суббота, 1 сентября 2018 г.

Meini Hirion Prehistoric Standing Stones, Llanbedr, North Wales,…








Meini Hirion Prehistoric Standing Stones, Llanbedr, North Wales, 28.8.18.


This is another first visit for me. This pair of standing stones sits in a field close to the centre of Llanbedr and near to the church. The two stones vary noticeably in size and shape; the smaller of the two being virtually covered in a white lichen on at least one face.


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Shape-shifting Schistosomes When it comes to transformations…


Shape-shifting Schistosomes



When it comes to transformations in Nature, what comes to mind? Caterpillars into butterflies? Tadpoles into frogs? What about flatworms? Probably not your first answer but schistosomes – parasitic flatworms that cause potentially fatal schistosomiasis – undergo multiple transformations as they adapt to their different hosts, namely snails and mammals. Researchers probe the stem cells responsible for these transformations. They infected snails with schistosome larvae (pictured, multicoloured), harvested the resulting mature larvae and used these to infect mice. The parasites were collected at different stages along this infectious journey and their stem cells isolated. Looking at the genes activated in these cells revealed a group of stem cells that make germline cells, which form sperm and eggs. Interfering with one gene in particular in the stem cells disrupted germline cell production. These insights could help develop ways to stop the reproduction of schistosomes, which infect 250 million people worldwide.


Written by Lux Fatimathas



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Space Station Science Highlights: Week of August 27, 2018


ISS – Expedition 56 Mission patch.


Aug. 31, 2018


This week, NASA astronaut Ricky Arnold became the first person to sequence RNA in space, another molecular milestone aboard the orbiting laboratory. Arnold’s work was part of a robust week of science, leading into a new, busy month for the Expedition 56 crew aboard the International Space Station. Japan is preparing to launch its seventh resupply mission, Kounotori HTV-7 on September 10, and three astronauts are gearing up for two spacewalks next month.



Image above: NASA astronaut Serena M. Auñón-Chancellor works with the Bone Densitometer. Densitometry measures the mass per unit volume (density) of minerals in bone. Quantitative measures of bone loss in mice during space flight are necessary for the development of countermeasures for human crew members, as well as for bone-loss syndromes on Earth. Image Credit: NASA.


This week, crew members conducted hours of science and conducted repair work after a small leak was detected in the orbital compartment, or upper section, of the Soyuz MS-09 spacecraft attached to the Rassvet module of the Russian segment of the station. The station’s cabin pressure is holding steady following the repair.


Read more details about the scientific work conducted aboard your orbiting laboratory:


RNA sequenced in space for the first time


Much of present-day science focuses on exploring the molecular world. A primary tool is DNA sequencing, performed for the first time on the orbiting lab in August 2016.



Image above: NASA astronaut Ricky Arnold conducts the WetLab-2 Parra investigation. WetLab-2 Parra tests a passive method to remove air bubbles from a liquid sample. Image Credit: NASA.


Biomolecule Extraction and Sequencing Technology (BEST) seeks to advance use of sequencing in space in three ways: identifying microbes aboard the space station that current methods cannot detect, assessing microbial mutations in the genome because of spaceflight and performing direct RNA sequencing.



Animation above: NASA astronaut Ricky Arnold loads RNA into the minION device as a part of the BEST investigation. BEST seeks to advance DNA and RNA sequencing in space. Animation Credit: NASA.


This week, Arnold became the first person to sequence RNA in space. Within the first few minutes, more than 15,000 RNA molecules had been sequenced, matching and surpassing many ground sequencing runs. The run continued for 48 hours.


Learn more about the BEST investigation here: https://www.nasa.gov/mission_pages/station/research/news/BEST_DNA_RNA


Station catches glimpses of the moon


Communication is a vital piece of long-duration, deep-space exploration. If a spacecraft loses communication with the ground or with NASA’s Deep Space Network, its crew must navigate just as ancient mariners did, using the moon and stars. The Moon Imagery investigation collects pictures of the moon from the station, and then uses them to calibrate navigation software to guide the Orion Multi-Purpose Crew Vehicle, in case its transponder-based navigation capability is lost. Crewmembers photograph the moon’s phases during one 29-day cycle, providing images of varying brightness to calibrate Orion’s camera software.


This week, crew members took photographs of the full moon during a day pass and downlinked them for analysis on the ground.


