пятница, 9 ноября 2018 г.

Recovery of endangered whales hampered by humans long after hunting

When an endangered female North Atlantic right whale spends months, even years, disentangling itself from cast-off fishing nets, there’s not much energy left over for mating and nursing calves.











Recovery of endangered whales hampered by humans long after hunting
This endangered North Atlantic right whale is entangled in heavy plastic fishing link off Cape Cod, Massachusetts
[Credit: NOAA/AFP]

Coping with such debris, along with ship collisions and other forms of human encroachment, have severely stymied recovery of the majestic sea mammals long after explosive harpoons and factory ships nearly wiped them out, according to a study published Wednesday.


Once numbering in the tens of thousands, the northern whale’s population — hovering around 450 today — climbed slowly from 1990, but began to drop again around 2010.


Had the Canadian and US waters they plied during that quarter of a century been pristine and uncluttered by human traffic, “the species’ numbers would be almost double what they are now, and their current emergency wouldn’t be so dire,” scientists led by Peter Corkeron of the NOAA Northeastern Fisheries Science Center in Massachusetts reported.


More to the point, there would be twice as many female whales: “The general slope of the recovery trajectory is driven by female mortality,” they added.


From 1970 to 2009, 80 percent of 122 known North Atlantic right whale deaths were caused by human objects or activity.


The species has not been hunted for more than half a century.


Sister species


But beyond the number of whales killed was the question of whether the species’ population might have been curtailed in more subtle ways by people.


To find out, Corkeron compared birth rates with the Southern right whale, a sister species in the southern hemisphere — estimated to number about 15,000 — that is in much better shape and far less exposed to harmful human emanations.


Data gathered over the last three decades made it possible to count the number of new calves born in different sub-populations at both poles.


The Northern and Southern whales were long thought to be one species until genetic analysis showed otherwise.


As suspected, the three groups of Southern whales — off the coasts of eastern South America, southern Africa and southwest Australia — produced offspring at twice the rate as their northern kin.


Further evidence that the North Atlantic environment was taking a toll was the poor health of females and their calves, the study found.


‘Ghost nets’


“That female baleen whales forgo reproduction in response to poor body conditions is well established,” the authors said.


What caused the lacerations, reduced body weight, and apparent unwillingness to mate?


The most likely culprit is “ghost nets”, sprawling webs of fishing gear often made of synthetic fibres as strong as they are long-lasting, the study concluded.


More than 80 percent of all North Atlantic right whales are known to have been entangled in abandoned netting at least once, and well over half have been there twice or more.


“Entanglements can last from months to years, and recovery can take a similar time,” the authors wrote in Royal Society Open Science.


For the Southern whales, the problem is non-existent.


Once numbered in the hundreds of thousands, slow moving right whales — migrating along coastlines — were both easy and preferred prey for whalers well into the 20th century.


The species can grow to 20 metres (65 feet) and weigh 100 tonnes, more than a fully-loaded commercial jet.


They are also docile and full of the blubber from which whale oil was made.


Author: Marlowe Hood | Source: AFP [November 07, 2018]



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Climate change causing more severe wildfires, larger insect outbreaks in temperate...

A warmer, drier climate is expected is increase the likelihood of larger-scale forest disturbances such as wildfires, insect outbreaks, disease and drought, according to a new study co-authored by a Portland State University professor.











Climate change causing more severe wildfires, larger insect outbreaks in temperate forests
The southern slope of Mount Adams in Washington has burned four times in the last 14 years,
which is significantly more frequent than expected at that elevation and forest types
[Credit: Courtesy of Sebastian Busby]

The study, published in the journal Nature Communications, sought to provide a more complete snapshot of disturbances in the world’s temperate forests by quantifying the size, shape and prevalence of disturbances and understanding their drivers.


The researchers analyzed 50 protected areas like national parks as well as their immediate surroundings, allowing them to compare disturbances inside protected areas that are more climate-related from those just outside that would also be impacted by human land use.


The study found that while many temperate forests are dominated by small-scale disturbance events — driven largely by windstorms and cooler, wetter conditions — there was also a strong link between high disturbance activity and warmer and drier-than-average climate conditions. Andrés Holz, a co-author and geography professor in PSU’s College of Liberal Arts and Sciences, said this suggests that with a warming climate, disturbances are expected to become larger and more severe in some temperate forests including the western U.S.


“Under the warmer conditions we have been seeing, it is likely that we’re going to see a higher probability of areas that tend to have very big disturbances,” he said.


Among the study’s findings:


Areas with low disturbance activity were largely associated with windstorms under cooler, rainy conditions, while areas with large disturbance activity were largely associated with wildfires, bark beetle outbreaks and drought under warmer, drier conditions.


In the majority of landscapes outside protected areas, disturbance patches were generally larger and less complex in shape than in protected areas. For example, human-made disturbances like logging are simpler in shape than the path a wildfire, storm or insect outbreak might take inside a protected area. But in landscapes affected by large-scale fires or outbreaks, the size and complexity of what happens inside and outside the protected areas are more comparable.


“Climate change is mimicking the footprint of disturbances in protected areas to what we are doing through land-use change outside of protected areas,” Holz said. “Under warmer conditions, we might see more similarities between protected areas and their surroundings in some temperate forests globally.”


Source: Portland State University [November 07, 2018]



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New hope for world’s most endangered mammal

New genetic analysis of white rhino populations suggests it could be possible to rescue the critically endangered northern white rhinoceros from extinction, using the genes of its less threatened southern cousin.











New hope for world's most endangered mammal
Credit: Getty Images

Analysing genetic samples from 232 rhinos, researchers from Cardiff University and the University of Venda found that despite the northern and southern populations of white rhinos splitting from each other one million years ago they have occasionally shared genes during cold and arid periods, when African grasslands expanded, as recent as 14,000 years ago.
Dr Isa-Rita Russo from Cardiff University, said: “By looking at the white rhino’s population history we’ve been able to establish that there was contact between northern and southern rhino populations throughout history.


“This is an exciting find! Genetic proof of contact between the populations suggests it may be possible to successfully rescue the northern white rhinoceros using southern white rhinoceros genes to create embryos, although further data would need to be collected to confirm this.”


White rhinoceros distribution across Africa is divided into populations in the north and south. The southern population declined to its lowest number around the turn of the nineteenth century, but recovered to become the world’s most numerous rhinoceros. In contrast, the northern population was common during much of the twentieth century, declining rapidly since the 1970s, leaving only two remaining post-reproductive rhinos.


