вторник, 9 октября 2018 г.

A Pristine Star

Pristine_221.8781+9.7844 and its surroundings

Credits: N. Martin and the Pristine collaboration, DECam Legacy Survey, Aladin Sky Atlas.”

The spectrum observed with the William Herschel Telescope on La Palma for Pristine_221.8781+9.7844, compared to the spectrum of the Sun. As can be seen, the spectrum of Pristine_221.8781+9.7844 contains far fewer feature. Only hydrogen (the large dips) and a small amount of Calcium (the small dip) can be seen in the spectrum of Pristine_221.8781+9.7844. This tells us that the star is ultra metal-poor, it has an unusual lack of heavy elements in its atmosphere, which means that it belongs to an early generation of stars formed in the Galaxy. Credits: E. Starkenburg and the Pristine collaboration.

An international team of researchers using Megacam at the Canada-France-Hawaii Telescope discovered a star that is among the least polluted by heavy elements. Such stars are extremely rare survivors of the early ages of the universe, when the gas stars are formed from hadn’t yet been contaminated by the remnants of successive generations of dead stars. This new discovery opens a window onto star formation at the beginning of our universe.

For the study of the early universe, astronomers have different methods at their disposal. One is to look far into the Universe and back in time, to see the first stars and galaxies growing. Another option is to examine the oldest surviving stars of our home galaxy, the Milky Way, for information from the early universe. The “Pristine” survey, led by Nicolas Martin (CNRS/INSU, University of Strasbourg) and Else Starkenburg (Leibniz Institute for Astrophysics, Potsdam) is looking for exactly these pristine stars.

The early universe contained almost exclusively hydrogen and helium. Throughout the life of any star, the thermonuclear reactions takes place at their core create elements heavier than helium (carbon, oxygen, calcium, iron, etc.) from the hydrogen and helium making up the vast majority of their gas. When these stars explode at the end of their lifetime, they enrich the surrounding gas of with these “heavy” elements. This newly enriched gas serves as the birthplace for the next generation of stars. Each subsequent generation becomes more and more enriched with heavy elements created by their ancestors. Our sun, for example, is made up of about 2% of these heavy elements. On the contrary, very old stars contain very small quantities of heavy elements. They are however extremely rare and extremely difficult to find in our cosmic neighborhood.

The discovery of the star unveiled by the “Pristine” team was made possible thanks to a new mapping of the night sky conducted at the Canada-France-Hawaii Telescope, located in Hawaii. The Pristine team uses Megacam at CFHT to observea small part of the ultra-violet light that is very sensitive to the abundance in heavy elements and enables a discrimination of the rare, pristine stars from the much more common stars polluted in heavy elements. The team estimates that less than one star in a million is as pristine as the newly discovered star. Follow up observations with spectrographs of the Isaac Newton Group, located in Spain, and the European Southern Observatory, located in Chile, confirmed that star Pristine_221.8781+9.7844 is almost void of heavy elements, with the concentration of heavy elements being 10,000 to 100,000 times lower than those found in the atmosphere of our sun.

This star, whose discovery is presented in a publication of the Monthly Notices of the Royal Astronomical Society, Oxford University Press, brings strongly needed constraints on star formation models of the very first stars and opens a window onto an epoch that is still poorly understood. The discovery of Pristine_221.8781+9.7844 at the start of the “Pristine” project bodes well for the discovery of many such stars in the years to come.

Additional information

Link to the Paper

Contact Information:

Media contacts

Mary Beth Laychak, Outreach manager
Canada-France-Hawaii Telescope

Science contacts

Else Starkenburg
Leibniz-Institut fur Astrophysik Potsdam

Nicolas Martin
Observatory Astrononomy de Strasbourg

Archive link

Elephants and ivory – protecting the world’s largest land mammal

In the run-up to the forthcoming illegal wildlife trade conference in London, Fauna & Flora international (FFI) has made a point of shining the spotlight on some of the neglected casualties of wildlife crime, from lizards and lansan trees to seahorses and sturgeon. But this passion for pangolins and other less well-publicised victims of large-scale poaching and trafficking doesn’t preclude us from protecting some of the most iconic species on the planet.

Elephants and ivory – protecting the world's largest land mammal
Bull elephant slaughtered for its ivory by poachers equipped
with automatic weaponry [Credit: JABRUSON]

Mammoth task

Elephant conservation – in Asia as well as Africa – has featured prominently throughout FFI’s long history. In addition to securing the landscapes and corridors of habitat that these massive mammals require, and defusing the conflict between people and elephants that may arise when their worlds collide, we are also addressing the issue of ivory poaching and its devastating impact on elephants.

