Astronomers just found the smallest yet most massive dead star ever discovered

A dead star the size of the Moon is the smallest of its kind we've ever seen.

It's a white dwarf star, the ultradense collapsed core of a star in the mass range of the Sun, but it's just 4,280 kilometers (2,660 miles) across. It's also the most massive white dwarf star we've ever seen, clocking in at around 1.35 times the mass of the Sun.

Just take a second to wrap your head around that - a tad over our Sun's mass packed into a sphere only slightly larger than the size of our Moon. Pretty incredible, isn't it?

And the white dwarf, named ZTF J1901+1458 and located around 130 light-years away, really is incredible. Its dense and mass place it right on the verge of the Chandrasekhar limit - the maximum mass a white dwarf can be before it becomes so unstable that it blows up in a spectacular supernova.

"We caught this very interesting object that wasn't quite massive enough to explode," said theoretical astrophysicist Ilaria Caiazzo of Caltech. "We are truly probing how massive a white dwarf can be."

White dwarfs are the smallest class of dead star on the dead star continuum. They are formed from the collapsed cores of stars up to eight times the mass of the Sun; when these stars end their main-sequence (nuclear fusion) lifespans, they blow off their outer material, and the remaining core, no longer supported by the outward pressure of fusion, collapses into an ultradense object.

Up to the Chandrasekhar limit, around 1.4 solar masses, something called electron degeneracy pressure keeps the white dwarf from collapsing further under its own gravity. At a certain pressure level, electrons are stripped from their atomic nuclei - and, because identical electrons can't occupy the same space, these electrons supply the outward pressure that keeps the star from collapsing.

A lot of white dwarf stars exist in binary systems, though. That means they are locked in an orbital dance with another star. If the two stars are close enough, the white dwarf will siphon material off its binary companion, a process that can tip the dead star past the Chandrasekhar limit, often triggering a Type Ia supernova.

ZTF J1901+1458 seems to be a special case.

According to the team's analysis, the white dwarf is the product of a merger between two smaller white dwarfs; together, they were not quite massive enough to reach the Chandrasekhar limit and produce a Type Ia supernova.

It's only up to about 100 million years old, with an insane magnetic field for a white dwarf, about a billion times more powerful than the Sun. It also has an extreme rotation, spinning around once every seven minutes. That's not the fastest white dwarf rotation ever, but it's up there. These characteristics suggest a merger in the past.

What happens from this point could be absolutely fascinating.

"This is highly speculative, but it's possible that the white dwarf is massive enough to further collapse into a neutron star," Caiazzo explained.

"It is so massive and dense that, in its core, electrons are being captured by protons in nuclei to form neutrons. Because the pressure from electrons pushes against the force of gravity, keeping the star intact, the core collapses when a large enough number of electrons are removed."

Neutron stars - even denser than white dwarfs, and supported by neutron degeneracy pressure - form when a star between 8 and 30 times the mass of the Sun reaches the end of its lifespan. Once it goes kablooey, blowing off its outer material, the stellar core collapses into a neutron star.

ZTF J1901+1458, if the team's analysis is correct, suggests another formation pathway for the lower-mass examples of these extreme objects.

This, in turn, could mean that ZTF J1901+1458, and other stars like it, can tell us a lot about the types of white dwarf binaries that turn into neutron stars. The team hopes to find them.

"There are so many questions to address, such as what is the rate of white dwarf mergers in the galaxy, and is it enough to explain the number of type Ia supernovae? How is a magnetic field generated in these powerful events, and why is there such diversity in magnetic field strengths among white dwarfs?" Caiazzo said.

"Finding a large population of white dwarfs born from mergers will help us answer all these questions and more."

The research has been published in Nature.

#Space | https://sciencespies.com/space/astronomers-just-found-the-smallest-yet-most-massive-dead-star-ever-discovered/

Who'd win in a fight - scorpion or tarantula? A venom scientist has the answer

Scorpions and tarantulas are two ancient arachnids that have been walking the Earth for hundreds of millions of years - even before the time of the dinosaurs.

And the question of which would win in a fight has been the subject of numerous YouTube videos, online forums and even research papers.

Well, with more than 900 species of tarantulas and 2,500 species of scorpions found worldwide, the winner depends on who's facing off in the ring. The question comes down to three things: size, speed, and venom.

Choose your fighter

In the wild, scorpions and tarantulas rarely cross paths, but they will battle to protect their territory or themselves as sometimes they try to eat each other.

At first glance, the fight seems evenly matched. Scorpions and tarantulas are typically ambush predators that "sit and wait" for their prey. Both are highly armed.

On Team Scorpion, we have tough armor in the form of a hardened exoskeleton made of overlapping layers of chitin, a protein that's similar to the keratin in our nails.

Scorpions also have grasping pincers to catch and tear prey, which they could use to grab onto the tarantula. One of the world's largest scorpions, the giant forest scorpion (Heterometrus swammerdami), can grow up to 22 centimeters long, and could use its powerful pincers to crush a tarantula.

Luckily, in a pinch, a tarantula could drop its leg to get away, and regrow the leg as it continues molting.

Spiders on Team Tarantula also have the advantage of size. The goliath birdeater (Theraphosa blondi) in South America, for example, has an impressive body length of 12 centimeters, with legs spanning nearly 30 centimeters (the size of an A4 page).

What spiders lack in pincers, they make up for with metal-tipped fangs, enabling them to easily punch through chitin and inflict painful puncture wounds.

Many tarantula species have another special defense called urticating hairs, which are barbed bristles flung from the abdomen against potential attackers. These hairs can severely irritate soft mammalian skin and eyes; however, they would be ineffective against the scorpion's tough exoskeleton.

Superweapon: venoms

Scorpions and tarantulas have a superweapon in their arsenal: venom. Scorpions inject venom via the stinger in their tail, while tarantulas inject via their fangs.

Both spider and scorpion venoms are complex cocktails of thousands of different molecules that mainly target the nervous system. They've been fine-tuned by hundreds of millions of years of evolution to be fast-acting, potent and selective, allowing them to catch their prey (usually insects) and defend themselves from predators (such as mice and birds).

Although spiders have the more fearsome reputation, it's actually scorpion venoms you should be worried about. There are estimated to be over one million scorpion envenomations each year, resulting in more than 3,000 fatalities worldwide.

As a general rule of thumb, the smaller the scorpion pincers, the more potent the venom. For example, deathstalker scorpions (genus: Leiurus) have slender pincers, but their potent venom is filled with neurotoxins that overexcite the nervous system, leading to myocardial injury, pulmonary oedema, and cardiogenic shock. In other words, your heart cannot pump enough blood to key organs like the brain and kidneys.

Meanwhile, tarantula venoms are generally not considered dangerous to humans, with no recorded fatalities to date.

One group of tarantulas you should watch out for are the ornamental tarantulas (genus: Poecilotheria), found in Southeast Asia. These tree-dwelling tarantulas are brilliantly colored, move with lightning speed, and inject large volumes of very potent venom, causing extreme pain and muscle cramps that can last for weeks.

Size and speed

Venoms are typically fast-acting, so whoever is fast enough to get the first strike in the battle has a big advantage.

Using high speed video, scientists found a species of deathstalker scorpion (Leiurus quinquestriatus) can whip its tail at 128 centimeters per second in a defensive strike.

Another study found Texas brown tarantulas (Aphonopelma hentzi) can sprint at similar speeds.

While venoms have evolved as powerful chemical defenses to help level the playing field for these arachnids, there's no doubt size plays an important role in this battle, too. The bigger the animal, the larger the dose of venom required to affect it.

Several studies have recorded scorpions hunting smaller spiders. In Western Australia, the spiral burrow scorpion (Isometroides vescus) specializes in hunting burrow-dwelling spiders, such as trapdoor spiders and wolf spiders.

When the spiders get bigger, however, the tables turn. Some tarantulas are known predators of scorpions.

