четверг, 5 декабря 2019 г.

SpaceX Gears Up for Second CRS-19 Launch Attempt













SpaceX - CRS-19 Dragon patch.

December 5, 2019

SpaceX is preparing for the second launch attempt of its 19th Commercial Resupply Services (CRS-19) mission to the International Space Station today at 12:29 p.m. EST (17:29:23 GMT). The company’s Falcon 9 rocket and uncrewed Dragon spacecraft will lift off from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. Join us here on the blog, as well as on NASA TV and the agency’s website, for live launch countdown coverage, beginning at 12 p.m. EST.


Image above: A SpaceX Falcon 9 rocket stands ready for liftoff at Cape Canaveral Air Force Station’s Space Launch Complex 40 in Florida on Dec. 5, 2019, for the company’s 19th Commercial Resupply Services mission to the International Space Station. Launch is scheduled for 12:29 p.m. EST. Photo credit: NASA.

SpaceX made the decision to call off the first launch attempt yesterday due to upper-altitude winds and high winds at sea, creating dangerous conditions around the drone ship “Of Course I Still Love You,” which the rocket’s first stage will attempt landing on following its separation from the rest of the launch vehicle.

The Dragon spacecraft that will deliver critical supplies, equipment and material to the space station on this mission first flew to the orbiting laboratory in 2014 on CRS-4, and then again on CRS-11, making it the first spacecraft that SpaceX reused for resupply missions. Now preparing to fly for a third time, the material it will carry on CRS-19 will directly support dozens of research investigations taking place in space. To learn more about some of those research experiments, visit: https://www.nasa.gov/mission_pages/station/research/news/spx19-research/

Related links:

International Space Station: https://www.nasa.gov/mission_pages/station/main/index.html

NASA TV: https://www.nasa.gov/nasalive

Image (mentioned), Text, Credits: NASA/Danielle Sempsrott.

Greetings, Orbiter.ch

* This article was originally published here

Compound eyes: The visual apparatus of today's horseshoe crabs goes back 400 million years


The eyes of the extinct sea scorpion Jaekelopterus rhenaniae have the same structure as the eyes of modern horseshoe crabs (Limulidae). The compound eyes of the giant predator exhibited lens cylinders and concentrically organized sensory cells enclosing the end of a highly specialized cell. This is the result of research Dr Brigitte Schoenemann, professor of zoology at the Institute of Biology Didactics at the University of Cologne, conducted with an electron microscope.

Compound eyes: The visual apparatus of today's horseshoe crabs goes back 400 million years
Horseshoe crab [Credit: Shutterstock]
The eyes of modern horseshoe crabs consist of compounds, so-called ommatidia. Unlike, for example, insects that have compound eyes with a simple lens, the ommatidia of horseshoe crabs are equipped with a lens cylinder that continuously refracts light and transmits it to the sensory cells.


These sensory cells are grouped in the form of a rosette around a central light conductor, the rhabdom, which is part of the sensory cells and converts light signals into nerve signals to transmit them to the central nervous system. At the centre of this 'light transmitter' in horseshoe crabs is a highly specialized cell end, which can connect the signals of neighbouring compounds in such a way that the crab perceives contours more clearly. This can be particularly useful in conditions of low visibility under water. In the cross-section of the ommatidium, it is possible to identify the end of this specialized cell as a bright point in the centre of the rhabdom.

Compound eyes: The visual apparatus of today's horseshoe crabs goes back 400 million years
Fossil of J. rhenaniae [Credit: wanderflechten/flickr]
Brigitte Schoenemann used electron microscopes to examine fossil Jaekelopterus rhenaniae specimens to find out whether the compound eyes of the giant scorpion and the related horseshoe crabs are similar or whether they are more similar to insect or crustacean eyes. She found the same structures as in horseshoe crabs. Lens cylinders, sensory cells and even the highly specialized cells were clearly discernible.


'This bright spot belongs to a special cell that only occurs in horseshoe crabs today, but apparently already existed in eurypterida,' explained Schoenemann. 'The structures of the systems are identical. It follows that very probably this sort of contrast enhancement already evolved more than 400 million years ago,' she added. Jaekelopterus most likely hunted placoderm. Here, its visual apparatus was clearly an advantage in the murky seawater.

Compound eyes: The visual apparatus of today's horseshoe crabs goes back 400 million years
Close-up of impressions and fossilizations of the eyes of eurypterid Jaekelopterus rhenaniae
[Credit: Schoenemann et al. 2019]
Sea scorpions, which first appeared 470 million years ago, died out about 250 million years ago, at the end of the Permian age - along with about 95 percent of all marine life. Some specimens were large oceanic predators, such as Jaekelopterus rhenaniae. It reached a length of 2.5 meters and belonged to the family of eurypterida, the extinct relatives of the horseshoe crab. Eurypterida are arthropods, which belong to the subphylum Chelicerata, and are therefore related to spiders and scorpions.