The ivory trade isn’t a recent phenomenon – witness the naming of Côte d’Ivoire by French merchant explorers as long ago as the 15th century. Not long after FFI was first established in 1903, its founding fathers were already pressing the colonial authorities for an increase in the minimum permissible weight of any tusk intended for sale, saying it would be ‘a disgrace to our age to allow such a fine and noble animal as the African elephant to perish’.

Those words are equally applicable today. The difference is that we’re rapidly running out of elephants to protect. The poaching epidemic – fuelled by rocketing demand for ivory from an affluent and rapidly expanding group of consumers in countries such as China – continues to take a heavy toll. A wave of assaults by heavily armed poachers linked to increasingly sophisticated trafficking networks is posing an unprecedented threat to the future of the world’s largest land animal.

Demand for ivory is by no means the only threat to the African elephant’s survival; habitat loss, hunting for bushmeat and revenge killing in retaliation for crop raiding all contribute significantly to the downward trend. But ivory poaching is without doubt the main driver of the current crisis.

Elephants and ivory – protecting the world's largest land mammal
The versatile trunk of an elephant – used here for browsing – fulfils many other purposes
beyond collecting food [Credit: Juan Pablo Moreiras/FFI]

Massive loss

The senseless slaughter of a magnificent tusker for its super-sized incisors is all the more sickening once you gain an insight into the beast behind the ivory. Elephants have the largest brain of any terrestrial mammal, a memory impressive enough to have inspired a proverb, and a complex matriarchal social structure that creates powerful family bonds – they even appear to mourn their dead.

Their awesome physical attributes include a multi-purpose trunk with over 40,000 muscles. This built-in toolkit is capable of plucking a berry from a bush or uprooting a tree. It’s a water detector, power shower, snorkel, drinking straw, extendable arm, trumpet, early-warning system, hand of friendship and defensive weapon all rolled into one.

Saving African elephants – and their Asian counterparts – is not just a moral imperative. The ecological and economic arguments for protecting them are equally persuasive. As a keystone species, they play a unique role in shaping their ecosystem by, for example, maintaining grassland habitat, creating waterholes and dispersing seeds. They are a massive (in both senses) tourist attraction, generating vital revenue for governments and communities.

Combating the ivory trade on both sides of the globe

The vast Niassa National Reserve – one of Africa’s last great wilderness areas – harbours 40% of Mozambique’s entire elephant population. By virtue of its immense size, the reserve is difficult to protect; patrolling an area the size of Denmark isn’t a realistic option. The growing demand for elephant ivory and consequent explosion in poaching activity in Niassa exacerbated that problem.

Elephants and ivory – protecting the world's largest land mammal
Stockpile of confiscated elephant ivory [Credit: JABRUSON]

In 2012, FFI took the strategic decision to secure a key area of the reserve – at the coalface of the poaching threat – by establishing Chuilexi Conservancy as a safe haven for Mozambique’s beleaguered elephants and other wildlife at the heart of Niassa. An ambitious programme of anti-poaching measures – including year-round, conservancy-wide patrols by better-equipped rangers – is helping to alleviate the unprecedented poaching pressure. Crucially, the conservancy is also demonstrably benefiting the local communities on whom long-term success in ending wildlife crime will ultimately depend.
In 2017, funding from the UK government’s Department for Environment, Food & Rural Affairs (Defra) provided a welcome boost to Cambodia’s first conservation genetics laboratory, which FFI helped to create. The new grant will support DNA analysis – coordinated by our partner Royal Zoological Society of Scotland – to identify the origin of seized elephant ivory, helping us to stay ahead of the curve and disrupt ivory trade networks in a country that has been identified by CITES as a potential hub for illicit trafficking of ivory following China’s near-total ban on the trade.

What happens next?

The impact of the decision taken this week at the 70th meeting of the CITES Standing Committee to release six countries, including China, from the National Ivory Action Plan process remains to be seen. In the meantime, all eyes will be on the London conference.

Let’s hope that any declarations of intent include proposals to safeguard Asian elephants, which are much closer to the brink than their African counterparts. In line with our policy of championing species that might otherwise drop off the radar, FFI has taken great pains to put these neglected cousins on the conservation map, not least when we established the Asian Elephant Conservation Programme in the mid 1990s. But that’s another story.

