The Guardian reports: It is one of cosmology’s more perplexing problems: that up to 90% of the ordinary matter in the universe appears to have gone missing.
Now astronomers have detected about half of this missing content for the first time, in a discovery that could resolve a long-standing paradox.
The conundrum first arose from measurements of radiation left over from the Big Bang, which allowed scientists to calculate how much matter there is in the universe and what form it takes. This showed that about 5% of the mass in the universe comes in the form of ordinary matter, with the rest being accounted for by dark matter and dark energy.
Dark matter has never been directly observed and the nature of dark energy is almost completely mysterious, but even tracking down the 5% of ordinary stuff has proved more complicated than expected. When scientists have counted up all the observable objects in the sky – stars, planets, galaxies and so on – this only seems to account for between a 10th and a fifth of what ought to be out there.
The deficit is known as the “missing baryon problem”, baryons being ordinary subatomic particles like protons and neutrons.
Richard Ellis, a professor of astrophysics at the University College London, said: “People agree that there’s a lot missing, raising the question where is it?” [Continue reading…]
NOAA scientists caught sight of it last year near the mouth of the Mariana’s Sirena Deep. It isn’t an isolated incursion, but it was nevertheless startling, the sight of those timeless golden letters bright against the deep ocean bottom.
Shortly after came news from another team of scientists who had found in the Mariana an innovation less familiar than shelf-stable meat, but far more significant. In the bodies of deep-dwelling creatures were found traces of industrial chemicals responsible for the rise of modern America—polychlorinated biphenyls.
PCBs had been detected in Hirondellea gigas, tiny shrimp-like amphipods scooped up by deepwater trawlers. Results from the expedition, led by Newcastle University’s hadal-zone expert Alan Jamieson, were preliminary released last year and then published in February.
PCBs have been found the world over—from the bed of the Hudson River to the fat of polar bears roaming the high Arctic—but never before in the creatures of the extreme deep, a bioregion about which science knows relatively little.
How PCBs reached the Mariana is still under investigation. Jamieson and colleagues speculated on multiple, regional sources. A nearby military base. The industrial corridors along the Asian coastline. And the Great Pacific Garbage Patch, where PCBs glom onto plastic particles caught in the current. Over time, the plastic degrades and descends into the depths, ferrying PCBs with them.
But the true origin of PCBs lies in another time and place, in Depression-era Alabama, and before that, 19th-century Germany at the pinnacle of German chemistry. [Continue reading…]
Jordan Ellenberg writes: About as many Democrats live in Wisconsin as Republicans do. But you wouldn’t know it from the Wisconsin State Assembly, where Republicans hold 65 percent of the seats, a bigger majority than Republican legislators enjoy in conservative states like Texas and Kentucky.
The United States Supreme Court is trying to understand how that happened. On Tuesday, the justices heard oral arguments in Gill v. Whitford, reviewing a three-judge panel’s determination that Wisconsin’s Republican-drawn district map is so flagrantly gerrymandered that it denies Wisconsinites their full right to vote. A long list of elected officials, representing both parties, have filed briefs asking the justices to uphold the panel’s ruling.
Other people don’t see a problem. Politics, they say, is a game where whoever’s ahead gets to change the rules on the fly. It’s about winning, not being fair.
But this isn’t just a politics story; it’s also a technology story. Gerrymandering used to be an art, but advanced computation has made it a science. Wisconsin’s Republican legislators, after their victory in the census year of 2010, tried out map after map, tweak after tweak. They ran each potential map through computer algorithms that tested its performance in a wide range of political climates. The map they adopted is precisely engineered to assure Republican control in all but the most extreme circumstances. [Continue reading…]
Andrea Wulf writes: In late 1849, two years after Henry David Thoreau left Walden Pond—where he had lived for two years, two months, and two days in a cabin that he had built himself—he began the process of completely reorienting his life again. His hermit-style interlude at the pond had attracted quite a bit of attention in his hometown of Concord, Massachusetts. “Living alone on the pond in ostentatious simplicity, right in sight of a main road,” his latest biographer, Laura Dassow Walls, writes, “he became a spectacle,” admired by some and belittled by others. Thoreau’s subsequent life change was less conspicuous. Yet it engaged him in a quest more enlightening and relevant today than the proud asceticism he flaunted throughout Walden, a book that has never ceased to inspire reverence or provoke contempt.