The team also found that population decline was very different in the north and south, with the northern white rhinoceros declining about 1,370 years ago, coincident with the Bantu migration, and the southern white rhinoceros declining during colonialism, starting 400 years ago.


Professor Yoshan Moodley, University of Venda, said: “It appears that the white rhinoceros is no stranger to low genetic diversity, as our results show that the species was subjected to several climatically and anthropogenically driven population declines, which would have reduced and compressed genetic diversity in the past.


“This is one of the few large animals to survive the last ice age, and it seems that the additional human pressure on an already genetically compromised species has pushed the white rhinoceros further along the road to extinction.”


The study is published in Proceedings of the Royal Society B: Biological Sciences.


Source: Cardiff University [November 07, 2018]



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Goldilocks and the optimal mating distance: Neither too small nor too large but just...

Evolutionary theory predicts that the fitness of an individual is maximized when the genetic differences between its parents are neither too small nor too large but some ideal amount known as the optimal mating distance.











Goldilocks and the optimal mating distance: Neither too small nor too large but just right
Baker’s yeast (Saccharomyces cerevisiae) [Credit: University of Michigan]

However, decades of research have generally failed to validate this prediction or to identify the optimal mating distance.


To test the idea of an optimal mating distance and to attempt to estimate it, two University of Michigan evolutionary biologists analyzed previously published data on more than 400 genetic crosses between three types of model organisms representing three major lineages of eukaryotic organisms: fungi, plants and animals.


In the latest edition of the journal Science Advances, they report the detection of the optimal mating distance in all three model organisms–baker’s yeast, the Arabidopsis plant and the mouse. When displayed on a graph, they found that the relationship between mating distance and fitness exhibits the distinctive humped shape that had long been predicted but had remained elusive.


In each of the three species, they found that the optimal mating distance is close to the nucleotide diversity, which is the average genetic difference between two individuals of the same species.











Goldilocks and the optimal mating distance: Neither too small nor too large but just right
Arabidopsis plant (Arabidopsis thaliana) [Credit: University of Michigan]

The findings, according to authors Xinzhu Wei and Jianzhi Zhang, have theoretical and practical implications for animal and plant breeding and for conservation. Zhang is a professor in the U-M Department of Ecology and Evolutionary Biology. Wei was a doctoral student in Zhang’s lab when the work was done and is now a postdoctoral fellow at the University of California, Berkeley.


“In animal and plant breeding, inbred lines of various genetic distances are crossed to produce hybrids of higher yields. To conserve species, scientists sometimes mate organisms from two distinct, deteriorating populations in the hope of producing fitter hybrids,” Zhang said. “Our finding–that mating between individuals with approximately the mean genetic distance within the species results in the fittest offspring–can guide these efforts.”


Fitness is a concept that biologists use to describe the degree to which an organism’s characteristics increase its number of offspring. A pure-white coat might increase an Arctic hare’s chances of evading predators in the winter and surviving to reproduce the next spring. In that example, the genes for a pure-white coat confer increased fitness.


The genetic distance between the two parents of an individual, known as mating distance, influences the individual’s fitness via two competing mechanisms.











Goldilocks and the optimal mating distance: Neither too small nor too large but just right
Mouse (Mus musculus) [Credit: University of Michigan]

On one hand, increasing the genetic distance is beneficial because of the phenomenon of heterosis, also known as hybrid vigor. Plant and animal breeders routinely exploit the genetic benefits of this phenomenon by breeding together two distinct parental lines.


Such crosses can impart increased fitness by producing hybrid offspring that are larger and healthier–and in the case of corn plants, more productive–than their inbred parents.


But too large a genetic distance between individuals can be harmful owing to genetic incompatibility.


Biologists have long suspected that the optimal mating distance represents an intermediate point that marks a tradeoff between the advantages of heterosis and the harmful effects of genetic incompatibility. The new study confirms those suspicions.


The results suggest that in both plant breeding and conservation, using mating distances close to the OMD, the optimal mating distance, will likely optimize a suite of fitness-related traits.


Source: University of Michigan [November 07, 2018]



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Codebreaker Turing’s theory explains how shark scales are patterned

A system proposed by world war two codebreaker Alan Turing more than 60 years ago can explain the patterning of tooth-like scales possessed by sharks, according to new research.











Codebreaker Turing's theory explains how shark scales are patterned
Catshark hatchling rostrum scales SEM [Credit: Rory Cooper/University of Sheffield]

Scientists from the University of Sheffield’s Department of Animal and Plant Sciences found that Turing’s reaction-diffusion theory – widely accepted as the patterning method in mouse hair and chicken feathers – also applies to shark scales.


The findings can explain how the pattern of shark scales has evolved to reduce drag whilst swimming, thereby saving energy during movement. Scientists believe studying the patterning could help to design new shark-inspired materials to improve energy and transport efficiency.


Turing, forefather of the computer, came up with the reaction-diffusion system which was published in 1952, two years before his death. His equations describe how molecular signals can interact to form complex patterns.


In the paper, published in the journal Science Advances, researchers compared the patterning of shark scales to that of chicken feathers.


They found that the same core genes underlying feather patterning also underlie the development of shark scales and suggest these genes may be involved in the patterning of other diverse vertebrate skin structures, such as spines and teeth.


Dr Gareth Fraser, formerly of the University of Sheffield and now at the University of Florida, said: “We started looking at chicks and how they develop their feathers. We found these very nice lines of gene expression that pattern where these spots appear that eventually grow into feathers. We thought maybe the shark does a similar thing, and we found two rows on the dorsal surface, which start the whole process.


“We teamed up with a mathematician to figure out what the pattern is and whether we can model it. We found that shark skin denticles are precisely patterned through a set of equations that Alan Turing — the mathematician, computer scientist and the code breaker — came up with. These equations describe how certain chemicals interact during animal development and we found that these equations explain the patterning of these units.”











Codebreaker Turing's theory explains how shark scales are patterned
Catshark embryo computed tomography scan (90 days post fertilization) [Credit: Rendered by Rory Cooper, scanned
by Kyle Martin and Amin Garbout at The Imaging and Analysis Centre, Natural History Museum, London]

Researchers also demonstrated how tweaking the inputs of Turing’s system can result in diverse scale patterns comparable to those seen in shark and ray species alive today.


They suggest that natural variations to Turing’s system may have enabled the evolution of different traits within these animals, including the provision of drag reduction and defensive armour.


