Elon Musk predicted this week that SpaceX will be able to fly humans to Mars within the next 10 years. From a report: Musk made the bold prediction during an appearance on the Lex Fridman podcast. The Tesla founder reiterated his view that humanity should become a "multi-planet species" and detailed SpaceX's plans to develop the necessary technology for the trip. "Best case is about five years. Worst case, 10 years," Musk said. He noted that "engineering the vehicle" required for the trip remains a key factor in establishing a timeframe. "Starship is the most complex and advanced rocket that's ever been made by, I don't know, an order of magnitude or something like that," Musk added. "It's a lot. It's really next level." SpaceX has ramped up its operations in recent years as part of Musk's long-term goal to establish a colony on Mars. Earlier this month, Musk revealed SpaceX has begun building a launchpad in Florida that can accommodate Starship rockets. SpaceX has begun testing prototypes of the 400-foot rocket ahead of a planned orbital launch. During the podcast interview, Musk said his private aviation firm is still working to optimize its Starship design and cut down on the projected cost of a Mars trip.

Rarely does a country get a chance to lay out its ideals as a nation and write a new constitution for itself. Almost never does the climate and ecological crisis play a central role. That is, until now, in Chile, where a national reinvention is underway. The New York Times: After months of protests over social and environmental grievances, 155 Chileans have been elected to write a new constitution amid what they have declared a "climate and ecological emergency." Their work will not only shape how this country of 19 million is governed. It will also determine the future of a soft, lustrous metal, lithium, lurking in the salt waters beneath this vast ethereal desert beside the Andes Mountains. Lithium is an essential component of batteries. And as the global economy seeks alternatives to fossil fuels to slow down climate change, lithium demand -- and prices -- are soaring.

Mining companies in Chile, the world's second-largest lithium producer after Australia, are keen to increase production, as are politicians who see mining as crucial to national prosperity. They face mounting opposition, though, from Chileans who argue that the country's very economic model, based on extraction of natural resources, has exacted too high an environmental cost and failed to spread the benefits to all citizens, including its Indigenous people. And so, it falls to the Constitutional Convention to decide what kind of country Chile wants to be. Convention members will decide many things, including: How should mining be regulated, and what voice should local communities have over mining? Should Chile retain a presidential system? Should nature have rights? How about future generations?

Scientists have compiled the world's oldest family tree from human bones interred at a 5,700-year-old tomb in the Cotswolds, UK. The BBC reports: Analysis of DNA from the tomb's occupants revealed the people buried there were from five continuous generations of one extended family. Most of those found in the tomb were descended from four women who all had children with the same man. The right to use the site was based on descent from one man. But people were buried in different parts of the tomb based on the first-generation matriarch they were descended from. This suggests that the first-generation women held a socially significant place in the memories of this community. The Neolithic tomb, or "cairn," at Hazleton North in Gloucestershire has two L-shaped chambers, one facing north and the other south.

Co-author Prof David Reich, from Harvard Medical School in Boston, US, who led the generation of ancient DNA from the remains, explained: "Two of the women, all of their children are in the south chamber - and their kids up to the fifth generation. "And then the other two women, their kids are primarily in the north chamber - although some of them switch to the south chamber later in the use life of the tomb - probably reflecting the collapse of the north passage which meant it wasn't possible to bury there anymore." Dr Chris Fowler of Newcastle University, UK, the first author and lead archaeologist in the study, said: "This is of wider importance because it suggests that the architectural layout of other Neolithic tombs might tell us about how kinship operated at those tombs."

The tomb dates to an important period just after farming was introduced to Britain by people whose ancestors had - several thousand years earlier - spread through Europe from Anatolia (modern Turkey) and the Aegean. The work will help researchers understand family dynamics among these Stone Age people and learn more about their culture. There are also indications that "stepsons" were adopted into the family, the researchers say - males whose mother was buried in the tomb but not their biological father, and whose mother had also had children with a male related to the original founder. The study has been published in the journal Nature.

