суббота, 13 октября 2018 г.

HiPOD (13 October 2018): Wrinkle Ridge on Olympus Mons   – This…


HiPOD (13 October 2018): Wrinkle Ridge on Olympus Mons


   – This wrinkle ridge has likely deflected older lava flows. (277 km above the surface, less than 5 km across)


NASA/JPL/University of Arizona


Plague of Marmots If you ever end up on a wildlife safari in…


Plague of Marmots


If you ever end up on a wildlife safari in central Asia, then watch out for Himalayan marmots – especially if they’re suspiciously still like this one spotted lying dead in a field in the Qinghai-Tibet plateau. As well as being the highest plateau in the world, it’s also one of the region’s highest risk areas for plague caused by infectious Yersinia pestis bacteria (the same bugs responsible for the Black Death), which is responsible for killing this poor rodent. Alarmingly, researchers have now discovered that Tibetan sheep can catch plague bacteria from dead marmots – maybe by licking them to extract extra nutrients or from fleas – and can also transfer them on to humans. Since the first marmot with plague was identified in 1954, there have been nearly 500 human plague cases and 240 deaths, suggesting that this is a significant route for transmission of the disease and needs further investigation.


Written by Kat Arney



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After Two Long Careers, QuikSCAT Rings Down the Curtain


NASA – SeaWinds scatterometer QuikSCAT Mission patch.


October 13, 2018


Launched in June 1999 for an intended two-year mission, NASA’s SeaWinds scatterometer instrument on the QuikSCAT spacecraft was turned off on Oct. 2 in accordance with its end-of-mission plan. QuikSCAT spent its first decade creating an unprecedented record of the speed and direction of winds at the ocean surface. Then, for another nine years, it served as the gold standard of accuracy against which new spaceborne scatterometers were calibrated.



Image above: QuikSCAT imaged winds during many storms, including Hurricane Katrina, shown here covering the Gulf of Mexico in August 2005. Highest wind speeds appear purple, with winds weakening outward from the eye. Barbs show wind direction; white barbs indicate heavy rainfall. Image Credits: NASA/JPL-Caltech.


Managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, QuikSCAT was a unique national resource that far surpassed NASA’s original science objective for the mission. During its 10 years of observing winds over the global ocean surface, QuikSCAT measurements were used by the world’s weather forecasting agencies to improve forecasts and identify and monitor hurricanes and other storms far out in the open seas. Its data also provided critical information for monitoring, researching, modeling, and forecasting the atmosphere, ocean, ice and climate.


Among its many accomplishments:


• QuikSCAT discovered that hurricane-strength winds occur frequently in the North Atlantic and North Pacific oceans, where such strong winds were not previously expected to exist.


• It provided high-resolution observations of the dramatically accelerating changes in sea ice cover on the Arctic Ocean.


• The mission’s measurements were used widely beyond weather forecasting and research — for example, to help identify efficient shipping routes, plan new offshore wind farms, and guide search-and-rescue operations at sea.


Michael Freilich, the QuikSCAT mission’s original principal investigator and now director of NASA’s Earth Science Division, noted, “QuikSCAT operated in space for nearly two decades, and we are certain that its impact and legacy will last much longer.”


Ernesto Rodríguez, QuikSCAT project scientist at JPL, said, “The decommissioning of QuikSCAT marks the passing of an era. Many scientists and forecasters have built their careers over the last 20 years using QuikSCAT. Its data led to major discoveries on the interaction between the ocean and the atmosphere.”


A few months after QuikSCAT’s 10th anniversary, an age-related problem caused its spinning antenna to stop rotating, reducing its observing swath to only 19 miles (30 kilometers) wide. The extreme accuracy of this narrow swath measurement, however, allowed QuikSCAT to take on a second mission: calibrating newer satellites to enable a much longer data record of ocean winds.



SeaWinds scatterometer QuikSCAT spacecraft. Image Credits: NASA/JPL

Satellite instruments are regularly calibrated to ensure their readings match other data that are known to be accurate, and to correct for an instrument’s normal drift in accuracy over time. QuikSCAT’s exceptional stability made it invaluable in assuring that newer missions from the Indian and European space agencies and from NASA are providing apples-to-apples measurements. This function proved so important to the research community that QuikSCAT’s decommissioning was postponed twice to allow time for new scatterometers to be launched and calibrated.


QuikSCAT project manager Rob Gaston of JPL said, “It’s a testament to the research community’s commitment to climate research that QuikSCAT’s intercalibration mission has continued to receive the highest possible marks for science relevance in the reviews that NASA follows to establish funding priorities for missions like QuikSCAT. The intercalibration mission has enabled research that would not have been possible but for the remarkable stability of the SeaWinds instrument and the exceptional reliability and longevity of the QuikSCAT spacecraft.”


QuikSCAT was originally a recovery mission after the loss of Japan’s Advanced Earth Observing Satellite, which hosted the NASA Scatterometer (NSCAT). The QuikSCAT mission was conceived, developed and launched in less than two years. Ball Aerospace & Technologies Corp. in Boulder, Colorado, built the spacecraft bus, and JPL designed and built the SeaWinds instrument. QuikSCAT was operated by the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.


NASA & JPL QuikSCAT: https://winds.jpl.nasa.gov/missions/quikscat/


ESA QuikSCAT: https://earth.esa.int/web/eoportal/satellite-missions/q/quikscat


Images (mentioned), Text, Credits: NASA/JPL/Esprit Smith/NASA’s Earth Science News Team, written by Carol Rasmussen.


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2018 October 13 Skygazers on the Beach Image Credit &…


2018 October 13


Skygazers on the Beach
Image Credit & Copyright: Jack Fusco


Explanation: Kona, a young boxer, is a dog who loves splashing in the waves along Solana Beach near San Diego, planet Earth. But he paused here, at least briefly, during an early evening romp on October 7. Along with two people friends he gazes skyward in this snapshot, dazzled by the flight of a Falcon 9 rocket. Their seaside view is of the sunlit exhaust plumes from the rocket’s first stage thrusters as it returns to Vandenberg Air Force base, its launch site over 250 miles to the north.


