среда, 6 марта 2019 г.

Catastrophic outlook for African savannahs due to rise in CO2 levels

A ground-breaking research study looking at modern and ancient landscapes has discovered African plants could be facing mass extinction faster than once thought.

Catastrophic outlook for African savannahs due to rise in CO2 levels
Credit: Princeton University

Scientists from the Lyell Centre, Heriot-Watt University, looked at chemical fossils, with special emphasis on plant vegetable oils preserved in ancient sediments.

The fossils revealed almost 8,000 sub-tropical African plant species from an estimated total of about 23,000 species could become extinct within the next few decades.

The worrying figure amounts to 33 per cent of Africa’s contemporary plant diversity, affecting basic ecosystems worldwide.

Academics also claim, the magnitude of biodiversity loss projected for southeast Africa over the next 100 years will be more significant than anything seen in the last 15,000 years or more.

The trend was discovered after researchers looked into the widespread rapid decrease of (sub) tropical biodiversity, including plants during the most recent large-scale global warming event (deglaciation amid 10,000 to 18,000 years ago) that followed the Last Glacial Maximum.

They discovered the decline was due to rapidly rising atmospheric CO2 levels which affected the ability of plants with specialised traits, to complete with more cosmopolitan and faster growing plants like weedy grasses.

This is due to the rate at which carbon dioxide increases and the fact that the specialised plants can’t find habitats suitable for reproduction.

Dr. Clayton Magill explains: “We used chemical fossils derived from vegetable oils to track the source and movement of plant taxa across modern and ancient landscapes.

“These chemical fossils carry important environmental information within themselves as reflected through differences in their carbon composition at the atomic level. We found carbon compositional differences, in turn reflect the diversity of differing plant-type contributions into sediments.

“To break it down, this situation is much like sharing a kitchen with many roommates. With few exceptions, roommates all have unique dietary preferences and the diversity of these preferences correlates with the diversity of roommates.

“If we assume that different dietary preferences lead to carbon compositional differences in roommates’ oils, then we can see that a larger range of compositional differences is indicative of increased diversity.

“Our study informs us of a possible catastrophic outlook for plants and diversity in this African region and the fact the magnitude of biodiversity loss will be especially pronounced for sub-tropical regions, such as savannahs.”

Dr. Magill goes on to explain that this discovery may be a cause for concern, for future generations, adding: “Plant diversity is important to human welfare worldwide and the next generation should be careful to look after eco-systems so there is no further decline.

“Our study is alarming due to the differentiation of key resources such as water, carbon and light among plants in hot, dry and heterogeneous environments.

“However, it’s important to note that the imminent extinctions suggested through this work are independent of the sources of CO2.”

This study was published via PLOS ONE.

Source: Heriot-Watt University [March 01, 2019]



A clearer view of past climate from tree rings

To see where the Earth’s climate is headed, we have to see where it’s been — and a new San Francisco State University study could offer a clearer picture. The study outlines a way to use a basic law of plant growth to improve estimates of historical temperature and rainfall from tree rings. The results could help answer one of the biggest questions facing climate scientists today.

A clearer view of past climate from tree rings
Credit: Garry Knight/Flickr

“There’s a big question here, which is: How warm will it get?” said San Francisco State Assistant Professor of Earth & Climate Sciences Alexander Stine, the sole author of the study. “One way to get at this problem is to build a long record of temperatures in the Earth’s past.”

The rings of a tree document how quickly that tree grew. In the hands of a skilled scientist that can be translated into information about the environment in which the tree grew. Such records are useful because they stretch thousands of years into the past — far older than any direct measurements made by humans — and because trees are usually abundant where people live.

But when a tree’s growth is threatened by other factors like poor soil quality, the record it holds of climate start to become messier. The new technique applies a simple principle for picking the trees that hold the most pristine record of climate from each moment in history: simply selecting those that were growing the best. “The assumption is that those trees which are most successful in that year are more likely to be responding to large-scale climate,” Stine explained.

Testing that assumption on a worldwide database of tree-ring measurements includes studies by over 300 researchers around the world, Stine showed that he could get more precise measurements of past temperature and precipitation than current methods. Depending on how the math was applied, that could mean anywhere from a single-digit percent improvement to an estimate that’s 82 percent more accurate than one created using other methods. Stine reported the results earlier this month in the journal Paleoceanography and Paleoclimatology.

The key to improving those estimates was applying “Liebig’s Law of the Minimum,” the widely accepted idea that a plant’s growth is tied to the most limiting factor in its environment. For instance, a slight dip in rainfall won’t affect a tree’s growth if it’s already being stunted by an intense cold snap.

“It’s a basic idea in ecology that’s old and well-understood,” said Stine. It’s the way that he applied it that’s novel. Because of Leibig’s law, he realized, a tree growing especially well is not likely to be held back by local factors like harmful insects, meaning that measurements of the tree’s growth will be tightly linked to the climate it’s experiencing.

Stine had presented the idea and tested it at smaller scales in the past, but this is the first demonstration that the method can improve past climate estimates for regions all over the world. There’s also reason to believe that the technique can be fine-tuned further: Stine says more work is needed to figure out the best way to apply the math to see the biggest advances.

And the stakes for making those improvements are high. “We have very short instrumental temperature and rainfall records,” said Stine. “And we’re living in a world where our theory tells us these things should be changing rapidly.”

Author: Patrick Monahan | Source: San Francisco State University [March 01, 2019]



Diversification after mass extinction

A team led by Ludwig-Maximilians-Universitaet (LMU) in Munich paleontologist Adriana López-Arbarello has identified three hitherto unknown fossil fish species in the Swiss Alps, which provide new insights into the diversification of the genus Eosemionotus.

Diversification after mass extinction
Fossil Fish E. diskosomus [Credit: A. Lopez-Arbarello]

Monte San Giorgio in the Swiss canton of Ticino is one of the most important known sources of marine fossils from the Middle Triassic Period (around 240 million years ago). The new and exquisitely preserved fossil fish specimens, which Dr. Adriana López-Arbarello (a member of the Institute of Paleontology and Geobiology and of the Geobiocenter at LMU) has been studying in collaboration with colleagues based in Switzerland were also discovered in these dolomites and limestones.

As the researchers now report in the online journal Palaeontologia Electronica, the specimens represent three previously unknown species of Eosemionotus, a genus of ray-finned fishes. “The largest episode of mass extinction in the history of the Earth took place about 250 million years ago,” as López-Arbarello explains. “Our finds now provide further evidence that after this catastrophic event, the biosphere recovered relatively fast and went through a period of rapid diversification and the emergence of numerous new species during the Middle Triassic.”