Among the arthropods there are two large groups: mandibulates (crustaceans, insects, trilobites) and chelicerates (arachnid animals such as sea scorpions). In recent years, Schoenemann has been able to clarify the eye structures of various trilobite species and to make decisive contributions to research into the evolution of the compound eye. 'Until recently, scientists thought that soft tissues do not fossilize. Hence these parts of specimens were not examined until not so long ago', she concluded.

Compound eyes: The visual apparatus of today's horseshoe crabs goes back 400 million years
Close-up of a massive Jaekelopterus on the seabed
[Credit: Lucas Lima and Earth Archives]
The new findings on the eye of the sea scorpion are important for the evolution of the compound eyes not only of chelicerates, but also for determining the position of sea scorpions in the pedigree of these animals and for the comparison with the eyes of the related group of mandibulates.

The findings have been published in the journal Scientific Reports.

Source: University of Cologne [December 03, 2019]



* This article was originally published here

First Giant Planet around White Dwarf Found













ESO - European Southern Observatory logo.

4 December 2019

ESO observations indicate the Neptune-like exoplanet is evaporating

 Artist’s impression of the WDJ0914+1914 system

Researchers using ESO’s Very Large Telescope have, for the first time, found evidence of a giant planet associated with a white dwarf star. The planet orbits the hot white dwarf, the remnant of a Sun-like star, at close range, causing its atmosphere to be stripped away and form a disc of gas around the star. This unique system hints at what our own Solar System might look like in the distant future.

“It was one of those chance discoveries,” says researcher Boris Gänsicke, from the University of Warwick in the UK, who led the study, published today in Nature. The team had inspected around 7000 white dwarfs observed by the Sloan Digital Sky Survey and found one to be unlike any other. By analysing subtle variations in the light from the star, they found traces of chemical elements in amounts that scientists had never before observed at a white dwarf. “We knew that there had to be something exceptional going on in this system, and speculated that it may be related to some type of planetary remnant.”

To get a better idea of the properties of this unusual star, named WDJ0914+1914, the team analysed it with the X-shooter instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert. These follow-up observations confirmed the presence of hydrogen, oxygen and sulphur associated with the white dwarf. By studying the fine details in the spectra taken by ESO’s X-shooter, the team discovered that these elements were in a disc of gas swirling into the white dwarf, and not coming from the star itself.

Location of WDJ0914+1914 in the constellation of Cancer

“It took a few weeks of very hard thinking to figure out that the only way to make such a disc is the evaporation of a giant planet,” says Matthias Schreiber from the University of Valparaiso in Chile, who computed the past and future evolution of this system.

The detected amounts of hydrogen, oxygen and sulphur are similar to those found in the deep atmospheric layers of icy, giant planets like Neptune and Uranus. If such a planet were orbiting close to a hot white dwarf, the extreme ultraviolet radiation from the star would strip away its outer layers and some of this stripped gas would swirl into a disc, itself accreting onto the white dwarf. This is what scientists think they are seeing around WDJ0914+1914: the first evaporating planet orbiting a white dwarf.

Combining observational data with theoretical models, the team of astronomers from the UK, Chile and Germany were able to paint a clearer image of this unique system. The white dwarf is small and, at a blistering 28 000 degrees Celsius (five times the Sun's temperature), extremely hot. By contrast, the planet is icy and large—at least twice as large as the star. Since it orbits the hot white dwarf at close range, making its way around it in just 10 days, the high-energy photons from the star are gradually blowing away the planet's atmosphere. Most of the gas escapes, but some is pulled into a disc swirling into the star at a rate of 3000 tonnes per second. It is this disc that makes the otherwise hidden Neptune-like planet visible.

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How does language emerge?


How the languages of the world emerged is largely a mystery. Considering that it might have taken millennia, it is intriguing to see how deaf people can create novel sign languages spontaneously. Observations have shown that when deaf strangers are brought together in a community, they come up with their own sign language in a considerably short amount of time. The most famous example of this is Nicaraguan Sign Language, which emerged in the 1980s. Interestingly, children played an important role in the development of these novel languages. However, how exactly this happened has not been documented, as Manuel Bohn describes: "We know relatively little about how social interaction becomes language. This is where our new study comes in."

How does language emerge?
Credit: Getty Images
In a series of studies, researchers at the Leipzig Research Centre for Early Childhood Development and the Max Planck Institute for Evolutionary Anthropology attempted to recreate exactly this process. The idea had been around for quite some time, says Gregor Kachel. But there was a problem: how to make children communicate with each other without them reverting to talking to each other?

The solution came up in Skype conversations between the two researchers from Germany and their colleague Michael Tomasello in the US. In the study, children were invited to stay in two different rooms and a Skype connection was established between them. After a brief familiarization with the set-up, the researchers sneakily turned off the sound and watched as the children found new ways of communicating that go beyond spoken language.