One study noted that in Yucatán Peninsula villages with high densities of tarantulas, scorpions were conspicuously absent. When the researchers brought the local Mexican red rump tarantula (Tliltocatl vagans) and bark scorpions (Centruroides species) into the laboratory, they found the tarantula successfully predated the scorpion every time, regardless of who attacked first.

Similarly in the US, researchers have recorded Arizona blonde tarantulas (Aphonopelma chalcodes) hunting and eating scorpions. However, lab studies with these species showed if the scorpion got the first sting in, the tarantula would retreat.

Overcoming scorpion venom

Both Arizona blonde and Mexican red rump tarantulas are considered harmless to humans, but bark scorpions have a potent, potentially lethal venom.

So how do these tarantulas overcome the lethal bark scorpions' sting?

Predators and prey are always in an evolutionary arms race, trying to develop strategies to overcome each other's weapons to survive. For example, one bark scorpion predator, the grasshopper mouse, has evolved very slight mutations in its nervous system that make the scorpion toxins much less effective, thereby protecting the mouse.

Another study showed some scorpion venom toxins were active on tarantula nerves, but less so than on insect and mammalian nerves. This means that tarantulas may also have evolved mutations to help protect them from scorpion venom, perhaps even natural means of detoxifying the scorpion venom in some tarantula species' haemolymph (the spider equivalent of blood).

Overall, the battle of the arachnids depends on the size, speed and venom of the contenders — but my money is on the tarantula.

Samantha Nixon, Research officer, The University of Queensland.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

#Nature | https://sciencespies.com/nature/whod-win-in-a-fight-scorpion-or-tarantula-a-venom-scientist-has-the-answer/

NIST laser 'comb' systems now measure all primary greenhouse gases in the air

Researchers at the National Institute of Standards and Technology (NIST) have upgraded their laser frequency-comb instrument to simultaneously measure three airborne greenhouse gases -- nitrous oxide, carbon dioxide and water vapor -- plus the major air pollutants ozone and carbon monoxide.

Combined with an earlier version of the system that measures methane, NIST's dual comb technology can now sense all four primary greenhouse gases, which could help in understanding and monitoring emissions of these heat-trapping gases implicated in climate change. The newest comb system can also help assess urban air quality.

These NIST instruments identify gas signatures by precisely measuring the amounts of light absorbed at each color in the broad laser spectrum as specially prepared beams trace a path through the air. Current applications include detecting leaks from oil and gas installations as well as measuring emissions from livestock. The comb systems can measure a larger number of gases than conventional sensors that sample air at specific locations can. The combs also offer greater precision and longer range than similar techniques using other sources of light.

NIST's latest advance, described in a new paper, shifts the spectrum of light analyzed from the near-infrared into the mid-infrared, enabling the identification of more and different gases. The older, near-infrared comb systems can identify carbon dioxide and methane but not nitrous oxide, ozone or carbon monoxide.

Researchers demonstrated the new system over round-trip paths with lengths of 600 meters and 2 kilometers. The light from two frequency combs was combined in optical fiber and transmitted from a telescope located at the top of a NIST building in Boulder, Colorado. One beam was sent to a reflector located on a balcony of another building, and a second beam to a reflector on a hill. The comb light bounced off the reflector and returned to the original location for analysis to identify the gases in the air.

A frequency comb is a very precise "ruler" for measuring exact colors of light. Each comb "tooth" identifies a different color. To reach the mid-infrared part of the spectrum, the key component is a specially engineered crystal material, known as periodically poled lithium niobate, that converts light between two colors. The system in this experiment split the near-infrared light from one comb into two branches, used special fiber and amplifiers to broaden and shift the spectrum of each branch differently and to boost power, then recombined the branches in the crystal. This produced mid-infrared light at a lower frequency (longer wavelength) that was the difference between the original colors in the two branches.

The system was precise enough to capture variations in atmospheric levels of all of the measured gases and agreed with results from a conventional point sensor for carbon monoxide and nitrous oxide. A major advantage in detecting multiple gases at once is the ability to measure correlations between them. For example, measured ratios of carbon dioxide to nitrous oxide agreed with other studies of emissions from traffic. In addition, the ratio of excess carbon monoxide versus carbon dioxide agreed with similar urban studies but was only about one-third the levels predicted by the U.S. National Emissions Inventory (NEI). These levels provide a measure of how efficiently fuel combusts in emissions sources such as cars.

The NIST measurements, in echoing other studies suggesting there is less carbon monoxide in the air than the NEI predicts, put the first hard numbers on the reference levels or "inventories" of pollutants in the Boulder-Denver area.

"The comparison with the NEI shows how hard it is to create inventories, especially that cover large areas, and that it is critical to have data to feed back to the inventories," lead author Kevin Cossel said. "This isn't something that will directly impact most people on a day-to-day basis -- the inventory is just trying to replicate what is actually happening. However, for understanding and predicting air quality and pollution impacts, modelers do rely on the inventories, so it is critical that the inventories be correct."

Researchers plan to further improve the new comb instrument. They plan to extend the reach to longer distances, as already demonstrated for the near-infrared system. They also plan to boost detection sensitivity by increasing the light power and other tweaks, to enable detection of additional gases. Finally, they are working on making the system more compact and robust. These advances may help improve understanding of air quality, specifically the interplay of factors influencing ozone formation.

#Environment | https://sciencespies.com/environment/nist-laser-comb-systems-now-measure-all-primary-greenhouse-gases-in-the-air/

Rattlesnakes may like climate change

When it comes to climate change, not all organisms will lose out. A new Cal Poly study finds that rattlesnakes are likely to benefit from a warming climate.

A combination of factors makes a warming climate beneficial to rattlesnakes that are found in almost every part of the continental United States but are especially common in the Southwest.

Rattlers are experts at thermoregulation. Researchers found that, when given a choice, the snakes prefer a body temperature of 86-89 degrees Fahrenheit, a much warmer temperature than they generally experience in nature. The average body temperature of coastal rattlesnakes in the study was 70 degrees, and for inland rattlers it was 74 degrees Fahrenheit.

"We were surprised to see how much lower the body temperatures of wild snakes were relative to their preferred body temperatures in the lab," said Hayley Crowell, a graduate student researcher and project lead. "There are a lot of ecological pressures in nature that could prevent rattlesnakes from basking, such as the risk of increased exposure to predators. A warmer climate may help these snakes heat up to temperatures that are more optimal for digestion or reproduction."

Longer periods of warmer temperatures would also give rattlesnakes a longer active season, giving them more time to hunt and feed. Because snakes are ectothermic, or cold-blooded, they cannot regulate their body temperatures like warm-blooded animals. Instead, they rely on their surroundings to provide heat, which restricts their activity in cold weather.

In addition to seasonal changes, rattlers could spend more active hours during a given day.

A possible lack of prey -- rattlesnakes eat mostly rodents, but may also eat insects and other reptiles -- resulting from a warming climate may not be a big problem for the snakes either.

The research team discovered that the snakes use energy extremely efficiently. To subsist, an adult male rattlesnake needs only 500-600 calories for an entire year, which is about one ground squirrel, the equivalent of only about half a large burrito. Though in the real world a rattler needs additional calories to hunt and bear young among other activities, the calculations point to the snakes' ability to survive even if prey isn't plentiful. Humans, by comparison, need about 1,300 times as many calories to survive.

"Rattlesnakes require very little energy to exist," said Crowell, who earned a master's degree in biological sciences at Cal Poly.

Rattlesnakes are widespread throughout California, and the seven species of these vipers in the Golden State can be found from the coast to the desert. An increase in the number of snakes could affect entire ecosystems. Rattlesnakes are a keystone predator for ground squirrels in California and are prey for raptors and many other animals.

"We are so used to climate change studies that forecast negative impacts on wildlife -- it was interesting to see such starkly different findings for these snakes," said Crowell, who is seeking a doctorate at the University of Michigan.

