Archaeological Headlines 

Archaeologist Creates 3-D Blueprints of Historic Yukon Structures
YUKON, CANADA—CBC News reports that archaeologist Peter Dawson of the University of Calgary and his colleagues are using a drone and a terrestrial laser scanner to create 3-D replicas of historic sites at Pauline Cove, which is located on Herschel Island, in the Beaufort Sea off Yukon’s northern coast. The sites are in danger of being destroyed by wild animals, polar tourism, and erosion. The island has lost about 65 feet of coastline in the past 20 years, Dawson explained. The sites include structures built by Inuvialuit, American whalers, Anglican missionaries, and the Northwest Mounted Police, he added. “It’s giving us a really, really good record of the outside of the buildings and the inside of the buildings and an overview of the historic settlement area,” Barbara Hogan, manager of historic sites for Yukon Tourism and Culture, said of the project. When completed, the images will be stored in an online archive with historic information for public use. To read about a 900-year-old barbed arrow point recovered from the ice in southern Yukon, go to "Time's Arrow."

Study Examines Food and Gender in Bronze Age China
DUNEDIN, NEW ZEALAND—According to an Otago Daily Times report, an analysis of isotopes in teeth suggests that boys and girls living in China’s Central Plains during the Eastern Zhou Dynasty some 2,500 years ago were fed different foods. Bioarchaeologist Melanie Miller and her colleagues found that children were breastfed until they were between the ages of two-and-a-half and four years old, when they were weaned onto foods made from wheat and soybeans. The girls, however, were weaned slightly earlier than the males, Miller said. Females continued to eat more wheat and soy as they grew up, while males ate more millet, she added. Miller and her team think these dietary differences could reflect the social inequality that emerged in China's Bronze Age. Read the original scholarly article about this research in the American Journal of Physical Anthropology. To read about hominin teeth that belonged to individuals living at least 80,000 years ago in southern China, go to "An Opportunity for Early Humans in China."


Donkeys in 1,100-Year-Old Chinese Tomb May Have Played Polo
SHAANXI PROVINCE, CHINA—A team led by Songmei Hu of the Shaanxi Provincial Institute of Archaeology analyzed animal bones recovered from the looted ninth-century A.D. tomb of a Chinese noblewoman named Cui Shi, and determined that she was buried with at least three donkeys, according to a Science Magazine report. Fiona Marshall of Washington University in St. Louis said donkeys were not usually buried in such high-status graves, even in northwest China’s Tang Dynasty capital of Xi’an, which was located at one end of the trade route known as the Silk Road. The donkey bones found in Cui Shi’s tomb, however, were too small to represent useful pack animals, and they also showed wear similar to that found on animals who run and make frequent turns, Marshall added. Ancient texts indicate that Cui Shi was married to a skilled polo player who won the favor of Emperor Xizong. Cui may have also played the popular, fast-paced game, which was usually played on horseback, while riding a slower, safer donkey, Marshall explained. To read about a tomb unearthed in Shaanxi that is decorated with paintings depicting a sumptuous family feast, go to "Underground Party."


Neolithic Artifacts Unearthed in Slovakia
TRNAVA, SLOVAKIA—According to a report in The Slovak Spectator, decorated ceramics, tools made of antler, and stone tool fragments made by members of the Lengyel culture have been unearthed in western Slovakia by a team led by archaeologist Andrej Žitňan. The artifacts, estimated to be more than 6,000 years old, were excavated near a medieval fortification wall in the town of Trnava. “Its existence until these days is a matter of lucky circumstances because it was preserved in the narrow area between the wall and the filled town ditch,” said Peter Grznár of the local Regional Monument Board. The town is also known for Neolithic figurines called the Trvana Venuses, which have been dated to about 6,700 years ago. Žitňan said the new discovery suggests the Neolithic settlement that once stood on the site was larger than previously thought. To read about a cache of Roman-era artifacts uncovered near Bratislava, go to "World Roundup: Slovakia."


“Little Foot” Fossils Examined with High-Tech Tools
JOHANNESBURG, SOUTH AFRICA—According to a statement released by the University of the Witwatersrand, Amélie Beaudet and her colleagues examined high-resolution microcomputer tomography scans of a 3.67 million-year-old fossilized skull and first cervical vertebra recovered from South Africa’s Sterkfontein cave system. The bones are part of a nearly complete Australopithecus skeleton known as “Little Foot.” The study suggests that the hominin moved its head in a manner consistent with tree-climbing ability. The well-preserved fossils also offer information about the size of arteries that passed through the vertebra, and thus the amount of blood flow to the brain. Little Foot’s blood flow is estimated to resemble the blood flow observed in modern chimpanzees, or about three times lower than in modern humans. Beaudet said the low blood flow to the brain could reflect the individual’s small brain size, a poor-quality diet, or a need for energy in another part of the Australopithecus anatomy. Increased blood flow to the brain is thought to have emerged much later in human evolution, she added. To read about another Australopithecus cranium found in Ethiopia, go to "Artifact."