The children's task was to describe an image with different motifs in a coordination game. With concrete things - like a hammer or a fork - children quickly found a solution by imitating the corresponding action (e.g. eating) in a gesture. But the researchers repeatedly challenged the children with new, more abstract pictures. For example, they introduced a white sheet of paper as a picture. The depicted "nothing" is difficult to imitate. Kachel describes how two children nevertheless mastered this task:

"The sender first tried all sorts of different gestures, but her partner let her know that she did not know what was meant. Suddenly our sender pulled her T-shirt to the side and pointed to a white dot on her coloured T-shirt. The two had a real breakthrough: of course! White! Like the white paper! Later, when the roles were switched, the recipient didn't have a white spot on her T-shirt, but she nevertheless took the same approach: she pulled her T-shirt to the side and pointed to it. Immediately her partner knew what to do."

How does language emerge?
Children within a dyad used the same gestures for the same objects – conventional mappings
between signs and referents are core feature of natural language
[Credit: M. Bohn]
Within a very short time, the two had established a sign for an abstract concept. In the course of the study, the images to be depicted became more and more complex, which was also reflected in the gestures that the children produced. In order to communicate, for example, an interaction between two animals, children invented separate gestures for actors and actions and began to combine them - thus creating a kind of small local grammar.

How does a language emerge? Based on the present study, the following steps appear plausible: first, people create reference to actions and objects via signs that resemble things. The prerequisite for this is a common ground of experience between interaction partners. Partners also coordinate by imitating each other such that they use the same signs for the same things. The signs thus gain interpersonal and eventually conventional meaning.


Over time, the relationships between the signs and things become more abstract and the meaning of the individual signs more specific. Grammatical structures are gradually introduced when there is a need to communicate more complex facts. However, the most remarkable aspect of the current studies is that these processes can be observed under controlled circumstances and within 30 minutes.

The studies demonstrate that communication cannot be reduced to words alone. When there is no way to use conventional spoken language, people find other ways to get their message across. This phenomenon forms the basis for the development of new languages.

The study by Manuel Bohn, Gregor Kachel and Michael Tomasello shows what the first steps in the development of a new language could look like. According to Bohn, however, numerous new questions arise at this point: "It would be very interesting to see how the newly invented communication systems change over time, for example when they are passed on to new 'generations' of users. There is evidence that language becomes more systematic when passed on."

The findings are published in Proceedings of the National Academy of Sciences.

Source: Max Planck Institute for Evolutionary Anthropology [December 03, 2019]



* This article was originally published here

Carina Nebula's 'Mystic Mountain'













NASA - Hubble Space Telescope patch.

Dec. 4, 2019


Within the tempestuous Carina Nebula lies “Mystic Mountain.” This three-light-year-tall cosmic pinnacle, imaged by the Hubble Space Telescope’s Wide Field Camera 3 in 2010, is made up primarily of dust and gas, and exhibits signs of intense star-forming activity. The colors in this composite image correspond to the glow of oxygen (blue), hydrogen and nitrogen (green) and sulfur (red).

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Image, Animation, Text, Credits: NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI)/Yvette Smith.

Greetings, Orbiter.ch

* This article was originally published here

The art of the Roman surveyors emerges from newly discovered pavements in Pompeii


The technical skills of the Roman agrimensores - the technicians in charge of the centuriations (division of the lands) and of other surveys such as planning towns and aqueducts - are simply legendary. For instance, extremely accurate projects of centuriations are still visible today in Italy and in other Mediterranean countries. Their work had also religious and symbolic connections being related with the foundation of towns and the Etruscan's tradition.

The art of the Roman surveyors emerges from newly discovered pavements in Pompeii
Plan of the house of Orion, showing the disposition of the newly discovered images (1,2)
and of the mosaics (3) [Credit: L. Ferro, G Magli, M. Osanna]
These technicians were called Gromatics due to their chief working instrument, called Groma. It was based on a cross made of four perpendicular arms each bringing cords with identical weights, acting as plumb-lines. The surveyor could align with extreme precision two opposite, very thin plumb-lines with reference poles held at various distances by assistants or fixed in the terrain, in the same manner as palines (red and white posts) are used in modern theodolite surveying.


Up to now, the unique known example of a Groma was coming from Pompeii excavations, while images illustrating the work of the Gromatics were passed on only by medieval codex's, dating to many centuries after the art of the agrimensores was not practiced any more. It now looks like that again Pompeii is the place where new information about these ancient architects can come out.

The art of the Roman surveyors emerges from newly discovered pavements in Pompeii
The newly discovered images probably referring to the Roman surveyors
[Credit: L. Ferro, G Magli, M. Osanna]
As part of the Great Pompeii Project indeed, inaugurated in 2014 and co-financed by the European Community, new archaeological investigations unearthed a house with a solemn, ancient facade. Inside, almost intact floors have been found containing two beautiful mosaics probably representing Orion, and a series of enigmatic images.


The interpretation of the images has been recently given in a joint paper by Massimo Osanna, Director of the Pompeii archaeological site, and Luisa Ferro and Giulio Magli, of the School of Architecture at the Politecnico of Milan. Among the images there is, for instance, a square inscribed in a circle.