An anonymous reader shares an excerpt from a report via Quanta Magazine, written by Thomas Lewton: During a summer storm in 2018, a momentous lightning bolt flashed above a network of radio telescopes in the Netherlands. The telescopes' detailed recordings, which were processed only recently, reveal something no one has seen before: lightning actually starting up inside a thundercloud. In a new paper that will soon be published in the journal Geophysical Research Letters, researchers used the observations to settle a long-standing debate about what triggers lightning -- the first step in the mysterious process by which bolts arise, grow and propagate to the ground. "It's kind of embarrassing. It's the most energetic process on the planet, we have religions centered around this thing, and we have no idea how it works," said Brian Hare, a lightning researcher at the University of Groningen and a co-author of the new paper. [...]

[Joseph Dwyer, a physicist at the University of New Hampshire and a co-author on the new paper] and his team turned to the Low Frequency Array (LOFAR), a network of thousands of small radio telescopes mostly in the Netherlands. LOFAR usually gazes at distant galaxies and exploding stars. But according to Dwyer, "it just so happens to work really well for measuring lightning, too." When thunderstorms roll overhead, there's little useful astronomy that LOFAR can do. So instead, the telescope tunes its antennas to detect a barrage of a million or so radio pulses that emanate from each lightning flash. Unlike visible light, radio pulses can pass through thick clouds. Using radio detectors to map lightning isn't new; purpose-built radio antennas have long observed storms in New Mexico. But those images are low-resolution or only in two dimensions. LOFAR, a state-of-the-art astronomical telescope, can map lighting on a meter-by-meter scale in three dimensions, and with a frame rate 200 times faster than previous instruments could achieve. "The LOFAR measurements are giving us the first really clear picture of what's happening inside the thunderstorm," said Dwyer.

A materializing lightning bolt produces millions of radio pulses. To reconstruct a 3D lightning image from the jumble of data, the researchers employed an algorithm similar to one used in the Apollo moon landings. The algorithm continuously updates what's known about an object's position. Whereas a single radio antenna can only indicate the rough direction of the flash, adding data from a second antenna updates the position. By steadily looping in thousands of LOFAR's antennas, the algorithm constructs a clear map. When the researchers analyzed the data from the August 2018 lightning flash, they saw that the radio pulses all emanated from a 70-meter-wide region deep inside the storm cloud. They quickly inferred that the pattern of pulses supports one of the two leading theories about how the most common type of lightning gets started.

One idea holds that cosmic rays -- particles from outer space -- collide with electrons inside thunderstorms, triggering electron avalanches that strengthen the electric fields. The new observations point to the rival theory. It starts with clusters of ice crystals inside the cloud. Turbulent collisions between the needle-shaped crystals brush off some of their electrons, leaving one end of each ice crystal positively charged and the other negatively charged. The positive end draws electrons from nearby air molecules. More electrons flow in from air molecules that are farther away, forming ribbons of ionized air that extend from each ice crystal tip. These are called streamers. Each crystal tip gives rise to hordes of streamers, with individual streamers branching off again and again. The streamers heat the surrounding air, ripping electrons from air molecules en masse so that a larger current flows onto the ice crystals. Eventually a streamer becomes hot and conductive enough to turn into a leader -- a channel along which a fully fledged streak of lightning can suddenly travel. Ute Ebert, a physicist at Eindhoven University of Technology in the Netherlands who studies lightning initiation but was not involved in the new work, notes, however, that despite its resolution, the initiation movie described in the new paper does not directly image ice particles ionizing the air -- it only shows what happens immediately afterward. "Where is the first electron coming from? How does the discharge start near to an ice particle?" she asked.

Few researchers still favor the rival theory that cosmic rays directly initiate lightning, but cosmic rays could still play a secondary role in creating electrons that trigger the first streamers that connect to ice crystals, said Ebert. Exactly how streamers turn into leaders is also a "matter of great debate," said Hare.

Research by South African scientists suggests that Omicron could displace the Delta variant of the coronavirus because infection with the new variant boosts immunity to the older one. From a report: The study only covered a small group of people and has not been peer-reviewed, but it found that people who were infected with Omicron, especially those who were vaccinated, developed enhanced immunity to the Delta variant. The analysis enrolled 33 vaccinated and unvaccinated people who were infected with the Omicron variant in South Africa. While the authors found that neutralisation of Omicron increased 14-fold over 14 days after the enrolment, they also found that there was a 4.4-fold increase in neutralisation of the Delta variant. "The increase in Delta variant neutralization in individuals infected with Omicron may result in decreased ability of Delta to re-infect those individuals," the scientists who conducted the study said.