Rory Cooper, PhD student at the University of Sheffield, said: “Sharks belong to an ancient vertebrate group, long separated from most other jawed vertebrates. Studying their development gives us an idea of what skin structures may have looked like early in vertebrate evolution. We wanted to learn about the developmental processes that control how these diverse structures are patterned, and therefore the processes which facilitate their various functions.”


Scientists used a combination of techniques including reaction-diffusion modelling to create a simulation based on Turing’s equations, to demonstrate that his system can explain shark scale patterning, when the parameters are tuned appropriately.


Mr Cooper added: “Scientists and engineers have been trying to create shark-skin inspired materials to reduce drag and increase efficiency during locomotion, of both people and vehicles, for many years. Our findings help us to understand how shark scales are patterned, which is essential for enabling their function in drag reduction. Therefore, this research helps us to understand how these drag reductive properties first arose in sharks, and how they change between different species.”


Patterning is one important aspect that contributes to achieving drag reduction in certain shark species. Another is the shape of individual scales. Researchers now want to examine the developmental processes which underlie the variation of shape both within and between different shark species.


“Understanding how both these factors contribute towards drag reduction will hopefully lead towards the production of improved, widely applicable shark-inspired materials capable of reducing drag and saving energy,” added Mr Cooper.


Source: University of Sheffield [November 07, 2018]



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Quantitative 3-D analysis of bone tools sheds light on ancient manufacture and use

Quantitative three-dimensional analysis of bone wear patterns can provide insight into the manufacture and use of early human tools, according to a study by Naomi Martisius of the University of California at Davis and colleagues, published in the open-access journal PLOS ONE.











Quantitative 3-D analysis of bone tools sheds light on ancient manufacture and use
Material wear on bone over time [Credit: Martisius et al., 2018]

Humans have been using bone tools for at least 2 million years, and by approximately 100 thousand years ago, were manufacturing them with formal processes such as grinding and scraping. Ancient bone tools carry marks of their manufacture and use, which can provide information about the group of people that made the tools and the specific uses to which tools were put.
Microscopy has been used to study these marks, but the study of use-wear on bone tools requires a comparative body of quantitative examples of wear over time and contact with different materials, to ensure that these studies are replicable. In the current study, the authors sought to determine the basics of use-wear formation over time by taking incremental molds of bone specimens subjected to a controlled, mechanical experiment.


The authors initially shaped bone with sandstone or flint, or left it unshaped, and then used it to work fresh skin, leather, or bark, all while taking sequential surface scans using confocal microscopy, to generate three-dimensional data for a quantitative Bayesian analysis.


While individual samples of bone varied in both texture and structure, they found that duration of use was the largest and most unequivocal determinant affecting the surface of the bone. Fresh skin was the most abrasive of the three materials, and the degree of wear correlated with duration of use for working skin.


Further refinement of the specific methodological techniques may be needed to fully investigate correlations that link tool shaping and target material to observed wear patterns. However, the study provides a proof of principle for application of quantitative measures to bone wear analysis. The novel technique provides a possible alternative to current methods of bone wear analysis, which are largely qualitative and dependent on expert interpretation.


Martisius adds: “If we want to understand how ancient humans used bone tools, we need to understand what the traces left on the tools mean. We tested manufacturing and use variables over time using a quantitative method for looking at these traces, and by extension, at human behavior”


Source: Public Library of Science [November 07, 2018]




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Windy with a chance of magnetic storms – space weather science with Cluster


ESA – Cluster Mission logo.


8 November 2018


Space weather is no abstract concept – it may happen in space, but its effects on Earth can be significant. To help better forecast these effects, ESA’s Cluster mission, a quartet of spacecraft that was launched in 2000, is currently working to understand how our planet is connected to its magnetic environment, and unravelling the complex relationship between the Earth and its parent star.


Despite appearances, the space surrounding our planet is far from empty. The Earth is surrounded by various layers of atmosphere, is constantly bathed in a flow of charged particles streaming out from the Sun, known as the solar wind, and sends its own magnetic field lines out into the cosmos.



The Cluster quartet

This field floods our immediate patch of space, acting as a kind of shield against any extreme and potentially damaging radiation that might come our way. It also defines our planet’s magnetosphere, a region of space dominated by Earth’s magnetic field and filled with energy that is topped up by the solar wind and sporadically released into the near-Earth environment.


With this comes ‘weather’. We occasionally experience magnetic storms and events that disturb and interact with Earth’s radiation belts, atmosphere, and planetary surface. One of the most famous examples of this is the auroras that Earth experiences at its poles. These shimmering sheets of colour form as the solar wind disrupts and breaches the upper layers of our atmosphere.


Space weather has a real impact on our activities on Earth, and poses a significant risk to space-farers – robotic and human alike.


Sudden flurries of high-energy particles emanating from the Sun can contain up to 100 million tons of material; this can penetrate spacecraft walls or affect their electronics, disable satellites, and take down terrestrial electrical transformers and power grids. There are currently about 1800 active satellites circling our planet, and our dependence on space technology is only growing stronger.



Aurora over Norway

“This highlights a pressing need for more accurate space weather forecasts,” says Philippe Escoubet, Project Scientist for ESA’s Cluster mission.


“To understand and predict this weather, we need to know more about how the Earth and the Sun are connected, and what the magnetic environment around the Earth looks and acts like. This is what Cluster is helping us to do.”


Various spacecraft are investigating the magnetic environment around the Earth and how it interacts with the solar wind. Efforts have been internationally collaborative, from observatories including ESA’s Cluster and Swarm missions, NASA’s Magnetospheric MultiScale mission (MMS), the Van Allen Probes, and THEMIS (Time History of Events and Macroscale Interactions during Substorms), and the Japanese (JAXA/ISAS) Arase and Geotail missions.



The science of space weather

Cluster comprises four identical spacecraft that fly in a pyramid-like formation, and is able to gather incredibly detailed data on the complex structure and fluctuations of our magnetic environment.


For nearly two decades, this quartet has mapped our magnetosphere and pinpointed flows of cold plasma and interactions with the solar wind, probed our magnetotail – an extension of the magnetosphere that stretches beyond the Earth in the direction opposite to the Sun. The mission also modelled the small-scale turbulence and intricate dynamics of the solar wind itself, and helped to explain the mysteries of Earth’s auroras.


While this back catalogue of discoveries is impressive enough, Cluster is still producing new insights, especially in the realm of space weather. Recently, the mission has been instrumental in building more accurate models of our planet’s magnetic field both close to Earth (at so-called geosynchronous altitudes) and at large distances from Earth’s surface – no mean feat.