Possible Insect Rock Art Found in Iran
TEHRAN, IRAN—According to a statement released by Pensoft, a five- and one-half-inch petroglyph in central Iran has been described as a possible part man, part praying mantis by entomologists Mahmood Kolnegari of Islamic Azad University of Arak, Mandana Hazrati of Avaye Dornaye Khakestari Institute, Matan Shelomi of National Taiwan University, and archaeologist Mohammad Naserifard. Mantises have bulging eyes, flexible necks, elongated bodies, and enlarged forelegs for gripping prey such as flies, bees, and sometimes small birds. The image depicts a creature with six limbs, including grasping forearms, and middle limbs that end in loops or circles. It also has a triangular head topped with an extension resembling that found on the local species of mantis. The artwork is estimated to be between 4,000 and 40,000 years old. To read about a medieval Islamic empire in Iran, go to "Minaret in the Mountains."


Study Suggests Hominins Grew Faster Than Modern Humans
BURGOS, SPAIN—According to a statement released by Spain’s National Center for Research on Human Evolution, paleoanthropologist Mario Modesto-Mata and his colleagues suggest that the hominins who lived in northern Spain’s Sierra de Atapuerca reached adulthood several years earlier than modern humans. The researchers analyzed the hominins’ tooth enamel, which is set down in layers at regular intervals which are specific to each species, after they developed a technique to estimate the amount of tooth enamel lost through wear and tear. Modesto-Mata said the hominins from Sima del Elefante, who lived some 1.2 million years ago; Gran Dolina-TD6, who lived some 850,000 years ago; and Sima de los Huesos, who lived some 430,000 years ago, may have grown up to 25 percent faster than modern humans. Read the original scholarly article about this research in Scientific Reports. To read about the most complete hominin cranium older than 3 million years ago ever discovered, go to "Artifact."

Possible Maya Capital City Explored in Mexico
BOSTON, MASSACHUSETTS—According to a statement released by Brandeis University, a team of researchers including Charles Golden of Brandeis University and Andrew Scherer of Brown University has uncovered a Maya site in southeastern Mexico that may have been the capital of Sak Tz’i’, a kingdom mentioned in inscriptions uncovered at other Maya sites. Translated as “white dog,” Sak Tz’i’ was a small state founded in 750 B.C. and surrounded by more powerful states. The city was protected on one side by steep-walled streams, while masonry walls were built around the rest of the site, but the researchers suspect the city’s leaders must have engaged in political maneuverings with the kingdom’s stronger neighbors in order to survive for more than 1,000 years. The team members have found evidence of pyramids, a royal palace, a ball court, sculptures, and inscriptions describing rituals, battles, a mythical water serpent, and the dance of a rain god. The researchers will continue to work to stabilize the site’s ancient structures and to use light detection and ranging technology to map the area. Read the original scholarly article about this research in the Journal of Field Archaeology. To read about conflict between Maya centers, go to "Maya Total War."
 Share

Graves of Ottoman Soldiers Unearthed Near Istanbul
ISTANBUL, TURKEY—Hurriyet Daily News reports that the remains of 30 Ottoman soldiers have been unearthed in a suburb of Istanbul. Rahmi Asal of the Istanbul Archaeology Museums Directorate said the men had served in the 86th Regiment of the Ottoman Army during the Balkan War. More than 650 Ottoman soldiers were killed near the site where the graves were found by advancing Bulgarian soldiers on the evening of November 17, 1912. The excavation recovered uniform buttons, belts, belt buckles, spoons, pouches, a compass, cigarette holders, bayonets, mirrors, and two rings. Collar numbers and seals allowed researchers to identify five of the men, Asal added. To read about an archaeological survey conducted at the World War I battlefied of Gallipoli, go to "Letter from Turkey: Anzac's Next Chapter."

Traces of 18th-Century Glass Factory Revealed in Scotland
EDINBURGH, SCOTLAND—Construction work near the mouth of the Water of Leith revealed traces of the Edinburgh and Leith Glassworks, which was founded in the mid-eighteenth century and demolished in 1912, according to a report in the Edinburgh Evening News. The excavation unearthed remnants of one of the factory’s six huge furnace cones. Each one once stood between 80 and 100 feet tall with a 40-foot diameter base. Traces of buildings such as a workshop and a warehouse were also found. Edinburgh Council archaeologist John Lawson said the glassworks made bottles for French wine, Spanish sherry, and Portuguese port imported in wooden casks and barrels. Locally produced whisky and medicines also created a demand for glass bottles, he explained, until the late nineteenth century, when the glassworks was dissolved, the equipment sold off, and the site was converted to use as a lumber yard. To read about a nineteenth-century glass factory in the northeast United States, go to "Letter from Philadelphia: Empire of Glass."