∞ Source: apod.nasa.gov/apod/ap181013.html


Update on Opportunity Rover after Martian Dust Storm


NASA – Mars Exploration Rover B (MER-B) patch.


Oct. 12, 2018


One month since increasing their commanding frequency, engineers have yet to hear from NASA’s Opportunity rover.


NASA hasn’t set any deadlines for the mission but will be briefed later this month on the progress and prospects for the recovery campaign being carried out at the agency’s Jet Propulsion Laboratory in Pasadena, California.


JPL engineers are employing a combination of listening and commanding methods in case Opportunity is still operational. It’s possible that a layer of dust deposited on the rover’s solar panels by the recent global dust storm is blocking sunlight that could recharge its batteries. No one can tell just how much dust has been deposited on its panels.



Animation above: Side-by-side movies shows how dust has enveloped the Red Planet, courtesy of the Mars Color Imager (MARCI) wide-angle camera onboard NASA’s Mars Reconnaissance Orbiter (MRO). Animation Credits: NASA/JPL-Caltech/MSSS.


A windy period on Mars — known to Opportunity’s team as “dust-clearing season” — occurs in the November-to-January time frame and has helped clean the rover’s panels in the past. The team remains hopeful that some dust clearing may result in hearing from the rover in this period.


Opportunity has exceeded its expected lifespan many times over. Both Opportunity and its twin, Spirit, were designed to last only 90 days on the Martian surface, with the expectation that the planet’s extreme winters and dust storms could cut their mission short. The rover has lasted nearly 15 years: It last communicated on June 10 before being forced into hibernation by the growing dust storm.


Updated at 2:45 p.m. PDT on Sept. 11, 2018


Scientists reviewing data from the Mars Color Imager (MARCI) aboard NASA’s Mars Reconnaissance Orbiter (MRO) have determined that the tau estimate (a measure of the amount of haze in the Martian atmosphere) in the skies above the rover Opportunity has been below 1.5 for two consecutive measurements. With more sunlight reaching the rover’s solar array, the Opportunity team at NASA’s Jet Propulsion Laboratory in Pasadena, California, are increasing the frequency of commands it beams to the 14-plus-year-old rover via the dishes of NASA’s Deep Space Network from three times a week to multiple times per day. Passive listening for Opportunity will also continue to be performed by JPL’s Radio Science Group, which records radio signals emanating from Mars with a very sensitive broadband receiver.


The original story has been updated in paragraph six to reflect NASA review at each step of the recovery process. Updates on the 2018 dust storm and tau can be found here.


A planet-encircling dust storm on Mars, which was first detected May 30 and halted operations for the Opportunity rover, continues to abate.


With clearing skies over Opportunity’s resting spot in Mars’ Perseverance Valley, engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, believe the nearly 15-year-old, solar-powered rover will soon receive enough sunlight to automatically initiate recovery procedures — if the rover is able to do so. To prepare, the Opportunity mission team has developed a two-step plan to provide the highest probability of successfully communicating with the rover and bringing it back online.



Image above: Opportunity’s panoramic camera (Pancam) took the component images for this view from a position outside Endeavor Crater during the span of June 7 to June 19, 2017. Toward the right side of this scene is a broad notch in the crest of the western rim of crater. Image Credits: NASA/JPL-Caltech/Cornell/Arizona State Univ.


“The Sun is breaking through the haze over Perseverance Valley, and soon there will be enough sunlight present that Opportunity should be able to recharge its batteries,” said John Callas, Opportunity project manager at JPL. “When the tau level [a measure of the amount of particulate matter in the Martian sky] dips below 1.5, we will begin a period of actively attempting to communicate with the rover by sending it commands via the antennas of NASA’s Deep Space Network. Assuming that we hear back from Opportunity, we will begin the process of discerning its status and bringing it back online.”


The rover’s last communication with Earth was received June 10, and Opportunity’s current health is unknown. Opportunity engineers are relying on the expertise of Mars scientists analyzing data from the Mars Color Imager (MARCI) aboard NASA’s Mars Reconnaissance Orbiter (MRO) to estimate the tau near the rover’s position.


“The dust haze produced by the Martian global dust storm of 2018 is one of the most extensive on record, but all indications are it is finally coming to a close,” said MRO Project Scientist Rich Zurek at JPL. “MARCI images of the Opportunity site have shown no active dust storms for some time within 3,000 kilometers [about 1,900 miles] of the rover site.”


With skies clearing, mission managers are hopeful the rover will attempt to call home, but they are also prepared for an extended period of silence. “If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” said Callas. At that point, the team will report to NASA HQ to determine whether to continue with the strategy or adjust it. Callas added, “In the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”


The additional several months for passive listening are an allowance for the possibility that a Red Planet dust devil could come along and literally dust off Opportunity’s solar arrays. Such “cleaning events” were first discovered by Mars rover teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity increased by several percent during a single Martian night, when the logical expectation was that they would continue to decrease. These cleaning dust devils have even been imaged by both rovers on the surface and spacecraft in orbit (see https://www.youtube.com/watch?v=k8lfJ0c7WQ8 and  https://mars.nasa.gov/resources/5307/the-serpent-dust-devil-of-mars/).


The chances are small that dust accumulation would be the root cause of Opportunity’s lack of communication. Nonetheless, each day during the passive phase, JPL’s Radio Science group will scour the signal records taken by a very sensitive broadband receiver of radio frequencies emanating from Mars, looking for a sign that the rover is trying to reach out.



Mars Exploration Rover (MER): Image Credits: NASA/JPL-Caltech/AP

Even if the team hears back from Opportunity during either phase, there is no assurance the rover will be operational. The impact of this latest storm on Opportunity’s systems is unknown but could have resulted in reduced energy production, diminished battery performance, or other unforeseen damage that could make it difficult for the rover to fully return online.


