понедельник, 20 августа 2018 г.

Organised Chaos The brain’s nerve fibres can sometimes look a…


Organised Chaos


The brain’s nerve fibres can sometimes look a bit jumbled up, like a mesh of wires that badly needs tidying. In particular, the fibres that ultimately connect our nose to the part of the brain that interprets the smells we encounter (shown here as green, red-brown and white layers) have long been thought to be a bit disorganised. However, scientists have recently shown how this chaotic arrangement is actually what helps mice distinguish between similar odours. Rather than each ‘wire’ being responsible for a particular smell, the team found that they carry signals from many different smells. Mice can differentiate between odours because the pattern of signals carried in these nerves is distinctive for each smell, leaving a unique odour ‘fingerprint’ on this part of the brain. Perhaps there’s method in the madness of brain fibres after all, and that seemingly random connections may be more organised than we originally thought.


Written by Gaëlle Coullon



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Roman magistrate’s statue found at Heraklea Sintica in southwest Bulgaria

A Roman statue from the end of the first or beginning of the 2nd century AD depicting a local Roman magistrate has been discovered by the archaeologists excavating the Graeco-Roman city of Heraklea Sintica near Petrich in southwest Bulgaria.











Roman magistrate's statue found at Heraklea Sintica in southwest Bulgaria
The life-size statue of an Ancient Roman magistrate from around 100 AD has been discovered
beneath the steps of the Roman Forum of Heraklea Sintica, in Bulgaria’s very southwest
[Credit: Archaeology in Bulgaria]

Heraclea Sintica is thought to have been established ca. 300 BC by Kassandros, King of Macedon in 305-297 BC, who also founded Thessaloniki, in Greece. It is possible, however, that Heraklea Sintica was first settled even earlier.


The city was named ‘Heraklea’ after the mythical Greek hero Herakles, more popularly known today as Hercules, and ‘Sintica’ after the Thracian tribe of the Sintians who inhabited the valley of the Struma River at the time.


The statue was found at a depth of 4 metres (appr. 12 feet) beneath the steps of the Roman Forum of Heraklea Sintica.


It is life-size or very slightly larger than life-size, and very well preserved. The only part missing is the head


Next to the left leg of the statue – which depicts a male dressed in a toga – there is a box for papyrus scrolls, a clear indication that the man was a high-ranking magistrate.


It is thought the statue depicts a certain Tiberius Claudius Bachius, a wealthy benefactor of the city of Heraklea Sintica.


Source: Archaeology in Bulgaria [August 19, 2018]



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2018 August 20 Active Prominences on a Quiet Sun Image Credit…


2018 August 20


Active Prominences on a Quiet Sun
Image Credit & Copyright: Alan Friedman (Averted Imagination)


Explanation: Why is the Sun so quiet? As the Sun enters into a period of time known as a Solar Minimum, it is, as expected, showing fewer sunspots and active regions than usual. The quietness is somewhat unsettling, though, as so far this year, most days show no sunspots at all. In contrast, from 2011 – 2015, during Solar Maximum, the Sun displayed spots just about every day. Maxima and minima occur on an 11-year cycle, with the last Solar Minimum being the most quiet in a century. Will this current Solar Minimum go even deeper? Even though the Sun’s activity affects the Earth and its surroundings, no one knows for sure what the Sun will do next, and the physics behind the processes remain an active topic of research. The featured image was taken three weeks ago and shows that our Sun is busy even on a quiet day. Prominences of hot plasma, some larger than the Earth, dance continually and are most easily visible over the edge.


∞ Source: apod.nasa.gov/apod/ap180820.html


Capturing Space Stories, One Click at a Time!

It’s World Photography Day!


To celebrate the occasion, we’re sharing photos from our photographers that chronicle what’s making news across the agency – from launches and landings to important science announcements to images taken from the vantage point of space.


Take a look!



A Closer View of the Moon 


image


Posted to Twitter by European Space Agency astronaut Alexander Gerst, this image shows our planet’s Moon as seen from the International Space Station. As he said in the tweet, “By orbiting the Earth almost 16 times per day, the #ISS crew travel the distance to the Moon and back – every day. #Horizons”


The International Space Station is the world’s only orbital laboratory. An international partnership of space agencies provides and operates the elements of the station. The principals are the space agencies of the United States, Russia, Europe, Japan and Canada.


Photo Credit: NASA



Spacewalk Selfie


image


NASA astronaut Ricky Arnold took this selfie during the May 16, 2018, spacewalk to perform upgrades on the International Space Station, saying in a tweet “An amazing view of our one and only planet.”


Arnold and fellow spacewalker Drew Feustel donned spacesuits and worked for more than six hours outside the station to finish upgrading cooling system hardware and install new and updated communications equipment for future dockings of commercial crew spacecraft.


Photo Credit: NASA



Preparing to Leave Earth




The mobile service tower at Space Launch Complex-3 is rolled back to reveal the United Launch Alliance Atlas-V rocket with NASA’s InSight spacecraft onboard, Friday, May 4, 2018, at Vandenberg Air Force Base in California. InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is a Mars lander designed to study the “inner space” of Mars: its crust, mantle, and core. 