These recent models were based on data from Cluster and other missions mentioned above, and put together by scientists including Nikolai Tsyganenko and Varvara Andreeva of Saint-Petersburg State University, Russia. They provide a way to trace magnetic field lines and determine how they evolve and change during storms, and can thus create a magnetic map of all the satellites currently in orbit around the Earth down to low altitudes.


In addition, ESA’s Swarm mission is also providing insight into our planet’smagnetic field. Launched in 2013 and comprising three identical satellites, Swarm has been measuringpreciselythe magnetic signals that stem from Earth’s core, mantle, crust and oceans, as well as from the ionosphere and magnetosphere.


“This kind of research is invaluable,” adds Escoubet. “Unexpected or extreme outbursts of space weather can badly damage any satellites we have in orbit around the Earth, so being able to keep better track of them – while simultaneously gaining a better understanding of our planet’s dynamic magnetic field structure – is key to their safety.”


Cluster also recently tracked the impact of huge outbursts of highly energetic particles and photons from the outer layers of the Sun known as coronal mass ejections (CMEs). The data showed that CMEs are able to trigger both strong and weak geomagnetic storms as they meet and are deformed at Earth’s bow shock – the boundary where the solar wind meets the outer limits of our magnetosphere.



Coronal mass ejection

Such storms are extreme events. Cluster explored a specific storm that occurred in September 2017, triggered by two consecutive CMEs separated by 24 hours. It studied how the storm affected the flow of charged particles leaving the polar regions of the ionosphere, a layer of Earth’s upper atmosphere, above around 100 km, and found this flow to have increased around the polar cap by more than 30 times. This enhanced flow has consequences for space weather, such as increased drag for satellites, and is thought to be a result of the ionosphere being heated by multiple intense solar flares.


The mission has observed how various other phenomena affect our magnetosphere, too. It spotted tiny, hot, local anomalies in the flow of solar wind that caused the entire magnetosphere to vibrate, and watched the magnetosphere growing and shrinking significantly in size back in 2013, interacting with the radiation beltsthat encircle our planet as it did so. 


Importantly, it also measured the speed of the solar wind at the ‘nose’ of the bow shock. These observations connect data gathered near Earth to those obtained by Sun-watching satellites some 1.5 million km away at a location known as Lagrangian Point 1 – such as the ESA/NASA Solar and Heliospheric Observatory (SOHO) and NASA’s Advanced Composition Explorer (ACE). These data offer all-important evidence for solar wind dynamics in this complex and unclear region of space.


“All of this, and more, has really made it possible to better understand the dynamics of Earth’s magnetic field, and how it relates to the space weather we see,” says Escoubet.


“Cluster has produced such wonderful science in the past 18 years – but there’s still so much more to come.”


Notes for editors:


This article uses information from “Data-based modeling of the geomagnetosphere with an IMF-dependent magnetopause” by N.A. Tsyganenko (2014) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JA019346; “Empirical modeling of the quiet and storm time geosynchronous magnetic field” by V.A. Andreeva & N.A. Tsyganenko (2018) https://doi.org/10.1002/2017SW001684; “Statistical study of the alteration of the magnetic structure of magnetic clouds in the Earth’s magnetosheath” by L. Turc et al (2017) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JA023654; “O+ escape during the extreme space weather event of 4–10 September 2017” by A. Schillings et al (2018) https://doi.org/10.1029/2018SW001881; “A statistical study on hot flow anomaly current sheets” by L.L. Zhao et al (2017) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JA023319; “Earth’s magnetosphere and outer radiation belt under sub-Alfvénic solar wind” by N. Lugaz et al (2016) https://www.nature.com/articles/ncomms13001; “A statistical comparison of solar wind propagation delays derived from multi spacecraft techniques” by N.A. Case & J.A. Wild (2012) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JA016946.


Related article:


ESA rocks space weather:
https://orbiterchspacenews.blogspot.com/2018/11/esa-rocks-space-weather.html


Related links:


Space weather: http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/ESA_rocks_space_weather


ESA’s Cluster: http://sci.esa.int/cluster


ESA’s Swarm: http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm


ESA/NASA Solar and Heliospheric Observatory (SOHO): http://sci.esa.int/soho/


Catalogue of discoveries: http://sci.esa.int/cluster/59954-understanding-earth-what-the-cluster-mission-has-taught-us-so-far/


Space weather and its hazards: http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Space_weather_and_its_hazards


Space Weather Segment: http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Space_Weather_Segment


Monitoring space weather: http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Monitoring_space_weather


Images, Video, Text, Credits: ESA/Philippe Escoubet/Markus Bauer/S. Mazrouei/CC BY-SA 3.0 IGO.


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2018 November 9 Little Planet Lookout Image Credit &…


2018 November 9


Little Planet Lookout
Image Credit & Copyright: Gyorgy Soponyai


Explanation: Don’t panic. This little planet projection looks confusing, but it’s actually just a digitally warped and stitched, nadir centered mosaic of images that covers nearly 360×180 degrees. The images were taken on the night of October 31 from a 30 meter tall hill-top lookout tower near Tatabanya, Hungary, planet Earth. The laticed lookout tower construction was converted from a local mine elevator. Since planet Earth is rotating, the 126 frames of 75 second long exposures also show warped, concentric star trails with the north celestial pole at the left. Of course at this location the south celestial pole is just right of center but below the the little planet’s horizon.


∞ Source: apod.nasa.gov/apod/ap181109.html


Multimessenger Links to NASA’s Fermi Mission Show How Luck Favors the Prepared


NASA – Fermi Gamma-ray Space Telescope logo.


Nov. 8, 2018


In 2017, NASA’s Fermi Gamma-ray Space Telescope played a pivotal role in two important breakthroughs occurring just five weeks apart. But what might seem like extraordinary good luck is really the product of research, analysis, preparation and development extending back more than a century.


On Aug. 17, 2017, Fermi detected the first light ever seen from a source of gravitational waves — ripples in space-time produced, in this event, by the merger of two superdense neutron stars. Just five weeks later, a single high-energy particle discovered by the National Science Foundation’s (NSF) IceCube Neutrino Observatory was traced to a distant galaxy powered by a supermassive black hole thanks to a gamma-ray flare observed by Fermi. 


“For millennia, light was our only source of information about the universe,” said Julie McEnery, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The recent discoveries connect light, our best-known cosmic courier, to gravitational waves and particles like neutrinos — new messengers delivering different kinds of information that we’re just beginning to explore.”