Islamic-Era Palace Gate Uncovered in Spain
ANDALUSIA, SPAIN—According to a Times of London report, traces of a multilevel gateway to the massive fortified palace built in the tenth century A.D. by Abd-al-Rahman III, the first caliph of Cordoba, have been uncovered in southern Spain. Alberto Canto of the Autonomous University of Madrid said that the gate is thought to mark the eastern entrance to the palace parade ground at the ruins of the royal city of Medina Azahara. As many as 20,000 people were once part of the lavish palace household, which included a zoo, an aviary, four fish ponds, 300 baths, weapons factories, and barracks for the soldiers of the royal guard. The palace was destroyed in A.D. 1010 during a civil war. “Everything collapsed and so we found buried the remains of its tiles, wood, nails, beams, hinges, and ornaments,” Canto said. To read about a Roman arch excavated in Andalusia, go to "Making an Entrance."

Stela Reveals Early Mayan Writing
EL ASINTAL, GUATEMALA—France24 reports that a stela discovered in September of 2018 at the Tak’alik Ab’aj Archaeological Park in western Guatemala has provided new insights into the development of early Mayan writing. Researchers are still in the process of translating and interpreting the glyphs on the stone, which is believed to have been erected sometime in the late Maya Preclassic period (ca. 300 B.C.- A.D. 250) and depicts a ruler adorned with regalia, as well as references to deities associated with maize and cacao. But according to Tak’alik Ab’aj technical director Christa Schieber, the site was a laboratory for experiments in early Mayan writing. The stela, she said, provides context for a vertical sequence of glyphs that will help scholars learn more about how the system developed. Tak’alik Ab’aj is thought to have been founded by the Olmecs around 1500 B.C. and was gradually absorbed into the growing Maya world some 800 years later. To read more about Maya archaeology in Guatemala, go to "The City at the Beginning of the World."

https://www.archaeology.org/news

HKU marine biologist and international team unveil impacts of heatwave on reef fishes

THE UNIVERSITY OF HONG KONG

   

IMAGE: WITH ELEVATED TEMPERATURES DURING A MARINE HEATWAVE THIS CARDINALFISH SPECIES (CHEILODIPTERUS QUINQUELINEATUS) SHOWS THE LEAST CHANGES IN GENE EXPRESSION AND APPEARS TO BE MORE TOLERANT. view more 

CREDIT: @THE UNIVERSITY OF HONG KONG

The marine heatwave of 2016 was one of longest and hottest thermal anomalies recorded on the Great Barrier Reef in Australia, influencing multiple species of marine ectotherms, including coral reef fishes.

Dr Celia Schunter from School of Biological Sciences and the Swire Institute of Marine Science (SWIMS), The University of Hong Kong (HKU) and a team of international scientists conducted a study attempting to understand the molecular response of five species to the 2016 heatwave conditions that killed a third of the Great Barrier Reef corals. This is the world-first study tracking how wild fish populations respond to a severe marine heatwave. The results of the study were published in the journal Science Advances.

Marine heatwaves (MHWs) are elevated extreme temperatures in the oceans for an extended period of time, similar to an atmospheric heatwave. These elevated temperatures can have a significant impact on marine life, possibly pushing the thermal limits of many organisms. With the frequency and intensity of heatwaves predicted to increase in the future, this could have greater impacts on the performance of ectotherms, when compared to slight thermal increments over years or decades.

"To understand the challenges fish face under such conditions we used a molecular approach to evaluate how acute warming events directly affect reef fish communities in nature," said Dr Celia Schunter. "We chose to work with five different species which are commonly found on the reef to be able to understand differences in reactions among fish species with different life histories to get a broader overview of the reaction and impact."

"Our study shows that reef fishes are directly affected by heatwaves, but their responses vary greatly among species," said co-author Associate Professor Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU). Dr Rummer was part of the international team that studied changes in the expression of thousands of different genes in five species of coral reef fish, collected at different points before, during and after the 2016 heatwave.

"Changes in gene expression can tell us how an animal responds physiologically to an environmental shock, such as a heatwave," said Dr Celia Schunter from HKU School of Biological Sciences and SWIMS, one of the lead authors in the study. "We measured RNA levels in livers in the fish. This can control when proteins are made and in what amount, and these proteins dictate how the cells of the body function. We saw many genes change expression levels across the timepoints of a heatwave revealing important functions such as cellular stress response and changes in metabolic functions."

Through these genetic analyses, the team identified species-specific physiological responses to the heightened temperatures. "Fast water warming causes an increase of the metabolic demands in fishes, which are similar to what happens to an athlete doing intense exercises. When water temperature increases, fishes have a higher demand for energy and oxygen, which leaves a signal that is measurable with genetic techniques. This higher energy demand at warming can affect their reproduction, swimming and development, and that is why it is important to understand the response to warming." said Dr Moisés A Bernal, co-author of the study from Auburn University.

Interestingly, "these patterns of gene expression also changed with the duration of the heatwave," said Dr Rummer. "This suggests that the physiological mechanisms the fish use to cope with the warmer waters changed as the heatwave progressed. The results suggest fish populations are influenced by both the intensity of a heatwave and how long it lasts." This signals potential long-term consequences for the health of fish populations as extreme heat events increase in frequency, duration and magnitude under human-induced climate change.