Photo Credit: NASA/Bill Ingalls



Launch Long Exposure


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The United Launch Alliance Delta IV Heavy rocket is seen in this long exposure photograph as it launches NASA’s Parker Solar Probe to touch the Sun, Sunday, Aug. 12, 2018 from Launch Complex 37 at Cape Canaveral Air Force Station, Florida. Parker Solar Probe is humanity’s first-ever mission into a part of the Sun’s atmosphere called the corona.  Here it will directly explore solar processes that are key to understanding and forecasting space weather events that can impact life on Earth.


Photo Credit: NASA/Bill Ingalls



Waving Farewell


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Expedition 56 flight engineer Serena Auñón-Chancellor of NASA waves farewell to family and friends as she and Soyuz Commander Sergey Prokopyev of Roscosmos and flight engineer Alexander Gerst of European Space Agency depart Building 254 for the launch pad a few hours before their launch, Wednesday, June 6, 2018 at the Baikonur Cosmodrome in Kazakhstan. Auñón-Chancellor, Prokopyev, and Gerst launched aboard the Soyuz MS-09 spacecraft at 7:12am EDT (5:12pm Baikonur time) on June 6 to begin their journey to the International Space Station.


Photo Credit: NASA/Victor Zelentsov



Launching Humans to Space


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The Soyuz MS-09 rocket is launched with Expedition 56 Soyuz Commander Sergey Prokopyev of Roscosmos, flight engineer Serena Auñón-Chancellor of NASA, and flight engineer Alexander Gerst of ESA (European Space Agency), Wednesday, June 6, 2018 at the Baikonur Cosmodrome in Kazakhstan. Prokopyev, Auñón-Chancellor, and Gerst will spend the next six months living and working aboard the International Space Station


Photo Credit: NASA/Joel Kowsky



Rethinking Aircraft Design


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In an effort to improve fuel efficiency, NASA

and the aircraft industry are rethinking aircraft design. Inside the 8’ x 6’

wind tunnel at NASA Glenn Research Center, engineers tested a fan and inlet design, commonly

called a propulsor, which could use four to eight percent less fuel than

today’s advanced aircraft.



Photo Credit: NASA/Rami Daud



Flying Observatory


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SOFIA, the Stratospheric Observatory for Infrared Astronomy, is the largest airborne observatory in the world, capable of making observations that are impossible for even the largest and highest ground-based telescopes. During its lifetime, SOFIA also will inspire the development of new scientific instrumentation and foster the education of young scientists and engineers.


Photo Credit: NASA/SOFIA/Waynne Williams



Experimenting with Venus-like conditions


image


A close-up view of crystals that developed on

materials exposed to conditions on Venus in NASA Glenn’s Extreme Environments

Rig
. This unique and world class ground-based test rig can accurately most simulate atmospheric conditions for any planet or moon in the solar system and beyond.


Photo Credit: NASA/Bridget Caswell



Honeycomb Close Up


image


A close-up view of 3-D printed honeycomb

patterns made in NASA Glenn manufacturing lab using a method called binder

jetting. The honeycomb structures can find use in several applications such as

a strong core for lightweight sandwich panels, acoustic panels for noise attenuation

and innovative cellular structures.


Photo Credit: NASA/Marvin Smith



To see even more photos of our space exploration efforts, visit us on Flickr: https://www.flickr.com/photos/nasahqphoto/.


Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.


First Science with ALMA’s Highest-Frequency Capabilities





Illustration highlighting ALMA’s high-frequency observing capabilities.

Credit: NRAO/AUI/NSF, S. Dagnello. Hi-res image



The upper blue portion of this graph shows the spectral lines ALMA detected in a star-forming region of the Cat’s Paw Nebula. The lower black portion shows the lines detected by the European Space Agency’s Herschel Space Observatory. The ALMA observations detected more than ten times as many spectral lines. Note that the Herschel data have been inverted for comparison. Two molecular lines are labeled for reference. Credit: NRAO/AUI/NSF, B. McGuire et al. Hi-res image



Composite ALMA image of NGC 6334I, a star-forming region in the Cat’s Paw Nebula, taken with the Band 10 receivers, ALMA’s highest-frequency vision. The blue component is heavy water (HDO) streaming away from either a single protostar or a small cluster of protostars. The orange region is the “continuum emission” in the same region, which scientists found is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule. Credit: ALMA (ESO/NAOJ/NRAO): NRAO/AUI/NSF, B. Saxton. Hi-res image




ALMA Band 10 image of heavy water (HDO) streaming away from NGC 6334I in the Cat’s Paw Nebula. This image is the result of ALMA’s highest-frequency observing capabilities, which push the limits of ground-based astronomy. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton. Hi-res image



Pictured here is one of the cold cartridge assemblies of the Band 10 receiver, which gives ALMA its highest-frequency capabilities. Credit: ALMA (ESO/NAOJ/NRAO).  Hi-res image




Astronomers observe cosmic steam jets and molecules galore




The ALMA telescope in Chile has transformed how we see the universe, showing us otherwise invisible parts of the cosmos. This array of incredibly precise antennas studies a comparatively high-frequency sliver of radio light: waves that range from a few tenths of a millimeter to several millimeters in length. Recently, scientists pushed ALMA to its limits, harnessing the array’s highest-frequency (shortest wavelength) capabilities, which peer into a part of the electromagnetic spectrum that straddles the line between infrared light and radio waves.