The 3D maps may help researchers track and predict the ocean's response to climate change. From a report: Life is teeming nearly everywhere in the oceans, except in certain pockets where oxygen naturally plummets and waters become unlivable for most aerobic organisms. These desolate pools are "oxygen-deficient zones," or ODZs. And though they make up less than 1 percent of the ocean's total volume, they are a significant source of nitrous oxide, a potent greenhouse gas. Their boundaries can also limit the extent of fisheries and marine ecosystems. Now MIT scientists have generated the most detailed, three-dimensional "atlas" of the largest ODZs in the world. The new atlas provides high-resolution maps of the two major, oxygen-starved bodies of water in the tropical Pacific. These maps reveal the volume, extent, and varying depths of each ODZ, along with fine-scale features, such as ribbons of oxygenated water that intrude into otherwise depleted zones.

The team used a new method to process over 40 years' worth of ocean data, comprising nearly 15 million measurements taken by many research cruises and autonomous robots deployed across the tropical Pacific. The researchers compiled then analyzed this vast and fine-grained data to generate maps of oxygen-deficient zones at various depths, similar to the many slices of a three-dimensional scan. From these maps, the researchers estimated the total volume of the two major ODZs in the tropical Pacific, more precisely than previous efforts. The first zone, which stretches out from the coast of South America, measures about 600,000 cubic kilometers -- roughly the volume of water that would fill 240 billion Olympic-sized pools. The second zone, off the coast of Central America, is roughly three times larger. The atlas serves as a reference for where ODZs lie today. The team hopes scientists can add to this atlas with continued measurements, to better track changes in these zones and predict how they may shift as the climate warms.

Chinese citizens lashed out online against billionaire Tesla and SpaceX CEO Elon Musk on Monday after China complained that its space station was forced to take evasive action to avoid collision with satellites launched by Musk's Starlink program. CNBC reports: The satellites from Starlink Internet Services, a division of Musk's SpaceX aerospace company, had two "close encounters" with the Chinese space station on July 1 and Oct. 21, according to a document submitted by China earlier this month to the U.N.'s space agency. "For safety reasons, the China Space Station implemented preventive collision avoidance control," China said in a document published on the website of the United Nations Office for Outer Space Affairs. The complaints have not been independently verified.

In a post on China's Twitter-like Weibo microblogging platform on Monday, one user said Starlink's satellites were "just a pile of space junk," while another described them as "American space warfare weapons." SpaceX alone has deployed nearly 1,900 satellites to serve its Starlink broadband network, and is planning more. "The risks of Starlink are being gradually exposed, the whole human race will pay for their business activities," a user posting under the name Chen Haiying said on Weibo.

An anonymous reader quotes a report from Ars Technica: Velcro is an ingenious hook-and-loop fastener inspired by nature -- specifically, cockleburs. Now scientists at the Italian Institute of Technology are returning the favor. They have created the first biodegradable Velcro -- inspired by climbing plants -- and used it to build small devices to help monitor the health of crop plants and deliver pesticides and medicines as needed, according to a November paper published in the journal Communications Materials. [...] Co-author Isabella Fiorello and her colleagues were interested in developing innovative new technologies for monitoring plants in situ to detect disease, as well as delivering various substances to plants. However, few such devices can be attached directly to plant leaves without damaging them. The best current options are sensors attached with chemical glues, or with clips. There are also micro-needle-based patches under development able to penetrate leaves for disease detection. Fiorello et al. found inspiration in the common catchweed plant (Galium aparine). It can form dense, tangled mats on the ground, and while the plants can grow up to six feet, they can't stand on their own and instead must use other plants for support. For this purpose, catchweed plants rely on a "unique parasitic ratchet-like anchoring mechanism to climb over host plants, using microscopic hooks for mechanical interlocking to leaves," the authors wrote.