While the situation in Perseverance Valley is critical, the rover team is cautiously optimistic, knowing that Opportunity has overcome significant challenges during its 14-plus years on Mars. The rover lost use of its front steering — its left-front in June of 2017, and right front in 2005. Its 256-megabyte flash memory is no longer functioning. The team also knows that everything about the rover is well beyond its warranty period — both Opportunity and its twin rover, Spirit, were constructed for 90-day missions (Spirit lasted 20 times longer and Opportunity is going on 60 times). The rovers were designed to travel about 1,000 yards, and Opportunity has logged more than 28 miles. Through thick and thin, the team has seen their rover soldier on. Now, Opportunity engineers and scientists of Opportunity are planning, and hoping, that this latest dilemma is just another bump in their Martian road.


“In a situation like this you hope for the best but plan for all eventualities,” said Callas. “We are pulling for our tenacious rover to pull her feet from the fire one more time. And if she does, we will be there to hear her.”


Updates on the dust storm and tau can be found here: https://mars.nasa.gov/mer/mission/status_opportunityAll.html


JPL, a division of Caltech in Pasadena, built Opportunity and manages the mission for NASA’s Science Mission Directorate, Washington.


Related articles:


Martian Skies Clearing over Opportunity Rover:
https://orbiterchspacenews.blogspot.com/2018/08/martian-skies-clearing-over-opportunity.html


Six Things About Opportunity’s Recovery Efforts:
https://orbiterchspacenews.blogspot.com/2018/08/six-things-about-opportunitys-recovery.html


NASA Mars Exploration Rover Status Report:
https://orbiterchspacenews.blogspot.com/2018/08/nasa-mars-exploration-rover-status.html


Shades of Martian Darkness:
https://orbiterchspacenews.blogspot.com/2018/06/shades-of-martian-darkness.html


Opportunity Hunkers Down During Dust Storm:
https://orbiterchspacenews.blogspot.com/2018/06/opportunity-hunkers-down-during-dust.html


For more information about Opportunity, visit:


https://www.nasa.gov/rovers


https://marsrovers.jpl.nasa.gov


Animation (mentioned), Images (mentioned), Text, Credits: NASA/JoAnna Wendel/Tony Greicius/JPL/DC Agle/Andrew Good.


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Chandra Enters Safe Mode; Investigation Underway


NASA – Chandra X-ray Observatory patch.


Oct. 12, 2018


At approximately 9:55 a.m. EDT on Oct. 10, 2018, NASA’s Chandra X-ray Observatory entered safe mode, in which the observatory is put into a safe configuration, critical hardware is swapped to back-up units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun. Analysis of available data indicates the transition to safe mode was normal behavior for such an event. All systems functioned as expected and the scientific instruments are safe. The cause of the safe mode transition (possibly involving a gyroscope) is under investigation, and we will post more information when it becomes available.



Artist’s concept of Chandra X-ray Observatory. Image Credits: NASA/CXC/SAO

Chandra is 19 years old, which is well beyond the original design lifetime of 5 years. In 2001, NASA extended its lifetime to 10 years. It is now well into its extended mission and is expected to continue carrying out forefront science for many years to come.


Chandra X-Ray Observatory: https://www.nasa.gov/mission_pages/chandra/main/index.html


Image (mentioned), Text, Credits: NASA/Brian Dunbar.


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HiPOD (12 October 2018): A Linear Vent and Flows to the…



HiPOD (12 October 2018): A Linear Vent and Flows to the Southeast of Zunil Crater


   – This is located within the Elysium quadrangle on Mars, a region with a volcanic past that for which we can still see evidence of old lava flows. (279 km above the surface, less than 5 km across.)


NASA/JPL/University of Arizona


Inktober Sketch, 12.10.18.


Inktober Sketch, 12.10.18.


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Researchers solve mystery at the center of the Milky Way

Astronomers from Lund University in Sweden have now found the explanation to a recent mystery at the centre of the Milky Way galaxy: the high levels of scandium discovered last spring near the galaxy’s giant black hole were in fact an optical illusion.











Researchers solve mystery at the center of the Milky Way
The Milky Way [Credit: ESO/R.Schoedel]

Last spring, researchers published a study about the apparent presence of astonishing and dramatically high levels of three different elements in red giant stars, located less than three light years away from the big black hole at the centre of our galaxy. Various possible explanations were presented, for example that the high levels were a result of earlier stars being disrupted as they fall into the black hole, or a result of debris from the collisions of neutron stars.


Now another group of astronomers from Lund University among others, in collaboration with UCLA in California, have found an explanation for the high levels of scandium, vanadium and yttrium. They argue that the so-called spectral lines presented last spring were actually an optical illusion. Spectral lines are used to find out which elements a star contains – by using its own light.


“These giant red stars have used up most of their hydrogen fuel and their temperatures are therefore only half of the sun’s”, says Brian Thorsbro, lead author of the study and doctoral student in astronomy at Lund University.


According to the new study, the lower temperatures of the giant stars helped to create the optical illusion that appeared in the measurements of spectral lines. Specifically, it means that the electrons in the elements behave differently at different temperatures, which in turn can be misleading when measuring the spectral lines of elements in different stars. The conclusion is the result of a close collaboration between astronomers and atomic physicists.


Brian Thorsbro and his colleagues have had the world’s largest telescope, at the W. M. Keck Observatory on Mauna Kea, Hawaii, at their disposal, thanks to their collaboration with R. Michael Rich at UCLA. Using this telescope and others, the research team is currently conducting a comprehensive mapping of the central areas of the Milky Way, exploring the spectral lines in the light from different stars to find out which elements they contain. The purpose is to gain an understanding of the events that have occurred in the history of the Milky Way, but also to understand how galaxies in general have formed.


“Our research collaboration is world-leading in terms of systematically mapping the elements contained in the huge central star cluster – the star cluster that surrounds the black hole”, says research leader and astronomer Nils Ryde at Lund University.