Get a grip: Investigation studies motor control in microgravity environment


Microgravity provides a unique environment to study dexterous manipulation. The European Space Agency’s GRIP investigation studies long-duration spaceflight effects on the abilities of human subjects to regulate grip force and upper limb trajectories when manipulating objects using different kinds of movements (i.e.oscillatory movements, rapid discrete movements and tapping gestures).



Animation above: This week, the DLR Earth Sensing Imaging Spectrometer (DESIS) was checked out to be powered up. DESIS verifies and enhances the use of space-based hyperspectral imaging capabilities for Earth remote sensing, and provides an instrument which produces high value hyperspectral imagery for Teledyne Brown Engineering (TBE) commercial purposes. Animation Credit: NASA.


Data collected from this investigation may provide insight into potential hazards for astronauts as they manipulate objects in different gravitational environments. It could alsosupport design and control of haptic interfaces to be used in challenging environments and provide information about motor control that potentially will be useful for the evaluation and rehabilitation of patients with neurological diseases.



Space to Ground: Potential Game Changer: 08/31/2018

This week, the crew completed the first of three GRIP operations in the seated position.


Other work was done on these investigations: BPC-1, SpaceTex-2, Metabolic Space, Lighting Effects, Cerebral Autoregulation, BCAT-CS, CASIS PCG-13, CEO, ISS HAM, Rodent Research-7, SCAN Testbed, SPHERES SmoothNav, ACME CLD Flame, DESIS, MSRR, Tropical Cyclone, Cold Atom Lab, HDEV, Bone Densitometer, WetLab-2 Parra, and Food Acceptability.


Related links:


Biomolecule Extraction and Sequencing Technology (BEST): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7687


NASA’s Deep Space Network: https://deepspace.jpl.nasa.gov/


Moon Imagery: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1794


GRIP: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1188


BPC-1: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7729


SpaceTex-2: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7571


Metabolic Space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7574


Lighting Effects: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2013


Cerebral Autoregulation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1938


BCAT-CS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7668


CASIS PCG-13: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7690


CEO: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=84


ISS HAM: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=337


Rodent Research-7: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7425


SCAN Testbed: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=156


SPHERES SmoothNav: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7532


ACME CLD Flame: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7564


DESIS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1778


Tropical Cyclone: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1712


Cold Atom Lab: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7396


HDEV: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=892


Bone Densitometer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1059


WetLab-2 Parra: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7688


Food Acceptability: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562


Spot the Station: https://spotthestation.nasa.gov/


Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


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


Images (mentioned), Animations (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Yuri Guinart-Ramirez, Lead Increment Scientist Expeditions 55 & 56.


Greetings, Orbiter.chArchive link


Cefn-Isaf Prehistoric Burial Chamber, Rhoslan, North Wales,…









Cefn-Isaf Prehistoric Burial Chamber, Rhoslan, North Wales, 28.8.18.


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2018 September 9 Aerosol Earth Model Visualization Credit: NASA…


2018 September 9


Aerosol Earth
Model Visualization Credit: NASA Earth Observatory, GEOS FP, Joshua Stevens


Explanation: On August 23, 2018 the identification and distribution of aerosols in the Earth’s atmosphere is shown in this dramatic, planet-wide visualization. Produced in real time, the Goddard Earth Observing System Forward Processing (GEOS FP) model relies on a combination of Earth-observing satellite and ground-based data to calculate the presence of types of aerosols, tiny solid particles and liquid droplets, as they circulate above the entire planet. This August 23rd model shows black carbon particles in red from combustion processes, like smoke from the fires in the United States and Canada, spreading across large stretches of North America and Africa. Sea salt aerosols are in blue, swirling above threatening typhoons near South Korea and Japan, and the hurricane looming near Hawaii. Dust shown in purple hues is blowing over African and Asian deserts. The location of cities and towns can be found from the concentrations of lights based on satellite image data of the Earth at night.


∞ Source: apod.nasa.gov/apod/ap180901.html


Llety’r Filiast Prehistoric Burial Chamber, Great Orme,…







Llety’r Filiast Prehistoric Burial Chamber, Great Orme, Llandudno, North Wales, 28.8.18.


Situated close to the Great Orme Prehistoric Copper Mine, this communal burial chamber is thought to be anywhere from 6000 to 4000 years old.


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Hubble’s Lucky Observation of an Enigmatic Cloud


NASA – Hubble Space Telescope patch.