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#Nature | https://sciencespies.com/nature/rattlesnakes-may-like-climate-change/

Dutch administrative court sides with Inmarsat on spectrum auction plan

TAMPA, Fla. — An administrative court in the Netherlands has suspended the Dutch government’s plan to sell off 3.5 GHz spectrum, which British satellite operator Inmarsat uses for maritime safety and distress services.

The Hague District Court ordered a provisional injunction June 30, telling the government to consult with Inmarsat to find another solution for releasing the frequencies for terrestrial 5G services next year.

The current update to the government’s National Frequency Plan would give 5G providers full use of the spectrum, forcing Inmarsat to move a ground station in the northern part of the Netherlands.

“We are pleased that the vital safety services that protect the lives of 1.6 million seafarers worldwide daily delivered via Inmarsat satellites will not now be put at risk by the change to the National Frequency Plan,” Inmarsat General Counsel Brad Swann said in a statement.

“Inmarsat does not seek to halt the roll-out of 5G in the Netherlands and it can still proceed alongside the maintenance of essential satellite safety services.”

The satellite operator has said it uses about a quarter of the 3.5 GHz band, and that its technical studies have shown ways to coexist alongside 5G services in the region.

“We’ll continue our ongoing discussions with Inmarsat and other parties about a future solution for satellite communications like maritime safety services,” Harald Hanemaaijer, spokesperson for the Dutch Ministry of Economic Affairs and Climate Policy, told SpaceNews.

“The Dutch government acknowledges the importance of these services.”

The preliminary judgment cannot be appealed but precedes a full court judgment that will come at a date to be determined by the court.

#Space | https://sciencespies.com/space/dutch-administrative-court-sides-with-inmarsat-on-spectrum-auction-plan/

A mouse embryo with a beating heart has been grown entirely in a Petri dish

The most complex life forms ever developed entirely in Petri dishes can pump blood through tiny beating hearts, gradually growing nerves and muscles in a laboratory.

These little collections of mammalian cells form rudimentary mouse embryos, built from scratch out of stem cells - cells that have the potential to develop into any other cell type in the body.

While scientists have successfully been creating synthetic organs called organoids for a while now, these lack the full variety of cell types found in the real deal. This human-built mouse embryoid is a whole lot more intricate.

"Watching an embryo develop is a marvelous thing to behold," said developmental biologist Christine Thisse from the University of Virginia, one of the authors of the study.

"What is amazing is that we can get the variety of tissues that are present in an authentic mouse embryo. [This] model shows that we are able to induce cells to execute complex developmental programs in the right succession of steps."

The embryoid isn't a complete unborn mouse, and it can't fully develop into one as key parts are still missing - like a giant chunk of the brain. But the complexity of this experiment takes researchers a huge step towards being able to build fully functional organs in a lab.

"Human organs are made of multiple cell types that originate from different parts of the growing embryo," said developmental biologist Bernard Thisse. "The gut, for example, is made from cells that form a hollow tube. Models of this tube in a dish have been made and are called gut organoids.

"However, this tube is not enough to make a functional gut because this organ contains other components, such as smooth muscles, blood vessels and nerves that control the function of the gut and which are made from cells of different origins.

"The only way to have all the variety of cells necessary to the formation of functional organs is to develop systems in which all precursor cells are present. The embryo-like entities we have engineered using stem cells are providing just this."

Developing these fully functioning biological systems requires getting a slew of things just right - such as the correct cell type, spatial location, and timing of cell signals to get the desired outcome. Synthetically recreating these complex processes is only possible thanks to generations of research in developmental biology, including this team's previous research on zebrafish.

Many previous attempts have been built upon. These were missing things like entire types of tissues, didn't form a head structure, failed to organize tissues correctly, or develop to the embryonic stage called gastrulation.

Many of these issues involved the need to spatially confine the developmental chemical signals within the forming embryoid. Thisse and colleagues developed a way to do this in their zebrafish experiments - creating centers for the signalling chemicals that provide the cell clusters with a sense of direction - back and front, head and tail.

They could then control the timing, size, and strength of these signals.

Their work has now culminated in these miraculously functioning mouse embryos, with all the normal early embryonic tissue layers. The correctly organized cells and tissues are arranged properly around the embryoid spinal cord precursor (the notochord), including developing digestive, muscular, nervous and circulatory systems and a beating heart.

However, the embryoid is still missing parts of the brain, and the team suspects this may be because the chemical signal telling the cells they're at the butt end (called a WNT morphogen) spread too far.

"With the techniques we have developed, we should be able, at some point, to manipulate molecular signals that control embryo formation, and this should lead to generating embryo-like entities containing all tissues and organs including the anterior brain," said Bernard Thisse.

The researchers hope to learn how to fully control and manipulate the embryoid development, and think it may become a powerful tool for studying diseases.

"Having all the variety of tissues made allows us to hope that the scientific community will be able to build organs with a proper vascularization, innervation and interactions with other tissues," Christine Thisse said. 

"This is essential to be able one day to produce functional human replacement organs in a dish. This would overcome the shortage of organs for transplants."

Their research was published in Nature Communications.

#Nature | https://sciencespies.com/nature/a-mouse-embryo-with-a-beating-heart-has-been-grown-entirely-in-a-petri-dish/

DNA data and modelling reveal potential spread of invasive species

Scientists at the University of Southampton have found that a marine invasive species -- a sea squirt that lives on rocky shores -- could spread along 3,500 kilometres of South American coastline if climate change or human activities alter sea conditions.

The researchers -- working with colleagues at Pontificia Universidad Católica de Chile; Flinders University, Australia; University of Johannesburg and Rhodes University, South Africa -- analysed the creature's DNA and used predictive modelling to identify regions it could move to and thrive in.1 Findings are published in the journal PNAS.

The team took a multidisciplinary approach to predict the potential distribution of a species that is currently restricted. Studying species with small distributions provides a unique opportunity to understand how some eventually become widespread.

Pyura praeputialis is an invertebrate that dominates the ecology of the regions it lives in and has the capacity to alter, fundamentally, coastal habitats. By outcompeting and overgrowing native fauna, invasive species such as this can cause impacts to biodiversity and even important economic activities.

The team sequenced the DNA of 190 samples from 13 sites along South America and Australia. They discovered that the species found in South America originated from a single region off Sydney, Australia -- possibly transported to Antofagasta Bay in Chile on the hulls of wooden trading boats over 100 years ago. The population has remained trapped in the bay ever since, contained within its body of relatively warm water, which is 2-3 degrees higher than the surrounding sea.

However, this latest study suggests that just a slight change in currents, sea temperature and/or shipping routes may lead to an unchallenged expansion of the species to encompass a vast portion of coast, including northern Chile, Peru and much of Ecuador.

Lead researcher, research fellow Jamie Hudson comments: "Understanding why some species are widespread, whereas others have narrow ranges is a fundamental question in biological studies. Our work shows the importance that combining genomic data from DNA and habitat modelling can have in helping predict potential changes in the distribution of species and their impacts.

"The unusual conditions of Antofagasta Bay provided us with ideal conditions to study a species which has had its distribution restricted by local conditions. We found high genomic diversity in both native and introduced populations, indicating high adaptive potential in Chile."

The researchers concluded that further monitoring of Pyura praeputialis in the region is strongly recommended and that, more generally, future studies should consider both habitat suitability and genomic data to assess holistically the spread potential of invasive species.

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#Nature | https://sciencespies.com/nature/dna-data-and-modelling-reveal-potential-spread-of-invasive-species/

Air pollution from wildfires impacts ability to observe birds

As smoky air becomes more common during Washington's wildfire season, many wildlife enthusiasts wonder: What happens to the birds?

Few studies have looked at wildfire smoke impacts on animals, let alone birds. And as Washington and the larger West Coast continue to experience more massive wildfires and smoke-filled air, understanding how birds are affected by smoke -- and how air pollution may influence our ability to detect birds -- are important factors for bird conservation.