What the 32-year-old Thoreau quietly did in the fall of 1849 was to set up a new and systematic daily regimen. In the afternoons, he went on long walks, equipped with an array of instruments: his hat for specimen-collecting, a heavy book to press plants, a spyglass to watch birds, his walking stick to take measurements, and small scraps of paper for jotting down notes. Mornings and evenings were now dedicated to serious study, including reading scientific books such as those by the German explorer and visionary thinker Alexander von Humboldt, whose Cosmos (the first volume was published in 1845) had become an international best seller.
As important, Thoreau began to use his own observations in a new way, intensifying and expanding the journal writing that he’d undertaken shortly after graduating from Harvard in 1837, apparently at Ralph Waldo Emerson’s suggestion. In the evening, he often transferred the notes from his walks into his journal, and for the rest of his life, he created long entries on the natural world in and around Concord. Thoreau was staking out a new purpose: to create a continuous, meticulous documentary record of his forays. Especially pertinent two centuries after his birth, in an era haunted by inaction on climate change, he worried over a problem that felt personal but was also spiritual and political: how to be a rigorous scientist and a poet, imaginatively connected to the vast web of natural life. [Continue reading…]
Paul Lewis writes: Justin Rosenstein had tweaked his laptop’s operating system to block Reddit, banned himself from Snapchat, which he compares to heroin, and imposed limits on his use of Facebook. But even that wasn’t enough. In August, the 34-year-old tech executive took a more radical step to restrict his use of social media and other addictive technologies.
Rosenstein purchased a new iPhone and instructed his assistant to set up a parental-control feature to prevent him from downloading any apps.
He was particularly aware of the allure of Facebook “likes”, which he describes as “bright dings of pseudo-pleasure” that can be as hollow as they are seductive. And Rosenstein should know: he was the Facebook engineer who created the “like” button in the first place.
A decade after he stayed up all night coding a prototype of what was then called an “awesome” button, Rosenstein belongs to a small but growing band of Silicon Valley heretics who complain about the rise of the so-called “attention economy”: an internet shaped around the demands of an advertising economy.
These refuseniks are rarely founders or chief executives, who have little incentive to deviate from the mantra that their companies are making the world a better place. Instead, they tend to have worked a rung or two down the corporate ladder: designers, engineers and product managers who, like Rosenstein, several years ago put in place the building blocks of a digital world from which they are now trying to disentangle themselves. “It is very common,” Rosenstein says, “for humans to develop things with the best of intentions and for them to have unintended, negative consequences.” [Continue reading…]
Yuval Noah Harari writes: Though human beings are social animals, for millions of years they lived in small, intimate communities numbering no more than a few dozen people. Even today, as the evolutionary biologist Robin Dunbar has shown, most human beings find it impossible properly to know more than 150 individuals, irrespective of how many Facebook “friends” they boast. Human beings easily develop loyalty to small, intimate groups such as a tribe, an infantry company or a family business, but it is hardly natural for them to be loyal to millions of strangers. Such mass loyalties have appeared only in the past few thousand years as a means of solving practical problems that no single tribe could solve by itself. Ancient Egypt was created to help human beings gain control of the River Nile, and ancient China coalesced to help the people restrain the turbulent Yellow River.
Nations solved some problems and created new ones. In particular, big nations led to big wars. Yet people were willing to pay the price in blood, because nations provided them with unprecedented levels of security and prosperity. In the 19th and early 20th centuries the nationalist deal still looked very attractive. Nationalism was leading to horrendous conflicts on an unprecedented scale, but modern nation states also built systems of health care, education and welfare. National health services made Passchendaele and Verdun seem worthwhile.
Yet the invention of nuclear weapons sharply tilted the balance of the deal. After Hiroshima, people no longer feared that nationalism would lead to mere war: they began to fear it would lead to nuclear war. Total annihilation has a way of sharpening people’s minds, and thanks in no small measure to the atomic bomb, the impossible happened and the nationalist genie was squeezed at least halfway back into its bottle. Just as the ancient villagers of the Yellow River Basin redirected some of their loyalty from local clans to a much bigger nation that restrained the dangerous river, so in the nuclear age a global community gradually developed over and above the various nations because only such a community could restrain the nuclear demon.