The spectral lines for different elements are recorded in a high-resolution spectrometer – an advanced camera that generates a rainbow of the starlight. The research team has studied the part of the spectrum consisting of near-infrared light, i.e. the heat radiation emitted by the stars. The reason for this is that infrared light can penetrate the dust that obstructs the line-of-sight between us and the centre of the Milky Way, approximately 25 000 light years away. The technology for recording this light is very advanced, and has only recently become available to astronomers.


“We have only started to map the stellar compositions in these central areas of the Milky Way”, says Nils Ryde.


Source: Lund University [October 10, 2018]




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String theory: Is dark energy even allowed?

In string theory, a paradigm shift could be imminent. In June, a team of string theorists from Harvard and Caltech published a conjecture which sounded revolutionary: String theory is said to be fundamentally incompatible with our current understanding of “dark energy” — but only with “dark energy” can we explain the accelerated expansion of our current universe.











String theory: Is dark energy even allowed?
The ESA mission Euclid is supposed to gain new insights into fundamental questions concerning string theory
[Credit: ESA/C. Carreau and CERN/J. Ellis]

Timm Wrase of the Vienna University of Technology quickly realized something odd about this conjecture: it seemed to be incompatible with the existence of the Higgs particle. His calculations, which he carried out together with theorists from Columbia University in New York and the University of Heidelberg, have now been published in Physical Review D. At the moment, there are heated discussions about strings and dark energy all around the world. Wrase hopes that this will lead to new breakthroughs in this line of research.


The theory for everything


Great hope is placed in string theory. It is supposed to explain how gravity is related to quantum physics and how we can understand the laws of nature, which describe the entire physical world, from the smallest particles to the largest structure of the cosmos.


Often, string theory has been accused of merely providing abstract mathematical results and making too few predictions that can actually be verified in an experiment. Now, however, the string theory community all around the world is discussing a question that is closely related to cosmic experiments measuring the expansion of the universe. In 2011, the Nobel Prize in Physics was awarded for the discovery that the universe is not only constantly growing larger, but that this expansion is actually accelerating.


This phenomenon can only be explained by assuming an additional, previously unknown “dark energy.” This idea originally came from Albert Einstein, who added it as a “cosmological constant” to his theory of general relativity. Einstein actually did this to construct a non-expanding universe. When Hubble discovered in 1929 that the universe was in fact expanding, Einstein described this modification of his equations as the biggest blunder of his life. But with the discovery of the accelerated expansion of the cosmos, the cosmological constant has been reintroduced as dark energy into the current standard model of cosmology.


Like an apple in the fruit bowl


“For a long time, we thought that such a dark energy can be well accommodated in string theory,” says Timm Wrase from the Institute for Theoretical Physics of the Vienna University of Technology. String theory assumes that there are additional, previously unknown particles that can be described as fields.


These fields have a state of minimal energy — much like an apple lying in a bowl. It will always lie at the very bottom, at the lowest point of the bowl. Everywhere else its energy would be higher, if we want to shift it, we have to exert energy. But that does not mean that the apple at the lowest point has no energy at all. We can put the bowl with the apple on the ground, or on top of the table — there the apple has more energy but it still cannot move, because it is still in a state of minimal energy in its bowl.


“In string theory there are fields which could explain dark energy in a similar way — locally, they are in a state of minimal energy, but still their energy has a value greater than zero,” explains Timm Wrase. “So these fields would provide the so-called dark energy, with which we could explain the accelerated expansion of the universe.”


But Cumrun Vafa from Harvard University, one of the world’s most renowned string theorists, published an article on June 25, raising many eyebrows. He suggested that such “bowl-shaped” fields of positive energy are not possible in string theory.


The Higgs field – a contradiction


Timm Wrase of the Vienna University of Technology quickly realized the implications of this claim: “If that is true, the accelerated expansion of the universe, as we have imagined it so far, is not possible” he says. “The accelerated expansion would then have to be described by a field with quite different properties, like a tilted plane on which a ball rolls downhill, losing potential energy.” But in that case, the amount of “dark energy” in the universe would change over time, and the accelerated expansion of the universe may one day come to a halt. Gravity could then pull all matter back together and assemble everything at one point, similar to the time of the Big Bang.


But Timm Wrase, who had already dealt with similar questions in his doctoral thesis, found that this idea cannot be the whole truth either. “Cumrun Vafa’s conjecture, which prohibits certain types of fields, would also prohibit things that we already know to exist,” he explains.


Wrase was able to show that the Higgs field also has properties that should actually be forbidden by Vafa’s conjecture — and the Higgs field is considered an experimentally proven fact. For its discovery, the 2013 Nobel Prize in Physics was awarded. Wrase uploaded his results to the preprint website Arxiv, quickly sparking a lot of discussions in the string theory community. Now the work has been peer reviewed and published in the journal Physical Review.


“This controversy is a good thing for string theory,” Timm Wrase is convinced. “Suddenly, a lot of people have completely new ideas which nobody has thought about before.” Wrase and his team are now investigating which fields are allowed in string theory and at which points they violate Vafa’s conjecture. “Maybe that leads us to exciting new insights into the nature of dark energy — that would be a great success,” says Wrase.


The hypotheses that arise will (at least in part) soon be tested experimentally. In the next few years the accelerated expansion of the universe will be measured more accurately than ever before.