NASA’s Fermi Mission Shows How Luck Favors the Prepared

Video above: Explore how more than a century of scientific progress with gravitational waves, gamma rays and neutrinos has helped bring about the age of multimessenger astronomy. Video Credits: NASA’s Goddard Space Flight Center.


Deep roots


The origins of these discoveries stretch back to cutting-edge research as long ago as 1887. That’s when physicists Albert Michelson and Edward Morley conducted an experiment to detect a substance, called the aether, which was postulated as a medium that permitted light waves to travel through space. As their experiment showed and many since have confirmed, the aether doesn’t exist. But the negative result proved to be one of the inspirations for Albert Einstein’s 1905 special theory of relativity. He generalized this into a full-fledged theory of gravity in 1915, one that predicted the existence of gravitational waves.


A century later, on Sept. 14, 2015, the NSF’s Laser Interferometer Gravitational-Wave Observatory (LIGO) detected these space-time vibrations for the first time as waves from the merger of two black holes reached Earth. In between came a steady stream of advances, including lasers, improved instrumentation and increasingly more powerful computers and software.


“Just as inventing the detector technologies has taken decades, so too has the theoretical and computational framework for analyzing and interpreting multimessenger observations,” said Tyson Littenberg, the principal investigator of the LIGO research group at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “We went through countless simulations to test new ideas and improve on existing algorithms so that we were prepared to make the most out of the first observations, and that basic research and development work continues.”


Until 2005, it wasn’t even possible to simulate in detail what happens when a pair of orbiting black holes coalesce. The breakthrough came when separate teams at Goddard and the University of Texas at Brownsville independently developed new computational methods that overcame all previous hurdles. An accurate understanding of gravitational-wave signals was one important step in evolving techniques designed to rapidly detect and characterize them.



Fermi and LIGO Graphs of Observations From Aug- 2017 Gravitational Wave

Video above: On Aug. 17, 2017, gravitational waves from a neutron star merger produced a signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO). The sound in this video represents the same frequencies as the combined stretching and squeezing caused by waves passing through the LIGO detectors at Hanford, Washington, and Livingston, Louisiana. Just 1.7 seconds later, a brief burst of gamma-rays — indicated by a ping — was seen by NASA’s Fermi Gamma-ray Space Telescope. Video Credits: NASA’s Goddard Space Flight Center, Caltech/MIT/LIGO Lab.


“Another fundamental development was the highly optimized analysis pipelines and information technology infrastructure that can compare the theoretical model with the data, recognize the presence of a signal, calculate the location of the source on the sky and format the information in a way that the rest of the astronomical community could use,” explained Tito Dal Canton, a NASA Postdoctoral Program Fellow and a member of a LIGO research group at Goddard led by Jordan Camp.


Astronomers need to know about short-lived events as soon as possible so they can bring to bear a wide array of telescopes in space and on the ground. Back in 1993, scientists at Goddard and Marshall began developing an automated system for distributing the locations of gamma-ray bursts (GRBs) — distant, powerful explosions that typically last a minute or less — to astronomers around the world in real time. Located at Goddard and led by Principal Investigator Scott Barthelmy, the Gamma-ray Coordinates Network/Transient Astronomy Network now distributes alerts from many space missions as well as ground-based instruments like LIGO and IceCube.


Ghost particles


The historical thread for neutrinos began with French physicist Henri Becquerel and his 1895 discovery of radioactivity. In 1930, after studying a radioactive process called beta decay, Wolfang Pauli suggested it likely involved a new subatomic particle, later dubbed the neutrino. We now know neutrinos possess little mass, travel almost as fast as light, come in three varieties and are among the most abundant particles in the universe. But because they don’t readily interact with other matter, neutrinos weren’t discovered until 1956.


In 1912, Victor Hess discovered that charged particles, now called cosmic rays, continually enter Earth’s atmosphere from every direction, which means space is filled with them. When cosmic rays strike air molecules, the collision produces a shower of particles — including neutrinos — that rains down through the atmosphere. Searching for astronomical neutrino sources meant placing experiments underground to reduce interference from cosmic rays and building very large detectors to tease out the weak signals of publicity-shy neutrinos.



Image above: On Sept. 22, 2017, the IceCube Neutrino Observatory at the South Pole, represented in this illustration by strings of sensors under the ice, detected a high-energy neutrino that appeared to come from deep space. NASA’s Fermi Gamma-ray Space Telescope (center left) pinpointed the source as a supermassive black hole in a galaxy about 4 billion light-years away. It is the first high-energy neutrino source identified from outside our galaxy. Image Credits: NASA/Fermi and Aurore Simonnet, Sonoma State University.


Neutrinos produced by nuclear reactions inside the Sun’s core were first detected in 1968 thanks to an experiment using 100,000 gallons of dry-cleaning fluid located deep in a South Dakota gold mine. Discovering the next astronomical neutrino source would take another 19 years. Supernova 1987A, a stellar explosion in a nearby galaxy, remains the brightest and closest supernova seen in over 400 years and is the first for which the original star could be identified on pre-explosion images. Theorists anticipated that neutrinos, which escape a collapsing star more readily than light, would be the first signal from a new supernova. And hours before 1987A’s visible light arrived at Earth, experiments in Japan, the U.S. and Russia detected a brief burst of neutrinos, making the supernova the first source of neutrinos identified beyond the solar system.


“If none of these experiments was operating at the time, the neutrino signal would have passed by unnoticed,” said Francis Halzen, the principal investigator of IceCube, which is essentially a neutrino telescope build into a cubic kilometer of ice at the South Pole. “It isn’t enough to develop the technology, refine theories or even construct a detector. We need to be making observations as often as we can for the best chance of catching brief, rare and scientifically interesting events. Both Fermi and IceCube are operating continuously, making uninterrupted observations of the sky.”


Light fantastic


The third historical thread belongs to gamma rays, the highest-energy form of light, discovered in 1900 by the French physicist Paul Villard. When a gamma ray of sufficient energy interacts with matter, it provides a perfect demonstration of Einstein’s most famous equation, E=mc2, by instantly transforming into particles — an electron and its antimatter counterpart, a positron. Conversely, crash an electron and a positron together and a gamma ray results.


NASA’s Explorer 11 satellite, launched in 1961, detected the first gamma rays in space. In 1963, the U.S. Air Force began launching a series of satellites as part of Project Vela. These increasingly sophisticated satellites were designed to verify compliance with an international treaty that banned nuclear weapons tests in space or in the atmosphere. But starting in July 1967, scientists became aware the Vela satellites were seeing brief gamma-ray events that were clearly unrelated to weapons tests.