Aug. 31, 2018



The little-known nebula IRAS 05437+2502 billows out among the bright stars and dark dust clouds that surround it in this striking image from the Hubble Space Telescope. It is located in the constellation of Taurus (the Bull), close to the central plane of our Milky Way galaxy. Unlike many of Hubble’s targets, this object has not been studied in detail and its exact nature is unclear. At first glance it appears to be a small, rather isolated region of star formation, and one might assume that the effects of fierce ultraviolet radiation from bright, young stars probably were the cause of the eye-catching shapes of the gas. However, the bright, boomerang-shaped feature may tell a more dramatic tale. The interaction of a high-velocity young star with the cloud of gas and dust may have created this unusually sharp-edged, bright arc. Such a reckless star would have been ejected from the distant young cluster where it was born and would travel at 200,000 kilometers per hour (124,000 miles per hour) or more through the nebula.


This faint cloud was originally discovered in 1983 by the Infrared Astronomical Satellite (IRAS), the first space telescope to survey the whole sky in infrared light. IRAS was run by the United States, the Netherlands, and the United Kingdom and found huge numbers of new objects that were invisible from the ground.


This image was taken with the Wide Field Channel of the Advanced Camera for Surveys on Hubble. It was part of a “snapshot” survey. These are observations that are fitted into Hubble’s busy schedule when possible, without any guarantee that the observation will take place — so it was fortunate that the observation was made at all. This picture was created from images taken through yellow and near-infrared filters.



Hubble Space Telescope (HST)

For more information about Hubble, visit:


http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/


Image, Animation, Credits: ESA/Hubble, R. Sahai and NASA/Text Credits: European Space Agency (ESA)/NASA/Karl Hille.


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Crew Plans Quiet Labor Day Weekend After Repair Work


ISS – Expedition 56 Mission patch.


August 31, 2018


The Expedition 56 crew resumed a regular schedule of work Friday on the International Space Station after spending the day Thursday locating and repairing a leak in the upper section of one of the two Russian Soyuz vehicles attached to the complex.



Image above: The Soyuz MS-09 crew spacecraft from Roscosmos is pictured docked to the Rassvet module as the International Space Station was flying into an orbital night period. Image Credit: NASA.


With the station’s cabin pressure holding steady, most of the crew pressed ahead with a variety of scientific experiments. Station Commander Drew Feustel of NASA prepared tools to be used in a pair of spacewalks late next month to complete the change out of batteries on the port truss of the outpost. Six new lithium-ion batteries will be transported to the station in September on the Japanese HTV Transfer Vehicle, or HTV-7 cargo craft, that will replace a dozen older nickel-hydrogen batteries in a duplication of work conducted last year on the station’s starboard truss.


Flight controllers at the Mission Control Centers in Houston and Moscow, meanwhile, continued to monitor pressure levels on the station following the patching of a small hole Thursday in the orbital module, or upper portion of the Soyuz MS-09 spacecraft. The Soyuz is docked to the Rassvet module on the Earth-facing side of the Russian segment. The tiny hole created a slight loss in pressure late Wednesday and early Thursday before it was repaired by Soyuz commander Sergey Prokopyev of Roscosmos.



International Space Station (ISS). Animation Credit: NASA

The crew plans a quiet weekend before embarking on a busy schedule of research and routine maintenance work next week.


Related links:


Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


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


Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.


Best regards, Orbiter.chArchive link


Cosmologists propose new way to form primordial black holes

What is dark matter? How do supermassive black holes form? Primordial black holes might hold the answer to this longstanding question. Leiden and Chinese cosmologists have identified a new way in which these hypothetical objects could be produced immediately after the Big Bang. Their research has been published in Physical Review Letters.











Cosmologists propose new way to form primordial black holes
Credit: Leiden Institute of Physics

In their quest to understand the universe, scientists are faced with some major unsolved puzzles. For example, stars move around galaxies as if there is five times more mass present than that observed. What makes comprises this dark matter? And another riddle: Galaxies harbor enormous black holes in their cores, weighing millions of solar masses. In young galaxies, collapsed stars did not have enough time to grow that big. How did these so-called supermassive black holes form?
Cosmologists have proposed a hypothetical solution that could solve one of both riddles. Primordial black holes, spawned shortly after the Big Bang, have the ability to either remain tiny or quickly gain mass. In the former case, they are candidates for dark matter. In the latter case, they could serve as seeds for supermassive black holes. Cosmologist Dong-Gang Wang from Leiden University and his Chinese colleagues Yi-Fu Cai, Xi Tong and Sheng-Feng Yan of USTC University have reported a new way in which primordial black holes could have formed around the time of the Big Bang.