At a species level, Dr Rummer says the responses varied in intensity. Some fish struggled less than others. "The spiny damselfish responded strongly to the warmer conditions, with changes in the expression of thousands of genes, suggesting it is particularly sensitive to heatwaves. Other species appear to be more tolerant, with fewer changes in gene expression." said Dr Rummer . Two of the five studies species studied can also be found in waters around Hong Kong and Southern China as well as many more closely related fish species providing also some context for possible effects for waters around Hong Kong.

The study provides a possible approach for predicting which fish species are most at risk under repeated heatwave conditions, said another co-author Professor Timothy Ravasi, from the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University (OIST). "This has ramifications for policy makers and for the fishing industry, because not all species will be equally affected. We need to screen a large number of species to predict which will be sensitive and which will be more tolerant to warming waters and heatwaves."

"Over time, the fish may adapt to rising temperatures, or even migrate to cooler waters," Professor Ravasi said. "But these heatwaves are happening now, and it's necessary to understand and consider the immediate consequences."

In 2015 the South China Sea experienced a heatwave of a similar magnitude than the heatwave on the Great Barrier Reef studied here. The coastal waters of Hong Kong and the South China Sea are predicted to experience more frequent and intense marine heatwave events as seen on the global scale. It is now clear that these extreme events can have far-reaching effects on marine fishes, but also economic implications on aquaculture and fishing industries Dr Celia Schunter urges the need for more research into the impacts of such events in the marine waters of Hong Kong to avert the potential collapse in the marine ecosystem and the industries relying on it.

###

The paper:

'Species-specific molecular responses of wild coral reef fishes during a marine heatwave.' in Science Advances by Moisés A Bernal, Celia Schunter, Robert Lehmann, Damien J Lightfoot, Bridie J M Allan, Heather D Veilleux, Jodie L Rummer, Philip L Munday and Timothy Ravasi.'

Link of journal paper: https://advances.sciencemag.org/content/6/12/eaay3423

For more information about Dr Celia Schunter's research, please visit: http://www.celiaschunter.com/

ICE HOUSE, PRIMITIVE MAN, 1982

A pigment from ancient Egypt to modern microscopy

Göttingen research team produces new nanosheets for near infrared imaging

UNIVERSITY OF GÖTTINGENT

IMAGE: EGYPTIAN BLUE: THE RESEARCHERS OBTAINED THE NANOSHEETS FROM THIS POWDER. view more 

CREDIT: UNIVERSITY OF GOETTINGEN

Egyptian blue is one of the oldest manmade colour pigments. It adorns, for instance, the crown of the world famous bust of Nefertiti. But the pigment can do even more. An international research team led by Dr Sebastian Kruss from the Institute of Physical Chemistry at the University of Göttingen has produced a new nanomaterial based on the Egyptian blue pigment, which is ideally suited for applications in imaging using near infrared spectroscopy and microscopy. The results have been published in the journal Nature Communications.

Microscopy and optical imaging are important tools in basic research and biomedicine. They use substances that can release light when excited. Known as "fluorophores", these substances are used to stain very small structures in samples, enabling clear resolution using modern microscopes. Most fluorophores shine in the range of light visible to humans. When using light in the near infrared spectrum, with a wavelength starting at 800 nanometres, light penetrates even deeper into tissue and there are fewer distortions to the image. So far, however, there are only a few known fluorophores that work in the near infrared spectrum.

The research team has now succeeded in exfoliating extremely thin layers from grains of calcium copper silicate, also known as Egyptian blue. These nanosheets are 100,000 times thinner than a human hair and fluoresce in the near infrared range. "We were able to show that even the smallest nanosheets are extremely stable, shine brightly and do not bleach," says Dr Sebastian Kruss, "making them ideal for optical imaging."

The scientists tested their idea for microscopy in animals and plants. For example, they followed the movement of individual nanosheets in order to visualise mechanical processes and the structure of the tissue around cell nuclei in the fruit fly. In addition, they integrated the nanosheets into plants and were able to identify them even without a microscope, which promises future applications in the agricultural industry. "The potential for state-of-the-art microscopy from this material means that new findings in biomedical research can be expected in the future," says Kruss.

###

The study involved scientists from the Institute of Physical Chemistry, the Third Institute of Physics, the Department of Developmental Biochemistry and the Institute of Geology as well as the Department of Dermatology, Venereology and Allergology of the University Medical Center Göttingen and the University of California Riverside.