Researchers from the University of Washington now provide a first look at the probability of observing common birds as air pollution worsens during wildfire seasons. They found that smoke affected the ability to detect more than a third of the bird species studied in Washington state over a four-year period. Sometimes smoke made it harder to observe birds, while other species were actually easier to detect when smoke was present. The results were published June 29 in the journal Ornithological Applications.

"We want to know how wildfire smoke affects birds and other wildlife, and this study is a great place to start," said lead author Olivia Sanderfoot, a doctoral candidate in the UW School of Environmental and Forest Sciences. "Smoke clearly has an impact on detection of wildlife, and that hasn't been adequately explored in the literature to date. Now we know that smoke pollution specifically affects our observations of birds and our ability to detect them."

The researchers combined data from eBird, an online citizen-science program managed by the Cornell Lab of Ornithology, with publicly available data from an extensive network of air quality monitors across Washington state. They were able to analyze how fine particulate matter, known as PM2.5 and a marker of smoke pollution, affected the probability of observing 71 common bird species during the wildfire seasons of 2015 to 2018. Higher concentrations of smoke affected the chances of observing 37%, or 26, of the bird species included in the study.

Sixteen of the bird species were harder to observe with more wildfire smoke, the study found. These include turkey vultures, Canada geese, two gull species, bald eagles and several other birds of prey. Many of these birds are observed circling high above the ground, so it's not surprising that people would have a harder time detecting them on smoky days, the authors said. However, 10 additional species were easier to observe when smoke concentrations were higher. These include three types of warblers, cedar waxwing, spotted towhee and California quail.

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The reasons for this aren't clear and are outside of the scope of this study, but the authors lay out some hypotheses for future exploration. It could be that reduced visibility due to smoke pushes some birds lower to the ground where they can be more easily seen and heard. Or, as smoke prompts birds of prey to relocate, that could alleviate pressure on some songbirds and cause them to be more active -- and thus more detectable by people.

"These behavioral changes are all hypotheticals, and we very much hope that researchers follow up on them because we have a lot to learn about how smoke affects wildlife," Sanderfoot said.

Conservation and management efforts rely on the ability to observe animals in the wild, and it's no different for birds. Air pollution clearly plays a role in detecting animals, and this paper makes the case that it should be considered alongside other factors like time of day, temperature and precipitation that all can influence observations of animals.

"If we see or hear birds more or less frequently because of smoke, that also impacts bigger inferences we make in terms of how certain bird populations are doing," said senior author Beth Gardner, an associate professor in the School of Environmental and Forest Sciences. "We want to get that part right, so we first need to understand the effect of air pollution on how we're seeing birds in the wild."

The researchers chose a four-year study period that included some summers where wildfire smoke was heavy in parts of the state, and other summers where smoke was negligible. All of the species included in the study had to have had at least 750 observations recorded for the first year (2015), and all observations used were within about 20 miles (32 kilometers) of an air quality monitor in Washington.

Data from the catastrophic 2020 wildfire season was not part of this analysis, although air quality during that period was worse than in any of the years in the study. As extreme wildfire seasons like 2020 become more common, it's important to consider the influence of events like these in future studies, the researchers said.

This research was funded by the National Science Foundation and the McIntire-Stennis Cooperative Forestry Research Program from the USDA National Institute of Food and Agriculture.

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Materials provided by University of Washington. Original written by Michelle Ma. Note: Content may be edited for style and length.

#Environment | https://sciencespies.com/environment/air-pollution-from-wildfires-impacts-ability-to-observe-birds/

China outlines space plans to 2025

Country to focus on a range of exploration, human spaceflight, space infrastructure and transportation objectives.

HELSINKI — China’s space administration has outlined its priorities in space science, technology, applications and exploration for the coming years.

Lunar, interplanetary and near-Earth asteroid missions, space station construction, a national satellite internet project and developing heavy-lift launch vehicles and reusable space transportation systems are noted as major projects for the period 2021-2025.

China National Space Administration (CNSA) Secretary General Xu Hongliang laid out the main activities and focus of the country’s civilian space endeavors in a press conference June 12.

Boosting innovation, supporting economic and social development and engaging in international cooperation were noted as major objectives.

In lunar exploration the Chang’e-6 sample return and complex Chang’e-7 south pole mission are to be conducted during China’s “14th Five-Year Plan” period. Chang’e-8, to include in-situ resource utilization and 3D-printing technology tests, will follow. All missions will form part of the first phase of the International Lunar Research Station (ILRS) project with Russia.

CNSA is also looking to build on the recent success of the country’s first independent interplanetary expedition with the Tianwen-1 Mars orbiter and Zhurong rover. Development of a Mars sample return mission and a Jupiter probe for launches around 2028 and 2030 respectively are noted as follow-up projects.

“So far, our knowledge of the Jupiter system is very superficial, and the detections performed are also very limited,” said Zhang Rongqiao, chief designer of Tianwen-1.

“The Jupiter system offers a large number of opportunities for scientific discoveries.” One proposal for the mission includes a landing on the Galilean moon Callisto. 

A section of a panorama produced by Zhurong, released June 27, showing comms and solar arrays, roving tracks and the distant landing platform. Credit: CNSA/PEC

Zhang also stated that technology breakthroughs are needed for missions. “Everyone knows that, so far, no country in the world has been able to carry out a sample and return from Mars, because it is too technically difficult.” China performed a complex lunar sample return in late 2020 but Zhang noted that the challenges of launching samples from the surface Mars were different to that of the moon.

Launching around 2025 will be a near-Earth asteroid sample return mission to small body 469219 Kamo’oalewa. The mission was previously targeting a 2024 launch, with the secondary target following the delivery of samples to Earth last understood to be main-belt comet 311P/PANSTARRS. 

Not mentioned are a pair of probes to launch for the head and tail of the heliosphere, which is however led by figures from the Chinese Academy of Sciences (CAS).

In human spaceflight China aims to complete the construction of its three-module space station by the end of 2022. The Tianhe core module launched late April and is currently hosting its first crew. 

CNSA also aims to enhance satellite application capabilities over the next five years. Goals include improving national civil space infrastructure and supporting ground facilities and enhancing Earth observation, communication and broadcasting, and navigation and positioning capabilities, as well as promoting and supporting downstream applications and to boost economic development. China recently established a company to oversee development of a 13,000-satellite constellation for satellite internet.

Expanding international exchanges and cooperation is another major strand. Citing guiding principles of equality, mutual benefit, the peaceful use of outer space and inclusive development, Xu noted projects include the ILRS, a second Sino-Italian seismo-electromagnetic satellite, a follow-up to the China–Brazil Earth Resources Satellite (CBERS) program and the China-France SVOM astronomical X-ray space telescope.

The upcoming Chang’e and asteroid missions will also include international payloads. The future lunar, Mars and Jupiter missions will be opened to international cooperation, according to Xu.

Other cooperation activities promoting the construction of the “Belt and Road” spatial information corridor, the BRICS remote sensing satellite constellation and jointly responding to the common challenges of global climate change and dangers of near-Earth asteroids. The under-construction Wenchang International Aerospace City is expected to be developed as a hub for international scientific research, academic exchanges, exhibitions and training.

Details on launch vehicle technology were not offered, other than underlining its fundamental importance to progress in aforementioned missions. China’s government approved the development of separate super heavy-lift launchers in March for infrastructure and crewed flights. China’s main space contractor CASC is developing a first vertical takeoff, vertical landing launcher in the Long March 8 and working on a ‘reusable experimental spacecraft’ widely held to be a spaceplane.

China’s government is expected to publish a dedicated space white paper later in 2021. The document, published once every five years, will provide a longer, more detailed report on civil space activities from the past five years and those planned for 2021-2025. 

The country’s growing military space infrastructure, including a large intelligence, surveillance and reconnaissance network and missile and electronic anti-satellite capabilities overseen by the People’s Liberation Army Strategic Support Force (PLASSF), will fall outside of the scope of the report.