“High-frequency radio observations like these are normally not possible from the ground,” said Brett McGuire, a chemist at the National Radio Astronomy Observatory in Charlottesville, Virginia, and lead author on a paper appearing in the Astrophysical Journal Letters. “They require the extreme precision and sensitivity of ALMA, along with some of the driest and most stable atmospheric conditions that can be found on Earth.”


Under ideal atmospheric conditions, which occurred on the evening of 5 April 2018, astronomers trained ALMA’s highest-frequency, submillimeter vision on a curious region of the Cat’s Paw Nebula (also known as NGC 6334I), a star-forming complex located about 4,300 light-years from Earth in the direction of the southern constellation Scorpius.


Previous ALMA observations of this region at lower frequencies uncovered turbulent star formation, a highly dynamic environment, and a wealth of molecules inside the nebula.


To observe at higher frequencies, the ALMA antennas are designed to accommodate a series of “bands” — numbered 1 to 10 — that each study a particular sliver of the spectrum. The Band 10 receivers observe at the highest frequency (shortest wavelengths) of any of the ALMA instruments, covering wavelengths from 0.3 to 0.4 millimeters (787 to 950 gigahertz), which is also considered to be long-wavelength infrared light.


These first-of-their-kind ALMA observations with Band 10 produced two exciting results.

Jets of Steam from Protostar


One of ALMA’s first Band 10 results was also one of the most challenging, the direct observation of jets of water vapor streaming away from one of the massive protostars in the region. ALMA was able to detect the submillimeter-wavelength light naturally emitted by heavy water (water molecules made up of oxygen, hydrogen and deuterium atoms, which are hydrogen atoms with a proton and a neutron in their nucleus).


“Normally, we wouldn’t be able to directly see this particular signal at all from the ground,” said Crystal Brogan, an astronomer at the NRAO and co-author on the paper. “Earth’s atmosphere, even at remarkably arid places, still contains enough water vapor to completely overwhelm this signal from any cosmic source. During exceptionally pristine conditions in the high Atacama Desert, however, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.”


As stars begin to form out of massive clouds of dust and gas, the material surrounding the star falls onto the mass at the center. A portion of this material, however, is propelled away from the growing protostar as a pair of jets, which carry away gas and molecules, including water.


The heavy water the researchers observed is flowing away from either a single protostar or a small cluster of protostars. These jets are oriented differently from what appear to be much larger and potentially more-mature jets emanating from the same region. The astronomers speculate that the heavy-water jets seen by ALMA are relatively recent features just beginning to move out into the surrounding nebula.


These observations also show that in the regions where this water is slamming into the surrounding gas, low-frequency water masers – naturally occurring microwave versions of lasers — flare up. The masers were detected in complementary observations by the National Science Foundation’s Very Large Array.


ALMA Observes Molecules Galore


In addition to making striking images of objects in space, ALMA is also a supremely sensitive cosmic chemical sensor. As molecules tumble and vibrate in space, they naturally emit light at specific wavelengths, which appear as spikes and dips on a spectrum. All of ALMA’s receiver bands can detect these unique spectral fingerprints, but those lines at the highest frequencies offer unique insight into lighter, important chemicals, like heavy water. They also provide the ability to see signals from complex, warm molecules, which have weaker spectral lines at lower frequencies.



Using Band 10, the researchers were able to observe a region of the spectrum that is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule.


When compared to previous best-in-the-world observations of the same source with the European Space Agency’s Herschel Space Observatory, the ALMA observations detected more than ten times as many spectral lines.


“We detected a wealth of complex organic molecules surrounding this massive star-forming region,” said McGuire. “These results have been received with excitement by the astronomical community and show once again how ALMA will reshape our understanding of the universe.”


ALMA is able to take advantage of these rare windows of opportunity when the atmospheric conditions are “just right” by using dynamic scheduling. That means, the telescope operators and astronomers carefully monitor the weather and conduct those planned observations that best fit the prevailing conditions.


“There certainly are quite a few conditions that have to be met to conduct a successful observation using Band 10,” concluded Brogan. “But these new ALMA results demonstrate just how important these observations can be.”


“To remain at the forefront of discovery, observatories must continuously innovate to drive the leading edge of what astronomy can accomplish,” said Joe Pesce, the program director for the National Radio Astronomy Observatory at NSF. “That is a core element of NSF’s NRAO, and its ALMA telescope, and this discovery pushes the limit of what is possible through ground-based astronomy.”


The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.





Contact:

Charles Blue, Public Information Officer
(434) 296-0314; 
cblue@nrao.edu




This research is presented in a paper titled “First results of an ALMA band 10 spectral line survey of NGC 6334I: Detections of glycolaldehyde (HC(O)CH2OH) and a new compact bipolar outflow in HDO and CS,” by B. McGuire et al. in the Astrophysical Journal Letters. [http://apjl.aas.org] Preprint: [ https://arxiv.org/abs/1808.05438]



The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).



ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.




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Discovery of a structurally ‘inside-out’ planetary nebula

The Instituto de Astrofisica de Andalucia (IAA-CSIC) in Spain, the Laboratory for Space Research (LSR) of the University of Hong Kong (HKU), and an International team comprising scientists from Argentina, Mexico and Germany have discovered the unusual evolution of the central star of a planetary nebula in our Milky Way. This extraordinary discovery sheds light on the future evolution, and more importantly, the ultimate fate of the Sun.