In the 1964 US presidential campaign, Lyndon B Johnson aired the “Daisy” advertisement, one of the most successful pieces of propaganda in the annals of television. The advert opens with a little girl picking and counting the petals of a daisy, but when she reaches ten, a metallic male voice takes over, counting back from ten to zero as in a missile launch countdown. Upon it reaching zero, the bright flash of a nuclear explosion fills the screen, and Candidate Johnson addresses the American public: “These are the stakes – to make a world in which all of God’s children can live, or to go into the dark. We must either love each other. Or we must die.” We often associate the slogan “Make love, not war” with the late-1960s counterculture, but already in 1964 it was accepted wisdom, even among hard-nosed politicians such as Johnson. [Continue reading…]
Nathaniel Scharping reports: The advent of tools was a big deal for humanity. It made it far easier to manipulate our environment and mold the planet to serve our own interests—from the folsom point to the iPhone X.
Some animals use tools too, like the macaques of Thailand, who have figured out that their favorite shellfish snacks are much easier to eat if they bash them open with rocks first. They’ve become proficient shellfish smashers, so much so that the macaques are actually threatening the existence of oysters and snails an a small island there. It’s a tale of technology gone wrong — only this time, humans aren’t the villains.
Researchers from Thailand, Europe and Australia looked at two groups of long-tailed macaques on separate islands off the Thai coast. The two locations, both alike in shellfish populations, differed only in the number of macaques there. Koram is host to around 80 primates, while NomSao has but nine. Both groups have figured out how to use rocks to break open shellfish armor, behavior that has been observed among other groups of macaques in Thailand.
On Koram, though, the abundance of tool-wielding macaques has led to a crisis of sorts. In a paper published last week in the journal eLife, the researchers estimate that a single individual on the island slurps down 47 shellfish a day, mostly oysters. For the mere 26 macaques that the researchers studied, that works out to 441,000 a year. Looking at periwinkles, a small sea snail, the researchers estimated that the monkeys could eat the entire island’s population in just a year. On NomSao, the much smaller group eats only about an eighth of the available periwinkle population. [Continue reading…]
Space.com reports: After examining Saturn from up close for 13 years, the Cassini spacecraft is ending its long career with a boom — and there’s an important reason why.
Friday morning (Sept. 15), Cassini will complete the orbital pirouettes of its seven-year Solstice Mission and complete a self-destructing descent into Saturn’s atmosphere. This fierce ending is dramatic for a purpose: It will prevent Earth microbes from contaminating Saturn’s nearby moons.
When NASA’s Cassini spacecraft completed its first tour of Saturn in 2008, the mission team had to decide what would come next. [Cassini’s Saturn Crash 2017: How to Watch Its ‘Grand Finale’]
Cassini could have parted ways with the ringed planet. In 2009, studies showed that Cassini had enough fuel to reach Uranus or Neptune. Cassini could have traveled in the other direction, toward Jupiter, or it could have been sent to visit an assembly of asteroids known as the Centaurs in the outer limits of the solar system.
Instead, scientists chose to continue making discoveries about Saturn and its moons — first through a two-year extended mission known as the Cassini Equinox Mission, and then with a second extension in 2010 that would bring the spacecraft to the very limit of the fuel it carried. That made it clear that Cassini’s third mission, the Solstice Mission, would be how the spacecraft would end its career. It was during these missions that scientists discovered that two of Saturn’s moons, Titan and Enceladus, showed signs that they were well suited to life. But why the fiery plummet?
“The spacecraft will burn up and disintegrate like a meteor in the upper atmosphere of Saturn,” Preston Dyches, of NASA’s Jet Propulsion Laboratory (JPL), told Space.com via email. “This was determined to be the best way to ensure the safe disposal of the spacecraft, so that there would be no chance of future contamination of Enceladus by any hardy microbes that might have stowed away on board all these years.” [Continue reading…]
The Associated Press reports: Pope Francis has sharply criticized climate change doubters, saying history will judge those who failed to take the necessary decisions to curb heat-trapping emissions blamed for the warming of the Earth.
Francis was asked about climate change and the spate of hurricanes that have pummeled the U.S., Mexico and the Caribbean recently as his charter plane left Colombia on Sunday and flew over some of the devastated areas.
“Those who deny this must go to the scientists and ask them. They speak very clearly,” he said, referring to experts who blame global warming on man-made activities.
Francis said scientists have also clearly charted what needed to be done to reverse course on global warming and said individuals and politicians had a “moral responsibility” to do their part.
“These aren’t opinions pulled out of thin air. They are very clear,” he said. “Then they (leaders) decide and history will judge those decisions.”
Francis has made caring for the environment a hallmark of his papacy, writing an entire encyclical about how the poor in particular are most harmed when multinationals move into exploit natural resources. During his visit to Colombia, Francis spoke out frequently about the need to preserve the country’s rich biodiversity from overdevelopment and exploitation.