The first member of the genus Eosemionotus was discovered in the vicinity of Berlin in 1906, and was named E. vogeli. Almost a century later, in 2004, a second species was described from Monte San Giorgio as E. ceresiensis. Detailed anatomical studies of new material from this locality, carried out by López-Arbarello, have now enabled the recognition of three further species that can be assigned to same genus — E. diskosomus, E. sceltrichensis and E. minutus.

All five species are small in size, but they can be clearly distinguished from each other on the basis of the relative proportions of their bodies, the position of the fins, the morphology of the skull, and the disposition of teeth and scales. “These differences indicate that each species was adapted to different ecological niches,” López-Arbarello concludes.

These findings provide new insights into the evolution of the genus. “Our phylogenetic analyses demonstrate that Eosemionotus is the oldest known member of an extinct family within the Order Semionotiformes. Although the Semionotiformes were a species-rich and highly diversified clade during the Mesozoic Era, the order died out in the Cretaceous. Only a few members of its sister group have survived down to the present day, and this ancient lineage is now represented by a single family, the gars,” says López-Arbarello.

Source: Ludwig-Maximilians-Universität München [March 01, 2019]



How new species arise in the sea

For a new species to evolve, two things are essential: a characteristic — such as a colour — unique to one species and a mating preference for this characteristic. For example, individuals from a blue fish species prefer blue mates and individuals from a red fish species prefer red mates. If the two species interbreed, the process of sexual recombination is expected to destroy the coupling between colour and mate preferences and form red individuals with a preference for blue mates and vice versa. This will prevent the two species from diverging, and this is one of the reasons why it has been thought for a long time that new species can only evolve in absolute isolation, without interbreeding.

How new species arise in the sea
A barred Hamlet (Hypoplectrus puella) off the coast of Panama
[Credit: Kosmas Hench/GEOMAR]

However, the dynamics of this process depend on the exact number and location of genes underlying species characteristics and mate preferences, the strength of natural selection acting on these genes, and the amount of interbreeding between species.

In a new study, Professor Oscar Puebla from GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany together with colleagues from the Smithsonian Tropical Research Institute in Panama have found that natural selection can couple the evolution of genes for colour pattern and mate preferences when species still interbreed.

“To address this question, the first challenge was to identify an animal group in which species are still young and interbreed, with clear species characteristics, and in which the bases of reproductive isolation are well understood,” Oscar Puebla explains.

The hamlets, a group of closely related reef fishes from the wider Caribbean, constitute exactly such a group. The hamlets are extremely close genetically, differ essentially in terms of colour pattern, and are reproductively isolated through strong visually-based mate preferences.

How new species arise in the sea
Different types of hamlets differ in colour patterns the mating preference
for each pattern [Credit: Carlos & Allison Estape]

A second difficulty consists in identifying the genes that underlie species differences and mate preferences. The authors of the new study have assembled a reference genome for the hamlets and sequenced the whole genomes of 110 individuals from three species in Panama, Belize and Honduras.

“This powerful dataset allowed us to identify four narrow regions of the genome that are highly and consistently differentiated among species in a backdrop of almost no genetic differentiation in the rest of the genome,” co-author Kosmas Hench from GEOMAR says. In line with the ecology and reproductive biology of the hamlets, these four intervals include genes involved in vision and colour pattern.

The data also show that vision and colour pattern genes remain coupled despite the fact that they are located on three different chromosomes and that species still interbreed. Such a coupling had been previously reported when the two sets of genes are very close to each other on chromosomes, in which case they are protected from sexual recombination, but not when they are on different chromosomes. By capturing the very earliest stages of speciation in hamlets, the team shows how selection can contribute to the creation of new species.

“A lot of closely related coral reef fishes differ in little else but color and pattern,” said Owen McMillan, co-author and academic dean at the Smithsonian Tropical Research Institute. “I fully expect that the discoveries we have made in hamlets will apply to other forms of life and may ultimately explain the remarkable diversity of fishes on coral reefs around the world.”

The study has been published in the international journal Nature Ecology and Evolution.

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR) [March 04, 2019]



Seemingly dormant geologic fault damaged famous Roman buildings 1,500 years ago

A geologic fault system in central Italy that produced a deadly earthquake in 2016 is also responsible for a fifth-century earthquake that damaged many Roman monuments, including the Colosseum, according to new research.

Seemingly dormant geologic fault damaged famous Roman buildings 1,500 years ago
New research finds a geologic fault system in central Italy that produced a deadly earthquake in 2016
 is also responsible for a fifth-century earthquake that damaged many Roman monuments,
including the Colosseum [Credit: David Iliff]

The Mount Vettore fault system, which winds through Italy’s Apennine Mountains, ruptured in the middle of the night on August 24, 2016. The magnitude 6.2 earthquake it generated killed nearly 300 people and destroyed several villages in the surrounding region. The fault ruptured again in October 2016, producing two more earthquakes with magnitudes greater than 6.

Scientists had thought the Mount Vettore fault system was dormant until it ruptured in 2016. They knew it could produce earthquakes, but as far as anyone knew, this was the first time the fault had ruptured in recorded history.

But a new study in the AGU journal Tectonics combining geologic data with historical records shows the fault produced a major earthquake in 443 A.D. that damaged or destroyed many well-known monuments from Roman civilization.

Among the damaged buildings were the Colosseum, made famous by the Roman Empire’s gladiator contests, as well as Rome’s first permanent theater and several important early Christian churches.

Seemingly dormant geologic fault damaged famous Roman buildings 1,500 years ago
The surface of the Mount Vettore fault system, where it ruptured in 2016
[Credit: Paolo Galli]

The finding suggests dormant faults throughout the Apennines are a silent threat to Italians and the country’s numerous historical and cultural landmarks, according to the authors. Quiescent faults could be more destructive than active faults, because researchers don’t fully consider them when evaluating seismic hazards, said Paolo Galli, a geophysicist at Italy’s National Civil Protection Department in Rome and lead author of the new study.

Reconstructing Italy’s geologic past

Italy lies on the southern end of the Eurasian tectonic plate, close to where it meets the Adriatic, African, and Ionian Sea plates. The movement of these plates relative to each other created the Apennine mountains millions of years ago, and makes Italy seismically and volcanically active today.

Hundreds of kilometers of geologic faults snake through the Apennine Mountains. Seismologists consider some of these faults to be silent or dormant because they haven’t been linked to any known historical earthquakes.

