The Overnight News Digest on Saturdays is focused upon science.
Science NewsRumors hint that Google has accomplished quantum supremacy
A leaked paper suggests that Google has achieved a milestone known as quantum supremacy, using a quantum computer to perform a calculation that couldn’t be achieved even with the world’s most powerful supercomputers.
It’s a hotly anticipated goal, and one intended to mark the beginning of a new era of quantum computation (SN: 6/29/17). But it’s also largely symbolic: The calculation in question serves no practical purpose and is designed to be difficult for classical computers, standard computers that are not rooted in quantum physics.
On September 20, the Financial Times reported that a scientific paper, briefly published on a NASA website before being removed, claims that Google has built a quantum computer that achieved quantum supremacy. It’s a benchmark that the company’s quantum researchers, led by physicist John Martinis of the University of California, Santa Barbara, have set their sights on for years (SN: 3/5/18). An apparent plain-text version of the paper, posted anonymously on the site Pastebin, has since been circulating among scientists and on Twitter. A spokesperson for Google declined to comment to Science News.
Can time travel survive a theory of everything?
[…] Time travel does not necessarily violate the laws of physics. In Einstein’s theory of gravity — general relativity — space and time are merged as spacetime, which allows for the possibility of pathways that could bend back to the past and loop back to the future.
Such paths are known as closed timelike curves. They’re a little like great circles around the surface of the Earth — if you start out in one direction and keep going straight, eventually you come back to where you started from. In that case the Earth’s curvature guides you back to your previous point in space; with closed timelike curves, the geometry of spacetime guides you back to an earlier moment in time. […]
So for practical purposes, time travel’s time has not yet arrived. But even if it’s possible only in principle, the potential ramifications for the basic physics of the universe might make it worth the time to investigate it. Time loops might not enable you to traverse the cosmos in a TARDIS, but perhaps could still help you understand the cosmos more deeply.
Why tumbleweeds may be more science fiction than Old West
Spotting a tumbleweed doesn’t necessarily mean you’re anywhere near the O.K. Corral.
Those dried-up, gray and brown tangles of Salsola plants have blown through many a Western movie, but they aren’t all that Western. You can find the common S. tragus in Maine, Louisiana, Hawaii and at least 42 other states. What’s more, S. tragus isn’t even native to North America, says evolutionary ecologist Shana Welles of Chapman University in Orange, Calif.
When the plant arrived on the continent over a century ago, it wasn’t welcome. An 1895 agricultural bulletin blames the accidental arrival on “impure” flax seed brought from Russia to South Dakota during the 1870s. From there, the adaptable S. tragus rode the rails, surviving a range of climates and really thriving in places like California’s Central Valley. Welles, who is 5’8”, says, “I definitely have stood next to ones that were taller than me.”
Tech XploreUsing machine learning to reconstruct deteriorated Van Gogh drawings
Researchers at TU Delft in the Netherlands have recently developed a convolutional neural network (CNN)-based model to reconstruct drawings that have deteriorated over time. In their study, published in Springer's Machine Vision and Applications, they specifically used the model to reconstruct some of Vincent Van Gogh's drawings that were ruined over the years due to ink fading and discoloration.
"The Netherlands has an international reputation with respect to arts, with famous artists like Rembrandt, Mondrian and Van Gogh," Jan van der Lubbe, one of the researchers who carried out the study, told TechXplore. "Therefore, art historical research and research into how to preserve cultural heritage play an important role in the Netherlands."
Study: Even short-lived solar panels can be economically viable
A new study shows that, contrary to widespread belief within the solar power industry, new kinds of solar cells and panels don't necessarily have to last for 25 to 30 years in order to be economically viable in today's market.
Rather, solar panels with initial lifetimes of as little as 10 years can sometimes make economic sense, even for grid-scale installations—thus potentially opening the door to promising new solar photovoltaic technologies that have been considered insufficiently durable for widespread use.