Author: Tim Knight | Source: Fauna & Flora International [October 05, 2018]



Corpus of Jewish inscriptions found in Greece published by museum

The corpus of all Jewish inscriptions found in mainland Greece and the islands was recently published by the Jewish Museum of Greece (JMG) in Athens.

Corpus of Jewish inscriptions found in Greece published by museum
Credit: CIJG/Jewish Museum

The Corpus Inscriptionum Judaicarum Graeciae contains inscriptions found at antiquities ephorates in Greece and museums dating from the 4th century BC/BCE to the 15th century AD/CE.

As Jeanette Battinou, archaeologist and director of JMG says in the foreword, the effort began in 1999, when the museum moved to its current facilities on Nikis Street in central Athens.

The purpose of the collection was to decipher regional and unpublicized findings, and contribute to historical research.

Battinou contacted the Ministry of Culture, antiquities departments and museums in August 2000 and the project progressed slowly up to 2006. Next year, efforts picked up again when archaeologist Anastasia Loudarou joined the project team.

The edition is meant for both the wider public and archaeologists and includes about 150 inscriptions related to Jewish culture and/or in Hebrew, classified by location. Each item is photographed and described.

A team of Greek and foreign specialists collaborated on the edition, which was funded by Aliki and Nora Benroubi, and JMG board member Samouil (Makis) Matsas.

Source: AMNA [October 05, 2018]



Lessons from the 1918 flu pandemic, 100 years on

This year marks the centenary of the 1918 influenza pandemic, the worst flu outbreak in recorded history. A new study into the human, viral and societal factors behind its severity provides valuable lessons that could save lives in future pandemics. Publishing in Frontiers in Cellular and Infection Microbiology, the authors warn that while the world is better prepared than 100 years ago, new challenges will affect the impact of the next influenza virus pandemic — including changing population demographics, antibiotic resistance and climate change.

Lessons from the 1918 flu pandemic, 100 years on
Influenza victims crowd into an emergency hospital near Fort Riley, Kansas, 1918
[Credit: National Museum of Health/AP]

“We’ve seen three additional influenza pandemics since 1918: the 1957 ‘Asian’ flu, the 1968 ‘Hong Kong’ flu and the 2009 ‘swine’ flu. Although milder than the 1918 pandemic, these highlight the constant threat that influenza virus poses to human health,” says University of Melbourne Professor Katherine Kedzierska of the Peter Doherty Institute for Infection and Immunity (Doherty Institute), Australia.

“Like the 1918 pandemic, the severity of any future outbreak will result from a complex interplay between viral, host and societal factors,” adds the Doherty Institute’s Dr. Carolien van de Sandt. “Understanding these factors is vital for influenza pandemic preparedness.”

The 1918 influenza pandemic infected a third of the world’s population and killed 50 million people. However, many people managed to survive a severe infection and others displayed only mild symptoms.

“We always wondered why some people can effectively control viral infections while others succumb to the disease,” says Kedzierska. To investigate this — and why the 1918 outbreak was so virulent — Kedzierska, van de Sandt and Dr. Kirsty Short of Australia’s University of Queensland reviewed a large number of influenza studies.

One explanation for the pandemic’s severity is the viral strain itself. Some studies show the 1918 virus could spread to other tissues beyond the respiratory tract, resulting in more widespread damage. In addition, the virus had mutations that allowed it to be more easily transmitted between humans.

Unlike in 1918, when the cause of influenza was unknown, scientists today can evaluate the pandemic potential of new viruses, both in animals and once a strain has crossed into humans. But, as the authors point out, such surveillance efforts are required across the world — a factor that will become even more important with continued climate change.

Lessons from the 1918 flu pandemic, 100 years on
The severity and transmissibility of pandemic influenza viruses are the result of a complex interplay of viral,
host and external factors. We have come a long way since 1918 and pandemic preparedness programs have
 learned from the 1918 and later pandemic outbreaks. Although unlikely, we cannot exclude the possibility
that an influenza pandemic with similar severity will repeat itself in the future. However, lessons
learned from the 1918 influenza pandemic will ensure that we are better prepared
[Credit: Kedzierska, Van de Sandt and Short]

“Climate changes affect animal reservoirs of influenza viruses and bird migration patterns. This could spread viruses to new locations and across a wider range of bird species,” says van de Sandt.