Scientists thought Mount Vettore was one of these silent fault systems until it ruptured in 2016. After Galli and his colleagues mapped the fault’s rupture in 2016, they decided to look for evidence of it having ruptured in the past.

Seemingly dormant geologic fault damaged famous Roman buildings 1,500 years ago
A recently reassembled epigraph, or stone inscription, of the prefect Rufius Caecina Felix Lampadius, describing
 restorations for the Colosseum after the 443 AD earthquake [Credit: Paolo Galli]

To do so, they dug deep trenches around parts of the fault system that ruptured in October 2016. The trenches allowed them to see the various sediment layers on either side of the fault and to determine whether the two sides of the fault had moved relative to each other at any other times in the past – in other words, if the fault had generated past earthquakes.
In the new study, Galli and his colleagues analyzed the sediment layers in the trenches and found the Mount Vettore system ruptured five other times in the past 9,000 years, in addition to 2016. One of those ruptures occurred in the middle of the fifth century, at the very end of the Roman period. Averaging the time between ruptures, they found the Mount Vettore system produces major earthquakes every 1,500 to 2,100 years.

Combining science and history

Using data from past archaeological digs in Italy and historical records from the Roman Empire, Galli and his colleagues matched the fifth-century rupture of Mount Vettore to an earthquake that rocked central Italy in 443 A.D., just three decades before the final Roman emperor was deposed.

Seemingly dormant geologic fault damaged famous Roman buildings 1,500 years ago
A timeline of past earthquakes that have damaged Roman ruins
during the common era (AD) [Credit: GeoSpace]

The 443 earthquake destroyed many towns in the Italian countryside and damaged numerous landmarks in Rome, including the Colosseum and the Theater of Pompey, Rome’s first permanent theater. The earthquake also damaged several famous early Christian churches, such as Saint Paul’s Basilica and the Church of Saint Peter in Chains, currently home to Michelangelo’s statue of Moses. Inscriptions written by Pope Leo I, emperors Valentinianus III and Theodosius II in the fifth century refer to restorations made to these structures likely as a result of this earthquake.

The new study’s results suggest the 2016 earthquake was not as unexpected as scientists thought, and other Apennine faults considered dormant by scientists may in fact pose a seismic hazard to central Italy. Considering the immense historical and cultural value of Roman ruins in this region, Galli’s priority is to better understand the rest of the silent faults on the Italian peninsula.

Author: Lauren Lipuma | Source: American Geophysical Union [March 05, 2019]



Cave with hundreds of Mayan objects discovered under Chichén Itzá

Mexican archaeologists said Monday they have found a cave at the Mayan ruins of Chichen Itza with offerings of about 200 ceramic vessels in nearly untouched condition.

Cave with hundreds of Mayan objects discovered under Chichén Itzá
Archaeologist Guillermo de Anda stands next to pre-columbian artifacts in a cave at the Mayan ruins of Chichen Itza,
 Yucatan, Mexico [Credit: Karla Ortega/Mexico’s National Institute of Anthropology and History via AP]

The National Institute of Anthropology and History said the vessels appear to date back to around A.D. 1000 and contain bone fragments and burnt offering materials that are being analyzed.
Archaeologist Guillermo de Anda said exploration of the cave began in 2018 after local Maya residents told experts about it.

Cave with hundreds of Mayan objects discovered under Chichén Itzá
Pre-columbian artifacts sit in a cave at the Mayan ruins of Chichen Itza, Yucatan, Mexico 
[Credit: Karla Ortega/Mexico’s National Institute of Anthropology and History via AP]

It turned out the cave had been discovered, but apparently not fully explored, by locals about 50 years earlier. They told an archaeologist about it then, but he ordered it sealed — perhaps to protect it — and only issued a brief report that was essentially forgotten in government archives.
The 155 ceramic braziers and incense burners found by the experts bear the likeness of Tlaloc, the rain god of central Mexico. The Mayas also had their own rain god, Chaac, and may have imported Tlaloc from other pre-Hispanic cultures. There were also clay boxes and other vessels. The team plans to leave all the objects in the cave.

Cave with hundreds of Mayan objects discovered under Chichén Itzá
Pre-columbian artifacts sit in a cave at the Mayan ruins of Chichen Itza, Yucatan, Mexico
[Credit: Karla Ortega/Mexico’s National Institute of Anthropology and History via AP]

De Anda said ancient Mayas had to crawl on their bellies through the extremely narrow cave to deposit the offerings inside a few larger, higher chambers. The offerings were apparently meant to ask for rain.
The cave, called Balamku, is about 1.7 miles (2.75 kilometers) east of the main pyramid of Kukulkan, also known as El Castillo, “The Castle.”

Cave with hundreds of Mayan objects discovered under Chichén Itzá
Archaeologist Guillermo de Anda sits next to pre-columbian artifacts in a cave at the Mayan ruins of Chichen Itza, 
Yucatan, Mexico [Credit: Karla Ortega/Mexico’s National Institute of Anthropology and History via AP]

De Anda and his team are exploring Chichen Itza to establish the routes and sites of its underground water system. A series of sinkhole lakes known as cenotes are visible on the surface of the Chichen Itza site, but there are other, undiscovered water sites beneath the pyramids, patios and temples.
Water was always central to Chichen Itza, whose very name means “at the mouth of the well of the Water Wizards” in Maya.

De Anda said experts have crawled a few hundred meters (yards) into the cave, which in places is just 16 inches (40 centimeters) tall, in hopes of finding the connection to a cenote cave believed to lie under the pyramid of Kukulkan.

“Let’s hope this leads us there. That is part of the reason why we are entering these sites, to find a connection to the cenote under the Castillo,” De Anda said.

Source: Associated Press [March 05, 2019]



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Geology Page



An abundance of beneficial mutations

Despite its key importance, the genetic architecture of adaptive processes remains largely unresolved. Now a team of researchers from Vetmeduni Vienna, experimenting with fruit flies, has succeeded in solving at least a part of this puzzle. They were able to show that many genes can contribute to adaptation even though only some of them are actually being used (genetic redundancy).

An abundance of beneficial mutations
In fruit flies, many genes can contribute to adaptation, but only some of them
are actually being used [Credit: PopGen/Vetmeduni Vienna)]

Not just since climate change has it been of enormous interest to understand how populations adapt to new environmental conditions. Scientists assume that most adaptations involve a large number of different genes, but most molecularly characterized adaptations are based on only one or a few genes. This discrepancy has been the source of much conjecture but has remained largely unresolved.