Source: Vienna University of Technology [October 10, 2018]



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Galactic archaeology

The star Pristine 221.8781+9.7844 is one of the oldest stars in the Milky Way. We know this because of its atmosphere. Just after the Big Bang the universe was full of hydrogen and helium with very little lithium there were no heavier elements because these are synthesized in the interiors of stars. David Aguado´s view is that “As the atmosphere of the star we have analyzed is very poor in metals, we can say with confidence that this is one of the oldest objects in the Milky Way, and of course it is much older than the Sun” and he adds that “This star will help us to better understand certain features of the origin of the Milky Way and how the first stars formed”











Galactic archaeology
The star Pristine 221.8781 + 9.7844 was formed from the material ejected by these first supernovas
[Credit: Gabriel Pérez, SMM (IAC)]

To reach this conclusion detailed studies have been performed with the ISIS spectrograph on the William Herschel Telescope and with the IDS spectrograph on the Isaac Newton Telescope, both belonging to the Isaac Newton Group of Telescopes (ING) at the Roque de los Muchachos Observatory (Garafía, La Palma).
“The spectroscopic data with intermediate resolution obtain on the INT and the WHT, telescopes on La Palma have allowed us to show the low content of carbon, which is usually very abundant in this type of stars” explains Carlos Allende, a Professor at the IAC and one of the researchers in this project.


The study of these very old stars, which have been catalogued and analysed in the Pristine survey, led from the Leibniz Institute of Astrophysics (Potsdam, Germany) and from the University of Strasbourg (France), help us to learn more about the state of the universe in its early days, just after the Big Bang.











Galactic archaeology
Spectrum of the star Pristine 221.8781 + 9.7844 as observed with the ISIS instrument
of the William Herschel telescope [Credit: Else Starkenburg]

To make the first detections of these stars, which are survivors from the first stages of the universe, and have pristine atmospheres, the team used a special colour filter on the Canada-France-Hawaii Telescope (CFHT) on the top of Mauna Kea (Hawaii).
In this study has been used high-resolution spectroscopy obtained with the UVES spectrograph in the VLT telescope (Paranal, ESO).


“The high resolution spectroscopic data from UVES and the VLT have allowed us to measure the abundance of lithium in the atmosphere of this star, which gives us additional information about the origin of the universe” says Jonay González, a Ramon and Cajal researcher of the IAC and a collaborator in the Pristine project.


The study is published in Monthly Notices of the Royal Astronomical Society.


Source: Instituto De Astrofísica De Canarias (IAC) [October 10, 2018]



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Evolutionary ‘arms race’ — how dolphins and whales fight disease...

Dolphins, whales and other cetaceans are susceptible to many of the same health hazards as humans including mercury, brevotoxin (e.g. Red Tide), and lobomycosis. They also serve as important sentinel species to highlight concerns relevant to environmental and public health. Yet understanding how these aquatic mammals fight disease-causing pathogens, how they adapt to changing pathogenic threats, and how their immune responses are triggered has been challenging.











Evolutionary 'arms race' -- how dolphins and whales fight disease threats
Bottlenose dolphins reside in nearshore waters along Florida’s Atlantic coast as well as in a number of estuaries,
bays, and lagoons. As pathogenic threats and the risk of infectious disease changes, whales and dolphins
must adapt to those changes [Credit: Wendy Noke, NOAA permit no. 572-1869-02]

Two recent papers by Florida Atlantic University researchers reveal how cetaceans compete for survival in an evolutionary “arms race” with changing pathogen communities. As pathogenic threats and the risk of infectious disease changes, whales and dolphins must adapt to those changes. The question today is can they adapt fast enough?


In a groundbreaking study published in PLOS One, researchers from FAU’s Harbor Branch Oceanographic Institute found that cetaceans use several strategies for success in this evolutionary arms race. The immune response in vertebrates is mediated through a series of rapidly evolving genes called the major histocompatibility complex or MHC. The MHC acts as an early warning system against pathogens that not only sounds the alarm, but also activates an armed response. In order to do this, MHC proteins need to be able to distinguish “friend” from “foe” at a molecular level. Similar to a lock-and-key mechanism, an individual’s MHC ‘lock’ has to be able to bind to a pathogen’s peptide ‘key’ to launch the defense sequence.


The FAU team found that not only are these cetaceans preserving genetic diversity in the types of locks, that is, the conformation of the binding pockets that help trigger the immune response, they also are selecting for diversity in how to regulate the production of the many locks that are needed. MHC is regulated to prevent too much activity, where the immune system might attack one’s own cells as well as too little activity, where the immune system does not react quickly or strongly enough to a real threat.


“This is the first attempt within cetacean populations to use both MHC conformation and regulatory genetic variation as early indicators for disease susceptibility,” said Heidi J.T. Pagan, Ph.D., lead author of the study and a research associate at FAU’s Harbor Branch.


Pagan and collaborators wanted to develop a more comprehensive MHC marker system for cetaceans and combine traditional and next generation sequencing methods for genotyping. They applied this marker system to investigate the evolutionary and demographic forces shaping dolphin MHC diversity in contrasting estuarine and marine habitats.


By combining these genetic data with an immunoproteomic approach developed by Colette T. Dooley, Ph.D., at Torrey Pines Institute for Molecular Studies, the researchers now have a much more inclusive picture of how whales and dolphins are continuing to adapt to their current pathogenic environment.


Dooley applied immunogenetic and immunoproteomic techniques and model combinatorial libraries to figure out what types of peptides (‘keys’) the MHC found in estuary and coastal bottlenose dolphins in Florida were capable of recognizing. From there, she used bioinformatics to determine what microorganisms likely produce these signature molecules.


“For the first time, we have a clear idea of the pathogens involved, and we now have a roadmap for research teams working on other species, including humans, to use to get there,” said Dooley, who published these findings with the FAU team in PLOS One in August. “These insights will enable us to improve predictions of population health for these cetaceans that are exposed to a particular disease threat.”


Bottlenose dolphins reside in nearshore waters along Florida’s Atlantic coast as well as in a number of estuaries, bays, and lagoons, including the 256 kilometer-long Indian River Lagoon (IRL) Estuary System. Coastal populations have been found to be demographically and genetically distinct from a number of these embayed and lagoon populations, although some gene flow and movement also has been documented.


Chemical contamination, high nutrient input, decreased salinity, loss of sea grass habitat, and eutrophication have all culminated in poor habitat quality in the IRL Estuary System. Disparity between populations and even individual susceptibility to diseases has been documented for several cetaceans and is often linked to concentrations of immunosuppressive contaminants.