The art of the Roman surveyors emerges from newly discovered pavements in Pompeii
An image from a Codex of the Middle Age showing the work of the Gromatics and,
in particular, a circle-cross nearly identical to the one just discovered
[Credit: AAAS]


The circle is cut by two perpendicular lines, one of which coincides with the longitudinal axis of the atrium of the house and appears as a sort of rose of the winds that identifies a regular division of the circle in eight equally spaced sectors.

The image is strikingly similar to one used in the medieval codex's to illustrate the way in which the Gromatics divided the space. Another, complex image shows a circle with an orthogonal cross inscribed in it, connected by five dots disposed as a sort of small circle to a straight line with a base. The whole appears as the depiction of a Groma.

Was the house used for meetings and/or the owner himself belonged to the gromatic's guild? We do not know it for sure. In any case however, and once again, Pompeii reveals itself as an invaluable source in understanding key aspects of the Roman life and civilization.

Source: Politecnico di Milano [December 03, 2019]



* This article was originally published here

2019 December 5 Spiral Galaxy NGC 6744 Image Credit &...



2019 December 5

Spiral Galaxy NGC 6744
Image Credit & Copyright: Zhuokai Liu, Jiang Yuhang

Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo and appears as only a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably detailed galaxy portrait, a telescopic view that spans an area about the angular size of a full moon. In it, the giant galaxy’s elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past a smaller satellite galaxy (NGC 6744A) at the lower right. NGC 6744’s galactic companion is reminiscent of the Milky Way’s satellite galaxy the Large Magellanic Cloud.

∞ Source: apod.nasa.gov/apod/ap191205.html



* This article was originally published here

First experimental genetic evidence of the human self-domestication hypothesis


The study, published in Science Advances, results from the collaboration between a UB team led by Cedric Boeckx, ICREA professor from the Section of General Linguistics at the Department of Catalan Philology and General Linguistics, and member of the Institute of Complex Systems of the UB (UBICS), and researchers from the team led by Giuseppe Testa, lecturer at the University of Milan and the European Institute of Oncology.

First experimental genetic evidence of the human self-domestication hypothesis
Research study from the University of Barcelona identified a genetic network involved in the unique
evolutionary trajectory of the modern human face and prosociality not found in Neanderthals
[Credit: Thomas Ôrourke/UB]
An evolutionary process similar to animal domestication

The idea of human self-domestication dates back to the 19th century. It is the claim that anatomical and cognitive-behavioral hallmarks of modern humans, such as docility or a gracile physiognomy, could result from an evolutionary process bearing significant similarities to the domestication of animals.

The key role of neural crest cells

Earlier research by the team of Cedric Boeckx had found genetic similarities between humans and domesticated animals in genes. The aim of the present study was to take a step further and deliver empirical evidence focusing on neural crest cells. This is a population of migratory and pluripotent cells - able to form all the cell types in a body - that form during the development of vertebrates with great importance in development.


"A mild deficit of neural crest cells has already been hypothesized to be the factor underlying animal domestication. Could it be that humans got a more prosocial cognition and a retracted face relative to other extinct humans in the course of our evolution as a result of changes affecting neural crest cells?" asks Alejandro Andirkó, PhD students at the Department of Catalan Philology and General Linguistics of the UB, who took part in the study.

To test this relationship, researchers focused on Williams Syndrome disorder, a specific human neurodevelopmental disorder characterized by both craniofacial and cognitive-behavioral traits relevant to domestication. The syndrome is a neurocristopathy: a deficit of a specific cell type during embryogenesis. In this case, neural crest cells.

In this study, researchers from the team led by Giuseppe Testa used in vitro models of Williams syndrome with stem cells derived from the skin. Results showed that the BAZ1B gene -which lies in the region of the genome causing Williams Syndrome- controls neural crest cell behavior: lower levels of BAZ1B resulted in reduced neural-crest migration, and higher levels produced greater neural-crest migration.

Comparing modern human and Neanderthal genomes

Researchers examined this gene in archaic and modern human genomes. "We wanted to understand if neural crest cell genetic networks were affected in human evolution compared to the Neanderthal genomes", Cedric Boeckx said.


Results showed that that BAZ1B affects a significant number of genes accumulating mutations in high frequency in all living human populations that are not found in archaic genomes currently available. "We take this to mean that BAZ1B genetic network is an important reason our face is so different when compared with our extinct relatives, the Neanderthals," Boeckx said. "In the big picture, it provides for the first time experimental validation of the neural crest-based self-domestication hypothesis," continues.

An empirical way to test evolutionary claims

These results open the road to studies tackling the role of neural crest cells in prosociality and other cognitive domains but is also one of the first examples of a potential subfield to test evolutionary claims. "This research constitutes one of the first studies that uses cutting-edge empirical technologies in a clinical setting to understand how humans have evolved since the split with Neanderthals, and establishes Williams Syndrome in particular as a unique atypical neurodevelopmental window onto the evolution of our species," Boeckx concludes.