Original publication: Selvaggio et al. "Exfoliated near infrared fluorescent silicate nanosheets for (bio)photonics". Nature Communications, DOI: 10.1038/s41467-020-15299-5

See also - https://www.nature.com/articles/s41467-020-15299-5

Merger between two stars led to blue supergiant, iconic supernova

by RIKEN

Figure 1: This computer simulation of a supernova shows how matter is ejected from

 the heart of an exploding star. Credit: RIKEN Astrophysical Big Bang Laboratory

A supernova in a nearby galaxy may have originated from an explosion of a blue supergiant formed by the merger of two stars, simulations by RIKEN astrophysicists suggest. The asymmetric nature of this explosion may provide hints for where to look for the elusive neutron star birthed in this stellar cataclysm.

A core-collapse supernova occurs when the core of a massive star can no longer withstand its own gravity. The core collapses in on itself, triggering a violent explosion that blasts away the star's outer layers, leaving behind a neutron star or black hole.

In 1987, astronomers saw a star explode in the Large Magellanic Cloud, one of our galaxy's closest neighbors. Since then, scientists have intensively studied the aftermath of this supernova, known as SN 1987A, to understand the nature of the progenitor star and its fate.

The progenitor of this type of supernova is usually a red supergiant, but observations have shown that SN 1987A was caused by a compact blue supergiant. "It has been a mystery why the progenitor star was a blue supergiant," says Masaomi Ono at the RIKEN Astrophysical Big Bang Laboratory.

Meanwhile, X-ray and gamma-ray observations of SN 1987A have revealed clumps of radioactive nickel in the ejected matter. This nickel was formed in the star's core during its collapse, and is now hurtling away from the star at speeds of more than 4,000 kilometers per second. Previous simulations of the supernova had been unable to fully explain how this nickel could escape so rapidly.

Ono and co-workers simulated asymmetric core-collapse supernova explosions of four progenitor stars and compared them with observations of SN 1987A. The closest match involved a blue supergiant progenitor formed by a merger between two stars: a red supergiant and a main-sequence star. During the merger, the larger star would have stripped matter from its smaller companion, which spiraled inward until it was completely absorbed, forming a rapidly rotating blue supergiant.

This is the first time that a binary-merger scenario has been tested for the nickel clumping of this supernova, Ono says. The simulation accurately reproduced the speeding clumps of nickel along with two jets of ejecta.

The simulation may also help to find the neutron star that formed during the supernova, which has not been located despite 30 years of searching. In an aspherical explosion, the neutron star could have been kicked in the opposite direction to the bulk of the ejecta, and Ono's team suggests that astronomers should look for it in the northern part of the inner region of ejected material.

Modeling a core collapse supernova

---

More information: View the 3-D model: sketchfab.com/3d-models/elemen … 4d3c924e03e51dccd84d

Masaomi Ono et al. Matter Mixing in Aspherical Core-collapse Supernovae: Three-dimensional Simulations with Single-star and Binary Merger Progenitor Models for SN 1987A, The Astrophysical Journal (2020). DOI: 10.3847/1538-4357/ab5dba

Iron is everywhere in Earth's vicinity, suggest two decades of Cluster data

by European Space Agency
 

An illustration of the Sun (on the left) and the solar wind, a constant flow of charged particles – electrons, which have negative charge, and positively charged ions – that permeates the Solar System and impacts on Earth's magnetic environment (on the right). Credit: ESA; Sun: ESA/NASA/SOHO/LASCO/EIT

Using over 18 years of data from ESA's Cluster mission, scientists have mapped the heavy metals in the space surrounding Earth, finding an unexpected distribution and prevalence of iron and shedding light on the composition of our cosmic environment.


Space is often presumed to be devoid of matter, but technically it is not really empty: the distribution of matter is just very, very sparse. In the vicinity of Earth, the space that scientists call 'geospace' is actually filled with charged particles: a mixture of electrons, which have negative charge, and positively charged ions. These ions are key players in the electrodynamics processes we see in geospace, and contribute to the turbulent, changeable nature of this part of the cosmos.

A surprising detection

A new study uses over 18 years of data from ESA's Cluster mission—launched in August 2000 and approaching its 20th anniversary in space—to explore the prevalence of an important ion thought to be relatively rare near Earth: iron. By delving into Cluster data gathered from 2001 to 2018, the researchers detected an unexpected distribution of iron throughout geospace.

"Although the amounts are tiny, we found iron everywhere: across the entire region of geospace covered by Cluster, and in the near-Earth solar wind—the continuous outpouring of charged particles from the sun," says lead author Stein Haaland of the Max Planck Institute for Solar System Research in Göttingen, Germany, and the Birkeland Centre for Space Science at the University of Bergen, Norway.

"We detected iron in roughly 10% of the observations which, given the relative rarity of the ion, is surprising. We didn't expect to find it so often."

However, it is not the presence of iron itself that is surprising, but rather its properties. The JAXA/NASA Geotail satellite, which has spent over 25 years observing Earth's magnetic environment, had detected singly-ionised iron in geospace in 2017. These are atoms of iron that have been stripped only of the most external of their electrons. The new results not only confirm this finding, but provide an essential new part of the picture.

