originally thought,” says Reinberger. These foreign soldiers might have been hired mercenaries, she says.
    “Isotopic studies suggest that these could have been people hired all the way from the Catalan coast, from the Iberian peninsula, or from mainland Greece or even from the Black Sea coast,” says Mario Novak at the Institute for Anthropological Research in Croatia.
    “So, this could have been either Greeks but also some Indigenous people that classical sources considered barbarians. Obviously, these ‘barbarians’ were much more incorporated into the everyday lives of the “proper” Greeks than previously thought,” he says.
    The team theorises that historical accounts downplayed the involvement of foreign mercenaries in order to create a more Greek-centric narrative and align the victory of the first battle with Greek successes against other forces they were facing at the time, including the Persians under Xerxes the Great.
    Journal reference: PLoS One, DOI: 10.1371/journal.pone.0248803
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