Source: University of Barcelona [December 04, 2019]



* This article was originally published here

First Giant Planet around White Dwarf Found

Artist’s impression of the WDJ0914+1914 system

Location of WDJ0914+1914 in the constellation of Cancer


Videos

ESOcast 212 Light: First Giant Planet around White Dwarf Found
ESOcast 212 Light: First Giant Planet around White Dwarf Found

Artist’s animation of the WDJ0914+1914 system
Artist’s animation of the WDJ0914+1914 system

Artist’s animation of the Sun becoming a red giant
Artist’s animation of the Sun becoming a red giant



ESO observations indicate the Neptune-like exoplanet is evaporating

Researchers using ESO’s Very Large Telescope have, for the first time, found evidence of a giant planet associated with a white dwarf star. The planet orbits the hot white dwarf, the remnant of a Sun-like star, at close range, causing its atmosphere to be stripped away and form a disc of gas around the star. This unique system hints at what our own Solar System might look like in the distant future.

It was one of those chance discoveries,” says researcher Boris Gänsicke, from the University of Warwick in the UK, who led the study, published today in Nature. The team had inspected around 7000 white dwarfs observed by the Sloan Digital Sky Survey and found one to be unlike any other. By analysing subtle variations in the light from the star, they found traces of chemical elements in amounts that scientists had never before observed at a white dwarf. “We knew that there had to be something exceptional going on in this system, and speculated that it may be related to some type of planetary remnant.” 

To get a better idea of the properties of this unusual star, named WDJ0914+1914, the team analysed it with the X-shooter instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert. These follow-up observations confirmed the presence of hydrogen, oxygen and sulphur associated with the white dwarf. By studying the fine details in the spectra taken by ESO’s X-shooter, the team discovered that these elements were in a disc of gas swirling into the white dwarf, and not coming from the star itself.

It took a few weeks of very hard thinking to figure out that the only way to make such a disc is the evaporation of a giant planet,” says Matthias Schreiber from the University of Valparaiso in Chile, who computed the past and future evolution of this system.

The detected amounts of hydrogen, oxygen and sulphur are similar to those found in the deep atmospheric layers of icy, giant planets like Neptune and Uranus. If such a planet were orbiting close to a hot white dwarf, the extreme ultraviolet radiation from the star would strip away its outer layers and some of this stripped gas would swirl into a disc, itself accreting onto the white dwarf. This is what scientists think they are seeing around WDJ0914+1914: the first evaporating planet orbiting a white dwarf.

Combining observational data with theoretical models, the team of astronomers from the UK, Chile and Germany were able to paint a clearer image of this unique system. The white dwarf is small and, at a blistering 28 000 degrees Celsius (five times the Sun's temperature), extremely hot. By contrast, the planet is icy and large—at least twice as large as the star. Since it orbits the hot white dwarf at close range, making its way around it in just 10 days, the high-energy photons from the star are gradually blowing away the planet's atmosphere. Most of the gas escapes, but some is pulled into a disc swirling into the star at a rate of 3000 tonnes per second. It is this disc that makes the otherwise hidden Neptune-like planet visible.

This is the first time we can measure the amounts of gases like oxygen and sulphur in the disc, which provides clues to the composition of exoplanet atmospheres,” says Odette Toloza from the University of Warwick, who developed a model for the disc of gas surrounding the white dwarf.

The discovery also opens up a new window into the final fate of planetary systems,” adds Gänsicke.

Stars like our Sun burn hydrogen in their cores for most of their lives. Once they run out of this fuel, they puff up into red giants, becoming hundreds of times larger and engulfing nearby planets. In the case of the Solar System, this will include Mercury, Venus, and even Earth, which will all be consumed by the red-giant Sun in about 5 billion years. Eventually, Sun-like stars lose their outer layers, leaving behind only a burnt-out core, a white dwarf. Such stellar remnants can still host planets, and many of these star systems are thought to exist in our galaxy. However, until now, scientists had never found evidence of a surviving giant planet around a white dwarf. The detection of an exoplanet in orbit around WDJ0914+1914, located about 1500 light years away in the constellation of Cancer, may be the first of many orbiting such stars.

According to the researchers, the exoplanet now found with the help of ESO’s X-shooter orbits the white dwarf at a distance of only 10 million kilometres, or 15 times the solar radius, which would have been deep inside the red giant. The unusual position of the planet implies that at some point after the host star became a white dwarf, the planet moved closer to it. The astronomers believe that this new orbit could be the result of gravitational interactions with other planets in the system, meaning that more than one planet may have survived its host star’s violent transition.

Until recently, very few astronomers paused to ponder the fate of planets orbiting dying stars. This discovery of a planet orbiting closely around a burnt-out stellar core forcefully demonstrates that the Universe is time and again challenging our minds to step beyond our established ideas,” concludes Gänsicke.



More Information

This research was presented in a paper to appear in Nature.

The team is composed of Boris Gänsicke (Department of Physics & Centre for Exoplanets and Habitability, University of Warwick, UK), Matthias Schreiber (Institute of Physics and Astronomy, Millennium Nucleus for Planet Formation, Valparaiso University, Chile), Odette Toloza (Department of Physics, University of Warwick, UK), Nicola Gentile Fusillo (Department of Physics, University of Warwick, UK), Detlev Koester (Institute for Theoretical Physics and Astrophysics, University of Kiel, Germany), and Christopher Manser (Department of Physics, University of Warwick, UK).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory.

ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.



Links



Contacts

Boris Gänsicke
University of Warwick
UK
Tel: +44 247 657 4741

Matthias Schreiber
Valparaiso University
Chile
Tel: +56 32 299 5518

Odette Toloza
University of Warwick
UK

Nicola Gentile Fusillo (study co-author)
European Southern Observatory and University of Warwick
Germany
Tel: +49 8932 0067 50
Cell: +44 7476 9595 49

Christopher Manser (study co-author)
University of Warwick
UK
Tel: +44 7516 8167 53

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6670

Source: ESO/News




* This article was originally published here

Justinianic plague not a landmark pandemic?


Researchers now have a clearer picture of the impact of the first plague pandemic, the Justinianic Plague, which lasted from about 541-750 CE.

Justinianic plague not a landmark pandemic?
Credit: Elizabeth Herzfeldt-Kamprath, SESYNC
Led by researchers at the University of Maryland's National-Socio Environmental Synthesis Center (SESYNC), the international team of scholars found that the plague's effects may have been exaggerated. They examined diverse datasets, but found no concrete effects they could conclusively attribute to the plague. Their paper appears in the Proceedings of the National Academy of Sciences.

"Our article is the first time such a large body of novel interdisciplinary evidence has been investigated in this context," said lead author Lee Mordechai, a postdoctoral fellow at SESYNC, and co-lead of Princeton's Climate Change and History Research Initiative (CCHRI). He is now a senior lecturer at Hebrew University of Jerusalem. "If this plague was a key moment in human history that killed between a third and half the population of the Mediterranean world in just a few years, as is often claimed, we should have evidence for it but our survey of datasets found none."

The research team, which collaborated through the CCHRI, examined contemporary written sources, inscriptions, coinage, papyrus documents, pollen samples, plague genomes, and mortuary archaeology.


The researchers focused on the period known as Late Antiquity (300-800 CE) that included major events such as the fall of the Western Roman Empire and the rise of Islam--events that have been sometimes attributed to plague, including in history textbooks.

"Our paper rewrites the history of Late Antiquity from an environmental perspective that doesn't assume plague was responsible for changing the world," said Merle Eisenberg, also a SESYNC postdoctoral fellow, member of the CCHRI and a co-author on the paper. "The paper is notable because historians led this PNAS publication, and we asked historical questions that focused on the potential social and economic effects of plague."

The team found that previous scholars have focused on the most evocative written accounts, applying them to other places in the Mediterranean world while ignoring hundreds of contemporary texts that do not mention plague.

"While plague studies is an interdisciplinary, demanding field of study, most plague scholars rely solely on the types of evidence they are trained to use. We are the first team to look for the impacts of the first plague pandemic in very diverse datasets. We found no reason to argue that the plague killed tens of millions of people as many have claimed," said co-author Timothy Newfield, another co-lead of the CCHRI who is now an assistant professor of history and biology at Georgetown University. "Plague is often construed as shifting the course of history. It's an easy explanation, too easy. It's essential to establish a causal connection."


Many of these datasets, such as agricultural production, show that trends that began before the plague outbreak continued without change.

"We used pollen evidence to estimate agricultural production, which shows no decrease associable with plague mortality. If there were fewer people working the land, this should have shown up in pollen, but it has failed to so far," said co-author Adam Izdebski, a member of CCHRI who is now a research group leader at the Max Planck Institute for the Science of Human History and an assistant professor of history at Jagiellonian University.

Even some of the most well-known effects of large epidemics, such as changes in burial traditions, follow existing trends that began centuries earlier.

"We investigated a large dataset of human burials from before and after the plague outbreak, and the plague did not result in a significant change whether people buried the dead alone or with many others," said co-author Janet Kay, a lecturer in the Council of the Humanities and history and the CSLA-Cotsen Postdoctoral Fellow in Late Antiquity in the Society of Fellows at Princeton University. She contrasted that with the Black Death, a plague that took place about 800 years after the Justinianic Plague. "The Black Death killed vast numbers of people and did change how people disposed of corpses," she said.

The researchers also used available plague genomes to trace the origin and evolution of the plague strains responsible for outbreak, which certainly killed people across Eurasia--how many people is the question.

Co-author Hendrik Poinar, a professor of evolutionary biology and director of the Ancient DNA Centre at McMaster University, added: "Although tracing the origins and development of the plague bacterium is crucial, the presence of the pathogen does not in itself mean catastrophe."

Source: National Socio-Environmental Synthesis Center [December 02, 2019]



* This article was originally published here

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Votive Offerings of Roman Coins, some pierced and used as pendants, The National Museum of Scotland,...

Votive Offerings of Roman Coins, some pierced and used as pendants, The National Museum of Scotland, Edinburgh, November 2019.



* This article was originally published here

NASA’s OSIRIS-REx in the Midst of Site Selection












NASA - OSIRIS-REx Mission logo.