The new findings are described in a paper in the journal Joule, by Joel Jean, a former MIT postdoc and CEO of startup company Swift Solar; Vladimir Bulovic, professor of electrical engineering and computer science and director of MIT.nano; and Michael Woodhouse of the National Renewable Energy Laboratory (NREL) in Colorado.
Phys.orgSurface melting causes Antarctic glaciers to slip faster towards the ocean, new research shows
Surface meltwater draining through the ice and beneath Antarctic glaciers is causing sudden and rapid accelerations in their flow towards the sea, according to new research.
This is the first time scientists have found that melting on the surface impacts the flow of glaciers in Antarctica. […]
The new research, published today in Nature Communications, shows that accelerations in Antarctic Peninsula glaciers' movements coincide with spikes in snowmelt. This association occurs because surface meltwater penetrates to the ice bed and lubricates glacier flow.
A trio of researchers with Boston University and Dartmouth College has found that one of our ancient ancestors likely had a much easier time giving birth than modern humans. In their paper published on the open-access site PLOS ONE, Natalie Laudicina, Frankee Rodriguez and Jeremy DeSilva describe how they created 3-D computer models of some of our ancient ancestors and compared them with modern humans and chimpanzees—and describe what they found. […]
In sharp contrast, chimpanzees give birth in short order and appear to experience very little pain. In this new effort, the researchers wondered about the birth experience for one of our ancestors, Australopithecus sediba—a hominin that lived approximately 1.95 million years ago. To find out, they created a 3-D representation of an A. sediba pelvis using imagery from several fossils. While they were at it, they also created 3-D representations of Australopithecus afarensis and Homo erectus. And for additional comparison, they also created 3-D images of a modern human and a chimpanzee pelvis. To study the degree of difficulty of giving birth, the researchers also added baby human skull-sized objects to the 3-D images as they would normally sit in the birth canal.
A new study led by a University of Central Florida researcher may fundamentally alter our understanding of how comets arrive from the outskirts of the solar system and are funneled to the inner solar system coming closer to Earth.
In a study to be published in the Astrophysical Journal Letters this week, scientist Gal Sarid and co-authors describe the discovery of an orbital "gateway" through which many comets pass before they approach our sun. The gateway was uncovered as part of a simulation of centaurs, small icy bodies traveling on chaotic orbits between Jupiter and Neptune. The study team modeled the evolution of bodies from beyond Neptune's orbit, through the giant planet's region, and inside Jupiter's orbit. These icy bodies are considered nearly pristine remnants of material from the birth of our solar system.
Science DailyUS and Canada have lost more than 1 in 4 birds in the past 50 years
A study published today in the journal Science reveals that since 1970, bird populations in the United States and Canada have declined by 29 percent, or almost 3 billion birds, signaling a widespread ecological crisis. The results show tremendous losses across diverse groups of birds and habitats -- from iconic songsters such as meadowlarks to long-distance migrants such as swallows and backyard birds including sparrows.
"Multiple, independent lines of evidence show a massive reduction in the abundance of birds," said Ken Rosenberg, the study's lead author and a senior scientist at the Cornell Lab of Ornithology and American Bird Conservancy. "We expected to see continuing declines of threatened species. But for the first time, the results also showed pervasive losses among common birds across all habitats, including backyard birds."
The study notes that birds are indicators of environmental health, signaling that natural systems across the U.S. and Canada are now being so severely impacted by human activities that they no longer support the same robust wildlife populations.
Division by subtraction: Extinction of large mammal species likely drove survivors apart
When a series of large mammal species began going extinct roughly 12,000 years ago, many surviving species began going their separate ways, says new research led by Macquarie University and the University of Nebraska-Lincoln.
Published Sept. 20 in the journal Science, the study analyzed distributions of mammal fossils across North America following the last ice age, after the retreat of massive glaciers that had encroached south to the modern-day United States. The aftermath saw the disappearance of many famously large mammal species: mammoths, mastodons, saber-toothed cats, dire wolves and ground sloths, among others.