Cosmologists propose new way to form primordial black holes
This figure shows the fraction of dark matter due to primordial black holes (vertical axis), as a function of their
individual mass in solar masses (horizontal axis). The shaded areas are excluded by astronomical observations.
The resonance effect manifests itself as narrow peaks (red and blue dotted lines) that show the mass distribution
of primordial black holes. Because the peaks are narrow, all primordial black holes are predicted to have the
same mass. For our Universe, there is only one real peak, depending on (still unknown) details of the Big Bang.
For instance, the blue peak corresponds to black holes of about 10 – 100 solar masses—the range recently
detected by the LIGO/VIRGO gravitational wave experiment [Credit: Leiden Institute of Physics]

After the Big Bang, the universe contained small density perturbations caused by random quantum fluctuations. These are large enough to form stars and galaxies, but too small to grow into primordial black holes on their own. Wang and his collaborators have identified a new resonance effect that makes primordial black holes possible by enhancing certain perturbations selectively. This leads to the prediction that all primordial black holes should have approximately the same mass. The narrow peaks in figure 1 show a range of possible masses as a consequence of the resonance.
“Other calculations have different ways to enhance perturbations, but run into problems,” says Wang. “We use resonance during inflation, when the universe grew exponentially shortly after the Big Bang. Our calculations are simple enough so that we can work with it. In reality, the mechanism might be more complicated, but this is a start. The narrow peaks that we get are inherent to the mechanism, because it uses resonance.”


Author: Erik Arends | Source: Leiden Institute of Physics [August 29, 2018]



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Water discovered in the Great Red Spot indicates Jupiter might have plenty more

On Dec. 7, 1995, NASA’s historic Galileo probe plunged into Jupiter’s atmosphere at 106,000 mph, relaying 58 minutes of data back to Earth before it was pulverized in the depths of the enormous planet’s crushing interior.











Water discovered in the Great Red Spot indicates Jupiter might have plenty more
This image of Jupiter was captured by NASA’s Juno spacecraft [Credit: NASA]

In terms of atmospheric composition, some of what the probe measured met expectations. But there were also some surprises, one of the most baffling being that the region Galileo entered was drier than astrophysicists had anticipated. Jupiter’s 79 moons are mostly made of ice, so it had been assumed that the planet’s atmosphere would contain a considerable amount of water. If so, the 750-pound probe didn’t find it that day.


Almost a quarter of a century later, experts are still debating how much water might be swirling within Jupiter’s howling atmosphere. Recent research by a national team of scientists – including Clemson University astrophysicist Máté Ádámkovics – indicates that the answer is … a lot.


“By formulating and analyzing data obtained using ground-based telescopes, our team has detected the chemical signatures of water deep beneath the surface of Jupiter’s Great Red Spot,” said Ádámkovics, an assistant professor in the College of Science’s department of physics and astronomy. “Jupiter is a gas giant that contains more than twice the mass of all of our other planets combined. And though 99 percent of Jupiter’s atmosphere is composed of hydrogen and helium, even solar fractions of water on a planet this massive would add up to a lot of water – many times more water than we have here on Earth.”


Ádámkovics’ collaborative research was recently featured in Astronomical Journal, one of the world’s premier journals for astronomy. He was part of a team that included Gordon L. Bjoraker of NASA; Michael H. Wong and Imke de Pater of the University of California, Berkeley; Tilak Hewagama of the University of Maryland; and Glenn Orton of the California Institute of Technology. The paper was titled “The Gas Composition and Deep Cloud Structure of Jupiter’s Great Red Spot.”











Water discovered in the Great Red Spot indicates Jupiter might have plenty more
The Great Red Spot is the dark patch in the middle of this infrared image. It is dark due
 to the thick clouds that block thermal radiation. The yellow strip denotes the portion
of the Great Red Spot used in astrophysicist Gordon L. Bjoraker’s analysis
[Credit: NASA’s Goddard Space Flight Center/Gordon Bjoraker]

The team focused its sights on the Great Red Spot, a hurricane-like storm more than twice as wide as Earth that has been blustering in Jupiter’s skies for more than 150 years. The team searched for water by using radiation data collected by two instruments on ground-based telescopes: iSHELL on the NASA Infrared Telescope Facility and the Near Infrared Spectograph on the Keck 2 telescope, both of which are located on the remote summit of Maunakea in Hawaii. iShell is a high-resolution instrument that can detect a wide range of gases across the color spectrum. Keck 2 is the most sensitive infrared telescope on Earth.