To shed more light on this highly interesting area for the field of evolution, a research team from Vetmeduni Vienna used the method of experimental evolution. The goal of the experiment was to study the adaptive processes of fruit flies (Drosophila simulans) in a precisely controlled laboratory setting.

The scientists exposed the flies to a hot environment (up to 28°C) over 60 generations and monitored the genetic changes using the latest sequencing methods. In contrast to previous studies, the authors were able to demonstrate that many genes are involved in the adaptation.

A surprising result was that different combinations of genes produced similar adaptations in the different experimental populations. This leads first author Neda Barghi to conclude: “Fruit flies possess more paths for adapting to new environmental conditions than they actually use.” Experts call this observation “genetic redundancy”.

This study with fruit flies not only represents a milestone in the field of theoretical evolutionary biology but also has a concrete impact on studies which seek to demonstrate adaptive processes in natural populations.

“Usually parallel signatures of selection, i.e., selection signatures found in several populations, are considered to be especially reliable,” explains Christian Schlötterer from the Institute of Population Genetics.

“Our study shows, however, that this procedure must be thoroughly reconsidered in order to obtain a complete picture of the adaptive processes.”

The article was published in PLOS Biology.

Source: University of Veterinary Medicine—Vienna [March 01, 2019]



Two genes explain variation in colour and behaviour in the wall lizard

How are reptiles capable of generating such a diversity of bright colors? And how is it possible that within a single population of the same species, different individuals exhibit strikingly different coloration patterns? In a new paper published in the journal Proceedings of the National Academy of Sciences an international team of scientists, led by researchers from CIBIO/InBIO (University of Porto) and Uppsala University, reveal two genes implicated in yellow to red pigmentation in reptiles, and demonstrate that these “pigmentation genes” also affect behavior and other traits.

Two genes explain variation in colour and behaviour in the wall lizard
A common wall lizard individual exhibiting orange colouration. The presence of orange is explained by variation
 in the SPR gene, which is a gene in a highly conserved pathway that is linked to the production
of neurotransmitters like serotonin and dopamine [Credit: Guillem Perez i de Lanuza]

The study focused on the European wall lizard, which is common across most of Southern Europe.

“While for a casual observer it may seem like an ordinary lizard, with its camouflaged back blending perfectly with rocky surroundings, in most populations of this species the belly and throat show a remarkable diversity in color, being either white, bright orange/red or bright yellow. Strikingly, lizards of different colors differ in other characteristics, such as size, fighting ability and reproductive strategies. They also preferentially mate with individuals of their own color,” said Pedro Andrade, PhD student at the University of Porto and lead author of the paper.

The researchers found that the genomes of differently colored lizards are virtually identical – except for very specific portions of the DNA sequence. “In nature, when individuals from different populations or species differ in multiple characteristics, the expectation is that many genes are involved. So, for us it was a big surprise to see that in these lizards, the color differences and associated characteristics are largely explained by small regions of the genome that contain only two genes,” said senior author Miguel Carneiro from CIBIO, University of Porto.

Orange/red hues are explained by the SPR gene, a vital gene in the pterin synthesis pathway, while yellow hues are explained by the BCO2 gene, which is involved in the metabolism of carotenoids. “The characterization of the molecular basis of the color variation is an important step because it allows us to understand how it has originated and exactly which metabolic pathways are involved,” said Catarina Pinho, researcher from the University of Porto and co-first author of the work. “There are previous studies showing a relationship between BCO2 and yellow coloration in other organisms, namely birds, and it is interesting that the same gene is being recruited for the same role in different branches of the animal tree of life.”

Two genes explain variation in colour and behaviour in the wall lizard
While at first glance, a wall lizard may look like another well camouflaged reptile (left), in reality this species presents
 a stunning set of well distinct morphs that differ in the colouration of their throat and bellies (right)
[Credit: Guillem Perez i de Lanuza and Javier Abalos]

The gene SPR is of particular interest. The metabolic byproducts of this gene’s activity are closely linked to the production of neurotransmitters like serotonin and dopamine. These are chemicals that, also in humans, are responsible for the transmission of information between neurons.

“Our results implicate that these “pigmentation genes” lead to other “side-effects”, such as potential differences in the functioning of the brain that could explain why lizards of different color behave differently or have slightly different habitat choices,” said Professor Leif Andersson from Uppsala University, another senior author of the paper.

The team also found that the DNA sequences associated with different colors were extremely divergent. The divergence in DNA sequence was big enough to go beyond what one would expect to find between species. The differences were up to six times larger than what is normally found when comparing human and chimpanzee DNA. Further DNA analyzes showed that this genetic variation is shared with multiple lizard species that occur in the Mediterranean. The likely explanation for this pattern is that the DNA sequences associated with coloration are millions of years old and that some species have been exchanging them through natural hybridization. This highlights how hybridization is an important mechanism for the fast acquisition of new characteristics – even humans are an example of this, as shown by multiple evidence of hybridization between modern and archaic humans like Neanderthals.

This international team of researchers has an ongoing research program focused on how color variation and associated characteristics arise and are maintained. Ongoing work leverages techniques and expertise in the fields of genome sciences, animal behavior, and neurobiology and aims to help decipher other interesting aspects of the biology of the color variation and what exactly the different colors are signaling to lizards, which is something that remains a mystery.

Source: Uppsala University [March 01, 2019]



Scientists discover how surfaces may have helped early life on Earth begin

On early earth, a series of spontaneous events needed to happen in order for life as we know it to begin. One of those phenomena is the formation of compartments enclosed by lipid membranes. New research by Irep Gözen, Elif Koksal, and colleagues at the University of Oslo reveals, for the first time, how these vesicles can self-assemble on surfaces without external input.

Scientists discover how surfaces may have helped early life on Earth begin
Spontaneously formed protocells, which resemble balloons anchored to a surface by a network of ropes,
 are visualized by 3D confocal microscopy [Credit: Irep Gozen]

The team discovered the most straight-forward and plausible explanation so far with the simplest assumptions. They will present their research at the 63rd Biophysical Society Annual Meeting, to be held March 2 – 6, 2019 in Baltimore, Maryland.

Gözen’s lab was originally focused on biomaterials, not origins of life research.

“We were actually trying to do another experiment and this came as a discovery,” said Gözen. “The formation of lipid tubes and the emergence of thousands of vesicles was happening spontaneously when we left lipids on a silicon dioxide surface.”