The authors identify public health as another important factor. In 1918, people suffering from malnutrition and underlying diseases, such as tuberculosis, were more likely to die from the infection. This is still relevant today: climate change could result in crop losses and malnutrition, while increasing antibiotic resistance could see bacterial infections becoming more prevalent. Future pandemics will also face the challenge of obesity, which increases the risk of dying from influenza.

Population demographics also play a role. Strangely, one of the most severely affected groups in 1918 was one that is usually resilient — young adults. The researchers think older people may have been spared due to previous exposure to other viruses, giving them greater immunity to the 1918 viral strains. However, given that seasonal flu typically kills the very old, today’s aging population will likely be another challenge in any future pandemic.

“Providing emergency vaccines during future pandemics should take in account different age groups, viral and host factors,” says Kedzierska.

The researchers also report that basic methods to reduce disease transmission, such as banning public gatherings and hand washing, helped to reduce levels of infection and death during the 1918 pandemic — but only when they were applied early and for the entire duration of the pandemic.

“Until a broadly-protective vaccine is available, governments must inform the public on what to expect and how to act during a pandemic,” says van de Sandt. “An important lesson from the 1918 influenza pandemic is that a well-prepared public response can save many lives.”

If a similar pandemic occurred today, scientists estimate the death toll could be as high as 147 million. While it is impossible to know when or how the next flu pandemic will emerge, one thing is certain — future pandemics won’t be exactly like the 1918 pandemic, but it still has lessons to teach us.

Source: Frontiers [October 08, 2018]



Small-brained female guppies aren’t drawn to attractive males

Female guppies with smaller brains can distinguish attractive males, but they don’t recognise them as being more appealing or choose to mate with them, according to a new study by UCL and Stockholm University researchers.

Small-brained female guppies aren't drawn to attractive males
These are two male Trinidadian guppies, showing the range of color patterns observed in the population
[Credit: Dr Jake Morris (UCL Genetics, Evolution & Environment)]

The study, published in Nature Ecology & Evolution, adds weight to the link between mate preference and cognitive ability.

“One of the biggest decisions a female guppy has to make in its life is choosing who to mate with. It is very important, so you might think they would all prefer a single most attractive male,” said one of the study’s senior authors, Professor Judith Mank (UCL Genetics, Evolution & Environment).

“But we found that it takes a certain amount of brain-power to size up an attractive mate.”

The research team studied female Trinidadian guppies in two groups differentiated by brain size and mating preferences. The fish were exposed to males that were either colourful with long tails, which are more commonly attractive to females, or males that were less colourful.

The researchers allowed the female fish to evaluate the males, keeping the fish in separate tanks so exposure was only visual. They then measured gene expression on the brain tissue of the females to gauge which genes were being actively expressed in two brain areas involved in processing visual signals and in integrating those signals to make complex decisions.

The researchers found that all of the females exhibited similar patterns of activity in the sensory processing areas of the brain when they saw an attractive male, suggesting they can all see the difference between attractive and dull males. But only the larger-brained fish showed different patterns of activity in decision-making brain regions when they saw attractive or unattractive males.

Among the females with clear mate preferences, the genes that were activated by seeing an attractive male were more strongly connected to decision-making pathways.

“Guppies are an excellent example of ecological adaptation, and this raises questions about potential trade-offs with increasing intelligence,” said the study’s first author, Dr Natasha Bloch (UCL Genetics, Evolution & Environment).

“Brighter colours could attract predators, so there’s an assumption that fish in environments with many predators would evolve to be less colourful, but there may be a more complex relationship involving predation pressure, female choice and cognitive ability,” she said.

“While the exact mechanisms behind female preferences in guppies require further investigation, we know that not choosing colourful and long-tailed males would be disadvantageous, as their sons would not inherit the optimal genes for appearance, and would thus have a harder time finding a mate,” added co-author Dr Alberto Corral-Lopez (Stockholm University).

“By clarifying what happens in the earliest stage of female mate preference behaviour in animals with different cognitive abilities, we have shed light on the structure of the genetic networks underlying female mate preferences, adding to our understanding of how animals evolve different mating patterns,” said co-senior author Professor Niclas Kolm (Stockholm University).

Source: University College London [October 08, 2018]



Getting a grip on the slow but unique evolution of sharks

Scientists at the RIKEN Center for Biosystems Dynamics Research (BDR) in Japan, in collaboration with other Japanese institutes and aquariums, have decoded the whole genomes of two shark species for the first time and improved the whale shark genome sequences released previously. By analyzing the genomes and comparing them with those of other vertebrate species, they have constructed an overview of their unique life histories and evolutionary paths. This work was published online in Nature Ecology and Evolution.