The team found evidence of three cloud layers in the Great Red Spot, with the deepest cloud layer at 5-7 bars. A bar is a metric unit of pressure that approximates the average atmospheric pressure on Earth at sea level. Altitude on Jupiter is measured in bars because the planet doesn’t have an Earth-like surface from which to measure elevation. At about 5-7 bars – or about 100 miles below the cloud tops – is where the scientists believed the temperature would reach the freezing point for water. The deepest of the three cloud layers identified by the team was believed to be composed of frozen water.


“The discovery of water on Jupiter using our technique is important in many ways. Our current study focused on the red spot, but future projects will be able to estimate how much water exists on the entire planet,” Ádámkovics said. “Water may play a critical role in Jupiter’s dynamic weather patterns, so this will help advance our understanding of what makes the planet’s atmosphere so turbulent. And, finally, where there’s the potential for liquid water, the possibility of life cannot be completely ruled out. So, though it appears very unlikely, life on Jupiter is not beyond the range of our imaginations.”


Clemson’s main role in the research was to use specially designed software to transform raw data into science-quality data that could be more easily analyzed and also shared with scientists at Clemson and around the world. This type of work was performed this past spring by Rachel Conway, an undergraduate student in physics and astronomy who became involved in the project via Clemson’s Creative Inquiry program.



“When I initially began, I started by running the data through. The code was already written and I was just plugging in new data sets and generating output files,” said Conway, a native of Watertown, Connecticut. “But then I began fixing errors and learning more about what was actually going on. I’m interested in everything and anything that’s out there, so learning more about what we don’t know is always cool.”


NASA’s Juno spacecraft, which arrived at Jupiter in 2016 and will be orbiting and studying the planet until at least 2021, has revealed many secrets about a planet so large it almost became a star. Juno is also searching for water by using its own high-tech infrared spectrometer. If Juno’s observations match ground-based observations, then the latter can be applied not just to the Great Red Spot, but to all of Jupiter. The technique also can be used to study Saturn, Uranus and Neptune, our solar system’s three other gas planets.


“Starting this fall, the next project will be to get a lot more data of this kind to measure not just one spot on Jupiter. but all over Jupiter,” said Ádámkovics, whose research focus is on the physics and chemistry of planet formation, planetary atmospheres and circumstellar disks. “To do this, we’ll be collecting many gigabytes of data with the new instrument, iSHELL, that works at a very high resolution and will complement Juno’s observations. The new part of this next project will be to write the automated software for all this data so that we can get a full picture of the planet’s water abundance.”


This time around, Ádámkovics and Conway will have some new members on their Clemson team. Ádámkovics will add six to eight Creative Inquiry students to assist with analyzing the raw data.


“In addition to physics students, we also have students who are computer scientists and who specialize in other fields,” Ádámkovics said. “We expect that these cross-disciplinary skill sets will complement each other by enhancing our effectiveness and efficiency. Jupiter still has many mysteries. But we’ve never been more ready or more able to solve them.”


Author: Jim Melvin | Source: Clemson University [August 29, 2018]



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Unstoppable monster in the early universe

Astronomers obtained the most detailed anatomy chart of a monster galaxy located 12.4 billion light-years away. Using the Atacama Large Millimeter/submillimeter Array (ALMA), the team revealed that the molecular clouds in the galaxy are highly unstable, which leads to runaway star formation. Monster galaxies are thought to be the ancestors of the huge elliptical galaxies in today’s universe, therefore these findings pave the way to understand the formation and evolution of such galaxies.











Unstoppable monster in the early universe
Artist’s impression of the monster galaxy COSMOS-AzTEC-1. This galaxy is located 12.4 billion light-years away
and is forming stars 1,000 times more rapidly than our Milky Way galaxy. ALMA observations revealed
dense gas concentrations in the disk, and intense star formation in those concentrations
[Credit: National Astronomical Observatory of Japan]

“One of the best parts of ALMA observations is to see the far-away galaxies with unprecedented resolution,” says Ken-ichi Tadaki, a postdoctoral researcher at the Japan Society for the Promotion of Science and the National Astronomical Observatory of Japan, the lead author of the research paper published in the journal Nature.