The lipids in their experiment were similar to those in bacteria membranes and have water-loving heads and water-avoiding tails. Because of these water-preferring properties, they spontaneously organize with their tails facing inward and their heads facing out. On the silicon dioxide surface, the lipids became sheets, with layers of these organized lipids.

Due to the stickiness of the surface, at some points the two layers separate, and the top layer bulges out, creating tubes and then round balls as they gain more lipids. The entire process is fully autonomous. A gentle flow from the movement of liquid can then cause these vesicles to detach from the surface creating protocells, like those believed to be a stepping-stone to the origin of life.

“This is a new and novel means of compartmentalization,” Gözen said.

It is conceivable that something similar happened on early earth. Silicone dioxide, or silica, is one of the most abundant minerals on the earth’s surface. Fatty molecules could have easily existed in the previological era, as confirmed by the results of their successful synthesis performed in possible primitive Earth conditions, together with their traces found in fossils and meteorites. Intriguingly, silicon dioxide was recently detected on Mars by the Curiosity Rover.

Another puzzle in life’s beginnings is how genetic material got inside of protocells. It is not known whether the compartments formed around the already-existing lengthy genetic chains such as RNA, or if the small building blocks somehow found their way inside these tiny bubbles and made the chains inside.

Gözen and colleagues added a light-emitting organic molecule similar in size to nucleotides, the genetic building blocks, to the surrounding of the bubbles. Such molecules which were too big to diffuse through the wall of the bubble, could get inside without compromising the protocells. They speculate it gets through transient defects or pores in the protocell wall.

“Our research may explain, for the first time, the details of self-directed transition from weakly organized lipids on solid surfaces to protocells with secluded internal contents,” Gözen said.

Source: The Biophysical Society [March 01, 2019]



New clues to the lost tomb of Alexander the Great discovered in Egypt

It was the last hour of the last day of a long, frustrating dig, and Calliope Limneos-Papakosta was ready to go home. For 14 years the Greek archaeologist had been scouring Shallalat Gardens, a public park in the heart of Alexandria, Egypt, for traces of Alexander the Great, the ancient conqueror-turned-pharaoh who gave the city his name. Now it was time to leave—empty-handed.

New clues to the lost tomb of Alexander the Great discovered in Egypt
Buried and forgotten for centuries, the foundation walls of a monumental building dating to the era
of Alexander the Great have been uncovered in the Egyptian city named in his honour
[Credit: National Geographic]

Then a bit of soil shifted in the pit and Papakosta’s assistants called her over to inspect a piece of white marble poking out of the dirt. She had been disappointed in the dig, but when Papakosta saw the flash of white stone, she felt a surge of hope.

Buried and forgotten for centuries, the foundation walls of a monumental building dating to the era of Alexander the Great have been uncovered in the Egyptian city named in his honor.

“I was praying,” she says. “I hoped that it was not just a piece of marble.”

Her prayer was answered. The artifact turned out to be an early Hellenistic statue bearing every hallmark of Alexander the Great. It was a powerful incentive for the discouraged archaeologist to keep digging.

New clues to the lost tomb of Alexander the Great discovered in Egypt
Archaeologist Calliope Limneos-Papakosta has been digging for more than 20 years in hopes of finding
the tomb of Alexander the Great. “I have a dream,” she says, “and I will go on until I fulfill it”
[Credit: National Geographic]

Seven years later, Papakosta, who directs the Hellenic Research Institute of the Alexandrian Civilization, has dug down 35 feet beneath modern-day Alexandria and uncovered the ancient city’s royal quarter.

“This is the first time the original foundations of Alexandria have been found,” says Fredrik Hiebert, archaeologist in residence at the National Geographic Society. “It gave me goosebumps to see it.”

And the site may yield one of archaeology’s biggest prizes—the lost tomb of Alexander the Great.

Rising seas, sinking site

Once the world’s most powerful leader, Alexander was just 20 years old when he became king of Macedonia following the assassination of his father, Philip II, in 356 B.C. Over the next 12 years the brilliant, ambitious Alexander toppled every rival empire in his path, including Persia and Egypt, where he declared himself pharaoh. The restless warrior died in 323 B.C. at age 32. His remains did not rest easy.

New clues to the lost tomb of Alexander the Great discovered in Egypt
After 14 years of fruitless digging, Papakosta unearthed this early Hellenistic marble statue
of Alexander the Great, now exhibited at the National Museum of Alexandria.
The discovery, she says, was her “greatest moment”
[Credit: National Geographic]

After being argued over by his advisers, Alexander’s body was buried first in Memphis, Egypt, then in the city that bears his name. There, his tomb was visited and venerated like the temple of a god.

After 14 years of fruitless digging, Papakosta unearthed this early Hellenistic marble statue of Alexander the Great, now exhibited at the National Museum of Alexandria. The discovery, she says, was her “greatest moment.”

But Alexandria and its founder’s tomb were under threat—not from invading forces, but from nature. A decade before Alexander’s birth, in 365 B.C., a tsunami inundated the city. The disaster marked the start of a long era of earthquakes and rising sea levels. (Sea level rise still threatens Alexandria today.)

As the sea encroached to the north, the waters of the Nile Delta on which Alexandria is situated caused the ancient part of the city to slowly sink at a rate of up to 0.25 centimeters a year—as much as 12 feet since Alexander’s time. The city survived, building over its ancient portions and ballooning to a population of more than five million.

Over time the city’s foundations were buried and forgotten, along with the location of Alexander’s tomb. Though ancient authors such as Strabo, Leo Africanus, and others described the tomb, its location relative to the modern city remains a mystery.

The tomb’s murky location hasn’t kept archaeologists from searching for it. Records exist of more than 140 officially sanctioned excavations, all of which failed. But the tomb’s elusiveness has only increased its cachet: To find Alexander’s tomb would be on par with discovering Tuthankhamun’s.

Shovels, pumps, and persistence

Hope of a historic find keeps Papakosta digging, guided by ancient accounts and a 19th-century map of Alexandria before its boom. She also uses modern technology, such as electrical resistivity tomography (ERT), to determine where to dig. ERT passes an electrical current into the soil to measure resistance and detect subsurface objects. So far, her team has identified 14 anomalies that may be structures far beneath the ground.

Using these and other methods, Papakosta is uncovering more and more of the city’s ancient royal quarter—including a Roman road and the remains of a massive public building that could point to Alexander’s tomb.

New clues to the lost tomb of Alexander the Great discovered in Egypt
During his 12-year reign, Alexander the Great conquered mighty empires and became
a god-like figure. Despite centuries of searching, his tomb has yet to be found
[Credit: Universal Archive/Getty]

During his 12-year reign, Alexander the Great conquered mighty empires and became a god-like figure. Despite centuries of searching, his tomb has yet to be found.