"The Cluster observations focus on a far higher energy range than Geotail, and give us a more complete view of the space around us, detecting not only singly-ionised iron but also multiply-ionised iron—these are ions in higher energetic states which have been stripped of more than one electron," adds Stein. "Iron in the solar wind tends to be seen in higher charge states, so we need this wider, higher energy range to understand the solar wind in particular and its impact on Earth's magnetic environment."

Distance between the Cluster spacecraft during the mission

The source of iron in geospace

Ions can enter geospace from above or below. Some travel up from Earth's atmosphere, while others stream in from the solar wind. The source of heavy metals, such as iron, is still debated—where do these ions come from, and how do they contribute to the phenomena we see around us?

"The Geotail observations focused on iron moving up from Earth's atmosphere, and at rather low energies," explains Stein. "We found that there is much more iron coming from the sun, and at far higher energies. We also found iron in the regions above Earth's polar caps—a location that Geotail did not cover."

Building upon previous results, the new study explores the potential source of the ionised iron in more depth. This is a key factor in understanding the dynamics and properties of geospace, our magnetosphere, the solar wind, and how these structures meet and interact.

Previous research has proposed that detections of iron ions at higher latitudes may be due to a variety of factors, including meteorites entering Earth's atmosphere and breaking up, particles being elevated from certain layers of the atmosphere, or even particles being ejected from the Moon. However, the new Cluster results do not show convincing evidence of any of these processes; instead, they suggest that the iron comes straight from the sun.

"The data on iron distribution and presence varied over time in a way that matched up with disturbances in Earth's magnetic field, and long-term fluctuations in solar activity," says Stein. "This suggests that the most of the iron in geospace originated from solar wind that passed through the magnetosphere, rather than traveling upwards from our planet's atmosphere."

Hidden in the data

To map the composition of geospace, Stein and colleagues used Cluster data in an unexpected way. They exploited measurements that were gathered not for scientific purposes, but for operational diagnostics of one of the spacecraft's instruments—RAPID (Research with Adaptive Particle Imaging Detectors).

The instrument identifies and characterises the various ions it detects by measuring their energies and travel time inside the detector. For the ordinary scientific activity, RAPID calculates these properties only for hydrogen, helium and oxygen atoms; however, for diagnostic purposes, the instrument provides additional properties for a limited number of particles, extending the probed range to heavier ions.

These measurements serve to calibrate the instrument and ensure that it is functioning as intended. However, the scientists used these diagnostic observations—a total of 122 000 hours—to determine the composition of incoming ions and identify iron particles.

"RAPID's ability to measure ion composition was essential. We need composition measurements to help us better understand where the various elements found on or near Earth come from, and to characterise our cosmic environment," says Stein.

Mining the archives

Understanding the space surrounding Earth is one of Cluster's core objectives. The quartet of spacecraft, flying in formation around Earth, has spent years passing in and out of our planet's magnetic field, investigating how the sun and Earth interact and characterising the phenomena caused by these interactions.

The mission's longevity and its wide orbit have enabled it to gather nearly two decades of data covering all near-Earth regions of space, and large parts of the solar wind.

"We needed this long timespan for our research—and this was only possible thanks to the Cluster Science Archive, which provides best-quality data for the scientific community to use," adds co-author Patrick Daly, also of the Max Planck Institute for Solar System Research and Principal Investigator of the RAPID instrument.

"It took considerable effort to set up this archive, and to continually maintain its very high standards of calibration and reliability. The archive is a credit to the numerous dedicated engineers, spacecraft operators and data archiving teams that have ensured that Cluster remains operational and still provides new, exciting, accessible information about near-Earth space."

Notably, the datasets in the Cluster Science Archive include detailed diagnostic data—something that is not usually included in all mission archives.

"This highlights the importance of science archives in general and diagnostic data in particular, showing how really valuable information can be gleaned from these versatile datasets in order to produce cutting-edge scientific results," says Philippe Escoubet, ESA Cluster Project Scientist.

"It also nicely demonstrates how research continually evolves and pushes forward. Detecting iron would have been a totally unexpected result back when Cluster first launched, but the mission continues to provide a treasure trove of data about Earth's environment."

Solar Orbiter mission to track the sun's active regions, improve space weather prediction

More information: S. Haaland et al. Suprathermal Fe in the Earth's Plasma Environment: Cluster RAPID Observations, Journal of Geophysical Research: Space Physics (2020). DOI: 10.1029/2019JA027596

SpaceX plans first manned flight to space station in May

The billionaire's Falcon 9 rocket will transport Nasa crew-members

Elon Musk's SpaceX will send astronauts to the International Space Station for the first time in May, NASA said, announcing the first crewed launch from the United States to the platform since 2011.

The tech entrepreneur's company will launch a Falcon 9 rocket to transport NASA astronauts Bob Behnken and Doug Hurley in a first for the space agency as it looks to cut costs.

"NASA and SpaceX are currently targeting no earlier than mid-to-late May for launch," the US space agency said in a statement Wednesday.