Dec. 4, 2019

NASA’s OSIRIS-REx mission is just days away from selecting the site where the spacecraft will snag a sample from asteroid Bennu. After a lengthy and challenging process, the team is finally ready to down-select from the four candidate sites to a primary and backup site.

OSIRIS-REx is NASA’s first asteroid sample return mission, so this decision of a sample collection site is key for asteroid operations and mission success.

After selecting the four candidate sample sites – Sandpiper, Osprey, Kingfisher, and Nightingale – in July, the mission completed its Reconnaissance A phase. During Recon A, the OSIRIS-REx spacecraft performed a month-long series of four flyovers – one over each potential sample collection site. This mission phase provided the team with high-resolution imagery in order to thoroughly examine the sampleability (fine-grained material), topography, albedo, and color of each site. The data collected from these high-altitude flyovers is central for determining which site is best-suited for sample collection.


Image above: These images show the four candidate sample collection sites on asteroid Bennu: Nightingale, Kingfisher, Osprey and Sandpiper. One of these four sites will ultimately be the location on which NASA’s OSIRIS-REx spacecraft will touch down to collect a sample. Image Credits: NASA/Goddard/University of Arizona.

While the mission is one step closer to collecting a sample, Recon A observations have revealed that even the best candidate sites on Bennu pose significant challenges to sample collection, and the choice before the site selection board is not an easy one.

“Sample site selection really is a comprehensive activity. It requires that we look at many different types of data in many different ways to ensure the selected site is the best choice in terms of spacecraft safety, presence of sampleable material, and science value,” said Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona, Tucson, and chair of the sample site selection board. “Our team is incredibly innovative and integrated, which is what makes the selection process work.”

The most recent images show that while there is fine-grained material (smaller than 2.5 cm in diameter), much of it may not be easily accessible. The mission was originally designed for a beach-like surface, with “ponds” of sandy material, not for Bennu’s rugged terrain. In reality the potential sample sites are not large, clear areas, but rather small spaces surrounded by large boulders, so navigating the spacecraft in and out of the sites will require a bit more fine-tuning than originally planned.

Starting in Bennu’s southern hemisphere, site Sandpiper was the first flyover of the Recon A mission phase. Sandpiper is one of the “safer” sites because it is located in a relatively flat area, making it easier for the spacecraft to navigate in and out. The most recent images show that fine-grained material is present, but the sandy regolith is trapped between larger rocks, which makes it difficult for the sampling mechanism to operate.

OSIRIS-REx collecting sample on Bennu. Image Credit: NASA

Site Osprey was the second site observed during Recon A. This site was originally chosen based on its strong spectral signature of carbon-rich material and because of a dark patch in the center of the crater, which was thought to possibly be fine-grained material. However, the latest high-resolution imagery of Osprey suggests that the site is scattered with material that may be too large to ingest for the sampling mechanism.

Site Kingfisher was selected because it is located in a small crater – meaning that it may be a relatively young feature compared to Bennu’s larger craters (such as the one in which Sandpiper is located). Younger craters generally hold fresher, minimally-altered material. High-resolution imagery captured during the Recon A flyover revealed that while the original crater may be too rocky, a neighboring crater appears to contain fine-grained material.

Recon A concluded with a flyover of site Nightingale. Images show that the crater holds a good amount of unobstructed fine-grained material. However, while the sampleability of the site ranks high, Nightingale is located far to the north where the lighting conditions create additional challenges for spacecraft navigation. There is also a building-size boulder situated on the crater’s eastern rim, which could be a hazard to the spacecraft when backing away after contacting the site.


Image above: This flat projection mosaic of asteroid Bennu shows the relative locations of the four candidate sample collection sites on the asteroid: Nightingale, Kingfisher, Osprey and Sandpiper. NASA’s OSIRIS-REx spacecraft is scheduled to touch down on one of these four sites to collect a sample in summer 2020. Image Credits: NASA/Goddard/University of Arizona.

Bennu has also made it a challenge for the mission to identify a site that won’t trigger the spacecraft’s safety mechanisms. During Recon A, the team began cataloguing Bennu’s surface features to create maps for the Natural Feature Tracking (NFT) autonomous navigation system. During the sample collection event, the spacecraft will use NFT to navigate to the asteroid’s surface by comparing the onboard image catalog to the navigation images it will take during descent. In response to Bennu’s extremely rocky surface, the NFT system has been augmented with a new safety feature, which instructs it to wave-off the sampling attempt and back away if it determines the point of contact is near a potentially hazardous surface feature. With Bennu’s building-sized boulders and small target sites, the team realizes that there is a possibility that the spacecraft will wave-off the first time it descends to collect a sample.

“Bennu’s challenges are an inherent part of this mission, and the OSIRIS-REx team has responded by developing robust measures to overcome them,” said Mike Moreau, OSIRIS-REx deputy project manager at Goddard. “If the spacecraft executes a wave-off while attempting to collect a sample, that simply means that both the team and the spacecraft have done their jobs to ensure the spacecraft can fly another day. The success of the mission is our first priority.”