For those who have denied climate change, or delayed actions to counter it, he responded with an Old Testament saying: “Man is stupid.”
“When you don’t want to see, you don’t see,” he said.
In an editorial, the New York Times says: The news was hard to digest until one realized it was part of a much larger and increasingly disturbing pattern in the Trump administration. On Aug. 18, the National Academies of Sciences, Engineering and Medicine received an order from the Interior Department that it stop work on what seemed a useful and overdue study of the health risks of mountaintop-removal coal mining.
The $1 million study had been requested by two West Virginia health agencies following multiple studies suggesting increased rates of birth defects, cancer and other health problems among people living near big surface coal-mining operations in Appalachia. The order to shut it down came just hours before the scientists were scheduled to meet with affected residents of Kentucky.
The Interior Department said the project was put on hold as a result of an agencywide budgetary review of grants and projects costing more than $100,000.
This was not persuasive to anyone who had been paying attention. From Day 1, the White House and its lackeys in certain federal agencies have been waging what amounts to a war on science, appointing people with few scientific credentials to key positions, defunding programs that could lead to a cleaner and safer environment and a healthier population, and, most ominously, censoring scientific inquiry that could inform the public and government policy. [Continue reading…]
The Guardian reports: An enormous black hole one hundred thousand times more massive than the sun has been found hiding in a toxic gas cloud wafting around near the heart of the Milky Way.
If the discovery is confirmed, the invisible behemoth will rank as the second largest black hole ever seen in the Milky Way after the supermassive black hole known as Sagittarius A* that is anchored at the very centre of the galaxy.
Astronomers in Japan found evidence for the new object when they turned a powerful telescope in the Atacama desert in Chile towards the gas cloud in the hope of understanding the strange movement of its gases. Unlike those that make up other interstellar clouds, the gases in this cloud – including hydrogen cyanide and carbon monoxide – move at wildly different speeds.
Observations from the Alma telescope in Chile showed that molecules in the elliptical cloud, which is 200 light years from the centre of the Milky Way and 150 trillion kilometres wide, were being pulled around by immense gravitational forces. The most likely cause, according to computer models, was a black hole no more than 1.4 trillion km across. [Continue reading…]
Tyler Nordgren writes: As a kid visiting the Oregon coast I often wondered, “How wide is the ocean, and what is there beyond the horizon?” As I grew older and turned my sights to the night sky, I wondered something very similar: “How far away are the stars, and are there other planets there?” Even though very few of us have ever circumnavigated the globe, and no human being has ever ventured into space beyond the moon, we do know some of the answers to these questions. Immensity isn’t immeasurable. While these vast numbers may make little sense in our daily lives, we at least know they are known.
Consider what it must have been like to live in a world where this was not true: where the sense of immeasurability, the certainty of the unfathomable, was commonplace, and the thought that the world could be known was a novel idea. The philosopher Anaxagoras was born in about 500 B.C. in the eastern Mediterranean on what is now the coast of Turkey. It was a time when philosophy had only recently turned its attention to the natural world. Less than a hundred years before, Thales of Miletus supposedly predicted the solar eclipse that ended a war, thus implying that our world was predictable and events were not just the random whims of the gods.
In such a world of physical phenomena, Anaxagoras was the first, as far as we know, to understand that eclipses occur when one heavenly body blocks the light from another. This rejection of gods and dragons as the causes of eclipses was a revolutionary thought by itself, but Anaxagoras took it further: If solar eclipses happened only because the Earth had moved into the shadow of the moon, he reasoned, then the size of the shadow must tell us something about the size of the moon. Additionally, since the moon covered the sun, the sun must be farther away. Yet to appear nearly the same size, the sun must be larger than the moon. Herein lies the power of scientific thought: Measure the extent of the shadow sweeping across the Earth, and you know the moon must be at least as big as the shadow, and the sun larger still. Mysticism provided no such opportunity: If eclipses occur when a demon devours the sun, there is no reason to believe that any measurement we make here on Earth should reveal the demon’s size.[Continue reading…]
Science News reports: The moon had a magnetic field for at least 2 billion years, or maybe longer.
Analysis of a relatively young rock collected by Apollo astronauts reveals the moon had a weak magnetic field until 1 billion to 2.5 billion years ago, at least a billion years later than previous data showed. Extending this lifetime offers insights into how small bodies generate magnetic fields, researchers report August 9 in Science Advances. The result may also suggest how life could survive on tiny planets or moons.