Surviving mammal species often responded by distancing themselves from their neighbors, the study found, potentially reducing how often they interacted as predators and prey, territorial competitors or scavengers.
NatureThe hard truths of climate change — by the numbers
[…] Nature documents the scale of the challenge in an infographic that explores energy use, carbon dioxide pollution and issues of climate justice. At a time when countries have pledged to curb greenhouse gases sharply, the data show that annual emissions spiked by 2.1% in 2018 — owing in part to increased demand for coal in places such as China and India.
First portrait of mysterious Denisovans drawn from DNA
For the first time, scientists analysing the DNA of Denisovans — an extinct group of hominins that was discovered around a decade ago — have offered a glimpse of what they might have looked like.
Ever since archaeologists uncovered the first fragmented Denisovan remains in a Siberian cave, researchers have scoured the globe for clues to how the mysterious hominins looked. Denisova Cave has yielded a few more small fossils, mostly teeth. A jawbone from the Tibetan Plateau added detail this year, as did information on a missing finger bone that moved between labs in Russia, California and Paris. But none of these fossils is large or complete enough to reconstruct many anatomical details.
Now, computational biologists have produced a rough sketch of Denisovan anatomy based on epigenetic changes — chemical modifications to DNA that can alter gene activity. Their approach reveals that Denisovans were similar in appearance to Neanderthals but had some subtle differences, such as a wider jaw and skull.
Popular ScienceThe asteroid collision that changed life on Earth forever—without killing the dinosaurs
Something mysterious happened nearly half a billion years ago that triggered one of the most important changes in the history of life on Earth. Suddenly, there was an explosion of species, with the biodiversity of invertebrate animals increasing from a very low level to something similar to what we see today. The most popular explanation for this "Great Ordovician Biodiversification Event" is that it was a result of an uncomfortably hot Earth cooling and eventually heading into an ice age.
But what actually triggered the change in temperature? In our new paper, published in Science Advances, we show that its onset coincided exactly with the largest documented asteroid breakup in the asteroid belt during the past two billion years, caused by a collision with another asteroid or a comet. Even today, almost a third of all meteorites falling on Earth originate from the breakup of this 150 kilometer-wide asteroid between Jupiter and Mars.
Meet the hero who saved everything you love about modern cities
In November 1958, local politicians and angry mothers gathered in New York City’s Washington Square Park for a ribbon-tying ceremony. The activists arranged the photo-op—a sly inversion of a ribbon-cutting —as a cheeky victory lap. […]
Many figures played a role in the victory. Shirley Hayes, a mother of four, created a committee to save the park… But preeminent among them was Jane Jacobs, a writer and city planning activist raising a family on nearby Hudson Street.
A tall woman with a wispy white bob, Jacobs wrote fiercely for publications like Architectural Forum about what defines a good cityscape. She favored a hodge-podge of old and new structures, an engaged community of people who watched out for each other, and buildings that combined commercial and residential space. Her forward-thinking books, particularly the 1961 classic The Death and Life of Great American Cities, challenged conventional practice on urban planning, which favored centralized design and control. Her writings made Jacobs a controversial figure, but also one who established new rules that municipalities follow today. Where Moses and other "master builders" preferred razing old homes and paving new streets, she called for preserving the "weird wisdom" of communities. She was the unbuilder.
MongabayDeforestation increase dovetails with armed conflict in Colombia, study finds’
Many of the world’s armed conflicts occur in areas with high biodiversity, according to a 2009 study published in Biological Conservation. The study found that more than 80 percent of such conflicts occurred in biodiversity hotspots, yet their impact on flora and fauna have rarely been studied since.
Colombia is home to so many species that it is considered “megadiverse,” and it has also experienced relatively high levels of armed conflict. A new study published in Biological Conservation analyzed the relationship between armed conflict and deforestation in Colombia between 2000 and 2015. The study also involved 17 other related variables, including the distribution of coca crops, the plant from which cocaine is produced.