#Space | https://sciencespies.com/space/china-outlines-space-plans-to-2025/

Mysterious mineral only ever seen in meteorites inexplicably found by the Dead Sea

A very rare mineral that's previously been found only in extraterrestrial meteorites has been discovered in Earth's own rocks for the first time, lying in a sedimentary formation not far from the shores of the Dead Sea.

Allabogdanite, a phosphide mineral, was unknown to science until just a couple of decades ago, after fragments of a small iron meteorite were recovered from the Bolshoi Dolguchan River in Eastern Yakutia, Russia.

A sample of the fragments later revealed the presence of a new mineral structure occurring as thin layers of crystals spread throughout the meteorite's plessite mixture. The discoverers named it after Russian geologist Alla Bogdanova.

Subsequently, allabogdanite has been found in other meteorites too, suggesting that the rare mineral might not be quite as exclusive as had been believed.

Even so, only being found in rocks falling out of the sky is still a pretty special status all told – and yet now it seems allabogdanite also has Earthly origins we never knew about.

(Mineralogical Society of America)

Above: General view of a sample from the Hatrurim basin. Left: Polished cross-section showing allabogdanite and barringerite grains (white pebbles). Right: The same fragment showing grains of allabogdanite (mixed colors) and barringerite (yellow).

In a new study, scientists report the discovery of allabogdanite in the Negev Desert of Israel, located to the southwest of the Dead Sea.

"The discovery of the high-pressure polymorph of (Fe,Ni)2P, allabogdanite in the surficial pyrometamorphic rocks of the Hatrurim Formation (the Mottled Zone) surrounding the Dead Sea basin in Israel is the first terrestrial occurrence of a mineral previously only found in iron meteorites," a team of researchers, led by crystallographer Sergey Britvin from St Petersburg University in Russia, explains in the new paper.

While the Dead Sea's allabogdanite might not come from outer space, it still remains possible – perhaps – that it was born out of some kind of extraterrestrial event, the researchers say.

Analysis of the Hatrurim sample – and experiments exploring how it transitions from its low-pressure polymorph state, the mineral barringerite – suggest this terrestrial allabogdanite only forms under extremely high pressure: over 25 gigapascals.

"Such high pressures on Earth can be attained during catastrophic collisions with large meteorite impactors, or at the Earth's mantle conditions, at a depth of more than 500 kilometers," Britvin says.

However, as there's no evidence of large meteorite collisions in the region – nor any signs that the rocks in the Mottled Zone have deep ties to Earth's mantle – it's not exactly clear how this terrestrial allabogdanite came to be.

If we can locate other instances of terrestrial allabogdanite, it might give us more to go on. But until we can find another source of this unusual mineral on Earth, it's hard to say more, the team concludes.

"Therefore, the origin of terrestrial allabogdanite in the rocks of the Mottled Zone remains unresolved and adds to the number of mineralogical enigmas of this unusual metamorphic complex," the researchers explain.

The findings are reported in American Mineralogist.

#Nature | https://sciencespies.com/nature/mysterious-mineral-only-ever-seen-in-meteorites-inexplicably-found-by-the-dead-sea/

Virgin Orbit looks to increase launch rates in 2022

WASHINGTON — On the eve of its second revenue-generating launch, Virgin Orbit is looking to 2022 to ramp up its launch activity and operate from several airports in the United States and Great Britain.

In a call with reporters June 209, Virgin Orbit Chief Executive Dan Hart confirmed that the company was “green for launch” on a LauncherOne mission called “Tubular Bells: Part One.” The company’s Boeing 747 aircraft, which serves as the launch platform for the LauncherOne rocket, is scheduled to take off from Mojave Air and Space Port in California between 9 and 11 a.m. Eastern June 30, with release of the rocket about one hour after takeoff.

The mission is carrying seven cubesats for three customers: the U.S. Defense Department’s Space Test Program, the Royal Netherlands Air Force and Polish satellite company SatRevolution. The satellites will be placed into low Earth orbit, although Virgin Orbit did not disclose specific orbital parameters.

The launch is the first for Virgin Orbit since January, when a LauncherOne successfully placed 10 cubesats into orbit on a NASA-funded mission called Launch Demo 2. That came after the company’s initial launch attempt in May 2020, which failed to reach orbit when a propellant line ruptured seconds after main engine ignition.

Hart said that, after the “Tubular Bells: Part One” mission, the company expects to perform “at least” one more LauncherOne mission this year, also flying out of Mojave. He did not disclose a date or customer for that next mission.

He said the current relatively slow pace of activity is to take the time needed to review the data from launches and make modifications if needed. “You want to make sure you pore through the data very carefully and there may be minor adjustments that you make along the way,” he said.

That included what Hart called “very minor” hardware changes based on a review of data from the January launch. “There was a little bit of tweaks as this was the first time we got full aerodynamics through the entire flight regime,” he said, such as adjusting flight controls and optimizing propellant management during the coast phase after reaching orbit.

Virgin Orbit expects to increase launch activity in 2022. “We will be ramping up sharply,” Hart said, with six launches projected next year, including from Andersen Air Force Base in Guam and Spaceport Cornwall in England. Five rockets are in various phases of integration at the company’s factory.

“Now it’s a matter of just continuing to ramp up,” he said, “and moving rockets through integration.”

Virgin Orbit also announced June 29 that it signed a memorandum of understanding with SatRevolution that it said could lead to later launch contracts for “hundreds” of satellites through 2026. SatRevolution said it’s planning a “constellation of constellations” for imaging, synthetic aperture radar and internet of things services.

“We have signed up quite a few folks over the last two or three months,” Hart said, with customer interest growing after its first successful launch, and even during it. “I got a launch agreement signed and texted to me, for instance, in the middle of the second-stage flight” of that earlier launch.

Hart declined to comment on investor interest in Virgin Orbit. The company has been working since last year to raise a new funding round. Sky News reported June 12 that the company was in “advanced talks” with NextGen Acquisition II, a special purpose acquisition corporation (SPAC), for a merger that would raise several hundred million dollars and take Virgin Orbit public with a valuation of about $3 billion.

“We’ve had terrific support from our investors, and continue to have very, very solid support,” he said.

#Space | https://sciencespies.com/space/virgin-orbit-looks-to-increase-launch-rates-in-2022/

An extreme supernova lit the skies 1,000 years ago. We may finally know its type

Way back in 1054 CE, a supernova stellar explosion lit up the skies with enough brightness that it could be seen from from Earth during the daytime, for 23 days straight.

Its remnants still exist today as the Crab Nebula, and new research gives us our best idea yet of exactly what happened to cause such a phenomenon.

Based on an analysis of a more recent supernova labeled SN 2018zd, astronomers think both SN 2018zd and the 1054 CE supernova are electron-capture supernovae – a rare third type of supernova alongside type I (thermonuclear) and type II (core collapse).

Experts have hypothesized about this third type of exploding star for decades at this point, though actual physical evidence of electron-capture supernovae has been difficult to come by. The unusual characteristics of SN 2018zd – a mere 31 million light-years away – may be the first one we've actually properly identified.

"This supernova is literally helping us decode thousand-year-old records from cultures all over the world," says astrophysicist Andrew Howell, from the University of California, Santa Barbara (UCSB). "And it is helping us associate one thing we don't fully understand, the Crab Nebula, with another thing we have incredible modern records of, this supernova.

"In the process it is teaching us about fundamental physics: how some neutron stars get made, how extreme stars live and die, and about how the elements we're made of get created and scattered around the Universe."

Every star is in a constant battle with gravity, with either ongoing fusion or densely packed atoms prolonging its lifespan. In the case of supernovae, typically either an increase in mass leads to a runaway thermonuclear explosion (type I), or the star runs out of fuel and its iron core collapses (type II).