Getting a grip on the slow but unique evolution of sharks
Whale Shark [Credit: WikiCommons]

Advances in genome sequencing have made it possible to compare genomes from different species, giving us insights into their evolutionary histories and characteristics. While data for many organisms are available, to date, genome sequencing for sharks has been hampered by their huge genomes, which are even larger than the human genome. The notable exception is the elephant shark, although strictly speaking this fish is not professionally classified as a true shark.

Sharks have many unique characteristics, including their body structures, reproductive systems, way of sensing, and extreme longevity — a shark species is known to live for more than three centuries. Fully decoded shark genomes will be a tremendous help to research aimed at discovering the molecular bases for these qualities.

With this ultimate goal in mind, a research team led by Shigehiro Kuraku at RIKEN BDR analyzed shark genomes using cutting-edge DNA sequencing technologies and comparative bioinformatics that were able to deal with gigabase-scale sequences. They chose two primary species — the brownbanded bamboo shark and the cloudy catshark — because they can be raised in aquariums, making it relatively easy to constantly obtain live specimen. They also performed an improved assembly of the whale shark genome, which had been previously released.

One of the puzzles regarding sharks is why their genomes are so large. The team found that the large genome size is due to massive insertions of repetitive elements. At the same time, shark genomes have been evolving slowly, which means that they have kept many ancestral gene repertoires and can be thought of as “living fossils” in a genomic sense.

The team found that sharks have counterparts of human genes regulating growth, reproduction, and homeostasis, such as obesity, appetite, and sleep, suggesting that elements of our molecular machinery for basic physiology have existed for more than 450 million years, before sharks split from our common ancestors.

The newly decoded shark genomes have already provided a number of insights, including those related to visual function. The researchers analyzed light absorption of visual pigments in the whale shark and found that its rhodopsin pigment is tuned to sense relatively short wavelengths of lights — close to 480 nm — that can penetrate deep-sea water. This is not true in its close relative the bamboo shark, and the researchers speculate that the altered rhodopsin function is related to the unique lifestyle of the whale shark, which dives down to about 2000 m when not feeding near the surface. This discovery was achieved by combining DNA sequence analysis and laboratory work using synthesized materials, but without animal experiments.

The team also showed that all three of the analyzed shark species have relatively few olfactory receptor genes, implying that they depend on other systems, such as sensing electromagnetic fields, for navigation.

“Our results will fill a long-standing gap in the genome biology of animals, and will also help us gain greater understanding about metabolism, reproductive cycle, and health monitoring of sharks,” says Keiichi Sato, an author and the deputy director of Okinawa Churaumi Aquarium. “Such understanding should contribute to the conservation of marine environments as well as to sustainable husbandry and exhibitions at aquariums that allow everyone to experience biodiversity up close.”

Source: RIKEN [October 08, 2018]



NASA Selects Two Companies to Help Take Out the Deep Space Trash

NASA logo.

Oct. 9, 2018

NASA has selected Sierra Nevada Corporation (SNC) and UTC Aerospace Systems (UTAS) to develop systems that can reduce trash volume, and process the resulting atmosphere contaminants during deep space missions. The U.S. companies responded to NASA’s Next Space Technologies for Exploration Partnerships (NextSTEP) Appendix F: Logistics Reduction (LR) in Space by Trash Compaction and Processing System (TCPS) Broad Agency Announcement, issued in July.

Managing trash aboard the International Space Station is an ongoing challenge for astronauts, who must manually compact and store garbage until they can offload it in departing ships bound for touchdown on Earth or directed into a controlled incineration during the descent through Earth’s atmosphere. Missions to the Moon or Mars will not have the benefit of the space station’s robust supply chain with regular visiting vehicles, so NASA is investing early to tackle the challenge of trash management in deep space.

Image above: Sierra Nevada Corporation has evolved heat melt compaction technology from initial development and demonstration efforts to the design of the Trash Compaction and Processing System planned for testing aboard the International Space Station. Image Credit: Sierra Nevada Corporation.

SNC (Madison, Wisconsin) and UTAS (Houston, Texas) will have approximately 18 months to develop and test their trash compaction and processing systems under Phase A, to a point at which a preliminary design review (PDR) can be conducted. PDR is a standard step in the engineering process that confirms a system’s design can meet all requirements with acceptable risk and within the estimated cost and schedule. Phase B will be a separate, follow-on procurement with a 24-30 month period of performance to complete flight hardware design in preparation for a flight to demonstrate the capability on the International Space Station.