“With these breakthroughs, we now finally have the tools to assist wildlife managers and health professionals assess disease risk from the perspective of how individual animals are engineered to recognize the molecules of microorganisms in the environment and launch an immune response,” said research team lead Greg O’Corry-Crowe, Ph.D., a research professor at FAU’s Harbor Branch. “We now need to bring these tools directly into the field and to apply them to other species.”


In 2013, an unusual number of Atlantic bottlenose dolphins died along the east coast of Florida all the way down to the Florida Keys. Yet dolphins in the Gulf of Mexico were not affected. This suggested to the researchers that multiple factors may influence the spatial variation of disease transmission and affect neighboring populations to varying degrees.


“Although we have learned a lot about variation in the kinds of ‘locks’ vertebrate populations possess, we knew very little about the confirmation of pathogenic ‘keys’ until now,” said O’Corry-Crowe.


“This issue has become a huge obstacle in applying studies of MHC diversity to real-world assessments of the capabilities of wild populations to deal with disease threats.”


Source: Florida Atlantic University [October 10, 2018]



TANN



Archive


A genome under influence: The faulty yardstick in genomics studies and how to cope with...

References form the basis of our comprehension of the world: they enable us to measure the height of our children or the efficiency of a drug. But when such yardsticks are faulty, doubts are cast on all the measurements that derive from them. Geneticists too use standards to reconstruct the history of a species or to evaluate the impact of mutations, in the form of genetic markers scattered throughout the genome. Provided these markers are neutral, i.e. that they have evolved randomly rather than through a selective process, they can be reliably used as “standards” to compare various parameters across populations.











A genome under influence: The faulty yardstick in genomics studies and how to cope with it
Setting a standard of reference: creation of the metre-alloy
 in 1874 at the Conservatoire des Arts et Métiers
[Credit: Swiss Institute of Bioinformatics]

However, what scientist Fanny Pouyet and colleagues from the Group of Laurent Excoffier at the SIB Swiss Institute of Bioinformatics and University of Bern recently discovered, is that 95% of our genome actually seems to be affected by selection and other genetic biases and that markers previously thought to be neutral appear to provide skewed estimates. Their study, published in eLife, calls for the re-examination of a plethora of results and provides the tools and recommendations to correct such issues in the future.
Not so neutral after all: 95% of our genome under influence


Models used to reconstruct the history of a species or to discover how populations are related to one another rely on a key assumption: that the genome regions under scrutiny are made of “neutral” snippets of DNA, i.e. parts that have evolved randomly rather than being selected for or against. But these regions might actually not be as neutral as previously thought, according to a recent finding by scientists at SIB and the University of Bern: “What we find is that less than 5% of the human genome can actually be considered as “neutral”,” says Fanny Pouyet, lead author of the study. “This is a striking finding: it means that 95% of the genome is indirectly influenced by functional sites, which themselves represent only 10% to 15% of the genome,” she concludes. These functional sites encompass both genes and regions involved in gene regulation.


A “universal” recipe for neutral markers


Scientists have long devised the best way to obtain “unbiased” sets of genomic markers and several such sets are routinely used in genetic studies. The study of Pouyet and colleagues now sheds concern on the reliability of these markers. “We re-examined all existing sets of markers presented as “neutral” and found that they provided, under one aspect or another, skewed estimates” indicates Pouyet. The team then went on to identify a new set of markers that matched, this time, all the neutrality criteria, using two whole genome datasets of over a hundred individuals in total. This neutral dataset has now been made available for humans, but the method could in theory be used to find such markers in any other species.


Calling for a re-examination of genetic studies


How has the use of non-neutral markers affected demographic inferences so far? In order to obtain an initial assessment of the situation, the team compared the outcomes of the use of non-neutral vs. neutral markers in the context of contemporary African and Japanese populations. “We found that such bias could lead one to wrongly infer that populations of constant size have grown, or to overlook events that drastically reduce the size of a population,” Excoffier points out. “While the nature and extent of the bias is difficult to predict for a given population, one thing that is certain is that the demography of all human populations should be re-examined on the basis of the new set of neutral markers. Actually not only demography: a biased neutral reference could also affect the measure of the impact of mutations,” he concludes.


Source: Swiss Institute of Bioinformatics [October 10, 2018]



TANN



Archive


Impressive new finds at Akrotiri on Greek island of Santorini

Significant new finds have been unearthed during the ongoing excavation directed by Prof. Christos Doumas at Akrotiri, Thira, which are sponsored by the Kaspersky Lab and taking place under the auspices of the Archaeological Society at Athens.











Impressive new finds at Akrotiri on Greek island of Santorini

Credit: Hellenic Ministry of Culture/Cyclades Ephorate



According to a culture ministry announcement, the finds were made under rubble inside a large and probably public building known as the ‘House of Benches’ that is south of Xeste 3, near where the golden ibex now on display at the Museum of Prehistoric Thira was also found (1999) inside a clay chest beside a pile of animal horns.
Following the gradual revealing and cleaning of the small chest in the northwest corner of the space, a marble Proto-Cycladic female figurine was found placed diagonally along the bottom of the vessel.


From the group of chests in the southeast corner of the space, three were uncovered, of which the two smallest were filled with egg-shaped masses of clay while the largest contained two small marble Proto-Cycladic collared jars, placed upside down, a marble vial and an alabaster vase, the announcement said.


Impressive new finds at Akrotiri on Greek island of Santorini

Impressive new finds at Akrotiri on Greek island of Santorini










Impressive new finds at Akrotiri on Greek island of Santorini
Credit: Hellenic Ministry of Culture/Cyclades Ephorate


Impressive new finds at Akrotiri on Greek island of Santorini

Impressive new finds at Akrotiri on Greek island of Santorini










Impressive new finds at Akrotiri on Greek island of Santorini

Credit: Hellenic Ministry of Culture/Cyclades Ephorate



According to the ministry, the ongoing excavation at Akrotiri was gradually unveiling an area where ritual acts were performed that was very close to Xeste 3, an important public building decorated with rich murals at the southern edge of the settlement.
These finds are undoubtedly linked to the views and beliefs of Thiran society and provide a stimulus for a new interpretive drive on fundamental questions about the ideology and possibly the religion of prehistoric Aegean society, the announcement said.