These explosions were GRBs, an entirely new phenomenon now known to mark the death of certain types of massive stars or the merger of orbiting neutron stars. NASA further explored the gamma-ray sky with the Compton Gamma Ray Observatory, which operated from 1991 to 2000 and recorded thousands of GRBs. Starting in 1997, critical observations by the Italian-Dutch BeppoSAX satellite proved that GRBs were located far beyond our galaxy. Compton was succeeded by NASA’s Neil Gehrels Swift Observatory in 2004 and Fermi in 2008, missions that continue exploring the high-energy sky and that follow up on LIGO and IceCube alerts.


“In the fields of observation, chance favors only the prepared mind,” noted Louis Pasteur, the French chemist and microbiologist, in an 1854 lecture. Supported by decades of scientific discoveries and technological innovation, the burgeoning field of multimessenger astronomy is increasingly prepared for its next stroke of luck.   


NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.


For more about NASA’s Fermi mission, visit: https://www.nasa.gov/fermi


Related links:


NASA Postdoctoral Program Fellow: https://npp.usra.edu/


Gamma-ray Coordinates Network/Transient Astronomy Network: https://gcn.gsfc.nasa.gov/


Compton Gamma Ray Observatory: https://www.nasa.gov/feature/goddard/2016/nasa-celebrates-25-years-of-breakthrough-gamma-ray-science


BeppoSAX: http://ecuip.lib.uchicago.edu/multiwavelength-astronomy/gamma-ray/impact/07.html


Neil Gehrels Swift Observatory: https://swift.gsfc.nasa.gov/


NASA’s Explorer 11: https://heasarc.gsfc.nasa.gov/docs/heasarc/missions/explorer11.html


NASA’s Neil Gehrels Swift Observatory: https://swift.gsfc.nasa.gov/


Image (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Francis Reddy.


Best regards, Orbiter.chArchive link


Parker Solar Probe Reports Good Status After Close Solar Approach


NASA – Parker Solar Probe patch.


Nov. 7, 2018



Image above: Illustration of Parker Solar Probe approaching the Sun. Image Credits: ​NASA/Johns Hopkins APL/Steve Gribben.


Parker Solar Probe is alive and well after skimming by the Sun at just 15 million miles from our star’s surface. This is far closer than any spacecraft has ever gone — the previous record was set by Helios B in 1976 and broken by Parker on Oct. 29 — and this maneuver has exposed the spacecraft to intense heat and solar radiation in a complex solar wind environment.


“Parker Solar Probe was designed to take care of itself and its precious payload during this close approach, with no control from us on Earth — and now we know it succeeded,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate at the agency headquarters in Washington. “Parker is the culmination of six decades of scientific progress. Now, we have realized humanity’s first close visit to our star, which will have implications not just here on Earth, but for a deeper understanding of our universe.”


Mission controllers at the Johns Hopkins University Applied Physics Lab received the status beacon from the spacecraft at 4:46 p.m. EST on Nov. 7, 2018. The beacon indicates status “A” — the best of all four possible status signals, meaning that Parker Solar Probe is operating well with all instruments running and collecting science data and, if there were any minor issues, they were resolved autonomously by the spacecraft.



Image above: Members of the Parker Solar Probe mission team celebrate on Nov. 7, 2018, after receiving a beacon indicating the spacecraft is in good health following its first perihelion. Image Credits: NASA/Johns Hopkins APL/Ed Whitman.


At its closest approach on Nov. 5, called perihelion, Parker Solar Probe reached a top speed of 213,200 miles per hour, setting a new record for spacecraft speed. Along with new records for the closest approach to the Sun, Parker Solar Probe will repeatedly break its own speed record as its orbit draws closer to the star and the spacecraft travels faster and faster at perihelion.



First Perihelion: Into the Unknown – Parker Solar Probe

Video above: On Nov. 5, 2018, Parker Solar Probe achieved its first close approach to the Sun, called perihelion, a maneuver that exposed the spacecraft to intense heat and solar radiation. Video Credits: NASA/JHUAPL.


At this distance, the intense sunlight heated the Sun-facing side of Parker Solar Probe’s heat shield, called the Thermal Protection System, to about 820 degrees Fahrenheit. This temperature will climb up to 2,500 F as the spacecraft makes closer approaches to the Sun — but all the while, the spacecraft instruments and systems that are protected by the heat shield are generally kept in the mid-80s F.


Parker Solar Probe’s first solar encounter phase began on Oct. 31, and the spacecraft will continue collecting science data through the end of the solar encounter phase on Nov. 11. It will be several weeks after the end of the solar encounter phase before the science data begins downlinking to Earth.


Parker Solar Probe: https://www.nasa.gov/solarprobe


Images (mentioned), Video (mentioned), Text, Credits: NASA/Goddard Space Flight Center, by Sarah Frazier.


Greetings, Orbiter.chArchive link


U.S., Russian Spaceships Line Up for Launch After Japanese Vessel Departs


ISS – Expedition 57 Mission patch.


November 8, 2018


The Expedition 57 crew said farewell to a Japanese resupply ship Wednesday and is getting ready to welcome U.S. and Russian space freighters in less than two weeks. The trio first practiced International Space Station emergency procedures today then went on to space research and robotics training.


The U.S. company Northrop Grumman is getting its 10th Cygnus cargo craft packed and ready for launch atop an Antares rocket Nov. 15 at 4:49 a.m. EST. Russia will launch its 71st station resupply mission aboard a Progress spaceship the next day at 1:14 p.m.



Image above: Japan’s HTV-7 resupply ship is pictured after it was released from the grips of the Canadarm2 robotic arm. Both the HTV-7 and the International Space Station were orbiting about 254 miles above the Pacific Ocean and about 311 miles west of Baja California. Image Credit: NASA.


Both resupply ships are due to arrive at the station Sunday Nov. 18 just 10 hours apart. The Cygnus will get there first following its head start. Commander Alexander Gerst assisted by Flight Engineer Serena Auñón-Chancellor will capture the American vessel with the Canadarm2 robotic arm at 4:35 a.m. A few hours later, cosmonaut Sergey Prokopyev will monitor the approach and automated docking of the Russian Progress 71 cargo craft to the Zvezda service module at 2:30 p.m.


All three crew members called down to mission controls centers in Houston and Moscow for a coordinated emergency drill today. The orbital residents practiced communication and decision-making skills while maneuvering along evacuation paths and locating safety gear.