The Italian team closely studied that micro-hook structure and then used a high-resolution 3D printer to create artificial versions, using various materials -- including photosensitive and biodegradable materials made from a sugar-like substance known as isomalt. Their artificial reproductions proved quite capable of attaching to many different plant species, just like their natural counterparts. As an initial application, the team designed a device that could penetrate a plant cuticle with minimal invasiveness, thereby enabling the plant to be monitored and treated, if necessary. The isomalt microhooks attach to the vascular system of leaves and then dissolve inside, because isomalt is soluble. Fiorello et al.'s experiments demonstrated that their artificial micro hooks can be used as a plaster for targeted, controlled release of pesticides, bactericides, or pharmaceuticals onto the leaves. This would greatly reduce the need for broad application of pesticides. And since the plaster dissolves once it's applied, there is no additional waste.

The team also printed hooks made out of a photosensitive resin and assembled them together with sensors for light, temperature, and humidity to make intelligent clips to enable wireless monitoring of the plant's heath. The clips attach to individual leaves, transmitting data wirelessly thanks to customized computer software. The prototype proved resistant to windy conditions and was capable of making real-time measurements for up to 50 days. The devices could be used for small-scale botanical applications, or they could be scaled up. For instance, farmers could distribute many such devices to better map and monitor wide cultivation areas, according to the authors. Finally, Fiorello et al. developed a micro-robotic system capable of moving over the surface of leaves using micro steps, copying the ratchet-like motion of the catchweed plant. Similar actuation mechanisms have previously been demonstrated in Stanford University's SpinyBot -- capable of scaling hard, flat surfaces thanks to arrays of miniature spines on its feet -- and the University of California, Berkeley's CLASH robots, which are capable of climbing up loose suspended cloth surfaces, like curtains.

U.S. health officials on Monday cut isolation restrictions for Americans who catch the coronavirus from 10 to five days, and similarly shortened the time that close contacts need to quarantine. The Associated Press reports: Centers for Disease Control and Prevention officials said the guidance is in keeping with growing evidence that people with the coronavirus are most infectious in the two days before and three days after symptoms develop. The decision also was driven by a recent surge in COVID-19 cases, propelled by the omicron variant.

Early research suggests omicron may cause milder illnesses than earlier versions of the coronavirus. But the sheer number of people becoming infected -- and therefore having to isolate or quarantine -- threatens to crush the ability of hospitals, airlines and other businesses to stay open, experts say. CDC Director Rochelle Walensky said the country is about to see a lot of omicron cases. "Not all of those cases are going to be severe. In fact many are going to be asymptomatic," she told The Associated Press on Monday. "We want to make sure there is a mechanism by which we can safely continue to keep society functioning while following the science."

Last week, the agency loosened rules that previously called on health care workers to stay out of work for 10 days if they test positive. The new recommendations said workers could go back to work after seven days if they test negative and don't have symptoms. And the agency said isolation time could be cut to five days, or even fewer, if there are severe staffing shortages. Now, the CDC is changing the isolation and quarantine guidance for the general public to be even less stringent. The guidance is not a mandate; it's a recommendation to employers and state and local officials.

$100 billion was spent building the International Space Station — including 42 different assembly flights, reports Recode. Yet "after two decades in orbit, the International Space Station will shut down," as NASA re-focuses on sending humans back to the moon. (UPDATE: NASA has extended ISS operation through 2030.)

While they plan to keep it functioning as long as possible, NASA "has only technically certified the station's hardware until 2028 and has awarded more than $400 million to fund private replacements." (Which they estimate will save them $1 billion a year.)

So then what happens? When these stations are ready, NASA will guide the ISS into the atmosphere, where it will burn up and disintegrate. At that point, anyone hoping to work in space will have to choose among several different outposts. That means countries won't just be using these new stations to strengthen their own national space programs, but as lucrative business ventures, too. "Commercial companies have the capability now to do this, and so we don't want to compete with that," Robyn Gatens, the director of the ISS, told Recode. "We want to transition lower-Earth orbit over to commercial companies so that the government and NASA can go use resources to do harder things in deep space."

Private companies currently backed by NASA, including Lockheed Martin and Jeff Bezos's Blue Origin, could launch as many as four space stations into Earth's orbit over the next decade. NASA is also building a space station called Gateway near the moon; a SpaceX Falcon Heavy rocket carrying the living quarters for the station is scheduled to launch in 2024.

Russia and India are planning to launch their own space stations to low-Earth orbit, too, and China's Tiangong station, which is currently under construction, already has astronauts living aboard... Russia may leave the ISS as soon as 2025, the same year its space agency, Roscosmos, plans to launch its new $5 billion space station. The European Space Agency, which represents 22 different European countries, is now training its astronauts for eventual missions to Tiangong...