Source: The Greek Ministry of Culture [October 12, 2018]



TANN



Archive


Seeing Genes The first interaction we have with the visual…


Seeing Genes


The first interaction we have with the visual world around us is via a thin but distinct layer of cells in the retina, the light-sensitive tissue at the back of our eyes. Our brain’s ability to make sense of the visible environment relies on how these retinal cells (purple) and the nerves that connect them (green and red) are organised. For us to see properly, this circuitry must be precisely and accurately ordered. And now researchers have identified 16 genes responsible for controlling this systematic arrangement. These genes also help to ensure retinal cells have a good blood supply, so they can function properly. Since many of these 16 genes are linked to various diseases of the eye, the discovery may even pave the way for new potential therapies to treat retinal diseases.


Today is World Sight Day


Written by Gaëlle Coullon



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Practising for BepiColombo’s epic escape to Mercury


ESA – BepiColombo Mission patch.


12 October 2018


The international BepiColombo spacecraft will soon take flight, on a complex journey to the innermost planet of the Solar System, Mercury. Encompassing nine planetary flybys and travelling a total distance of nine billion km over a period of seven years, this will be one of the most intricate journeys ever flown by mission teams at ESA’s ESOC mission control centre.



BepiColombo at Mercury

With launch set for 20 October, flight controllers led by Operations Manager Elsa Montagnon are now busily preparing for the start of what will be Europe’s first mission to Mercury — the smallest and least explored terrestrial planet of the Solar System.


“Mission teams have spent months simulating BepiColombo’s unique and complex journey,” explains Elsa.



BepiColombo teams in training for voyage to Mercury

“Taking turns, in 12-hour shifts, we have been practising the spacecraft’s various launch and early mission processes and manoeuvres in real-time so we are prepared for every possible eventuality.”


BepiColombo is a joint mission between ESA and the Japan Aerospace Exploration Agency (JAXA). The mission comprises two science orbiters: ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO).


The ESA-built Mercury Transfer Module (MTM) will carry the orbiters to Mercury using a combination of solar electric propulsion and gravity assist flybys.



BepiColombo exploded view

After its arrival at the planet of extremes in 2025, it will spend at least a year in orbit gathering data on Mercury’s composition, density, magnetic field and exosphere, as well as probing the planet’s interaction with solar wind.


Before the science begins, however, the multi-module spacecraft has to safely escape Earth, switch on, and receive instructions from mission control on where to go next.


A rocky road


Europe’s space scientists have identified BepiColombo as one of the most challenging long-term planetary projects ever flown, as Mercury’s proximity to the Sun makes it difficult for spacecraft to reach without being pulled into the star’s enormous gravity.



Animation visualising BepiColombo’s journey to Mercury

“To get to Mercury without being subsumed by our giant star, the spacecraft will make a series of nine planetary flybys; circling Earth once, Venus twice, and Mercury itself six times,” explains Andrea Accomazzo, Flight Director for BepiColombo.


“Unlike missions that take spacecraft to the outer regions of the Solar System, the Mercury Transfer Module will use the gravity of these inner planets, in combination with the thrust provided by electric propulsion, to slow the spacecraft down.”


The Sun’s huge gravity field acts as an enormous gravity ‘well’. Getting a spacecraft to Mercury, and therefore close to the Sun, means dropping it into this steep well – the difficulty comes in ensuring the spacecraft ends up at Mercury and not at our gigantic star.


“The closer we get to the Sun the more we are constricted in our path,” explains Frank Budnik from the Flight Dynamics team.



BepiColombo cruise configuration

“For example, BepiColombo’s large solar arrays need to be tilted at just the right angle to get enough sunlight to power the high-energy demand of the propulsion system and keeping the spacecraft running. At the same time, they mustn’t get too much sunlight, or they could be beyond their limits.”


“There is only a small corridor in which the solar arrays can be operated to fulfil both of these constraints.”


BepiColombo will launch at 01:45 GMT (03:45 CEST) on 20 October, on board an Ariane 5 rocket. After the spacecraft separates from the rocket’s ‘upper stage’, teams at ESOC will take control, sending commands to the spacecraft to get it into normal operational mode — a process that is expected to take about four days.


This period, dubbed the ‘Launch and Early Orbit Phase’ (LEOP), sees the control systems and instruments switched on, and their health and proper functioning assessed.


This is a risky time when the satellite is unusually vulnerable — not yet fully functional but still exposed to the hazards of space.


Simulating the scene


In preparation for this vital period, mission control teams have spent months simulating every expected scenario — the perfect LEOP, launch and separation of the satellite from the launcher, as well as a whole host of scenarios in which something goes wrong.


Establishing contact between the spacecraft and mission controllers has also been rehearsed.


Deep space ground stations across three continents will support this mission, with ESA’s global antenna network maintaining links to and from BepiColombo throughout the journey.


“BepiColombo is one of the world’s most ambitious interplanetary missions, and it could not be in safer hands,” says Rolf Densing, Director of Operations at ESOC.


“With decades of collective experience and hundreds of hours of simulation practice, teams at ESA’s mission control are ready to set out for the rocky planet.”


Go to esa.int/live to watch the launch live from 03:15 CEST: http://esa.int/live


Related link:


ESA’s BepiColombo: http://sci.esa.int/bepicolombo/


Images, Video, Text, Credits: ESA/ATG medialab/CC BY-SA 3.0 IGO/NASA/JPL.


Best regards, Orbiter.chArchive link


Update on the Hubble Space Telescope Safe Mode


NASA – Hubble Space Telescope patch.