Even before this discovery though, scientists suspected a third scenario: where electrons in a star's oxygen-neon-magnesium core get smashed into atomic nuclei, causing it to collapse under its own weight. A very precise balance is required for this, otherwise the star is too heavy or light to be pulled into its death throes in this particular way.

Artist impressions of a super-asymptotic giant branch star and its core. (S. Wilkinson; Las Cumbres Observatory)

Scientists had already figured out that an electron-capture supernova should form from a rare and massive super-asymptotic giant branch (SAGB) star, and meet five other criteria – extensive mass loss before the supernova phase, an unusual chemical composition, a weak explosion, low radioactivity, and a neutron-rich core.

Using archival images taken by the Hubble Space Telescope before SN 2018zd exploded, as well as more recent readings post-explosion, astronomers noticed that SN 2018zd met all six indicators for an electron-capture supernova – the first supernova on record to do so.

"We started by asking 'what's this weirdo?'" says astrophysicist Daichi Hiramatsu, from UCSB. "Then we examined every aspect of SN 2018zd and realized that all of them can be explained in the electron-capture scenario."

While it was previously thought the Crab Nebula was the result of an electron-capture supernova, it's much trickier to try and piece together the physics of an explosion that was observed from Earth a thousand years ago. The new research makes it more likely that the 1054 CE event was a type III explosion, and partly explains its brightness.

The team thinks the material cast off by the exploding star collided with the remnants of the supernova, increasing its luminosity in the sky, because exactly the same effect was observed to happen for SN 2018zd.

Astronomer Ken Nomoto from the University of Tokyo in Japan, who made that first prediction of electron-capture supernovae back in 1980, has been able to see his hypothesis backed up with new findings discovered more than four decades later.

"I am very pleased that the electron-capture supernova was finally discovered, which my colleagues and I predicted to exist and have a connection to the Crab Nebula 40 years ago," says Nomoto.

"I very much appreciate the great efforts involved in obtaining these observations. This is a wonderful case of the combination of observations and theory."

The research has been published in Nature Astronomy.

#Space | https://sciencespies.com/space/an-extreme-supernova-lit-the-skies-1000-years-ago-we-may-finally-know-its-type/

This cool 4,400-year-old snake stick from Finland may have belonged to a shaman

A wooden stick carved into the shape of a snake dating back about 4,400 years has been discovered by a lake in southwest Finland. The stick may have been used for mystical purposes by a shaman.

"I have seen many extraordinary things in my work as a wetland archaeologist, but the discovery of this figurine made me utterly speechless and gave me the shivers," archaeologist Satu Koivisto said in a statement. Koivisto is a postdoctoral researcher at the University of Turku in Finland who leads research at Järvensuo, the site where the object was found. 

The figure, which is 21 inches (53 centimeters) long and about an inch (2.5 cm) thick, was "carved from a single piece of wood," Koivisto and co-author Antti Lahelma, an archaeologist at the University of Helsinki, wrote in a paper published June 29 in the journal Antiquity.

"The figurine is very naturalistic and resembles a grass snake (Natrix natrix) or a European adder (Vipera berus) in the act of slithering or swimming away," the researchers wrote.  

Related: The 25 most mysterious archaeological finds on Earth

A researcher not involved in the study suggested the artifact may depict a viper. "I would say that a viper is more correct, due to the shape of its head, the short body and distinguishable tail," Sonja Hukantaival, a postdoctoral researcher in Nordic Folkloristics at Åbo Akademi University in Finland, told Live Science in an email.

"This is interesting, since the viper has an important role in much later (historical) folk religion and magic."

The snake figurine where it was found and the excavated artefact photographed from above (S. Koivisto).

The carving could have been used as a decorative figurine, or perhaps it was a staff used by a shaman, the researchers wrote. 

"As a preliminary hypothesis, it seems reasonable, however, to place the artifact in the religious sphere," the researchers wrote. According to historical records that discuss pre-Christian beliefs, "snakes are loaded with symbolic meaning in both Finno-Ugric and Sámi cosmology, and shamans were believed to be able to transform into snakes" they said.

The Sámi live in northern Scandinavia and Russia, while Finno-Ugric languages are spoken in Scandinavia and eastern Europe. 

However, the artifact dates back to long before Finnish people began keeping written records, and researchers can't be certain that people held the same beliefs around 4,400 years ago, Koivisto told Live Science. 

The team has also found a large number of fishing artifacts at the Järvensuo site, suggesting ancient fishers frequented the area. 

Fascinating find

Experts not affiliated with the research told Live Science that they found the find fascinating. 

"This marvelous find shows that people in the Neolithic had a great concern over the subterranean world that we, today, are mostly unaware of," said Vesa-Pekka Herva, the head of the archaeology department at the University of Oulu in Finland. 

A few scholars that Live Science talked to raised the idea that the artifact could be an offering. The fact that it was found in a wetland by a lake "supports the idea that this precious artifact was an offering, and not an accidentally lost item," said Kristiina Mannermaa, a professor in the department of cultures at the University of Helsinki.

Mannermaa noted that Finland's acidic soil does not often preserve wooden artifacts for so long. "This is a remarkable sign for Finnish archaeologists that such wetland sites must be investigated before they are destroyed by, for example, drainage and peat extraction [a process in which peat is removed and sold as fertilizer]," said Mannermaa."

The discovery may be important for the modern day Sámi people said Francis Joy, a postdoctoral researcher at the University of Lapland.

If the artifact "was linked with the ancient ancestors of the Sámi it would bring into focus issues concerning repatriation and also give the Sámi people validation in terms of their prehistory in southern Finland" Joy told Live Science. At times the Sámi have faced discrimination and have campaigned for their rights for many years. 

Joy also said that more archaeological work should be done to see if there is an offering place close to where the artifact was found. 

Research at the site and analysis of the artifact are ongoing. Researchers are attempting to determine what kind of wood the artifact is made from.

Related content:

Back to the Stone Age: 17 key milestones in Paleolithic life

30 of the world's most valuable treasures that are still missing

7 bizarre ancient cultures that history forgot

This article was originally published by Live Science. Read the original article here.

#Humans | https://sciencespies.com/humans/this-cool-4400-year-old-snake-stick-from-finland-may-have-belonged-to-a-shaman/

Dinosaurs were in decline before the end

The death of the dinosaurs 66 million years ago was caused by the impact of a huge asteroid on the Earth. However, palaeontologists have continued to debate whether they were already in decline or not before the impact.

In a new study, published today in the journal Nature Communications, an international team of scientists, which includes the University of Bristol, show that they were already in decline for as much as ten million years before the final death blow.

Lead author, Fabien Condamine, a CNRS researcher from the Institut des Sciences de l'Evolution de Montpellier (France), said: "We looked at the six most abundant dinosaur families through the whole of the Cretaceous, spanning from 150 to 66 million years ago, and found that they were all evolving and expanding and clearly being successful.

"Then, 76 million years ago, they show a sudden downturn. Their rates of extinction rose and in some cases the rate of origin of new species dropped off."

The team used Bayesian modelling techniques to account for several kinds of uncertainties such as incomplete fossil records, uncertainties over age-dating the fossils, and uncertainties about the evolutionary models. The models were each run millions of times to consider all these possible sources of error and to find whether the analyses would converge on an agreed most probable result.

Guillaume Guinot, also of the Institut des Sciences de l'Evolution de Montpellier, who helped run the calculations, added: "In all cases, we found evidence for the decline prior to the bolide impact.

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"We also looked at how these dinosaur ecosystems functioned, and it became clear that the plant-eating species tended to disappear first, and this made the latest dinosaur ecosystems unstable and liable to collapse if environmental conditions became damaging."

Phil Currie, a co-author of the study, from the University of Edmonton (Alberta, Canada), said: "We used over 1,600 carefully checked records of dinosaurs through the Cretaceous.

"I have been collecting dinosaurs in North America, Mongolia, China, and other areas for some time, and I have seen huge improvements in our knowledge of the ages of the dinosaur-bearing rock formations.