“A magnetic field protects the atmosphere of a planet or moon, and the atmosphere protects the surface,” says study coauthor Sonia Tikoo, a planetary scientist at Rutgers University in New Brunswick, N.J. Together, the two protect the potential habitability of the planet or moon, possibly those far beyond our solar system.
The moon does not currently have a global magnetic field. Whether one ever existed was a question debated for decades (SN: 12/17/11, p. 17). On Earth, molten rock sloshes around the outer core of the planet over time, causing electrically conductive fluid moving inside to form a magnetic field. This setup is called a dynamo. At 1 percent of Earth’s mass, the moon would have cooled too quickly to generate a long-lived roiling interior.
Magnetized rocks brought back by Apollo astronauts, however, revealed that the moon must have had some magnetizing force. The rocks suggested that the magnetic field was strong at least 4.25 billion years ago, early on in the moon’s history, but then dwindled and maybe even got cut off about 3.1 billion years ago. [Continue reading…]
The New York Times reports: The impending release of a key government report on climate change will force President Trump to choose between accepting the conclusions of his administration’s scientists and the demands of his conservative supporters, who remain deeply unconvinced that humans are the cause of the planet’s warming.
A White House official said on Tuesday that it was still reviewing the draft document that was written by scientists, some of whom have said they fear Mr. Trump will seek to bury it or alter its contents before it is formally released. Sarah Huckabee Sanders, the White House press secretary, said the administration would not comment on the report before its scheduled release this fall.
But the looming publication of the climate report — which concludes that “evidence for a changing climate abounds, from the top of the atmosphere to the depths of the oceans” — once again raises a contentious policy issue that has deeply divided Mr. Trump’s closest advisers since he arrived in the Oval Office. [Continue reading…]
Scientific American reports: Neutrinos are famously antisocial. Of all the characters in the particle physics cast, they are the most reluctant to interact with other particles. Among the hundred trillion neutrinos that pass through you every second, only about one per week actually grazes a particle in your body.
That rarity has made life miserable for physicists, who resort to building huge underground detector tanks for a chance at catching the odd neutrino. But in a study published today in Science, researchers working at Oak Ridge National Laboratory (ORNL) detected never-before-seen neutrino interactions using a detector the size of a fire extinguisher. Their feat paves the way for new supernova research, dark matter searches and even nuclear nonproliferation monitoring.
Under previous approaches, a neutrino reveals itself by stumbling across a proton or neutron amidst the vast emptiness surrounding atomic nuclei, producing a flash of light or a single-atom chemical change. But neutrinos deign to communicate with other particles only via the “weak” force—the fundamental force that causes radioactive materials to decay. Because the weak force operates only at subatomic distances, the odds of a tiny neutrino bouncing off of an individual neutron or proton are minuscule. Physicists must compensate by offering thousands of tons of atoms for passing neutrinos to strike. [Continue reading…]
Jean M Twenge writes: One day last summer, around noon, I called Athena, a 13-year-old who lives in Houston, Texas. She answered her phone—she’s had an iPhone since she was 11—sounding as if she’d just woken up. We chatted about her favorite songs and TV shows, and I asked her what she likes to do with her friends. “We go to the mall,” she said. “Do your parents drop you off?,” I asked, recalling my own middle-school days, in the 1980s, when I’d enjoy a few parent-free hours shopping with my friends. “No—I go with my family,” she replied. “We’ll go with my mom and brothers and walk a little behind them. I just have to tell my mom where we’re going. I have to check in every hour or every 30 minutes.”
Those mall trips are infrequent—about once a month. More often, Athena and her friends spend time together on their phones, unchaperoned. Unlike the teens of my generation, who might have spent an evening tying up the family landline with gossip, they talk on Snapchat, the smartphone app that allows users to send pictures and videos that quickly disappear. They make sure to keep up their Snapstreaks, which show how many days in a row they have Snapchatted with each other. Sometimes they save screenshots of particularly ridiculous pictures of friends. “It’s good blackmail,” Athena said. (Because she’s a minor, I’m not using her real name.) She told me she’d spent most of the summer hanging out alone in her room with her phone. That’s just the way her generation is, she said. “We didn’t have a choice to know any life without iPads or iPhones. I think we like our phones more than we like actual people.”
I’ve been researching generational differences for 25 years, starting when I was a 22-year-old doctoral student in psychology. Typically, the characteristics that come to define a generation appear gradually, and along a continuum. Beliefs and behaviors that were already rising simply continue to do so. Millennials, for instance, are a highly individualistic generation, but individualism had been increasing since the Baby Boomers turned on, tuned in, and dropped out. I had grown accustomed to line graphs of trends that looked like modest hills and valleys. Then I began studying Athena’s generation.