Monster galaxies, or starburst galaxies, form stars at a startling pace; 1000 times higher than the star formation in our Galaxy. But why are they so active? To tackle this problem, researchers need to know the environment around the stellar nurseries. Drawing detailed maps of molecular clouds is an important step to scout a cosmic monster.


Tadaki and the team targeted a chimerical galaxy COSMOS-AzTEC-1. This galaxy was first discovered with the James Clerk Maxwell Telescope in Hawai`i, and later the Large Millimeter Telescope (LMT) in Mexico found an enormous amount of carbon monoxide gas in the galaxy and revealed its hidden starburst. The LMT observations also measured the distance to the galaxy, and found that it is 12.4 billion light-years (Note).


Researchers have found that COSMOS-AzTEC-1 is rich with the ingredients of stars, but it was still difficult to figure out the nature of the cosmic gas in the galaxy. The team utilized the high resolution and high sensitivity of ALMA to observe this monster galaxy and obtain a detailed map of the distribution and the motion of the gas. Thanks to the most extended ALMA antenna configuration of 16 km, this is the highest resolution molecular gas map of a distant monster galaxy ever made.











Unstoppable monster in the early universe
ALMA revealed the distribution of molecular gas (left) and dust particles (right). In addition to the dense cloud
in the center, the research team found two dense clouds several thousand light-years away from the center.
These dense clouds are dynamically unstable and thought to be the sites of intense star formation
[Credit: ALMA (ESO/NAOJ/NRAO), Tadaki et al.]

“We found that there are two distinct large clouds several thousand light-years away from the center,” explains Tadaki. “In most distant starburst galaxies, stars are actively formed in the center. So it is surprising to find off-center clouds.”


The astronomers further investigated the nature of the gas in COSMOS-AzTEC-1 and found that the clouds throughout the galaxy are very unstable, which is unusual. In a normal situation, the inward gravity and outward pressure are balanced in the clouds. Once gravity overcomes pressure, the gas cloud collapses and forms stars at a rapid pace.


Then, stars and supernova explosions at the end of the stellar life cycle blast out gases, which increase the outward pressure. As a result, the gravity and pressure reach a balanced state and star formation continues at a moderate pace. In this way star formation in galaxies is self-regulating. But, in COSMOS-AzTEC-1, the pressure is far weaker than the gravity and hard to balance. Therefore this galaxy shows runaway star formation and has morphed into an unstoppable monster galaxy.


The team estimated that the gas in COSMOS-AzTEC-1 will be completely consumed in 100 million years, which is 10 times faster than in other star forming galaxies. But why is the gas in COSMOS-AzTEC-1 so unstable? Researchers do not have a definitive answer yet, but galaxy merger is a possible cause. Galaxy collision may have efficiently transported the gas into a small area and ignited intense star formation.


“At this moment, we have no evidence of merger in this galaxy. By observing other similar galaxies with ALMA, we want to unveil the relation between galaxy mergers and monster galaxies,” summarizes Tadaki.


Source: National Institutes of Natural Sciences [August 29, 2018]




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‘Archived’ heat has reached deep into the Arctic interior, researchers say

Arctic sea ice isn’t just threatened by the melting of ice around its edges, a new study has found: Warmer water that originated hundreds of miles away has penetrated deep into the interior of the Arctic.











'Archived' heat has reached deep into the Arctic interior, researchers say
Heat currently trapped below the surface has the potential to melt the Arctic region’s entire sea-ice pack
 if it reaches the surface, according to researchers [Credit: Yale University]

That “archived” heat, currently trapped below the surface, has the potential to melt the region’s entire sea-ice pack if it reaches the surface, researchers say.
“We document a striking ocean warming in one of the main basins of the interior Arctic Ocean, the Canadian Basin,” said lead author Mary-Louise Timmermans, a professor of geology and geophysics at Yale University.


The upper ocean in the Canadian Basin has seen a two-fold increase in heat content over the past 30 years, the researchers said. They traced the source to waters hundreds of miles to the south, where reduced sea ice has left the surface ocean more exposed to summer solar warming. In turn, Arctic winds are driving the warmer water north, but below the surface waters.


“This means the effects of sea-ice loss are not limited to the ice-free regions themselves, but also lead to increased heat accumulation in the interior of the Arctic Ocean that can have climate effects well beyond the summer season,” Timmermans said. “Presently this heat is trapped below the surface layer. Should it be mixed up to the surface, there is enough heat to entirely melt the sea-ice pack that covers this region for most of the year.”