One of the study’s main conclusions was that “[d]eforestation was positively associated with armed conflict intensity and proximity to illegal coca plantations,” especially in the Colombian Amazon. Higher amounts of deforestation were also associated with proximity to mining concessions, oil wells, and road networks.
The GuardianAncient Australia was home to 'strange' marsupial giants, scientists find
The “strange” anatomy of a family of giant marsupials that roamed eastern Australia and Tasmania for much of the past 25m years has been revealed in a new study.
Scientists had already figured out that palorchestids had tapir-like skulls and large “scimitar-like claws”, but little was known about the limbs of one of the “strangest marsupial lineages to have existed”, according to the paper published by a group of Australian researchers.
By examining 60 fossil specimens of palorchestids of varying geologic ages, the scientists were able to get an idea of how their legs and arms would have looked, functioned and evolved over time.
Americans' love of hiking has driven elk to the brink, scientists say
Biologists used to count over 1,000 head of elk from the air near Vail, Colorado. The majestic brown animals, a symbol of the American west, dotted hundreds of square miles of slopes and valleys.
But when researchers flew the same area in February for an annual elk count, they saw only 53. “Very few elk, not even many tracks,” their notes read. “Lots of backcountry skiing tracks.”
The surprising culprit isn’t expanding fossil-fuel development, herd mismanagement by state agencies or predators, wildlife managers say. It’s increasing numbers of outdoor recreationists – everything from hikers, mountain bikers and backcountry skiers to Jeep, all-terrain vehicle and motorcycle riders. Researchers are now starting to understand why.
BBC NewsCuba's 'sonic weapon' may have been mosquito gas
Canadian researchers say they may have identified the cause of a mystery illness which plagued diplomatic staff in Cuba in 2016.
Some reports in the US suggested an "acoustic attack" caused US staff similar symptoms, sparking speculation about a secret sonic weapon.
But the Canadian team suggests that neurotoxins from mosquito fumigation are the more likely cause.
The Zika virus, carried by mosquitoes, was a major health concern at the time. So-called "Havana syndrome" caused symptoms including headaches, blurred vision, dizziness and tinnitus.
The discovery of the ancient Greek city of Tenea
It was a baking hot summer’s day and I was in a car driving through the dramatic hills and lush vegetation of the Peloponnese in Greece. “Look at this whole plain,” my driver, Eleni Korka, said, gesturing out the window. To our left was a huge, flat area, covered in olive trees and scrub bushes. Where it ended, the earth transformed sharply into forested mountains.
“The city of Tenea covered this whole place,” she told me. “It’s above sea level and there’s a cool breeze, so the summer palace would probably have been built here.” She pointed to a traditional restaurant tucked under a distinctive, almost square-shaped hill. “And this taverna is built under a watermill,” she said.
Korka is one of the country’s top archaeologists. A Greek American, she recently made the biggest discovery of her 40-year career. The lost city of Tenea, which is mentioned in multiple Greek myths and historical texts, such as the ancient legend of Oedipus, the mythical king of Thebes who unwittingly killed his father and married his mother, was uncovered by her and her team last October, buried under the fields we’re now driving past.
IFL ScienceScientists Think They've Found A Way To Stop The Common Cold In Its Tracks
[…] The new research, published in Nature Microbiology, found that disabling a specific protein in our cells halts the progression of cold viruses. It’s still very early days – the new method has only been tested out on mice and human cells in a dish – but the findings show promise.
“Our grandmas have always been asking us, ‘If you’re so smart, why haven’t you come up with a cure for the common cold?’” said senior author Dr Jan Carette. “Now we have a new way to do that.”
What would happen if a nuclear war was declared? Well, researchers at the Science & Global Security group at Princeton have one possible answer. Based on the current US and Russia war plans, 91.5 million people would be either dead (34.1 million) or injured (57.4 million) within just a few hours of the start of the conflict.