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First archaeological evidence of Christianity in Bahrain


Archaeologists have found the first evidence showing Christianity was practised in Bahrain, a discovery which sheds light on a missing part of the country’s history.

First archaeological evidence of Christianity in Bahrain
Potsherd decorated with a Cross [Credit: (c) T Insoll]
Ancient documents have suggested there were Christian communities in the country before the spread of Islam in the 7th century, but this is the first time buildings or objects have been discovered which prove this.

The remains are thought to be of a former monastery, which then became a Muslim cemetery, and in the 17th century a mosque was built on top. Archaeologists believe it is likely there are more Christian sites in Bahrain which could be discovered in the future.

Names of towns or villages had also provided evidence that Christianity was practiced in Bahrain between the 4th and 7th centuries, a village close to the archaeological site is called Deir, which means monastery in Arabic. Little is known about how Islam initially spread throughout the Gulf and why people stopped practising Christianity. Evidence of Christian sites have also been found on Islands belonging to Iran and Abu Dhabi.


Professor Tim Insoll, from the University of Exeter, worked on the excavations with the local community, who initially investigated the mound and who requested help in uncovering its history.

Professor Insoll said: “It has been hard to find evidence of Christian Bahrain because these sites and buildings have since been used for different purposes and are now underneath modern housing, which is why this discovery is so special”.

“The historical memory of these times exists in the names of towns, and even people, as well as historical documents, so we knew there was concrete evidence to discover, and we hope to find more in the future.”


The archaeological remains were found late last month in the village of Samahij, on the northern coast of Muharraq island. Samahij was probably the location of the episcopal seat of Meshmahig mentioned variously in historical sources between 410 and 647, and one of the centres of the country’s pearl trade.

Also found at the site were the remains of wine jars, glass goblets and pottery, which dates from the 7th century. One of the wine jars is inscribed in what is thought to be an Aramaic language called Psalter Pahlavi.

The work was led by Professor Insoll and Dr Rachel MacLean of the University of Exeter and Dr Salman Almahari of the Bahrain Authority for Culture and Antiquities, with additional input from Professor Robert Carter who studied the ceramics found.


The substantial building, measuring 17m x 10m, was probably part of a monastery or large house. The building was likely occupied in the 7th century just before the people converted to Islam. The building has several rooms and was decorated with carved plaster. A cross has been found carved onto a piece of stone and another cross was found painted on a pot sherd.

It is likely that the Christians who used the building were part of the Nestorian Church which flourished in the Gulf between the 4th/5th and 7th centuries.

The site was found in a mound located in the center of Samahij cemetery, no graves were disturbed. The remains of a small mosque known as the "Sheikh Malik mosque", was also discovered on the top of this mound, with the Christian building directly beneath it.

The mound was first investigated three years ago on a small scale by the Bahrain Authority for Culture and Antiquities at the request of the local people, and the joint British-Bahraini team resumed the work again this year. The research was sponsored by the Crown Prince of Bahrain, HRH Sheikh Salman bin Hamad Al Khalifa. Professor Insoll and his team hope to return to the site next year to complete further excavations.

Source: University of Exeter [December 04, 2019]



* This article was originally published here

NASA's Parker Solar Probe Sheds New Light on the Sun













NASA - Parker Solar Probe patch.

Dec. 4, 2019

In August 2018, NASA's Parker Solar Probe launched to space, soon becoming the closest-ever spacecraft to the Sun. With cutting-edge scientific instruments to measure the environment around the spacecraft, Parker Solar Probe has completed three of 24 planned passes through never-before-explored parts of the Sun's atmosphere, the corona. On Dec. 4, 2019, four new papers in the journal Nature describe what scientists have learned from this unprecedented exploration of our star — and what they look forward to learning next.

These findings reveal new information about the behavior of the material and particles that speed away from the Sun, bringing scientists closer to answering fundamental questions about the physics of our star. In the quest to protect astronauts and technology in space, the information Parker has uncovered about how the Sun constantly ejects material and energy will help scientists re-write the models we use to understand and predict the space weather around our planet and understand the process by which stars are created and evolve.

Illustration of Parker Solar Probe. Credit: NASA/Johns Hopkins APL

“This first data from Parker reveals our star, the Sun, in new and surprising ways,” said Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington. “Observing the Sun up close rather than from a much greater distance is giving us an unprecedented view into important solar phenomena and how they affect us on Earth, and gives us new insights relevant to the understanding of active stars across galaxies. It’s just the beginning of an incredibly exciting time for heliophysics with Parker at the vanguard of new discoveries.”

Though it may seem placid to us here on Earth, the Sun is anything but quiet. Our star is magnetically active, unleashing powerful bursts of light, deluges of particles moving near the speed of light and billion-ton clouds of magnetized material. All this activity affects our planet, injecting damaging particles into the space where our satellites and astronauts fly, disrupting communications and navigation signals, and even — when intense — triggering power outages. It’s been happening for the Sun's entire 5-billion-year lifetime, and will continue to shape the destinies of Earth and the other planets in our solar system into the future.

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