"This means that the data are getting better all the time. The decline in dinosaurs in their last ten million years makes sense, and indeed this is the best-sampled part of their fossil record as our study shows."

Professor Mike Benton from the University of Bristol's School of Earth Sciences, another co-author, added: "In the analyses, we explored different kinds of possible causes of the dinosaur decline.

"It became clear that there were two main factors, first that overall climates were becoming cooler, and this made life harder for the dinosaurs which likely relied on warm temperatures.

"Then, the loss of herbivores made the ecosystems unstable and prone to extinction cascade. We also found that the longer-lived dinosaur species were more liable to extinction, perhaps reflecting that they could not adapt to the new conditions on Earth."

Fabien Condamine added: "This was a key moment in the evolution of life. The world had been dominated by dinosaurs for over 160 million years, and as they declined other groups began their rise to dominance, including the mammals.

"The dinosaurs were mostly so huge they probably hardly knew that the furry little mammals were there in the undergrowth. But the mammals began to increase in numbers of species before the dinosaurs had gone, and then after the impact they had their chance to build new kinds of ecosystems which we see today."

#Nature | https://sciencespies.com/nature/dinosaurs-were-in-decline-before-the-end/

Op-ed | To solve for Arctic connectivity, governments need a network suited to their unique needs

The next wave of LEO infrastructure building should not be seen as individual satellites, but as always-on mesh networks.

Space is becoming more congested and communications all over the globe — but particularly in the Arctic region — are often contested.

Governments can in turn meet their urgent national security connectivity needs in the Far North through the proliferated architecture needed for resilient space operations.

Whether discussing Northern surveillance and NORAD modernization or the Enhanced Satellite Communication Project Polar (ESCP-P), governments are considering new infrastructure investments to meet defense mission requirements in these strategic locations.

But addressing these requirements doesn’t have to include building bespoke government networks. Several companies are investing billions of dollars in creating commercial satellite networks in low Earth orbit (LEO) and, with the right design, will be able to meet government needs. By clearly defining commercial space as part of their government space architecture and strategy, governments can in turn meet their urgent national security connectivity needs in the Far North through the proliferated architecture needed for resilient space operations.

Here’s a breakdown of why this is needed and how commercial networks designed with embedded security can meet government requirements:

CURRENT SHORTCOMINGS — AND WHAT GOVERNMENTS NEED

Current satellite connectivity has a number of shortcomings that prevent full global connectivity and are not at the standard that governments require. The first issue is coverage: geostationary (GEO) satellites, which account for most of the world’s connectivity today, are mostly at the equator and can’t “see” to the far north and south, allowing for “dead zones” of coverage. Cost is another challenge, as building the kind of network needed by governments from scratch is expensive.

Further, considering the sensitive nature of government and defense communications, secure and fast solutions are crucial. Traditional GEO satellites are more vulnerable because they operate at a single fixed point in the sky and can be compromised more easily, impacting critical operations. They also have higher latency, and in government and defense response, every millisecond counts.

WHERE DOES COMMERCIAL INNOVATION COME INTO PLAY?

Proliferated LEO networks are the solution to current shortcomings, including reaching into remote Northern areas, and present an opportunity for governments to leverage existing commercial investments that are already filling the gaps. Commercial LEO systems offer the ability to distribute national security communications through a variety of paths and spacecraft to provide a mesh network that is resistant to a single point of failure.

The next wave of LEO infrastructure building should not be seen as individual satellites, but emphatically as networks. Mesh networks, connected by inter-satellite links, allow continuous coverage of the Arctic: always-on, always-available connectivity which is suited to the national security importance of the Arctic mission. The minimum required technology includes satellites connected to other satellites in the mesh with high speed links, and onboard supercomputers to route messages at speed and volume.

This should also include interoperability between commercial and government satellites in order to dynamically and seamlessly respond to shifting needs; the capacity to deliver large amounts of throughput to specific areas; a lack of terrestrial touchpoints to mitigate security risks; and resiliency to ensure multiple satellites and communication paths are available from any point on Earth.

THE ANSWER TO ARCTIC CONNECTIVITY GAPS: PROLIFERATED SPACE ARCHITECTURE

Government and military programs around the world will be best served by including commercial space as an element in their security architecture, and looking to LEO networks that were designed for secure, enterprise-grade capacity and to reach the far Northern regions.

Companies are actively testing using this model, and the results speak for themselves; for example, DARPA’s Blackjack program, which recently moved into Phase 2 development and testing, and CASINO program are both working to demonstrate commercial LEO utility for defense communications. Other organizations such as the Space Development Agency are doing similar work, demonstrating commercial interoperability. Overall, initial testing and success seen in both Canada and the U.S. — two countries that regularly share in the business of Arctic connectivity — underscores the unique benefits of LEO networks for reaching these remote areas.

Tests like these further showcase how LEO networks can support government applications on a true global scale – and are a stark reminder of why governmental space architecture must be designed to include secure commercial LEO networks. Leveraging commercial LEO networks, governments can bridge connectivity gaps in the Arctic regions and establish secure and reliable communications channels for defense operations and threat assessment at scale.

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James J. Shaw is Director, Government Solutions of Telesat U.S. Services.

This article originally appeared in the June 2021 issue of SpaceNews magazine.

#Space | https://sciencespies.com/space/op-ed-to-solve-for-arctic-connectivity-governments-need-a-network-suited-to-their-unique-needs/

Scientists confirm black hole and neutron star collisions in world-first discovery

For the first time, scientists have unambiguously confirmed the collision of a black hole and a neutron star: The fateful moment two extreme objects come together in an event so immensely powerful, its ripples across the cosmos can still be discerned a billion years later.

Amazingly enough, this astronomical discovery has now been made not once, but twice, as an international collaboration of thousands of scientists reports.

In a new study confirming this world-first observation, researchers detail the detection of gravitational waves resulting from two separate and distinct neutron star-black hole mergers – each registered by astronomers just 10 days apart in January 2020.

"It's an awesome milestone for the nascent field of gravitational-wave astronomy," says astrophysicist Rory Smith from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) at Monash University.

"Neutron stars merging with black holes are amongst the most extreme phenomena in the Universe. Observing these collisions opens up new avenues to learn about fundamental physics, as well as how stars are born, live, and die."

Artist's impression of gravitational waves generated by a neutron star-black hole binary. (Mark Myers/OzGrav/Swinburne University)

The virtually simultaneous discovery of the two events – called GW200105 and GW200115 – speaks to the speed with which the field of gravitational wave science is evolving.

In just half a decade since the first confirmed discovery of gravitational waves, researchers have now detected these waves from dozens of events – in total, about 50 individual instances of black holes colliding with other black holes, or neutron stars colliding with other neutron stars.

But before now, a 'mixed' collision representing the merger of a neutron star with a black hole – called an NSBH binary – had never been confirmed, although scientists have previously picked up signals that were potentially suggestive of such a neutron star-black hole collision.

Now, however, the discovery is unambiguous.

"In January 2020, the LIGO-Virgo detector network observed gravitational-wave signals from two compact binary inspirals which are consistent with neutron star-black hole binaries," researchers from the international LIGO, Virgo, and Kagra collaborations explain in the new study.

"These represent the first confident observations to date of NSBH binaries via any observational means."

The first event, GW200105, was detected on 5 January 2020, involving a black hole (with about nine times the mass of the Sun, or 8.9 solar masses) colliding with a 1.9-solar-mass neutron star.

This collision took place about 900 million years ago, even though we've only just detected the gravitational waves rippling out from the two objects merging.

GW200115, detected on 15 January 2020, is even more ancient, occurring when a NSBH binary system coalesced around 1 billion years ago in the merger of a 6-solar-mass black hole and a 1.5-solar-mass neutron star.

"These collisions have shaken the Universe to its core and we've detected the ripples they have sent hurtling through the cosmos," says astrophysicist Susan Scott from Australian National University (ANU).