Discovery of a structurally 'inside-out' planetary nebula
Planetary nebula HuBi 1 shows a double-shell structure — a hydrogen-rich outer shell and a nitrogen-rich inner shell,
after its central star experienced a “born-again” event [Credit: Image adopted from Guerrero, Fang,
Miller Bertolami, et al., 2018, Nature Astronomy, tmp, 112]

The discovery of a structurally ‘inside-out’ planetary nebula — the ionized material that surrounds a white dwarf — was just reported online in Nature Astronomy. This is also the eighth research paper produced by HKU LSR with its international collaborators in the Nature journals since 2017.


The research team believes this inverted ionization structure of the nebula is resulted from the central star undergoing a ‘born-again’ event, ejecting material from its surface and creating a shock that excites the nebular material.


Planetary nebulae are ionized clouds of gas formed by the hydrogen-rich envelopes of low- and intermediate-mass stars ejected at late evolutionary stages. As these stars age, they typically strip their outer layers, forming a ‘wind’. As the star transitions from its red giant phase to become a white dwarf, it becomes hotter, and starts ionizing the material in the surrounding wind. This causes the gaseous material closer to the star to become highly ionized, while the gas material further out is less so.











Discovery of a structurally 'inside-out' planetary nebula
Planetary nebula HuBi 1 (left) and another planetary nebula Abell39 (right, 6800 light years away from our solar system).
 Abell39 is an archetypal, textbook case of a spherical nebula surrounding a bright central star (a white dwarf), its nebula
 composes of hydrogen-rich ionized gas. HuBi 1, its central star has undergone a “born-again” event ejecting metal-rich
material into the old, hydrogen-rich nebula, has a double-shell structure – a hydrogen-rich outer shell and a nitrogen-rich
inner shell [Credit: (HuBi 1 image adopted from Guerrero, Fang, Miller Bertolami, et al., 2018, Nature Astronomy,
 tmp, 112. Image credit for Abell39: The 3.5m WIYN Telescope, National Optical Astronomical Observatory,
NSF. URL: https://www.noao.edu)]

Studying the planetary nebula HuBi 1 (17,000 light years away and nearly 5 billion years ahead of our solar system in evolution), however, Dr Martin Guerrero et al. found the reverse: HuBi 1’s inner regions are less ionized, while the outer regions more so. Analysing the central star, with the participation of top theoretical astrophysicists, the authors found that it is surprisingly cool and metal-rich, and is evolved from a low-mass progenitor star which has a mass 1.1 times of the Sun.


The authors suggest that the inner nebula was excited by the passage of a shockwave caused by the star ejecting matter unusually late in its evolution. The stellar material cooled to form circumstellar dust, obscuring the star; this well explains why the central star’s optical brightness has diminished rapidly over the past 50 years. In the absence of ionizing photons from the central star, the outer nebula has begun recombining — becoming neutral. The authors conclude that, as HuBi 1 was roughly the same mass as the Sun, this finding provides a glimpse of a potential future for our solar system.


Dr Xuan Fang, co-author of the paper and a postdoctoral fellow at the HKU LSR and Department of Physics, said the extraordinary discovery resolves a long-lasting question regarding the evolutionary path of metal-rich central stars of planetary nebulae. Dr Fang has been observing the evolution of HuBi 1 early since 2014 using the Spanish flagship telescope Nordic Optical Telescope and was among the first astrophysicists to discover its inverted ionization structure.











Discovery of a structurally 'inside-out' planetary nebula
Left: Color-composite picture of planetary nebula (PN) HuBi 1 obtained at the 2.5-metre Nordic Optical Telescope;
red color is the [N II] l6583 line emission and green is Ha l6563.  Right: Evolutionary sequence of a PN progenitor
(with an initial mass of 1.1 solar masses) that experiences a very late thermal pulse (VLTP). Top-right panel shows
the evolutionary track in the Hertzsprung-Russell (H-R) diagram; the red symbol marks the current location of
HuBi 1’s central star. Bottom-right panel shows the post-asymptotic giant branch (post-AGB) time evolution of the
 central star temperature (Teff); the origin of time is set at the moment of the VLTP event; the red-dotted lines
mark the uncertainty in Teff [Credit: Images were adopted from Guerrero, Fang, Miller Bertolami, et al.
(2018, Nature Astronomy, tmp, 112)]

He said: “After noting HuBi 1’s inverted ionization structure and the unusual nature of its central star, we looked closer to find the reasons in collaboration with top theoretical astrophysicists in the world. We then came to realize that we had caught HuBi 1 at the exact moment when its central star underwent a brief ‘born-again’ process to become a hydrogen-poor [WC] and metal-rich star, which is very rare in white dwarf stars evolution.”


Dr Fang, however, said the discovery would not alter the fate of the Earth. He remarked: “Our findings suggest that the Sun may also experience a ‘born-again’ process while it is dying out in about 5 billion years from now; but way before that event, our earth will be engulfed by the Sun when it turns into a superhot red giant and nothing living will survive.”


HKU LSR Acting Director Professor Quentin Parker is exceptionally pleased with the findings of this international collaboration. He said: “I am delighted by this latest important contribution by Dr Xuan Fang who played a key role in this very unusual discovery of the international project. This exciting result in the area of evolved stars adds to several other impressive findings that members of the LSR have been producing over the last two years in astrophysics and planetary science research. It demonstrates yet again that the universe still has surprises for us. The LSR has an excellent and growing reputation in late-stage stellar evolution, high energy astrophysics, and planetary sciences and I expect this to continue.”