[C]ompetition for customers could get even more intense as space stations launched by China, Russia, and India open for business.
Recode ultimately sees a future where private-sector customers choose from competing space stations — and even have to consider the political consequences of "favoring one nation's space station over another..."

"In the best of scenarios, these new stations will learn from each other and massively expand scientific knowledge. But they will also make global politics a much bigger part of space, which could impact what happens here on Earth and how humanity explores the moon and Mars."

"Scientists have never been able to adequately explain where lightning comes from," writes Quanta magazine, sharing a remarkable new animation of a lightning flash recorded by the LOFAR radio telescope network" In a new paper that will soon be published in the journal Geophysical Research Letters, researchers used the observations to settle a long-standing debate about what triggers lightning — the first step in the mysterious process by which bolts arise, grow and propagate to the ground. "It's kind of embarrassing. It's the most energetic process on the planet, we have religions centered around this thing, and we have no idea how it works," said Brian Hare, a lightning researcher at the University of Groningen and a co-author of the new paper....

[T]he electric fields inside clouds are about 10 times too weak to create sparks. "People have been sending balloons, rockets and airplanes into thunderstorms for decades and never seen electric fields anywhere near large enough," said Joseph Dwyer, a physicist at the University of New Hampshire and a co-author on the new paper who has puzzled over the origins of lightning for over two decades. "It's been a real mystery how this gets going." A big impediment is that clouds are opaque; even the best cameras can't peek inside to see the moment of initiation. Until recently, this left scientists little choice but to venture into the storm — something they've been trying since Benjamin Franklin's famous kite experiment of 1752...

LOFAR, a state-of-the-art astronomical telescope, can map lighting on a meter-by-meter scale in three dimensions, and with a frame rate 200 times faster than previous instruments could achieve. "The LOFAR measurements are giving us the first really clear picture of what's happening inside the thunderstorm," said Dwyer...
Long-time Slashdot reader g01d4 summarizes their results: It seems to be something of a chain reaction starting with clusters of [charged] ice crystals inside the cloud... "More electrons flow in from air molecules that are farther away," according to the article, "forming ribbons of ionized air that extend from each ice crystal tip." These are called streamers which build up numbers until one becomes hot and conductive enough to turn into a leader — a channel along which a fully fledged streak of lightning can suddenly travel.
Quanta magazine adds that the key role of ice crystals "dovetails with recent findings that lightning activity dropped by more than 10% during the first three months of the COVID-19 pandemic. Researchers attribute this drop to lockdowns, which led to fewer pollutants in the air, and thus fewer nucleation sites for ice crystals."

U.S. President Abraham Lincoln pardoned a soldier in the Civil War, and in 1998 that document was re-discovered. But "It was the date that made the document significant," writes Ars Technica: April 14, 1865, "meaning the pardon was likely one of the last official acts of President Lincoln, since he was assassinated later that same day at Ford's Theater in Washington, D.C. The pardon was broadly interpreted as evidence for a historical narrative about the president's compassionate nature: i.e., his last act was one of mercy."

But now scientists at America's National Archives have conducted a new analysis (published in the journal Forensic Science International: Synergy), and "confirmed that the date was indeed forged (although the pardon is genuine)." An archivist named Trevor Plante became suspicious of the document, noting that the ink on the "5" in "1865" was noticeably darker. It also seemed as if another number was written underneath it. Then Plante consulted a seminal collection of Lincoln's writings from the 1950s. The pardon was there, but it was dated April 14, 1864 — a full year before Lincoln was assassinated by John Wilkes Booth. Clearly the document had been altered sometime between the 1950s and 1998 to make the pardon more historically significant..

Investigators naturally turned to the man who made the discovery for further information. They began corresponding with Thomas Lowry [a retired psychiatrist turned amateur historian] in 2010. Initially, Lowry seemed cooperative, but when he learned about the nature of the investigation, he stopped communicating with the Office of the Inspector General, thereby arousing suspicion. So the investigators knocked on the historian's door one January morning in 2011 for an interview. Shortly thereafter, the National Archives released a statement that Lowry had confessed to altering the date on the pardon. Lowry confessed to bringing a fountain pen into the research room, along with fade proof, pigment-based ink, and changing the "4" in "1864" to a "5." Lowry couldn't be charged with any crime because the statute of limitations for tampering with government property had run out, but he was barred from the National Archives for life.