In a YouTube video, the team describes Plan A, a likely nuclear war scenario. For the plan, they combined an extensive data set of nuclear weapons currently deployed, their yields, range, and “ideal” targets. They then divided the war into four phases, from nuclear warning shots to widespread destruction of major cities.
x xYouTube Video ScienceEPA signals retreat from controversial ‘secret science’ rule
The U.S. Environmental Protection Agency (EPA) is dropping plans to issue a final version this year of its divisive plan to limit the agency’s use of scientific studies in crafting major new regulations, Administrator Andrew Wheeler indicated at a congressional hearing this morning.
Instead, the agency will issue a supplemental proposal early next year, Wheeler told members of the House Science, Space and Technology Committee, adding that it will apply only to future rulemakings.
He again defended, however, the agency’s initial rationale for requiring only studies for which underlying data are available for “independent validation.”
The EconomistThe sound of sand reveals its source
Lift a shell from the sand to your ear and everyone knows you can hear the sea. But listen carefully enough and you can hear shells in the sand too. Sand, it turns out, has a signature sound of its own, and now scientists have found a way to tune in.
To the untrained eye, one bucket of beach sand looks much like another but mixed into the multitude of microscopic minerals are carbonate chemicals left behind from the shells of long-dead sea creatures such as molluscs. The carbonate concentration varies according to local geology, and Saskia van Ruth, a researcher at Wageningen University in the Netherlands, and her colleagues say this leaves each batch of sand with its own distinctive noise. The results could extend forensic techniques, providing a quick way to determine the source of disputed sand. […]
Writing in Applied Acoustics, Dr van Ruth’s team show they can distinguish between sand samples retrieved (legally) from nine seaside spots along the Dutch coast. And armed with that information as a reference tool, they could work out which beach a given sand sample had come from.
The scientists used a technique called Broad Acoustic Dissolution Spectroscopy analysis (BARDS). It is done with a sensitive listening device that picks up changes in acoustic properties when a scoop of sand or other powder is dropped into a beaker of mild acid and mixed. Chemical changes, including the breakdown of carbonates to carbon dioxide, release bubbles that increase the compressibility of the liquid and therefore slow down the passage of sound through it.
Live ScienceThe 'Spanish Stonehenge' Is Above Water for the First Time in 50 Years
After 50 years out of sight beneath the waters of a manmade lake in western Spain, the 7,000-year-old megalithic monument known as the Dolmen of Guadalperal is finally back on dry land — emphasis on dry.
As new imagery taken from NASA's Landsat 8 satellite shows, the reappearance of the ancient monument is owed to very low water levels in Spain's Valdecañas Reservoir following a summer of record heat and drought across Europe…
The Dolmen of Guadalperal is a large circle of about 150 standing stones, some more than 6 feet (1.8 meters) tall, arranged around a central, open oval. Archaeologists speculate that the structure was built in the 4th or 5th millennium B.C. […]
GizmodoNon-Drinkers Can Still Get Liver Disease, Thanks to Alcohol-Producing Gut Bacteria
Researchers say they’ve stumbled upon a peculiar cause of liver disease: a kind of bacteria that produces alcohol inside our gut.
According to lead author Jing Yuan, a doctor at the Capital Institute of Pediatrics in China, their discovery was completely accidental.
He and his colleagues had been treating a patient with severe fatty liver disease, a condition where too much fat builds up in the organ. A heavy drinking habit is the most common cause of fatty liver, but many people also develop non-alcoholic fatty liver disease (NAFLD). And in this patient’s case, the disease had progressed to the point where their liver was seriously inflamed. This form of NAFLD, called nonalcoholic steatohepatitis (NASH), can cause permanent liver damage and liver cancer.
Climate Change Is Already Killing Americans and Costing Billions in Medical Bills, Report Finds
Climate change will make our lives worse in the years to come, but a new report out this week highlights the stark costs people are already paying in the U.S. In 2012 alone, it found 10 major climate-related events likely led to nearly 1,000 extra deaths, almost 21,000 hospitalizations, and an added $10 billion in healthcare costs.