Source: The University of Hong Kong [August 16, 2018]



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Under pressure, hydrogen offers a reflection of giant planet interiors

Washington, DC–Lab-based mimicry allowed an international team of physicists including Carnegie’s Alexander Goncharov to probe hydrogen under the conditions found in the interiors of giant planets–where experts believe it gets squeezed until it becomes a liquid metal, capable of conducting electricity. Their work is published in Science.











Under pressure, hydrogen offers a reflection of giant planet interiors
Jovian cloudscape, courtesy of NASA’s Juno spacecraft [Credit: NASA/JPL-Caltech/SwRI/
MSSS/Gerald Eichstadt/Sean Dora]

Hydrogen is the most-abundant element in the universe and the simplest–comprised of only one proton and one electron in each atom. But that simplicity is deceptive, because there is still so much to learn about it, including its behavior under conditions not found on Earth.
For example, although hydrogen on the surface of giant planets, like our Solar System’s Jupiter and Saturn, is a gas, just like it is on our own planet, deep inside these giant planetary interiors, scientists believe it becomes a metallic liquid.


“This transformation has been a longstanding focus of attention in physics and planetary science,” said lead author Peter Celliers of Lawrence Livermore National Laboratory.


The research team–which also included scientists from the French Alternative Energies and Atomic Energy Commission, University of Edinburgh, University of Rochester, University of California Berkeley, and George Washington University–focused on this gas-to-metallic-liquid transition in molecular hydrogen’s heavier isotope deuterium. (Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons.)


They studied how deuterium’s ability to absorb or reflect light changed under up to nearly six million times normal atmospheric pressure (600 gigapascals) and at temperatures less than 1,700 degrees Celsius (about 3,140 degrees Fahrenheit). Reflectivity can indicate that a material is metallic.


They found that under about 1.5 million times normal atmospheric pressure (150 gigapascals) the deuterium switched from transparent to opaque–absorbing the light instead of allowing it to pass through. But a transition to metal-like reflectivity started at nearly 2 million times normal atmospheric pressure (200 gigapascals).


“To build better models of potential exoplanetary architecture, this transition between gas and metallic liquid hydrogen must be demonstrated and understood,” Goncharov explained. “Which is why we focused on pinpointing the onset of reflectivity in compressed deuterium, moving us closer to a complete vision of this important process.”


Source: Carnegie Institution for Science [August 16, 2018]




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Astronomers identify some of the oldest galaxies in the universe

Astronomers have identified some of the earliest galaxies in the Universe. The team from the Institute for Computational Cosmology at Durham University and the Harvard-Smithsonian Center for Astrophysics, has found evidence that the faintest satellite galaxies orbiting our own Milky Way galaxy are amongst the very first galaxies that formed in our Universe.











Astronomers identify some of the oldest galaxies in the universe
‘The distribution of satellite galaxies orbiting a computer-simulated galaxy, as predicted by the Lambda-cold-dark-matter
 cosmological model. The blue circles surround the brighter satellites, the white circles the ultrafaint satellites (so faint
that they are not readily visible in the image). The ultrafaint satellites are amongst the most ancient galaxies in the
Universe; they began to form when the Universe was only about 100 million years old (compared to its current age of
13.8 billion years). The image has been generated from simulations from the Auriga project carried out by researchers
 at the Institute for Computational Cosmology, Durham University, UK, the Heidelberg Institute for Theoretical
Studies, Germany, and the Max Planck Institute for Astrophysics, Germany’ [Credit: Institute for Computational
 Cosmology, Durham University, UK/Heidelberg Institute for Theoretical Studies, Germany/
Max Planck Institute for Astrophysics, Germany]

Scientists working on this research have described the finding as “hugely exciting” explaining that that finding some of the Universe’s earliest galaxies orbiting the Milky Way is “equivalent to finding the remains of the first humans that inhabited the Earth.”


The research group’s findings suggest that galaxies including Segue-1, Bootes I, Tucana II and Ursa Major I are in fact some of the first galaxies ever formed, thought to be over 13 billion years old.


When the Universe was about 380,000 years old, the very first atoms formed. These were hydrogen atoms, the simplest element in the periodic table. These atoms collected into clouds and began to cool gradually and settle into the small clumps or “halos” of dark matter that emerged from the Big Bang.


This cooling phase, known as the “Cosmic dark ages”, lasted about 100 million years. Eventually, the gas that had cooled inside the halos became unstable and began to form stars – these objects are the very first galaxies ever to have formed.


With the formation of the first galaxies, the Universe burst into light, bringing the cosmic dark ages to an end.


Dr Sownak Bose, at Harvard-Smithsonian Center for Astrophysics, working with Dr Alis Deason and Professor Carlos Frenk at Durham University’s ICC, identified two populations of satellite galaxies orbiting the Milky Way.


The first was a very faint population consisting of the galaxies that formed during the “cosmic dark ages”. The second was a slightly brighter population consisting of galaxies that formed hundreds of millions of years later, once the hydrogen that had been ionized by the intense ultraviolet radiation emitted by the first stars was able to cool into more massive dark matter halos.