But there's a twist: Lowry soon recanted, claiming he had signed the confession under duress from the National Archives investigators...
Long-time Slashdot reader waspleg writes that Ars Technica "goes through the analysis of how it was verified to be a forgery using several techniques," including ultraviolet light and X-ray fluorescence analysis to study chemicals in the ink. From the article: An examination under magnification and reflective fiber optic lighting showed the ink used to write the "5" was indeed different in overall color compared to the other numbers in the date. Furthermore, "Vestiges of ink from a scratched away number can be seen below and beside the darker '5,' as well as smeared across the paper," the authors wrote. Additional analysis under raking light — a technique that accentuates hills and valleys in the paper texture — revealed abrasions to the paper under and around the "5" that were not observed anywhere else on the document. The team also determined that the paper around the "5" is thinner than everywhere else, and that ink residue of the scratched-away "4" were caught in the abraded paper fibers, clearly visible using transmitted light microscopy...
"The authors also concluded that there is no way to restore the document to its original state without causing further damage."

"We have LIFTOFF of the @NASAWebb Space Telescope!" NASA tweeted seven hours ago, sharing a 32-second video of the launch. "At 7:20am ET (12:20 UTC), the beginning of a new, exciting decade of science climbed to the sky," they wrote, adding that the telescope "will change our understanding of space as we know it."

The CBC reports: The world's largest and most powerful space telescope rocketed away Saturday on a high-stakes quest to behold light from the first stars and galaxies, and scour the universe for hints of life.

NASA's James Webb Space Telescope soared from French Guiana on South America's northeastern coast, riding a European Ariane rocket into the Christmas morning sky. "What an amazing Christmas present," said Thomas Zurbuchen, NASA's science mission chief.

The $10-billion US observatory hurtled toward its destination 1.6 million kilometres away, or more than four times beyond the moon. It will take a month to get there and another five months before its infrared eyes are ready to start scanning the cosmos. First, the telescope's enormous mirror and sunshield need to unfurl; they were folded origami-style to fit into the rocket's nose cone. Otherwise, the observatory won't be able to peer back in time 13.7 billion years as anticipated, within a mere 100 million years of the universe-forming Big Bang. NASA administrator Bill Nelson called the telescope a time machine that will provide "a better understanding of our universe and our place in it: who we are, what we are, the search that's eternal."

"We are going to discover incredible things that we never imagined," Nelson said following liftoff, speaking from Florida's Kennedy Space Center. But he cautioned: "There are still innumerable things that have to work and they have to work perfectly.... We know that in great reward there is great risk...."

"We have delivered a Christmas gift today for humanity," said Josef Aschbacher, the European Space Agency's director general....

Cheers and applause erupted in and outside Launch Control following the telescope's flawless launch...
Official online dashboards are now tracking its position. (And you can watch complete footage of the entire launch here.) "If all goes well, the sunshield will be opened three days after liftoff, taking at least five days to unfold and lock into place," the CBC points out. "Next, the mirror segments should open up like the leaves of a drop-leaf table, 12 days or so into the flight." In all, hundreds of release mechanisms need to work — perfectly — in order for the telescope to succeed. Such a complex series of actions is unprecedented — "like nothing we've done before," noted NASA program director Greg Robinson.
Thanks to Slashdot readers Dave Knott and hackertourist for sharing the news...

"Early benchmarks from Denmark on infections and hospitalizations are providing grounds for guarded optimism that highly vaccinated countries might be able to weather the omicron wave," reports the Washington Post.

"The developments, coupled with Denmark's speedy rollout of booster shots, have raised hopes the country can avoid the dire surge for which it has been bracing..." [O]ver the last week, the country has fared better than it was expecting. After surging to record-breaking levels, the number of daily cases has stabilized. Officials recorded 12,500 cases on Thursday, compared to 11,000 late last week. More important, hospitalizations have come in — so far — on the very low end of what was projected. A week ago, Denmark's government science institute said daily new coronavirus hospital admissions could range between 120 and 250 patients by Christmas Eve. In recent days, daily admissions have hung around 125....