Researchers from Columbia University, the University of California Los Angeles, and the nonprofit environmental advocacy group Natural Resources Defense Council (NRDC) looked at the fallout of extreme weather events strongly linked to a warmer climate that took place in 2012. These included extreme heat days in Wisconsin, outbreaks of tick-borne Lyme disease in Michigan and the mosquito-borne West Nile virus in Texas, wildfires in Colorado and Washington, and the landfall of Hurricane Sandy in New York and New Jersey. Using various sources of data, including medical records and earlier studies, they then came up with their estimates.
Scientific AmericanPterosaurs Were Monsters of the Mesozoic Skies
[…] Pterosaurs were the first vertebrate creatures to evolve powered flight and conquer the air—long before birds took wing. They prevailed for more than 160 million years before vanishing along with the nonbird dinosaurs at the end of the Cretaceous period, around 66 million years ago. In that time, they evolved some of the most extreme anatomical adaptations of any animal, living or extinct. The smallest of these aerial predators was the size of a sparrow. The largest had a wingspan that rivaled that of an F-16 fighter jet. Many possessed heads larger than their bodies, making them, in essence, flying jaws of death. Pterosaurs patrolled every ocean and continent on Earth. No animal in the Mesozoic would have been safe from their gaze.
Unlike dinosaurs, which are survived today by birds, pterosaurs left behind no living descendants. As a result, all that paleontologists know about pterosaurs comes from the fossil record. And that record has been frustratingly fragmentary, leaving us with just a glimmer of their former glory and a host of questions about their bizarre anatomy and ill fate. Paleontologists have scratched their heads over these mysteries for decades. Now new fossil discoveries, combined with mathematical modeling methods in which anatomical structures are simplified just enough that equations of physical properties can be applied to get best estimates of strength, weight, speed, and so forth, are finally generating insights. And what scientists are finding is that pterosaurs were even more extraordinary than we ever imagined.
Sci-NewsResearchers Sequence Genomes of All Living Penguin Species
Penguins (Sphenisciformes) are a remarkable order of flightless wing-propelled diving seabirds distributed widely across the southern hemisphere.
Approximately 20 extant penguin species are recognized across 6 genera: Aptenodytes, Pygoscelis, Eudyptula, Spheniscus, Eudyptes, and Megadyptes. […]
“The population history of different penguin species can be seen in their genome,” said Dr. Theresa Cole, a researcher at the University of Otago.
“We will provide new insights into the population history of all penguins over dramatic climate events, to predict population trends under future climate change scenarios.”
Biologists Find Striking Similarities between Human and Archaeal Chromosomes
The similar clustering of DNA in the chromosomes of humans and Archaea is significant because certain genes activate or deactivate based upon how they’re folded, according to a paper published in the journal Cell.
Archaea are one of the primary domains of cellular life, and are possibly the most ancient form of life: putative fossils of archaeal cells in stromatolites have been dated to almost 3.5 billion years ago. […]
The new study, led by Indiana University’s Professor Stephen Bell, is the first to visualize the organization of DNA in archaeal chromosomes.
The Atlantic‘This Is Clearly Coming From Outside the Solar System’
No one knows where it came from, but it’s here now. And the chase is on.
Astronomers around the world are monitoring an interstellar comet hurtling through the solar system, known for the moment as C/2019 Q4. It’s the second time in less than two years that they’ve seen an object from another star swing through our cosmic neighborhood. The first time around, the discovery kicked off a worldwide sprint to inspect the object before it got away. It was mysterious enough that some astronomers even began to consider whether it was dispatched by an advanced alien civilization.
This second interstellar object was spotted in late August by Gennady Borisov, an amateur astronomer in Crimea. Borisov has a reputation for catching never-before-seen comets with his telescopes, but they’re from around here; like everything else in the solar system—the planets, the moons, a sea of asteroids—they trace an orbit around the sun. And over the past few weeks, it’s become very clear that this comet does not.