Afterward, Gerst and Serena partnered up and reviewed next Sunday’s Cygnus approach and rendezvous procedures. Gerst will command the Canadarm2 to reach out and grapple Cygnus as Serena monitors the spaceship’s telemetry and data.


Prokopyev continued his science and maintenance duties in the orbital lab’s Russian segment. The cosmonaut explored the physics of plasma-dust crystals then conducted an eye exam in conjunction with doctors on Earth. Prokopyev also photographed the inside of the Zvezda and stowed radiation detectors.



Image above: The Frozen Wild Dnieper River. Curling snow drifts are magnified by the terrain around the 1,400 mile Dnieper River, flowing from Russia to the Black Sea. European Space Agency astronaut Thomas Pesquet, a member of the Expedition 50 crew, captured this image from the International Space Station on “Feb. 9th, 2017, saying, “winter landscapes are also magical from the International Space Station: this river north of Kiev reminds me of a Hokusai painting.” Image Credits: NASA/ESA/Thomas Pesquet.


Each day, the International Space Station completes 16 orbits of our home planet as the crew conducts important science and research. Their work will not only benefit life here on Earth, but will help us venture deeper into space than ever before. Crew members on the space station photograph the Earth from their unique perspective, hovering 200 miles above us, documenting Earth from space. This record is crucial to how we see the planet changing over time, from human-caused changes like urban growth, to natural dynamic events such as hurricanes, and volcanic eruptions.


Related links:


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


Plasma-dust crystals: https://www.energia.ru/en/iss/researches/process/02.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), Text, Credits: NASA/Mark Garcia/Nasreen Alkhateeb.


Best regards, Orbiter.chArchive link


Meteor Activity Outlook for November 10-16, 2018

Craig Heden captured this bright Perseid passing near the Pleiades cluster on the morning of August 13, 2018, from Northern California, USA.

During this period the moon will reach its first quarter phase on Thursday November 15th. At this time the half-illuminated moon will be located in the early evening sky and will set near midnight local standard time (LST). This weekend the waxing crescent moon will set during the early evening hours allowing meteor observations under perfect conditions during the more active morning hours. The estimated total hourly meteor rates for evening observers this week is near 4 as seen from mid-northern latitudes (45N) and 3 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 21 as seen from mid-northern latitudes and 13 from the southern tropics. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.


The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning November 10/11. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.





Radiant Positions at 7pm LST


Radiant Positions at 7:00pm

Local Standard Time






Radiant Positions at 12:00 LST


Radiant Positions at 12:00am

Local Standard Time






Radiant Positions at 5am LST


Radiant Positions at 5:00am

Local Standard Time





These sources of meteoric activity are expected to be active this week.


.


The Andromedids (AND) are active from October 26 through November 17 with maximum activity occurring on November 5. The radiant is currently located at 01:47 (027) +30, which lies in western Triangulum, just northwest of the 3rd magnitude star known as alpha Trianguli. Rates should be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. The radiant is best located near 22:00 (10pm) LST when the radiant lies highest above the horizon. With an entry velocity of 18 km/sec., the average Andromedid meteor would be of slow velocity.


The Northern Taurids (NTA) are active from a large radiant located at 03:52 (058) +23. This area of the sky is located in northwestern Taurus, 3 degrees southeast of the naked eye open cluster known as the Pleiades. This position is close to the Southern Taurids so great care must be taken in separating these meteors. You must have the two radiants near the center of your field of view to properly differentiate these sources. Current rates would be 3 per hour as seen from the northern hemisphere and 2 per hour as seen from south of the equator. These meteors may be seen all night long but the radiant is best placed near midnight LST when it lies on the meridian and is located highest in the sky. With an entry velocity of 28 km/sec., the average Northern Taurid meteor would be of slow velocity.


The omicron Eridanids (OER) were discovered by Japanese observers using video data from SonotoCo in 2007-2008. This is a weak shower that usually produces rates less than 1 per hour, even at maximum activity. The radiant is currently located at 04:06 (061) -00, which places it on the Eridanus/Taurus border, 6 degrees southeast of the 4th magnitude star known as nu Tauri. These meteors may be seen all night long but the radiant is best placed near midnight LST when it lies on the meridian and is located highest in the sky. With an entry velocity of 29 km/sec., the average omicron Eridanid meteor would be of slow velocity.


The Southern Taurids (STA) are active from a large radiant centered near 04:07 (062) +16. This position lies in central Taurus, 5 degrees west of the orange 1st magnitude star known as Aldebaran (alpha Tauri). These meteors may be seen all night long but the radiant is best placed near midnight LST when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour regardless of your location. With an entry velocity of 27 km/sec., the average Southern Taurid meteor would be of slow velocity.


The chi Taurids (CTA) were discovered by Dr. Peter Brown during his 7 year survey using the Canadian Meteor Orbit Radar (CMOR). This source is active from October 20 through November 17 with a maximum occurring near November 3rd. Current rates should be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. The radiant is currently located at 04:51 (073) +28, which places it in northern Taurus, 8 degrees west of the 2nd magnitude star known as El Nath (beta Tauri). These meteors may be seen all night long but the radiant is best placed near 0100 LST when it lies on the meridian and is located highest in the sky. With an entry velocity of 41 km/sec., the average chi Taurid meteor would be of medium velocity.


The November Orionids (NOO) are now active from a radiant located at 04:51 (073) +16. This area of the sky lies in central Taurus, 3 degrees east of the 1st magnitude orange star known as Aldebaran (alpha Tauri). This area of the sky is best placed in the sky near 0100 LST, when it lies highest above the horizon. This stream is active from November 7 through December 17, with maximum activity occurring on November 29. Rates should be near 1 per hour no matter your location. With an entry velocity of 43 km/sec., most activity from this radiant would be of medium speed.


The Orionids (ORI) are still active from a radiant located at 07:46 (117) +15, which places it in eastern Gemini, almost directly between the bright stars known as Pollux (beta Geminorum) and Procyon (alpha Canis Minoris). This area of the sky is best placed in the sky near 0400 LST, when it lies highest above the horizon in a dark sky. Rates should be near 1 per hour no matter your location. With an entry velocity of 67 km/sec., most activity from this radiant would be of swift speed.


The last of the nu Eridanids (NUE) should be seen during this period from a radiant located at 08:11 (123) +16. This area of the sky lies in central Cancer, 1 degree southeast of the faint star known as zeta Cancri. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. This position is also very close the the Orionid radiant and some experts feel that these two sources are related. To separate any possible nu Eridanids from the stronger Orionids one must face in a direction so that both radiant are well within your field of view. Current rates are expected to be less than 1 per hour during this period no matter your location. With an entry velocity of 67 km/sec., the average meteor from this source would be of swift velocity.