The early signals from Denmark do not provide any direct measure on the severity of the variant, one of the key questions in this phase of the pandemic. But they track with other emerging data and studies from Britain and South Africa that suggest omicron is less likely to lead to hospitalization than the delta variant. Scientists caution that there are still many uncertainties, and that even if omicron is less likely to cause hospitalization, its increased transmissibility means countless sicknesses and disruptions. The virus could also spread so widely that it nonetheless leads to an influx at hospitals...

It's also unclear whether and to what extent omicron's reduced severity is a feature of the virus itself, or rather a sign of population-level immunity stemming from vaccinations and prior infections.

Compared with delta, omicron is far better at evading vaccines and causing infections in those who have already been inoculated. But Denmark's experience shows that a rapid booster rollout might be able to nonetheless help cut down rising infection numbers. A team of scientists at the State Serum Institute said in a research paper this week that Pfizer-BioNTech booster shots appeared to provide a 55 percent protection against infections, compared against cases from those who had received only two doses. Even if that level of protection dips over time, boosters "can help us through the next months," said Tyra Grove Krause, the chief epidemiologist at Denmark's State Serum Institute. According to Our World in Data, Denmark has issued the most per capita booster shots of any European Union country. Denmark said in its latest monitoring report, released Thursday, that 36.8 percent of its population had been boosted, more than double the level from two weeks earlier. Overall, 77.2 percent of the country's population has received at least two doses.

A team of chemists just solved the mystery of why comets' heads -- but not their tails -- glow green, which had puzzled researchers for decades. From a report: Studying an elusive molecule, which only fleetingly exists on Earth, was the key. Comets are speeding chunks of ice and dust left over from the formation of the solar system, which occasionally venture from the system's cold outer reaches to pass by Earth. Back in the 1930s, Gerhard Herzberg, who later won the Nobel prize for his research on free radicals and other molecules, guessed that the process behind the green comet glow might involve a molecule made from two carbon atoms bonded together, called dicarbon. A new study, published in the journal the Proceedings of the National Academy of Sciences, put Herzberg's theory to the test.

Dicarbon is so reactive that the team behind the study couldn't get their supply of it from a bottle, says Tim Schmidt, a chemist who oversaw the study at the University of New South Wales in Sydney, Australia. In space, it exists inside stars, nebulae, and comets. But when exposed to the oxygen in Earth's atmosphere, dicarbon will quickly react and "burn up," Schmidt says. Schmidt says this is the first time scientists have been able to examine precisely how the molecule breaks apart when exposed to powerful ultraviolet rays. In the lab, the team had to simulate the environment of near-Earth space with vacuum chambers and three different ultraviolet lasers. Because dicarbon reacts so quickly, they had to synthesize it on the spot by whittling away a larger molecule with a laser.

Nasa's Imaging X-ray Polarimetry Explorer (IXPE) has successfully extended its 4-metre boom arm to assume its operational configuration. From a report: Launched on 9 December atop a SpaceX Falcon 9 rocket from the Kennedy Space Centre in Florida, IXPE is a space observatory designed to study X-rays from black holes, neutron stars and other exotic celestial objects. To bring X-rays into focus requires a long telescope because mirrors cannot bend the highly energetic rays by large amounts. Instead they have to be coaxed into focus with a device called a grazing incidence telescope. IXPE has three of these. Each sits on the end of the boom arm and directs light into the instruments in the body of the spacecraft. By measuring the polarisation of the X-rays, IXPE will reveal information about the magnetic environment of their targets. At launch the spacecraft was roughly cubic, about 1-metre long on each side, with the 4-metre-long boom arm folded into a canister 0.3 metres in length. This allowed the IXPE to fit into the nose cone of the rocket. On 15 December, the spacecraft extended the boom. Mission personnel are now working to commission the telescope, ready for science observations to begin in the new year.