"Each collision isn't just the coming together of two massive and dense objects. It's really like Pac-Man, with a black hole swallowing its companion neutron star whole."

These binary systems have been predicted to exist for decades, but have never been observed before. Now, thanks to the detection of gravitational waves from their collisions, we know that these pairs do exist, even though many questions still remain.

"We've now seen the first examples of black holes merging with neutron stars, so we know that they're out there," says gravitational-wave astronomer Maya Fishbach from Northwestern University.

"But there's still so much we don't know about neutron stars and black holes – how small or big they can get, how fast they can spin, how they pair off into merger partners. With future gravitational wave data, we will have the statistics to answer these questions, and ultimately learn how the most extreme objects in our Universe are made."

The findings are reported in The Astrophysical Journal Letters.

#Space | https://sciencespies.com/space/scientists-confirm-black-hole-and-neutron-star-collisions-in-world-first-discovery/

Large dinosaurs were prone to extinction way before the asteroid, new study argues

After ruling the planet for more than 170 million years, non-avian dinosaurs were suddenly demoted from existence by the impact of a large asteroid that struck the Yucatán peninsula some 66 million years ago. 

The collision set off a cascade of environmental devastation, with debris in the atmosphere cutting off life-giving sunlight. Earth's surface temperatures plunged. Animals perished. 

Well, that's what most paleontologists think happened. 

While evidence for this end-Cretaceous impact is indisputable, debate within the paleontological community has been ongoing as to whether dinosaur extinction was abrupt or gradual. 

The extinctions do coincide with a period of long-term environmental upheaval, largely the result of the continued breaking up of the supercontinents Laurasia and Gondwana. High sea levels, cooling climates, the spread of new habitat on land, as well as massive volcanic activity, may have all played significant roles in the mass extinction event. 

Up until now, analysis of fossil data has yielded no convincing evidence of a decline in dinosaur species before their extinction. A phylogenetic study in 2016, which used dinosaur timetrees, challenged the idea of a sudden extinction, but this conclusion proved to be contentious. 

The fossil record is a notoriously difficult source of evidence, with critiques of that study pointing to gaps in the dinosaur fossil record and sampling biases which could have led to the under-reporting of certain Cretaceous dinosaur species. 

Now, a new study has lent additional evidence to the hypothesis that non-avian dinosaurs were already teetering on the edge of extinction before the cataclysmic events of the infamous asteroid impact.

Led by French National Center for Scientific Research phylogeneticist Fabien Condamine, the authors of the new study claim that methodological developments in data analysis have allowed them to take into account certain biases in fossil data, along with uncertainties around the ages of fossils. 

The team analysed 1,600 dinosaur fossils to assess the speciation and extinction rates of six major dinosaur families: Ankylosauridae, Ceratopsidae, Hadrosauridae, Dromaeosauridae, Troodontidae, and Tyrannosauridae. 

The team found that the diversity of non-avian dinosaurs started to decline approximately 76 million years ago - that's 10 million years prior to the Yucatán impact. They suggest the decline is linked to increased extinction rates in older species, who may have lacked evolutionary novelty and were unable to adapt to changing environmental conditions.

"These results imply that warm periods favored dinosaur diversification whereas cooler periods led to enhanced extinctions," state the authors. 

Ecological and physical factors point to a cooling climate as a catalyst for the decline of dinosaur species in the late Cretaceous. These cooling temperatures likely spelled trouble for large dinosaurs in particular, since they relied on a warm climate to maintain a stable body temperature. 

"A physiological explanation for the cooling-driven extinction could be the hypothesis that if sex determination in dinosaurs was temperature dependent, as in crocodiles and turtles, sex switching of embryos could have contributed to diversity loss with a cooling global climate at the end of the Cretaceous," the team added. 

The researchers also point to additional factors, such as hadrosaurs outcompeting other herbivores - their teeth show they were able to eat a greater variety of plants than more specialized competitors. With herbivores playing an interconnected role in the food web, their decline may have been detrimental to a number of additional dinosaur species. 

In the end, data from the new study suggest that the final extinction of dinosaurs really could not be solely attributed to a massive asteroid impact.

While the study could not point directly to the precise ecological mechanisms which underlay the effects of global cooling on dinosaur speciation and extinction rates, the results support the idea that long-term environmental changes likely made non-avian dinosaurs prone to extinction, even before a giant space rock smashed up their home planet. 

The study was published in Nature Communications.

#Nature | https://sciencespies.com/nature/large-dinosaurs-were-prone-to-extinction-way-before-the-asteroid-new-study-argues/

How humans brought change to a tropical paradise

After centuries of human impact on the world's ecosystems, a new study from Flinders University details an example of how a common native bee species has flourished since the very first land clearances by humans on Fiji.

In a new paper in Molecular Ecology, research led by Flinders University explores a link between the expansion of Homalictus fijiensis, a common bee in the lowlands of Fiji, which has increased its spread on the main island Viti Levu alongside advancing land clearance and the introduction of new plants and weeds to the environment.

"Earlier research connected the relatively recent population expansion to warming climates, but our study reveals an interesting and positive response from an endemic species to human modifications to the landscape which commenced about 1000BC," says lead author, Flinders University researcher James Dorey.

"This species is a super-generalist pollinator (pollinates many plant species) and likes to nest in open, cleared ground, so one of the most important bee pollinators in Fiji actually appears to have benefited from human arrival and subsequent clearing of land in Fiji."

The study examined changes in native bee populations in Fiji using phylogenetic analyses of mitochondrial and genomic DNA. They show that bee populations in Fiji expanded enormously, starting about 3000 years ago and accelerating from about 2000 years ago.

Compared to the main island, Mr Dorey says no corresponding change in bee population size was found for another major island, Kadavu, where human populations and agricultural activities have been historically very low.

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"That is too recent to be explained by a warming climate since the last glacial maximum which ended about 18,000 thousand years ago," says senior author Associate Professor Michael Schwarz in the new paper.

"Instead, we argue that the expansion of Fijian bee population better coincides with the early occupation of the Pacific islands by the somewhat-mysterious Lapita people, and this expansion accelerated with increasing presence of later Polynesians in Fiji who modified the landscape with their agricultural practices."

The research is an example of how the impacts of early human dispersals can be inferred even when fossil records are not available and when climate change is a complicating factor.

One possible downside of super-generalist pollinators, such as the endemic Fijian halictine bee Homalictus fijiensis, is that they could encourage the expansion of introduced weeds and exotic crop species -- exacerbating other ecosystem changes in the long run.

"As well, those research techniques could be applied to many other animal species. For example, changes in population sizes of mammals, such as kangaroos, wombats and koalas, could be explored by looking at their tick and lice parasites which might have better 'genetic signals' of how populations have fared over the last few thousands of years or more, adds Associate Professor Schwarz, who says high-resolution population genetic studies such as this are a good way to discriminate between older and 'natural' events due to climate change and those resulting from early human dispersal and colonisation.

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"A persistent question in studies of ecosystems over the last 60,000 years or so concerns the relative roles of climate change and human modifications of the environment. For example, there is a continuing debate about the extinction of megafauna in Australia -- was it due to humans, climate change, or both?

"Those kinds of question can be addressed if there are very good fossil records, but what about ecosystems where fossil records are very poor."

The new paper is a result of almost a decade of scientific studies into Fiji's biodiversity by SA Museum and Flinders University biological scientists and students.

SA Museum's research fellow in World Cultures, Dr Stephen Zagala (pictured attached), says the new study gives fascinating insights into how current ecosystems were assembled during the various phases of human migration and settlement.

"Early European explorers and naturalists were unaware that extensive human dispersals had already been transforming the ecologies of Pacific islands for millennia," he says. "This study adds important details to an emerging picture of the Pacific as a highly cultivated landscape."

#Nature | https://sciencespies.com/nature/how-humans-brought-change-to-a-tropical-paradise/