Activity from the Leonids (LEO) should now be visible in the morning sky. This well-known shower is active from November 2-30 with maximum activity occurring near November 17th. The radiant is currently located at 09:52 (148) +24. This area of the sky is located in western Leo, just east of the 3rd magnitude star known as Algenubi (epsilon Leonis). Rates are expected to be near 1 per hour this weekend increasing to 2-3 by the end of the week. Rates seen from the southern hemisphere will be slightly lower. These meteors are best seen during the last hour before dawn when the radiant lies highest above the horizon in a dark sky. With an entry velocity of 70 km/sec., the average Leonid meteor would be of swift velocity.


As seen from the mid-northern hemisphere (45N) one would expect to see approximately 11 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 7 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.


The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.








































































































SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Standard Time North-South
Andromedids (AND) Nov 05 01:47 (027) +30 18 22:00 1 – <1 III
Northern Taurids (NTA) Nov 02 03:52 (058) +23 28 00:00 3 – 2 II
omicron Eridanids (OER) Nov 04 04:06 (061) -00 29 00:00 <1 – <1 IV
Southern Taurids (STA) Oct 29-Nov 03 04:07 (062) +16 27 00:00 2 – 2 II
chi Taurids (CTA) Nov 03 04:51 (073) +28 41 01:00 1 – <1 IV
November Orionids (NOO) Nov 29 04:51 (073) +16 43 01:00 1 – 1 II
Orionids (ORI) Oct 22 07:46 (117) +15 67 04:00 1 – 1 I
nu Eridanids (NUE) Sep 08 08:11 (123) +16 67 05:00 <1 – <1 IV
Leonids (LEO) Nov 17 09:52 (148) +24 70 07:00 1 – <1 I

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Tiny Old Star Has Huge Impact


The newly discovered star system orbits the galaxy on a circular orbit that, like the orbit of the Sun, never gets too far from the plane of the galaxy. On the other hand, most ultra metal-poor stars have orbits that take them across the galaxy and far from its plane. Credit: Kevin Schlaufman.



The new discovery is only 14% the size of the Sun and is the new record holder for the star with the smallest complement of heavy elements. It has about the same heavy element proportion as Mercury, the smallest planet in our solar system. Credit: Kevin Schlaufman.Full resolution JPG


Astronomers use the Gemini Observatory to investigate a tiny star that is likely the oldest known star in the disk of our galaxy. The diminutive star could have a disproportionate impact on our understanding of the age and history of our Milky Way Galaxy. It also provides a unique glimpse into the conditions present in the young Universe shortly after the Big Bang.


A tiny star found in our galactic neighborhood is presenting astronomers with a compelling glimpse into the history of our galaxy and the early Universe. The star has some very interesting characteristics: it’s small, it’s old, and most significantly it’s made of material very similar to that spewed by the Big Bang. To host a star like this suggests that the disk of our galaxy could be up to three billion years older than previously thought.


“Our Sun likely descended from thousands of generations of short-lived massive stars that have lived and died since the Big Bang,” said Kevin Schlaufman of Johns Hopkins University, leader of this study published in the November 5th issue of The Astrophysical Journal. “However, what’s most interesting about this star is that it had perhaps only one ancestor separating it and the beginnings of everything,” Schlaufman adds.


The Big Bang theory dates our Universe at about 13.7 billion years and suggests that the first stars were made almost exclusively of hydrogen and helium. As stars die and gradually recycle their materials into new stars, heavier elements formed. Astronomers refer to stars which lack heavier elements as low metallicity stars. “But this one has such low metallicity,” said Schlaufman, “it’s known as an ultra metal poor star – this star may be one in ten million.


” The star, which goes by the designation 2MASS J18082002-5104378 B, also challenges the assumption that the first stars in the Universe were large, exclusively high-mass and short-lived stars. In addition, its location within the usually active and crowded disk of our galaxy is unexpected.


2MASS J18082002–5104378 B is a part of a binary star system. It is the smaller companion to a larger low-metallicity star observed in 2014 and 2015 by the European Southern Observatory’s Very Large Telescope UT2. Before the discovery of the tiny star, astronomers mistakenly believed that this binary system might contain a black hole or neutron star. From April 2016 to July 2017, Schlaufman and his team used both the Gemini Multi-Object Spectrograph (GMOS) on the Gemini South telescope in Chile and the Magellan Clay Telescope at Las Campanas Observatory to dissect the star system’s light and measure the object’s relative motions, thus discovering the tiny star by detecting its gravitational tug on its partner.


“Gemini was critical to this discovery, as its flexible observing modes enabled weekly check-ins on the system over six months,” Schlaufman confirms.


“Understanding the history of our own galaxy is critical for humanity to understand the broader history of the entire Universe,” said Chris Davis of the United State’s National Science Foundation (NSF). NSF funds the Gemini Observatory on behalf of the United States, additional international partners are listed at the end of this release.


2MASS J18082002–5104378 B has only about 14% the mass of our Sun making it a red dwarf star. While average-sized stars like our Sun live for approximately 10 billion years before extinguishing their nuclear fuel, low-mass stars can burn for trillions of years.


“Diminutive stars like these tend to shine for a very long time,” said Schlaufman. “This star has aged well. It looks exactly the same today as it did when it formed 13.5 billion years ago.”


The discovery of 2MASS J18082002–5104378 B gives astronomers hope for finding more of these old stars which provide a glimpse at the very early Universe. Only about 30 ultra metal poor stars have been identified. “Observations such as these are paving the way to perhaps one day finding that ever elusive first generation star,” concludes Schlaufman.


Johns Hopkins University news release


Media Contacts:

Peter Michaud
Public Information and Outreach manager
Gemini Observatory
Email: pmichaud@gemini.edu
Phone: 808-974-2510
Cell: 808-936-6643

Jill Rosen
Senior Media Relations Representative
Johns Hopkins University
Email: jrosen@jhu.edu
Desk: 443-997-9906
Cell: 443-547-8805

Science Contact:

Kevin Schlaufman
Assistant Professor of Physics and Astronomy
Johns Hopkins University
Email: kschlaufman@jhu.edu
Office Phone: 410-516-3295
Cell Phone: 814-490-9177






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Celtic Gods and Figureheads, Tullie House Museum and Gallery, Carlisle, 4.11.18.











Celtic Gods and Figureheads, Tullie House Museum and Gallery, Carlisle, 4.11.18.


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