Around 2012, I noticed abrupt shifts in teen behaviors and emotional states. The gentle slopes of the line graphs became steep mountains and sheer cliffs, and many of the distinctive characteristics of the Millennial generation began to disappear. In all my analyses of generational data—some reaching back to the 1930s—I had never seen anything like it.
At first I presumed these might be blips, but the trends persisted, across several years and a series of national surveys. The changes weren’t just in degree, but in kind. The biggest difference between the Millennials and their predecessors was in how they viewed the world; teens today differ from the Millennials not just in their views but in how they spend their time. The experiences they have every day are radically different from those of the generation that came of age just a few years before them.
What happened in 2012 to cause such dramatic shifts in behavior? It was after the Great Recession, which officially lasted from 2007 to 2009 and had a starker effect on Millennials trying to find a place in a sputtering economy. But it was exactly the moment when the proportion of Americans who owned a smartphone surpassed 50 percent.
The more I pored over yearly surveys of teen attitudes and behaviors, and the more I talked with young people like Athena, the clearer it became that theirs is a generation shaped by the smartphone and by the concomitant rise of social media. [Continue reading…]
Kai-Fu Lee writes: What worries you about the coming world of artificial intelligence?
Too often the answer to this question resembles the plot of a sci-fi thriller. People worry that developments in A.I. will bring about the “singularity” — that point in history when A.I. surpasses human intelligence, leading to an unimaginable revolution in human affairs. Or they wonder whether instead of our controlling artificial intelligence, it will control us, turning us, in effect, into cyborgs.
These are interesting issues to contemplate, but they are not pressing. They concern situations that may not arise for hundreds of years, if ever. At the moment, there is no known path from our best A.I. tools (like the Google computer program that recently beat the world’s best player of the game of Go) to “general” A.I. — self-aware computer programs that can engage in common-sense reasoning, attain knowledge in multiple domains, feel, express and understand emotions and so on.
This doesn’t mean we have nothing to worry about. On the contrary, the A.I. products that now exist are improving faster than most people realize and promise to radically transform our world, not always for the better. They are only tools, not a competing form of intelligence. But they will reshape what work means and how wealth is created, leading to unprecedented economic inequalities and even altering the global balance of power.
It is imperative that we turn our attention to these imminent challenges.
What is artificial intelligence today? Roughly speaking, it’s technology that takes in huge amounts of information from a specific domain (say, loan repayment histories) and uses it to make a decision in a specific case (whether to give an individual a loan) in the service of a specified goal (maximizing profits for the lender). Think of a spreadsheet on steroids, trained on big data. These tools can outperform human beings at a given task.
This kind of A.I. is spreading to thousands of domains (not just loans), and as it does, it will eliminate many jobs. Bank tellers, customer service representatives, telemarketers, stock and bond traders, even paralegals and radiologists will gradually be replaced by such software. Over time this technology will come to control semiautonomous and autonomous hardware like self-driving cars and robots, displacing factory workers, construction workers, drivers, delivery workers and many others.
Unlike the Industrial Revolution and the computer revolution, the A.I. revolution is not taking certain jobs (artisans, personal assistants who use paper and typewriters) and replacing them with other jobs (assembly-line workers, personal assistants conversant with computers). Instead, it is poised to bring about a wide-scale decimation of jobs — mostly lower-paying jobs, but some higher-paying ones, too. [Continue reading…]
The Guardian reports: Nearly half of the atoms that make up our bodies may have formed beyond the Milky Way and travelled to the solar system on intergalactic winds driven by giant exploding stars, astronomers claim.
The dramatic conclusion emerges from computer simulations that reveal how galaxies grow over aeons by absorbing huge amounts of material that is blasted out of neighbouring galaxies when stars explode at the end of their lives.
Powerful supernova explosions can fling trillions of tonnes of atoms into space with such ferocity that they escape their home galaxy’s gravitational pull and fall towards larger neighbours in enormous clouds that travel at hundreds of kilometres per second.
Astronomers have long known that elements forged in stars can travel from one galaxy to another, but the latest research is the first to reveal that up to half of the material in the Milky Way and similar-sized galaxies can arrive from smaller galactic neighbours.
Much of the hydrogen and helium that falls into galaxies forms new stars, while heavier elements, themselves created in stars and dispersed in the violent detonations, become the raw material for building comets and asteroids, planets and life. [Continue reading…]