The study appears in the journal Science Advances.


Author: Jim Shelton | Source: Yale University [August 29, 2018]



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AWAKE successfully accelerates electrons


CERN – European Organization for Nuclear Research logo.


31 Aug 2018


Early in the morning on Saturday, 26 May 2018, the AWAKE collaboration at CERN successfully accelerated electrons for the first time using a wakefield generated by protons zipping through a plasma. A paper describing this important result was published in the journal Nature. The electrons were accelerated by a factor of around 100 over a length of 10 metres: they were externally injected into AWAKE at an energy of around 19 MeV (million electronvolts) and attained an energy of almost 2 GeV (billion electronvolts). Although still at a very early stage of development, the use of plasma wakefields could drastically reduce the sizes, and therefore the costs, of the accelerators needed to achieve the high-energy collisions that physicists use to probe the fundamental laws of nature. The first demonstration of electron acceleration in AWAKE comes only five years after CERN approved the project in 2013 and is an important first step towards realising this vision.



AWAKE’s electron beam line (Image: Maximilien Brice/Julien Ordan/CERN)

AWAKE, which stands for “Advanced WAKEfield Experiment”, is a proof-of-principle R&D project investigating the use of protons to drive plasma wakefields for accelerating electrons to higher energies than can be achieved using conventional technologies. Traditional accelerators use what are known as radio-frequency (RF) cavities to kick the particle beams to higher energies. This involves alternating the electrical polarity of positively and negatively charged zones within the RF cavity, with the combination of attraction and repulsion accelerating the particles within the cavity. By contrast, in wakefield accelerators, the particles get accelerated by “surfing” on top of the plasma wave (or wakefield) that contains similar zones of positive and negative charges.


Plasma wakefields themselves are not new ideas; they were first proposed in the late 1970s. “Wakefield accelerators have two different beams: the beam of particles that is the target for the acceleration is known as a ‘witness beam’, while the beam that generates the wakefield itself is known as the ‘drive beam’,” explains Allen Caldwell, spokesperson of the AWAKE collaboration. Previous examples of wakefield acceleration have relied on using electrons or lasers for the drive beam. AWAKE is the first experiment to use protons for the drive beam, and CERN provides the perfect opportunity to try the concept. Drive beams of protons penetrate deeper into the plasma than drive beams of electrons and lasers. “Therefore,” Caldwell adds, “wakefield accelerators relying on protons for their drive beams can accelerate their witness beams for a greater distance, consequently allowing them to attain higher energies.”


AWAKE gets its drive-protons from the Super Proton Synchrotron (SPS), which is the last accelerator in the chain that delivers protons to the Large Hadron Collider (LHC). Protons from the SPS, travelling with an energy of 400 GeV, are injected into a so-called “plasma cell” of AWAKE, which contains Rubidium gas uniformly heated to around 200 ºC. These protons are accompanied by a laser pulse that transforms the Rubidium gas into a plasma – a special state of ionised gas – by ejecting electrons from the gas atoms. As this drive beam of positively charged protons travels through the plasma, it causes the otherwise-randomly-distributed negatively charged electrons within the plasma to oscillate in a wavelike pattern, much like a ship moving through the water generates oscillations in its wake. Witness-electrons are then injected at an angle into this oscillating plasma at relatively low energies and “ride” the plasma wave to get accelerated. At the other end of the plasma, a dipole magnet bends the incoming electrons onto a detector. “The magnetic field of the dipole can be adjusted so that only electrons with a specific energy go through to the detector and give a signal at a particular location inside it,” says Matthew Wing, deputy spokesperson of AWAKE, who is also responsible for this apparatus, known as the electron spectrometer. “This is how we were able to determine that the accelerated electrons reached an energy of up to 2 GeV.”


The strength at which an accelerator can accelerate a particle beam per unit of length is known as its acceleration gradient and is measured in volts-per-metre (V/m). The greater the acceleration gradient, the more effective the acceleration. The Large Electron-Positron collider (LEP), which operated at CERN between 1989 and 2000, used conventional RF cavities and had a nominal acceleration gradient of 6 MV/m. “By accelerating electrons to 2 GeV in just 10 metres, AWAKE has demonstrated that it can achieve an average gradient of around 200 MV/m,” says Edda Gschwendtner, technical coordinator and CERN project leader for AWAKE. Gschwendtner and colleagues are aiming to attain an eventual acceleration gradient of around 1000 MV/m (or 1 GV/m).