Oct. 12, 2018


NASA continues to work toward resuming science operations of the Hubble Space Telescope after the spacecraft entered safe mode due to a failed gyroscope (gyro) on Friday, Oct. 5.


Following the gyro failure, the Hubble operations team turned on a backup gyro on the spacecraft. However, that gyro did not perform as expected, reporting rotation rates that are orders of magnitude higher than they actually are. This past week, tests were conducted to assess the condition of that backup gyro. The tests showed that the gyro is properly tracking Hubble’s movement, but the rates reported are consistently higher than the true rates. This is similar to a speedometer on your car continuously showing that your speed is 100 miles per hour faster than it actually is; it properly shows when your car speeds up or slows down, and by how much, but the actual speed is inaccurate.


When the spacecraft turns across the sky from one target to the next, the gyro is put into a coarser (high) mode. In this high mode it may be possible to subtract out a consistent large offset to get an accurate reading. However, after the large turns are over, the spacecraft attempts to lock onto a target and stay very still. For this activity, the gyro goes into a precision (low) mode to measure very small movements. The extremely high rates currently being reported exceed the upper limit of the gyro in this low mode, preventing the gyro from reporting the spacecraft’s small movements.



NASA’s Hubble Space Telescope. Image Credit: NASA

An anomaly review board that consists of professionals experienced in the manufacturing of such gyros, Hubble operations personnel, flight software engineers and other experts was formed earlier this week to identify the cause of this behavior and determine what solutions can be implemented from the ground to correct or compensate for it.


If the team is successful in solving the problem, Hubble will return to normal, three-gyro operations. If it is not, the spacecraft will be configured for one-gyro operations, which will still provide excellent science well into the 2020s, enabling it to work alongside the James Webb Space Telescope and continue groundbreaking science.


Safe mode places the telescope into a stable configuration that suspends science observations and orients the spacecraft’s solar panels toward the Sun to ensure Hubble’s power requirements are met. The spacecraft remains in this configuration until ground control can correct or compensate for the issue. The rest of the spacecraft and its instruments are still fully functional and are expected to produce excellent science for years to come.



Hubble Space Telescope (HST). Animation Credits: NASA/ESA

A gyro is a device that measures the speed at which the spacecraft is turning, and is needed to help Hubble turn and lock on to new targets. To meet the stringent pointing requirements necessary to study far-off astronomical objects and obtain groundbreaking science data, Hubble’s gyros are extremely accurate. Hubble preferably uses three gyros at any given time to make the observatory as efficient as possible, and would work at slightly lower efficiency on only one gyro.


During Servicing Mission 4 in 2009, astronauts installed six new gyros on Hubble. Three gyros have since failed after achieving or exceeding the average runtime for a Hubble gyro. When fewer than three operational gyros remain, Hubble will continue to make scientific observations in a previously developed and tested mode that uses just one gyro in order to maximize the observatory’s lifetime.


Originally required to last 15 years, Hubble has now been operating for more than 28. The final servicing mission in 2009, expected to extend Hubble’s lifetime an additional 5 years, has now produced more than 9 years of science observations.


Hubble is managed and operated at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.


Related article:


Hubble in Safe Mode as Gyro Issues are Diagnosed:
https://orbiterchspacenews.blogspot.com/2018/10/hubble-in-safe-mode-as-gyro-issues-are.html


For more information about Hubble, visit:


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


Image (mentioned), Animation (mentioned), Text, Credits: NASA/Felicia Chou.


Greetings, Orbiter.chArchive link


Station Crew Busy With Science After Aborted Launch Ascent


ISS – Expedition 57 Mission patch.


October 12, 2018


Three Expedition 57 crew members are staying busy aboard the International Space Station after the climb to orbit of two crewmates was aborted Thursday morning. American Nick Hague and Russian Alexey Ovchinin made an emergency landing shortly after launch, but are in excellent shape and back in Russia. The trio in orbit is continuing science and maintenance aboard the orbital laboratory.



Image above: North Africa and the Mediterranean Sea are pictured as the International Space Station orbited 254 miles above the African continent. Japan’s Kounotori H-II Transfer Vehicle-7 (HTV-7) is pictured at left attached to the Harmony module. Image Credit: NASA.


NASA astronaut Hague and Roscosmos cosmonaut Ovchinin are safe and returned to Moscow with mission officials after their aborted mission. The Soyuz MS-10 rocket booster experienced a failure about two minutes after launching from the Baikonur Cosmodrome in Kazakhstan. Hague will return to Houston, Texas, on Saturday and Ovchinin will stay in Moscow. Investigations into the cause of the failure are beginning, and the space station international partner agencies are evaluating what changes to the station’s operating plan will need to be adopted.


The three humans still orbiting Earth are safe with plenty of supplies and work to do on orbit. Commander Alexander Gerst and Flight Engineer Serena Auñón-Chancellor started their day measuring how microgravity has impacted their muscles for the Myotones study. They then moved on to researching an ancient technique that may be used for emergency navigation on future space missions.


Serena Auñón-Chancellor is scheduled to talk with two different school groups on Monday and Thursday next week. One of those conversations will involve the flight of Seaman Jr., a plush toy that is part of the National Park Service’s celebration of its the 3,700 mile Lewis and Clark National Historic Trail.



Image above: Flying on the line of the Terrestrial Ecuador, Pacific Ocean, seen by EarthCam on ISS, speed: 27’607 Km/h, altitude: 408,06 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Live application with EarthCam’s from ISS on October 12, 2018 at 18:18 UTC. Image Credits: Orbiter.ch Aerospace/Roland Berga.


Flight Engineer Sergey Prokopyev maintained life support systems in the Russian segment of the space station. He also updated the station’s inventory system and checked on Russian science experiments.


Related links:


Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html


Myotones: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7573


Ancient technique: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7646


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), Text, Credits: NASA/Mark Garcia/Orbiter.ch Aerospace/Roland Berga.


Best regards, Orbiter.chArchive link


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