Remarkably, the team found that a model of galaxy formation that they had developed previously agreed perfectly with the data, allowing them to infer the formation times of the satellite galaxies.


Their findings are published in the Astrophysical Journal.


Professor Carlos Frenk, Director of Durham University’s Institute for Computational Cosmology, said: “Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way’s own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.


“Our finding supports the current model for the evolution of our Universe, the ‘Lambda-cold-dark-matter model’ in which the elementary particles that make up the dark matter drive cosmic evolution.”


The intense ultraviolet radiation emitted by the first galaxies destroyed the remaining hydrogen atoms by ionizing them (knocking out their electrons), making it difficult for this gas to cool and form new stars.


The process of galaxy formation ground to a halt and no new galaxies were able to form for the next billion years or so.


Eventually, the halos of dark matter became so massive that even ionized gas was able to cool. Galaxy formation resumed, culminating in the formation of spectacular bright galaxies like our own Milky Way.


Dr Sownak Bose, who was a PhD student at the ICC when this work began and is now a research fellow at the Harvard-Smithsonian Center for Astrophysics, said: “A nice aspect of this work is that it highlights the complementarity between the predictions of a theoretical model and real data.


“A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar. With the increasing sensitivity of present and future galaxy censuses, a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes.”


Dr Alis Deason, who is a Royal Society University Research Fellow at the ICC, Durham University, said: “This is a wonderful example of how observations of the tiniest dwarf galaxies residing in our own Milky Way can be used to learn about the early Universe.”


Source: Durham University [August 16, 2018]




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Am I Bleeding Again? Image of the Week – August 20, 2018CIL:221…


Am I Bleeding Again? Image of the Week – August 20, 2018


CIL:221http://cellimagelibrary.org/images/221


Description: Red blood cells (erythrocytes). This image of human red blood cells obtained by scanning electron microscopy, revealing their characteristic biconcave shape.


Author: Tina Carvalho


Licensing: Public Domain: This image is in the public domain and thus free of any copyright restrictions. However, as is the norm in scientific publishing and as a matter of courtesy, any user should credit the content provider for any public or private use of this image whenever possible.


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‘Abrupt thaw’ of permafrost beneath lakes could significantly affect climate...

Methane released by thawing permafrost from some Arctic lakes could significantly accelerate climate change, according to a new University of Alaska Fairbanks-led study.











'Abrupt thaw' of permafrost beneath lakes could significantly affect climate change models
Methane bubbles are trapped in the ice on a pond near Fairbanks, Alaska
[Credit: Katey Walter Anthony]

The study, which was published in the journal Nature Communications, focuses on the carbon released by thawing permafrost beneath thermokarst lakes. Such lakes develop when warming soil melts ground ice, causing the surface to collapse and form pools of water. Those pools accelerate permafrost thaw beneath the expanding lakes, providing food for microbes that produce the greenhouse gases carbon dioxide and methane.
Lead author Katey Walter Anthony and her colleagues studied hundreds of thermokarst lakes in Alaska and Siberia during a 12-year period, measuring their growth and how much methane was bubbling to their surface. By combining field work results with remote-sensing data of lake changes during the past two years, they determined the “abrupt thaw” beneath such lakes is likely to release large amounts of permafrost carbon into the atmosphere this century. The lake activity could potentially double the release from terrestrial landscapes by the 2050s.


The effort, conducted by a team of U.S. and German researchers, is part of a 10-year NASA-funded project to better understand climate change effects on the Arctic. Additional support by the National Science Foundation allowed scientists from UAF and the Alaska Division of Geological and Geophysical Surveys to collect data on permafrost location, thaw and associated greenhouse gas release from lakes in Interior Alaska’s Goldstream Valley.


The researchers found the release of greenhouse gases beneath thermokarst lakes is relatively rapid, with deep thawing taking place over the course of decades. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans. The release of that surface permafrost soil carbon is often offset by an increased growth in vegetation.


“Thermokarst lakes provide a completely different scenario. When the lakes form, they flash-thaw these permafrost areas,” said Walter Anthony, an associate professor with UAF’s Water and Environmental Research Center. “Instead of centimeters of thaw, which is common for terrestrial environments, we’ve seen 15 meters of thaw beneath newly formed lakes in Goldstream Valley within the past 60 years.”


Emissions from thermokarst lakes aren’t currently factored into global climate models because their small size makes individual lakes difficult to include. However, the study’s authors show that these lakes are hotspots of permafrost carbon release. They argue that not including them in global climate models overlooks their feedback effect, which occurs when the release of greenhouse gases from permafrost increases warming. That feedback is significant because methane is about 30 times more potent than carbon dioxide as a heat-trapping gas.


Existing models currently attribute about 20 percent of the permafrost carbon feedback this century to methane, with the rest due to carbon dioxide from terrestrial soils. By including thermokarst lakes, methane becomes the dominant driver, responsible for 70 to 80 percent of permafrost carbon-caused warming this century. Adding thermokarst methane to the models makes the feedback’s effect similar to that of land-use change, which is the second-largest source of manmade warming.


Unlike shallow, gradual thawing of terrestrial permafrost, the abrupt thaw beneath thermokarst lakes is irreversible this century. Even climate models that project only moderate warming this century will have to factor in their emissions, according to the study.


“You can’t stop the release of carbon from these lakes once they form,” Walter Anthony said. “We cannot get around this source of warming.”