AWAKE: Interview with Edda Gschwendtner, Technical Coordinator and CERN Project Leader

Video above: CERN project leader for AWAKE, Edda Gschwendtner, explains how the experiment accelerated electrons for the first time (Video: CERN).


AWAKE has made rapid progress since its inception. Civil-engineering works for the project began in 2014, and the plasma cell was installed in early 2016 in the tunnel formerly used by part of the CNGS facility at CERN. A few months later, the first drive beams of protons were injected into the plasma cell to commission the experimental apparatus, and a proton-driven wakefield was observed for the first time in late 2016. In late 2017, the electron source, electron beam line and electron spectrometer were installed in the AWAKE facility to complete the preparatory phase.


Now that they have demonstrated the ability to accelerate electrons using a proton-driven plasma wakefield, the AWAKE team is looking to the future. “Our next steps include plans for delivering accelerated electrons to a physics experiment and extending the project with a full-fledged physics programme of its own,” notes Patric Muggli, physics coordinator for AWAKE. AWAKE will continue testing the wakefield-acceleration of electrons for the rest of 2018, after which the entire accelerator complex at CERN will undergo a two-year shutdown for upgrades and maintenance. Gschwendtner is optimistic: “We are looking forward to obtaining more results from our experiment to demonstrate the scope of plasma wakefields as the basis for future particle accelerators.”


Note:


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.


The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.


Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.


Related links:


Journal Nature: https://doi.org/10.1038/s41586-018-0485-4


AWAKE collaboration at CERN: https://home.cern/about/experiments/awake


Super Proton Synchrotron (SPS): https://home.cern/about/accelerators/super-proton-synchrotron


CNGS: https://home.cern/about/accelerators/cern-neutrinos-gran-sasso


Large Hadron Collider (LHC): https://home.cern/topics/large-hadron-collider


For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/


Image (mentioned), Video (mentioned), Text, Credits: CERN/Achintya Rao.


Best regards, Orbiter.chArchive link


Hunting for dark quarks


CERN – European Organization for Nuclear Research logo.


31 Aug 2018



A proton–proton collision event with two emerging-jet candidates. (Image: CMS/CERN)

Quarks are the smallest particles that we know of. In fact, according to the Standard Model of particle physics, which describes all known particles and their interactions, quarks should be infinitely small. If that’s not mind-boggling enough, enter dark quarks – hypothetical particles that have been proposed to explain dark matter, an invisible form of matter that fills the universe and holds the Milky Way and other galaxies together.


In a recent study, the CMS collaboration describes how it has sifted through data from the Large Hadron Collider (LHC) to try and spot dark quarks. Although the search came up empty-handed, it allowed the team to inch closer to the parent particles from which dark quarks may originate.


One compelling theory extends the Standard Model to explain why the observed mass densities of normal matter and dark matter are similar. It does so by invoking the existence of dark quarks that interact with ordinary quarks via a mediator particle. If such mediator particles were produced in pairs in a proton–proton collision, each mediator particle of the pair would transform into a normal quark and a dark quark, both of which would produce a spray, or “jet”, of particles called hadrons, composed of quarks or dark quarks. In total, there would be two jets of regular hadrons originating from the collision point, and two “emerging” jets that would emerge a distance away from the collision point because dark hadrons would take some time to decay into visible particles.


In their study, the CMS researchers looked through data from proton–proton collisions collected at the LHC at an energy of 13 TeV to search for instances, or “events”, in which such mediator particles and associated emerging jets might occur. They used two distinguishing features to identify emerging jets and pick them out from a background of events that are expected to mimic their traits.



Large Hadron Collider (LHC). Animation Credit: CERN

The team found no strong evidence for the existence of such emerging jets, but the data allowed them to exclude masses for the hypothetical mediator particle of 400–1250 GeV for dark pions that travel for lengths between 5 and 225 mm before they decay. The results are the first from a dedicated search for such mediator particles and jets.


Note:


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.


The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.


Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.


Related links:


Standard Model of particle physics: https://home.cern/about/physics/standard-model


Dark matter: https://home.cern/about/physics/dark-matter


CMS experiment: https://home.cern/about/experiments/cms


Large Hadron Collider (LHC): https://home.cern/topics/large-hadron-collider


For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/


Image (mentioned), Animation (mentioned), Text, Credits: CERN/Achintya Rao.


Greetings, Orbiter.chArchive link


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