But each discovery is hard-won. “I’m happy that I did not give up when I first arrived at the water table,” says Papakosta, who had to engineer an elaborate system of pumps and hoses to keep the site dry enough to excavate. “I was insistent and continued. I go on.”

That persistence over many years of slow, muddy work sets Papakosta apart, says Hiebert. “It’s rare in my experience to find someone who’s stayed at a single site for 21 years.” He compares Papakosta to a boxer who falls down, then dusts herself off and goes back into the ring. “She goes the full nine rounds.”

Over the years, Papakosta has become increasingly convinced that she’s closing in on Alexander’s lost tomb. She tempers her optimism, though, with a healthy dose of realism.

“For sure, it’s not easy to find it,” she says. “But for sure, I am in the center of Alexandria in the royal quarter, and all these possibilities are in my favor.”

Author: Erin Blakemore | Source: National Geographic [March 01, 2019]



Earliest concepts of artificial intelligence, robots found in ancient Greek myths

Thousands of years before machine learning and self-driving cars became reality, the tales of giant bronze robot Talos, artificial woman Pandora and their creator god, Hephaestus, filled the imaginations of people in ancient Greece.

Earliest concepts of artificial intelligence, robots found in ancient Greek myths
A Greek vase painting, dating to about 450 BC, depicts the death of Talos.
[Credit: WikiCommons/Forzaruvo94]

Historians usually trace the idea of automata to the Middle Ages, when the first self-moving devices were invented, but the concept of artificial, lifelike creatures dates to the myths and legends from at least about 2,700 years ago, said Adrienne Mayor, a research scholar in the Department of Classics in the School of Humanities and Sciences. These ancient myths are the subject of Mayor’s latest book, Gods and Robots: Myths, Machines, and Ancient Dreams of Technology.

“Our ability to imagine artificial intelligence goes back to the ancient times,” said Mayor, who is also a 2018-19 fellow at the Center for Advanced Study in the Behavioral Sciences at Stanford. “Long before technological advances made self-moving devices possible, ideas about creating artificial life and robots were explored in ancient myths.”

Mayor, a historian of science, said that the earliest themes of artificial intelligence, robots and self-moving objects appear in the work of ancient Greek poets Hesiod and Homer, who were alive somewhere between 750 and 650 B.C.

The story of Talos, first mentioned around 700 B.C. by Hesiod, offers one of the earliest conceptions of a robot, Mayor said.

The myth describes Talos as a giant bronze man built by Hephaestus, the Greek god of invention and blacksmithing. Talos was commissioned by Zeus, the king of Greek gods, to protect the island of Crete from invaders. He marched around the island three times every day and hurled boulders at approaching enemy ships.

At his core, the giant had a tube running from his head to one of his feet that carried a mysterious life source of the gods the Greeks called ichor. Another ancient text, Argonautica, which dates to the third century B.C., describes how sorceress Medea defeated Talos by removing a bolt at his ankle and letting the ichor fluid flow out, Mayor said.

The myth of Pandora, first described in Hesiod’s Theogony, is another example of a mythical artificial being, Mayor said. Although much later versions of the story portray Pandora as an innocent woman who unknowingly opened a box of evil, Mayor said Hesiod’s original described Pandora as an artificial, evil woman built by Hephaestus and sent to Earth on the orders of Zeus to punish humans for discovering fire.

“It could be argued that Pandora was a kind of AI agent,” Mayor said. “Her only mission was to infiltrate the human world and release her jar of miseries.”

In addition to creating Talos and Pandora, mythical Hephaestus made other self-moving objects, including a set of automated servants, who looked like women but were made of gold, Mayor said. According to Homer’s recounting of the myth, Hephaestus gave these artificial women the gods’ knowledge. Mayor argues that they could be considered an ancient mythical version of artificial intelligence.

The ancient myths that Mayor examined in her research grapple with the moral implications of Hephaestus’ creations.

“Not one of those myths has a good ending once the artificial beings are sent to Earth,” Mayor said. “It’s almost as if the myths say that it’s great to have these artificial things up in heaven used by the gods. But once they interact with humans, we get chaos and destruction.”

Mayor said the myths underscore humanity’s fascination with creating artificial life.

“People have an impulse to imagine things that aren’t possible yet,” Mayor said. “There is a timeless link between imagination and science.”

Author: Alex Shashkevich | Source: Stanford University [March 01, 2019]



Egypt completes restoration of Kom el-Shuqafa catacombs

Egypt on Sunday completed a project to restore the catacombs of Kom el-Shuqafa in western Alexandria, which have been prone to groundwater leaks since they were discovered in the first decade of the 20th century.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit : Egypt. Ministry of Antiquities

The restoration, which began in late 2017, was completed using a $5.7 million grant from the U.S. Agency for International Development (USAID). The grant also covered maintenance and training for ministry employees.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit: Amr Abdallah Dalsh/Reuters

“The antiquity underwent many restoration projects, the most important of which was in the mid-nineties, which was an ambitious project supervised by the Supreme Council of Antiquities,” Antiquities Minister Khaled al-Anani said from the site on Sunday.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit : Egypt. Ministry of Antiquities

“But unfortunately, the water returned once again and complaints rolled in from parliamentarians, tour guides and archaeologists, which is what pushed us to act in cooperation with USAID.”

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit : Egypt. Ministry of Antiquities

The catacombs are unique, mixing ancient Egyptian and Graeco-Roman architectural styles. They were carved into the rock on three levels. The ground level was damaged by water from nearby farmland and a canal, as well as sewage water.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit: Egypt. Ministry of Antiquities

The antiquities ministry has previously cooperated with USAID on several groundwater-removal projects in Cairo, Giza, Luxor and Aswan.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit: Amr Abdallah Dalsh/Reuters

Al-Anani said a similar project will be opened on March 25 at Kom Ombo in Aswan governorate.

Egypt completes restoration of Kom el-Shuqafa catacombs
Credit: Amr Abdallah Dalsh/Reuters

Egypt has been working to revive its tourism industry – a key source of foreign currency – which was badly hit after the 2011 popular uprising that unseated Hosni Mubarak and was further hampered by a spate of militant attacks that sometimes targeted visitors.

Source: Reuters [March 03, 2019]



Kepler Space Telescope’s First Exoplanet Candidate Confirmed, Ten Years After...