Source: University of Alaska Fairbanks [August 16, 2018]



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99-million-year-old beetle trapped in amber served as pollinator to evergreen cycads

Flowering plants are well known for their special relationship to the insects and other animals that serve as their pollinators. But, before the rise of angiosperms, another group of unusual evergreen gymnosperms, known as cycads, may have been the first insect-pollinated plants. Now, researchers reporting in the journal Current Biology have uncovered the earliest definitive fossil evidence of that intimate relationship between cycads and insects.











99-million-year-old beetle trapped in amber served as pollinator to evergreen cycads
A dorsal view of the mid-Cretaceous beetle Cretoparacucujus cycadophilus
with a 1mm scale bar [Credit: Chenyang Cai]

The discovery came in the form of an ancient boganiid beetle preserved in Burmese amber for an estimated 99 million years along with grains of cycad pollen. The beetle also shows special adaptations, including mandibular patches, for the transport of cycad pollen.
“Boganiid beetles have been ancient pollinators for cycads since the Age of Cycads and Dinosaurs,” says Chenyang Cai, now a research fellow at the University of Bristol. “Our find indicates a probable ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before angiosperm dominance and the radiation of flowering-plant pollinators, such as bees, later in the Cretaceous.”











99-million-year-old beetle trapped in amber served as pollinator to evergreen cycads
Cycad pollen grains associated with C. cycadophilus [Credit: NIGPAS]

When Cai’s supervisor Diying Huang at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, first showed him the beetle trapped in amber, he was immediately intrigued. He recognized that its large mandibles with bristly cavities might suggest the beetle was a pollinator of cycads.
After cutting, trimming, and polishing the specimen to get a better look under a microscope, Cai’s excitement only grew. The beetle carried several clumps of tiny pollen grains. Cai consulted Liqin Li, an expert in ancient pollen at the Chinese Academy of Sciences, who confirmed that the pollen grains belonged to a cycad.











99-million-year-old beetle trapped in amber served as pollinator to evergreen cycads
An ecological reconstruction of the mid-Cretaceous beetle Cretoparacucujus burmiticus
[Credit: Chenyang Cai]

The researchers also conducted an extensive phylogenetic analysis to explore the beetle’s family tree. Their analysis indicates the fossilized beetle belonged to a sister group to the extant Australian Paracucujus, which pollinate the relic cycad Macrozamia riedlei. The finding, along with the current disjunct distribution of related beetle-herbivore and cycad-host pairs in South Africa and Australia, support an ancient origin of beetle pollination of cycads, the researchers say.


Cai notes that the findings together with the distribution of modern boganiid beetles lead him to suspect that similar beetle pollinators of cycads are yet to be found. He’s been looking for them for the last five years. The challenge, he says, is that older Jurassic beetles are generally found as compression fossils not trapped in amber.


Source: Cell Press [August 16, 2018]



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Microfossils, possibly world’s oldest, had biological characteristics

Scientists have confirmed that the 3.4 billion year old Strelley Pool microfossils had chemical characteristics similar to modern bacteria. This all but confirms their biological origin and ranks them amongst the world’s oldest microfossils. The work is presented at the Goldschmidt geochemistry conference in Boston, with simultaneous publication in the peer-reviewed journal Geochemical Perspectives Letters.











Microfossils, possibly world's oldest, had biological characteristics
(Left) an electron microscope image of a microfossil form Strelley Pool. On the right we see the pattern of X-ray absorption
for Strelley Pool, Gunflint, and modern microorganisms, with distinctive peaks indicating the presence of various molecular
 functional groups (including 285.1 eV for aromatic/olefinic groups, 286.7 eV for imine/nitrile/carbonyl/phenol groups,
288.2 eV for amide groups, 288.6 eV for carboxyl/ester/acetal groups, 289.4 eV for hydroxyl groups)
[Credit: Julian Alleon/GPL]

A team of scientists, led by Dr Julien Alleon (IMPMC, Paris, France; and MIT, Cambridge, MA, USA) have been able to show that the chemical residuals from ancient microfossils match those of younger bacterial fossils, and so are likely to have been laid down by early life forms.


They compared the results of synchrotron-based X-ray absorption spectroscopy analysis of the Strelley Pool microfossils with more recent ones from the Gunflint Formation (1.9 billion years old, found on the shores of Lake Superior, Ontario, Canada) and with modern bacteria. All showed similar absorption features, indicating that the residual chemicals were made from the same building blocks, thereby supporting a biological origin (see illustration below).


Dr Jullien Alleon said: “There are a couple of important points which come out of this work. Firstly, we demonstrate that the elemental and molecular characteristics of these 3.4 Ga microfossils are consistent with biological remains, slightly degraded by fossilization processes. This effectively supports the biological origin of the Strelley Pool microfossils. There are competing claims over which microfossils are actually the world’s oldest, this analytical strategy needs to be applied to other ancient samples to help settle the controversy.


Secondly, it is remarkable that these echoes of past life have survived the extreme conditions they have experienced over the last 3.4 billion years: we know from the molecular structure of the microfossils that they have been exposed to temperatures of up to 300 °C for long periods. And yet we are still able to see signs of their original chemistry.


This is a step forward to confirming that these are indeed the oldest fossils yet discovered.”