An 8-foot-long skull discovered in the Augusta Mountains of Nevada is the largest fossil ever found from its time. The research team believes that the remarkable discovery could provide insight into how modern whales developed, and how to preserve their presence in our oceans. From a report: The fossil -- a newly discovered species of ichthyosaur, a type of large aquatic reptile -- dates to about 246 million years ago. The newly-named cymbospondylus youngorum is, according to the research team, the largest animal found from that time period, both in the sea and on land. It currently holds the title of the first giant animal to ever inhabit Earth. The well-preserved skull was excavated along with part of the creature's backbone, shoulder and forefin. At more than 55 feet long, the ichthyosaur was estimated to be the size of a large sperm whale, according to the study released Thursday by the American Association for the Advancement of Science and the Natural History Museums of Los Angeles County. The ichthyosaur has an elongated snout and conical teeth, leading researchers to believe it ate squid and fish. It also could have hunted smaller marine reptiles and younger members of its species.

It's one of the biggest puzzles in modern astronomy: Based on multiple observations of stars and galaxies, the universe seems to be flying apart faster than our best models of the cosmos predict it should. Evidence of this conundrum has been accumulating for years, causing some researchers to call it a looming crisis in cosmology. Now a group of researchers using the Hubble Space Telescope has compiled a massive new dataset, and they've found a-million-to-one odds that the discrepancy is a statistical fluke. From a report: In other words, it's looking even more likely that there's some fundamental ingredient of the cosmos -- or some unexpected effect of the known ingredients -- that astronomers have yet to pin down. "The universe seems to throw a lot of surprises at us, and that's a good thing, because it helps us learn," says Adam Riess, an astronomer at Johns Hopkins University who led the latest effort to test the anomaly.

The conundrum is known as the Hubble tension, after astronomer Edwin Hubble. In 1929 he observed that the farther a galaxy is from us, the faster it recedes -- an observation that helped pave the way toward our current notion of the universe starting with the big bang and expanding ever since. Researchers have tried to measure the universe's current rate of expansion in two primary ways: by measuring distances to nearby stars, and by mapping a faint glow dating back to the infant universe. These dual approaches provide a way to test our understanding of the universe across more than 13 billion years of cosmic history. The research has also uncovered some key cosmic ingredients, such as "dark energy," the mysterious force thought to be driving the universe's accelerating expansion.

It's conceivable that extraterrestrial intelligences are using powerful lasers to grab our attention, but we lack the proper tools to notice. A newly deployed system might be exactly what's needed for us to finally make contact. From a report: Two laser-detecting devices were recently installed on the summit of Haleakala, also known as East Maui Volcano, according to a University of Hawai'i press release. The devices, mounted on the rooftops of an existing building, will now work in concert with similar devices installed in California, at the Robert Ferguson Observatory in Sonoma. Together, these scanners will scour the Pacific skies in hopes of detecting powerful laser pulses sent by an extraterrestrial civilization. Unlike traditional SETI, which seeks to detect alien radio transmissions, optical SETI looks for signs of artificially created light. It makes sense that advanced aliens would want to use lasers for the purpose of communication, as messages transmitted over light have "a fundamental advantage over radio in that it can, in principle, convey far more bits per second -- typically a half-million times as many," according to the SETI Institute, which runs the LaserSETI program. Aliens could use lasers to communicate across interstellar distances, whether to off-world colonies or fledgling civilizations seeking to make first contact. The newly installed system, a collaboration between the SETI Institute and the University of HawaiÊi Institute for Astronomy (IfA), can now monitor more sky than before.

FFP stands for "filtering face piece." It is a European standard for mask efficiency, ranging from one, the lowest grade, to three, the highest. The Economist adds: FFP2 masks filter at least 94% of all aerosols, including airborne viruses such as covid-19. America's N95 and China's KN95 masks provide similar levels of protection. These disposable masks have several layers of different fabrics, including a polypropylene filter, made by "melt-blowing" polymer to create miniscule, irregular fibre patterns that can trap the smallest airborne particles. A study published in December by the Max Planck Institute, a German research organisation, found well-fitting FFP2 masks reduced the risk of infection with covid-19 to 0.1%. Cloth or medical masks, on the other hand, merely disrupt the airflow of the speaker and trap the largest aerosol particles in their woven material. Their efficacy varies wildly depending on the design and fabric used: tight-fitting, multi-layered masks made from dense materials are much more effective than single-layer linen masks. One study in the Journal of Education and Health Promotion found surgical masks were three times more effective at preventing inhalation of aerosols than homemade cloth ones. Another study, in JAMA Internal Medicine, a journal, compared different cloth masks and found that their efficacy at containing viral particles ranged from 26% to 79%.