Artist’s concept of a Kepler-1658-like system. Sound waves propagating through the stellar interior were used to characterize the star and the planet. Kepler-1658b, orbiting with a period of just 3.8 days, was the first exoplanet candidate discovered by Kepler nearly 10 years ago. Credit: Gabriel Perez Diaz/Instituto de Astrofísica de Canarias. Low Resolution (jpg)

Kepler Space Telescope’s First Exoplanet Candidate Confirmed, Ten Years After Launch Cambridge, MA – An international team of astronomers, led by University of Hawai’i graduate student Ashley Chontos, announced the confirmation of the first exoplanet candidate identified by NASA’s Kepler Mission. The result was presented today at the fifth Kepler/K2 Science Conference held in Glendale, CA.

Launched almost exactly 10 years ago, the Kepler Space Telescope has discovered thousands of exoplanets using the transit method – small dips in a star’s brightness as planets cross in front of the star. Because other phenomena can mimic transits, Kepler data reveal planet candidates, but further analysis is required to confirm them as genuine planets.

Despite being the very first planet candidate discovered by NASA’s Kepler Space Telescope, the object now known as Kepler-1658 b had a rocky road to confirmation. The initial estimate of the size of the planet’s host star was incorrect, so the sizes of both the star and Kepler-1658 b were vastly underestimated. It was later set aside as a false positive when the numbers didn’t quite make sense for the effects seen on its star for a body of that size. Fortuitously, Chontos’ first year graduate research project, which focused on re-analyzing Kepler host stars, happened at just the right time.

“Our new analysis, which uses stellar sound waves observed in the Kepler data to characterize the host star, demonstrated that the star is in fact three times larger than previously thought. This in turn means that the planet is three times larger, revealing that Kepler-1658 b is actually a hot Jupiter-like planet,” said Chontos. With this refined analysis, everything pointed to the object truly being a planet, but confirmation from new observations was still needed.

“We alerted Dave Latham (a senior astronomer at the Smithsonian Astrophysical Observatory, and co-author on the paper) and his team collected the necessary spectroscopic data to unambiguously show that Kepler-1658 b is a planet,” said Dan Huber, co-author and astronomer at the University of Hawai’i. “As one of the pioneers of exoplanet science and a key figure behind the Kepler mission, it was particularly fitting to have Dave be part of this confirmation.”

Kepler-1658 is 50% more massive and three times larger than the Sun. The newly confirmed planet orbits at a distance of only twice the starʻs diameter, making it one of the closest-in planets around a more evolved star – one that resembles a future version of our Sun. Standing on the planet, the star would appear 60 times larger in diameter than the Sun as seen from Earth.

Planets orbiting evolved stars similar to Kepler-1658 are rare, and the reason for this absence is poorly understood. The extreme nature of the Kepler-1658 system allows astronomers to place new constraints on the complex physical interactions that can cause planets to spiral into their host stars. The insights gained from Kepler-1658b suggest that this process happens slower than previously thought, and therefore may not be the primary reason for the lack of planets around more evolved stars.

“Kepler-1658 is a perfect example of why a better understanding of host stars of exoplanets is so important,” said Chontos. “It also tells us that there are many treasures left to be found in the Kepler data.”

Paper preprint (Chontos et al., accepted for publication in AJ): http://www.ifa.hawaii.edu/~dhuber/docs/kepler1658-accepted.pdf

Headquartered in Cambridge, Mass., the Center for Astrophysics | Harvard & Smithsonian (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

Tyler Jump
Public Affairs
Center for Astrophysics | Harvard & Smithsonian
+1 617-495-7462

Ashley Chontos
+1 347-443-2505 (cell)

Daniel Huber
+1 808-773-2898 (cell)

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Movement Map Artificial intelligence software can accurately…

Movement Map

Artificial intelligence software can accurately predict a patient’s risk of heart failure by tracking cardiac movement on MRI scans. The software plots the motion of hundreds of points every second to create an incredibly detailed 3D map of heart function. Here, a model heart rotates with loops that each indicate the direction that a part of the heart moves through as it contracts and relaxes, with red loops moving more quickly than blue. The software then learns to predict patient outcomes using these maps of heart motion. It made accurate predictions about survival 75% of the time and outperformed the manual measurements that doctors currently rely on. The software was applied to 302 people with a heart condition called pulmonary hypertension, and it’s hoped that it will be extended to other causes of heart failure so that doctors and patients can make more informed choices about treatment.

Written by Deborah Oakley

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Cluster helps solve mysteries of geomagnetic storms

ESA – Cluster Mission logo.

05 March 2019

In a powerful example of combining multi-mission satellite data with computer simulations, scientists have used ESA’s Cluster mission to reveal details about how electrons interact with waves in Earth’s magnetic environment. This research helps explain the behaviour of particles during geomagnetic storms and has significant implications for our understanding of space weather, which is in turn necessary to help protect space technology from the potentially harmful effects of energetic particles generated during such storms.

Image above: Cluster and the Van Allen Probes in Earth’s magnetosphere. Image Credits: ESA/NASA/SOHO/LASCO/EIT.

The Sun constantly bombards Earth with a flow of charged particles known as the solar wind. Powerful shocks arising in this flow can cause disturbances in Earth’s magnetosphere – the protective bubble created by our planet’s magnetic field – which are known as geomagnetic storms.

These storms transfer a large amount of energy to the magnetosphere, eventually causing electrons to accelerate along magnetic field lines, which are continuous curves indicating the magnetic field direction, extending between the poles of our planet. When these electrons enter the ionosphere – the upper layer of Earth’s atmosphere – the resulting interaction causes atoms like nitrogen and oxygen to release light, leading to the beautiful displays known as the aurora. The most energetic electrons can also cause serious damage to satellites and other electronic infrastructure.

For a long time, the detailed mechanisms behind the movement of electrons between the magnetosphere and the ionosphere remained a mystery. But recently a team of scientists discovered that certain types of oscillations in Earth’s magnetic field can explain some intriguing observations of how electrons behave along magnetic field lines.

As the solar wind varies in speed and intensity, bursts of plasma can be fired from the magnetotail, in the opposite direction to the Sun, towards Earth, through a process known as magnetic reconnection. When these fast plasma streams reach Earth, they impact high-pressure plasma on the magnetic field lines. This causes the magnetic field lines to vibrate, giving rise to standing waves – also known as Alfvén waves – oscillating perpendicular to the dipolar magnetic field lines.