Commenting, Professor Vickie Bennett (Australian National University) said: “This is exciting work with the new types of analyses providing compelling evidence that the cherts contain biogenic microfossils. This is in line with other observations for early life from the Strelley Pool rocks, including stromatolites interpreted as microbial mats, and further confirming that the minimum age for life on Earth is 3.4 billion years.


The techniques used here are not applicable to the older rocks that host the claims for the oldest terrestrial life, as these rocks were exposed to much higher temperatures. These samples include the 3.7 billion year old stromatolites from Isua, Greenland and the 4.1 billion year old Canadian microfossils. However, this work shows how quickly the field is developing and that new capabilities for testing and confirming earlier evidence of life are in reach”.


Source: Goldschmidt Conference [August 16, 2018]



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Russian archaeologists discover medieval cemetery in Pskov

Russian archaeologists have discovered a medieval cemetery in the historical center of Pskov, first mentioned at the end of the fifteenth century, head of the archaeological center for the Pskov Region Marina Kulakova told journalists at a press conference on Wednesday.











Russian archaeologists discover medieval cemetery in Pskov
Credit: © Alexandr Ryumin/TASS

“During the excavations between Sverdlovka and Spegalsky streets, in the historical center of Pskov, near a monastery, we have discovered a part of a medieval cemetery, first mentioned at the end of the fifteenth century. We have studied 120 gravesites, now the anthropologists will start their work. The remaining monastery buildings were destroyed in the 1960s during the montage of communications, and the cemetery has been found just under the layer of concrete from the 1960s,” Kulakova said.
According to her, archaeologists have also found a bracelet and a glass bead dating to the twelfth century. “These findings give us reason to believe that the necropolis was built on another, more ancient one, dating to the eleventh-twelfth centuries,” Kulakova noted.











Russian archaeologists discover medieval cemetery in Pskov
Credit: arheologpskov

She added that this year, archaeologists have been studying several sites in Pskov, with the shared area of 3,000 square meters.


Source: TASS [August 16, 2018]



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Police investigating vandalism at Byzantine & Christian Museum in Athens

An official inquiry into an act of vandalism at the Byzantine and Christian Museum in Athens on July 28 has been initiated, the Ministry of Culture said on Thursday, adding that there was “no irreparable damage to exhibits.”











Police investigating vandalism at Byzantine & Christian Museum in Athens

Credit: Greek Ministry of Culture and Sports



According to the ministry’s statement, “two women walking through the halls of permanent and rotating exhibits” sprayed an oil-based liquid on exhbition objects, glass cases, walls and the floor, an act that was not noticed at the time.


The “malicious act”, the ministry said, “did not cause any irreparable damage to ancient objects, which have almost all been cleaned by now,” while an official police inquiry is under way to identify the culprits following the museum and ministry’s initiative.











Police investigating vandalism at Byzantine & Christian Museum in Athens

Credit: Greek Ministry of Culture and Sports



Museum Director Ekaterini Delaporta told the Athens-Macedonian News Agency (ANA) that “conservators undertook all analyses immediately and took all necessary measures” to restore “to a great degree the damage.” However, she added, “the damage to the building itself needs to be rectified because the walls and floors of the museum’s interior are sprayed with oil.”


She said that a Coptic cross dating to the 6th century AD sustained damage that may not be entirely reversible, as it is made of wood and it absorbed the oil. The investigation now rests with the ministry and the police, “who have taken over the case,” she told ANA.


Source: ANA-MPA [August 16, 2018]



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Roman magistrate’s statue found of Heraklea Sintica in southwest Bulgaria

A Roman statue from the end of the first or beginning of the 2nd century AD depicting a local Roman magistrate has been discovered by the archaeologists excavating the Graeco-Roman city of Heraklea Sintica near Petrich in southwest Bulgaria.











Roman magistrate's statue found of Heraklea Sintica in southwest Bulgaria
The life-size statue of an Ancient Roman magistrate from around 100 AD has been discovered
beneath the steps of the Roman Forum of Heraklea Sintica, in Bulgaria’s very southwest
[Credit: Archaeology in Bulgaria]

Heraclea Sintica is thought to have been established ca. 300 BC by Kassandros, King of Macedon in 305-297 BC, who also founded Thessaloniki, in Greece. It is possible, however, that Heraklea Sintica was first settled even earlier.


The city was named ‘Heraklea’ after the mythical Greek hero Herakles, more popularly known today as Hercules, and ‘Sintica’ after the Thracian tribe of the Sintians who inhabited the valley of the Struma River at the time.


The statue was found at a depth of 4 metres (appr. 12 feet) beneath the steps of the Roman Forum of Heraklea Sintica.


It is life-size or very slightly larger than life-size, and very well preserved. The only part missing is the head


Next to the left leg of the statue – which depicts a male dressed in a toga – there is a box for papyrus scrolls, a clear indication that the man was a high-ranking magistrate.


It is thought the statue depicts a certain Tiberius Claudius Bachius, a wealthy benefactor of the city of Heraklea Sintica.


Source: Archaeology in Bulgaria [August 19, 2018]



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‘Loanhead of Daviot’ Stone Circle, Aberdeenshire,…











‘Loanhead of Daviot’ Stone Circle, Aberdeenshire, Scotland, 19.8.18.


An atmospheric stone circle with recumbent features alongside an enclosed prehistoric burial ground (Images 8 and 9).


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