In March, Musk's Crew Dragon capsule made a round trip to the ISS, which is in orbit more than 250 miles (400 kilometers) above Earth, with a mannequin on board, before returning to the Atlantic after six days in space.

Since the last US space shuttle mission in 2011, after 30 years of service, only the Russians have been going back and forth to the ISS.

SpaceX has made the trip 15 times since 2012, but only to refuel the station.

It is not the only private company servicing NASA: Boeing has also won a contract and is developing its own Starliner capsule.

SpaceX Dragon has made several resupply trips to the International Space Station but May's launch will be the first crewed mission

SpaceX in 'perfect' test of Crew Dragon emergency abort system

Study suggests males with older brother more likely to be gay

by Bob Yirka , Phys.org

Credit: CC0 Public Domain

A team of researchers from the University of Toronto, the Institute of Sexology and Sexual Medicine, Charité – Universitätsmedizin Berlin and the University of Lethbridge has found evidence showing that males with an older brother have a greater chance of being gay than males that do not. In their paper published in the journal Proceedings of the Royal Society B, the group describes their study of data from past research efforts and what the learned from it.

Scientists are not currently able to explain homosexuality in either males or females, even as researchers continue to find the answer. In this new effort, the researchers were looking to find some commonalities between birth order and homosexuality. To that end, they analyzed data from 10 unrelated studies that included sexual orientation for 5,400 men and also sibling information.

The researchers found that the men in the study who had an older brother were 38 percent more likely to be gay than were those who did not have an older brother. They also found that the more older brothers a man had, the more likely he was to be gay—having three older brothers, for example, doubled a man's odds of being gay. But the same could not be said for females. The researchers were not able to find any pattern in siblings, male or female, that changed the odds for a woman being gay.

The researchers were not able to determine why birth order impacts the odds of male homosexuality, but suggest it is possible that the mother's immune response to having a male child has a later impact on male babies born thereafter. The theory, called "maternal immune hypothesis," suggests that when a woman carries and gives birth to a male baby, her body produces antibodies in response to certain male chemicals. The theory suggests that the antibodies produced remain in the woman's body and somehow make their way into the brains of future male babies. The theory has been proposed before by other researchers and has also been used to settle arguments surrounding the nature of homosexuality—specifically whether it is a matter of genetics or upbringing.

Study confirms link between the number of older brothers and increased odds of being homosexual

---

More information: Ray Blanchard et al. A method yielding comparable estimates of the fraternal birth order and female fecundity effects in male homosexuality, Proceedings of the Royal Society B: Biological Sciences (2020). DOI: 10.1098/rspb.2019.2907

Curiosity Mars rover takes a new selfie before record climb

by Andrew Good, Jet Propulsion Laboratory

This selfie was taken by NASA's Curiosity Mars rover on 

Feb. 26, 2020 (the 2,687th Martian day, or sol, of the mission). 

The crumbling rock layer at the top of the image is

 "the Greenheugh Pediment," which Curiosity climbed soon

 after taking the image. Credit: NASA/JPL-Caltech/MSSS

NASA's Curiosity Mars rover recently set a record for the steepest terrain it's ever climbed, cresting the "Greenheugh Pediment," a broad sheet of rock that sits atop a hill. And before doing that, the rover took a selfie, capturing the scene just below Greenheugh.

In front of the rover is a hole it drilled while sampling a bedrock target called "Hutton." The entire selfie is a 360-degree panorama stitched together from 86 images relayed to Earth. The selfie captures the rover about 11 feet (3.4 meters) below the point where it climbed onto the crumbling pediment.

Curiosity finally reached the top of the slope March 6 (the 2,696th Martian day, or sol, of the mission). It took three drives to scale the hill, the second of which tilted the rover 31 degrees—the most the rover has ever tilted on Mars and just shy of the now-inactive Opportunity rover's 32-degree tilt record, set in 2016. Curiosity took the selfie on Feb. 26, 2020 (Sol 2687).

Since 2014, Curiosity has been rolling up Mount Sharp, a 3-mile-tall (5-kilometer-tall) mountain at the center of Gale Crater. Rover operators at NASA's Jet Propulsion Laboratory in Southern California carefully map out each drive to make sure Curiosity will be safe. The rover is never in danger of tilting so much that it would flip over—Curiosity's rocker-bogie wheel system enables it to tilt up to 45 degrees safely—but the steep drives do cause the wheels to spin in place.

How Are Selfies Taken?

Before the climb, Curiosity used the black-and-white Navigation Cameras located on its mast to, for the first time, record a short movie of its "selfie stick," otherwise known as its robotic arm.

Curiosity's mission is to study whether the Martian environment could have supported microbial life billions of years ago. One tool for doing that is the Mars Hand Lens Camera, or MAHLI, located in the turret at the end of the robotic arm. This camera provides a close-up view of sand grains and rock textures, similarly to how a geologist uses a handheld magnifying glass for a closer look in the field on Earth.