Akin to waves on a guitar string, these oscillations occur on a range of scales, including small-scale waves comparable to the orbits of particles moving along the field lines. In this case, these waves are called Kinetic-Scale Field Line Resonances (KFLRs) and, while always present in the magnetosphere, they are enhanced when magnetic storms on the Sun send highly energetic solar wind flows towards Earth, triggering a geomagnetic storm.

Image above: Electrons trapped in kinetic scale field line resonance. Image Credit: ESA.

Studying observations of Earth’s magnetic field taken on different occasions by ESA’s Cluster mission and NASA’s Van Allen Probes, a team of scientists noticed that, in both sets of data, the distribution of electrons within these waves was stretched following the direction of magnetic field lines from the North Pole to the South Pole.

However, the detailed structure of the distributions was different in the two sets of observations, which were taken at significantly different points along the magnetic field. The Van Allen Probes observations were performed in June 2013 during a geomagnetic storm; the Cluster observations, dating back to February 2001, were obtained in storm-like circumstances, under enhanced auroral conditions.

To investigate the nature of the electron distributions and the differences in the details  seen by the two missions, the scientists brought in a computer simulation.

“I had created the computer model to study the interaction of electrons within magnetospheric Alfvén waves, and these observations provided us with the first opportunity to look specifically at kinetic-scale field line resonances in the inner magnetosphere,” explains project lead Peter Damiano from the University of Alaska Fairbanks, USA.

“We were surprised to find that the simulations reproduced the characteristics of the observations from both missions very well. And when we compared the observations and the simulations, it became clear that the stretching of the electron distribution in the direction of Earth’s magnetic field was caused, in both cases, by the trapping of electrons within the KFLRs.”

Image above: Cluster measurement of electron distribution function. Image Credits: ESA/Cluster; P. Damiano et al. (2018).

Since the KFLRs evolve over time, so does the trapped electron population, and this explains the difference between the observations by the two missions. The Cluster data demonstrated more clearly how the distribution changes over time, because observations were made every four seconds – similar to the oscillation period of the waves. The Van Allen Probes data, on the other hand, were taken every eleven seconds, so the distribution of electrons was smoothed out and it was more difficult to see how it changed over time. As the spacecraft took measurements while in different locations, the study also revealed that electrons could be trapped at different points along the magnetic field lines because of the global extent of the waves. This illustrates how the simulations help scientists connect and understand seemingly remote observations.

Being closer to the ionosphere, the Cluster observations of electron distribution functions also illustrated the significant loss of electrons from the magnetosphere to ionosphere – which can contribute to the generation of auroral emissions at high altitudes. The simulations showed that this loss might be due to the interaction of KFLRs with non-trapped electrons.

Image above: High-altitude red aurora observed from the International Space Station. Image Credits: ESA/NASA.

Although scientists have a good idea of how the magnetosphere works overall, many specific details are still unclear, and this study is one step towards furthering our understanding.

“Our ultimate goal is to understand magnetospheric processes well enough to forecast how particles behave around Earth, including predicting the locations of the most dangerous geomagnetic storms,” explains Philippe Escoubet, Cluster mission scientist.

“This would help us to forecast the impact of the energetic particle environment around Earth on all sorts of technological infrastructure.”

During geomagnetic storms, KFLRs are enhanced, modifying the distributions of particles in the Van Allen radiation belts – two doughnut-shaped regions of highly energetic charged particles surrounding Earth. These changes to the plasma can impact other electromagnetic waves that are linked to the acceleration of very high-energy electrons, and consequently the response of the magnetosphere during geomagnetic storms.

“Elucidating how electrons interact with KFLRs during such storms is vital for understanding and predicting space weather,” continues Damiano.

Space weather refers to the variable solar conditions that can influence our planet’s surroundings, with effects on the performance of human technology on ground and in space. As spacecraft electronics can be severely affected by highly-energetic charged particles, especially at times of strong geomagnetic activity, it is vital to recognise the impact of magnetospheric processes on satellite infrastructure, and science missions like Cluster and the Van Allen Probes are crucial to these efforts.

Image above: Artist’s impression of the Cluster spacecraft. Image Credits: ESA/ATG medialab.

“If we can accurately forecast when geomagnetic storms occur, we can take measures such as switching off spacecraft electronics to avoid short-circuiting, and flying aeroplanes around storms to prevent excess radiation exposure to crew and passengers,” continues Escoubet.

“Space weather can also affect GPS signals and better understanding its impacts would help us generate more accurate location data.”

Launched in 2000, Cluster has helped unearth a plethora of interesting details about the magnetosphere and its interaction with the solar wind. The mission’s four spacecraft can access high latitudes above our planet, providing new and unprecedented measurements of the magnetosphere.

This result highlights how combining data from more than one mission allows us to study magnetospheric phenomena in a totally new way. It also demonstrates the richness of the Cluster and Van Allen Probe data archives and their combined potential to make new discoveries with far-reaching applications.

Notes for Editors:

“Electron Distributions in Kinetic Scale Field Line Resonances: A Comparison of Simulations and Observations” by P.A. Damiano et al (2018) is published in Geophysical Research Letters: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL077748

Cluster is a constellation of four spacecraft flying in formation around Earth. It is the first space mission able to study, in three dimensions, the natural physical processes occurring within and in the near vicinity of the Earth’s magnetosphere. Launched in 2000, it is composed of four identical spacecraft orbiting the Earth in a pyramidal configuration, along a nominal polar orbit of 4 × 19.6 Earth radii (1 Earth radius = 6380 km). Cluster’s payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields over wide frequency ranges, and key physical parameters characterising electrons and ions from energies of near 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC) at the Rutherford Appleton Laboratory, United Kingdom, and implemented by ESA’s European Space Operations Centre (ESOC), in Darmstadt, Germany.

More information on the Cluster mission can be found here: http://sci.esa.int/cluster

NASA’s Van Allen Probes (formerly known as the Radiation Belt Storm Probes, RBSP) study two extreme and dynamic regions of space known as the Van Allen Radiation Belts that surround Earth. Named for their discoverer, James Van Allen, these two concentric, doughnut-shaped rings are filled with high-energy particles that gyrate, bounce, and drift through the region, sometimes shooting down to Earth’s atmosphere, sometimes escaping out into space. The radiation belts swell and shrink over time as part of a much larger space weather system driven by energy and material that erupt off the sun’s surface and fill the entire solar system.

More information on the Van Allen Probes can be found here: https://www.nasa.gov/mission_pages/rbsp/mission/index.html

Images (mentioned), Text, Credits: ESA/Philippe Escoubet/Geophysical Institute, University of Alaska Fairbanks/Peter A. Damiano.

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https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...