The Colonial Origins of Mexico’s National Dish
How indigenous tradition, Old World ingredients, Islamic cuisine, and a convent combined to make mole a staple.
[…] Rachel Laudan is a food historian and the author of Cuisine and Empire: Cooking in World History—but, when she started researching mole, the first document she uncovered was hardly deep in the archives. When she first visited Mexico, in the 1990s, Laudan went to a restaurant famous for its mole. “And, of course, they had the statutory place mat with the story of mole poblano being invented in a convent in the 18th century,” she told us.
According to the origin story on the place mat, some nuns, in a panic because an archbishop was visiting and they had nothing to serve him, threw a bunch of spices in a pot and somehow came up with the perfect rich, chocolate-brown sauce. “That, to me, just sounds like propaganda,” says Fernando Lopez, one of three siblings whose father founded Guelaguetza, an Angeleno restaurant that is a temple to Oaxacan mole. He believes mole is far too complex to have been created overnight. Plus, mole comes in many varieties and colors. Guelaguetza serves six kinds of mole—mole negro, mole rojo, mole coloradito, mole amarillo, mole verde, and mole estofado—but Sandra Aguilar-Rodriguez, an associate professor of Latin American history at Moravian College, in Pennsylvania, told us that she could name 10 versions off the top of her head, and that each town in the south of Mexico has its own variations on the classic recipes.
Ars TechnicaViking berserkers may have used henbane to induce trance-like state
The legendary Viking warriors known as berserkers were renowned for their ferocity in battle, purportedly fighting in a trance-like state of blind rage (berserkergang), howling like wild animals, biting their shields, and often unable to distinguish between friend and foe in the heat of battle. But historians know very little about the berserkers apart from scattered Old Norse myths and epic sagas. One intriguing hypothesis as to the source of their behavior is that the berserkers ingested a specific kind of mushroom with psychoactive properties. Now an ethnobotanist is challenging that hypothesis, suggesting in a recent paper in the Journal of Ethnopharmacology that henbane is a more likely candidate.
We can phase out fossil fuels fast without having a burst of warming
Burning fossil fuels spews carbon dioxide into the air, which warms the climate through the greenhouse effect (as if you didn’t know that). But burning fossil fuels also spews sulfur dioxide into the air, and sulfur dioxide forms aerosols that can deflect the sun’s rays and thus cool the climate. It has thus been argued that phasing out fossil fuels would have the undesirable effect of accelerating the warming of the planet in the near term, since we’d be getting rid of the cooling aerosols at the same time.
This very argument was made by countries with serious air pollution issues, and it indicated to Intergovernmental Panel on Climate Change policymakers that the countries were struggling to figure out how, and how much, to limit emissions.
But climate scientists Drew Shindell and Christopher Smith have now re-analyzed the modeling data and concluded that there is no way we could halt emissions quickly enough for the aerosols' "climate penalty" to be meaningful. "Even the most aggressive plausible transition to a clean-energy society," they write, "provides benefits for climate change mitigation."
Ancient slag offers insight into the uneven pace of technological advances
Sometimes, clues about ancient technology are hidden in the most mundane things. In this case, Tel-Aviv University archaeologist Erez Ben-Yosef and his colleagues went rummaging through heaps of slag, the glassy waste discarded after smelters separate copper from its ore. Their goal? To hunt for clues about industry and innovation in the ancient Edomite Kingdom.
Less copper mixed with the slag suggests more-efficient smelting, so by tracking changes in the slag, Ben-Yosef and his colleagues could track the progress of a technology that powered the ancient world.
The archaeologists found mostly small, gradual improvements over the course of five centuries, punctuated by a sudden, drastic increase in efficiency around 925 BCE in the wake of an Egyptian invasion of the area. That suggests that a model for the evolution of new species may also apply to human technology and that we may need a little instability to break out of equilibrium and trigger bursts of innovation. It also reveals how one society in particular benefitted from the Bronze Age Collapse and later took advantage of the disruption of a foreign invasion to make a leap forward in technology.