By rotating the turret to face the rover, the team can use MAHLI to show Curiosity. Because each MAHLI image covers only a small area, it requires many images and arm positions to fully capture the rover and its surroundings.

"We get asked so often how Curiosity takes a selfie," said Doug Ellison, a Curiosity camera operator at JPL. "We thought the best way to explain it would be to let the rover show everyone from its own point of view just how it's done."

This video shows how the robotic arm on NASA's Curiosity Mars rover moves as it takes a selfie. Credit: NASA/JPL-Caltech

In this video, JPL imaging specialist Justin Maki explains how NASA's Mars Curiosity rover takes a selfie. Credit: NASA/JPL-Caltech

Explore further

Curiosity Mars rover snaps its highest-resolution panorama yet

HOMESCHOOLING BY DEFAULT

'A really big experiment': Parents turn teachers amid virus

by Carolyn Thompson

Credit: CC0 Public Domain

After her sixth-grade son's school in Buffalo, New York, closed amid the coronavirus outbreak, Roxanne Ojeda-Valentin returned to campus with shopping bags to take home textbooks and weeks' worth of assignments prepared by teachers.

A single mother with a full-time job, she now joins millions of parents around the country—and the world—suddenly thrust into the role of their children's primary educators, leaving them scrambling to sift through educational resources and juggle lesson plans with jobs and other responsibilities.

"It's a really big experiment," Ojeda-Valentin said as she left the school, her second stop after picking up materials from her fourth-grade daughter's school.

Even in school districts that are providing remote instruction, the burden falls on parents to keep their children on task. In others, parents are left to find educational websites and curricular materials on their own. And while the challenges are daunting for all, they can be nearly impossible to overcome for parents limited by access to technology and their own levels of education.

Across the United States, more than 118,000 public and private schools in 45 states have closed, affecting 53 million students, according to a tally kept by Education Week. While many closures were initially announced as short-term, parents are wondering if schools will reopen this academic year as the outbreak intensifies.

After Kansas became the first state to announce schools would remain closed for the year, a task force recommended from 30 minutes of work a day for the youngest students to up to three hours daily for students in sixth grade and up. California Gov. Gavin Newsom also has urged the state's more than 6 million schoolchildren and their families to make long-term plans, telling them few, if any, schools would reopen before summer.

Los Angeles father Filiberto Gonzalez's three children have daily contact with their teachers and one to four hours of work they can do on an existing online platform that supplements classes. But he never thought the arrangement would transform from a stopgap measure to permanent situation.

"The news ... was a real shock to a lot of us," he said.

In Portland, Oregon, Katie Arnold's 7-year-old son has been spending his days in his mother's office, keeping busy on an iPad and her laptop while she's managing accounts for a catering company.

Oregon has shut down schools through April 28 and some districts have put optional activities online, though they are not meant to replace the regular curriculum. While her son's district explores virtual learning, she has been combing the internet and tapping friends for suggestions.

"Scholastic had a bunch of free things and I have a friend who's a teacher, so I've gotten a lot of workbook pages for him to do, just to try to keep him busy," said Arnold, who also has been using educational websites like ABCmouse.

Arnold is making plans with other parents to teach children in small groups if the closure is extended, and is resigned to the idea that her workdays will be followed by evening school sessions.

"We'll muster through it," she said.

Some parents are turning to those with experience homeschooling for guidance, unsure of whether to enforce strict schedules and where to look for academic help. Amid an influx of interest, the National Home School Association dropped its membership fee from $39 to $10 for access to tip sheets and teaching materials, executive director Allen Weston said.

The online site Outschool saw 20,000 new students enroll during a single weekend in March, compared to the 80,000 who have attended class since its 2017 launch, CEO Amir Nathoo said. The company offers live, teacher-led online classes beginning at $5 each, but has also offered free webinars on running online classes through video conferencing.

Child development researcher Jessica Logan and her husband continue to work full-time from home and have been tag-teaming school-related questions from their 8- and 12-year-old children, home from Columbus City Schools in Ohio.

"I see all these people writing out, 'Here are the six hours we're going to spend each day doing homework,' and was like, 'Not happening in my house,'" she said. "When am I going to get my work done? I still have my own work to do, so does my husband. Neither of us can take the entire day off to sit with them and do math worksheets or science experiments."

"All parents are in the same boat," Logan said. "Your kid is not going to fall behind if they don't do these assignments every day."

Nevertheless, Vancouver, Washington, teacher Renee Collins has committed to keeping not only her own 10- and 8-year-old children on track academically, but two of her friend's children and a second-grade neighbor as well.

"We're going to do Monday, Tuesday and Thursday with the five kids together and the other days I'll do individually with (her own kids). So we'll do five days," she said.

"The one thing that kind of gives a lot of us comfort," said Collins who teaches middle-school math, "is that it's not just our state. It's our entire nation. It's not just going to be the state of Washington that's behind. It's not just going to be my children that are going to be behind. It's going to be everybody."

The coronavirus may force American schools to teach online. Are they ready?