Both companies proposed trash compaction chambers that would use heat cycles to reduce and isolate gas or liquid contaminants to be vented outside the spacecraft. SNC also is designing a complementary system to recover water from solid waste and developing options to determine if it’s possible to treat contaminants for safe integration with onboard recycling systems.

Image above: The UTAS trash compaction and processing system Removes the majority of the air and water from the trash at low temperatures. The system recovers about 85 percent of air in the trash chamber, and about 90 percent of water suspended in the trash. Image Credit: UTC Aerospace Systems.

SNC and UTAS have already demonstrated their microgravity waste management competencies. UTAS is on contract with NASA to manage a different kind of waste—their Universal Waste Management System will be the toilet that astronauts in deep space use. SNC has experience designing space trash processing concepts under NASA’s Small Business Innovation Research program.

As with other NextSTEP partners, SNC and UTAS each will contribute 20 percent of their own corporate resources toward the overall effort – a measure to encourage simultaneous investment in potential commercial applications of their designs. NASA’s Advanced Exploration Systems Division manages NextSTEP partnerships, which support commercial development and reduce risk for deep space mission capabilities.

Related links:

Space by Trash Compaction and Processing System (TCPS): https://www.nasa.gov/nextstep/trash

Small Business Innovation Research: https://sbir.nasa.gov/

NASA’s Advanced Exploration Systems Division: https://www.nasa.gov/directorates/heo/aes/index.html

Moon to Mars: https://www.nasa.gov/topics/moon-to-mars/

Sierra Nevada Corporation (SNC): https://www.sncorp.com/

UTC Aerospace Systems (UTAS): https://utcaerospacesystems.com/

Images (mentioned), Text, Credits: NASA/Erin Mahoney.

Greetings, Orbiter.chArchive link

Meteor Activity for September 22-28, 2018

               Eliot Herman captured this fine example of a September epsilon Perseid on September 11, 2018 from Tucson, Arizona USA

During this period the moon will reach its full phase on Tuesday September 25th. At that time the moon will lie opposite the sun and will lie above the horizon all night long. This is the worst time of the month to view meteor activity as the brilliant moonlight will obscure all but the brightest meteors. The estimated total hourly meteor rates for evening observers this week is near 2 as seen from mid-northern latitudes and 1 for those viewing from subtropical southern latitudes (25S). For morning observers the estimated total hourly rates should be near 8 for those viewing from mid-northern latitudes and 6 for those viewing from subtropical southern latitudes (25S). 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. Rates are reduced during this period due to moonlight. 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 September 22/23. 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 21:00 LDT

Radiant Positions at 21:00

Local Daylight Saving Time

Radiant Positions at 01:00 LDT

Radiant Positions at 0100

Local Daylight Saving Time

Radiant Positions at 5:00 LDT

Radiant Positions at 05:00

Local Daylight Saving Time

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

Details of each source will continue next week as moonlight becomes less of a nuisance.

RA (RA in Deg.) DEC Km/Sec Local Daylight Saving Time North-South
Oct. Capricornids (OCC) Oct 03 19:32 (293) -12 10 21:00 <1 – <1 IV
Northern Taurids (NTA) Nov 02 00:30 (007) +10 28 02:00 1 – 1 II
Southern Taurids (STA) Oct 29 00:49 (012) +03 27 02:00 1 – 1 II
September Epsilon Perseids (SPE) Sep 10 04:11 (063) +41 65 06:00 <1 – <1 II
Orionids (ORI) Oct 22 04:24 (066) +17 66 06:00 <1 – <1 II
nu Eridanids (NUE) Sep 24 05:05 (076) +06 67 07:00 1 – 1 IV
Daytime Sextantids (DSX) Sep 29 09:54 (149) +01 33 12:00 <1 – <1 IV

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2018 October 9 NGC 1672: Barred Spiral Galaxy from Hubble Image…

2018 October 9

NGC 1672: Barred Spiral Galaxy from Hubble
Image Credit: Hubble Legacy Archive, NASA, ESA; Processing & Copyright: Domingo Pestana & Raul Villaverde

Explanation: Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar. Prominently barred spiral galaxy NGC 1672, featured here, was captured in spectacular detail in an image taken by the orbiting Hubble Space Telescope. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bright bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Light takes about 60 million years to reach us from NGC 1672, which spans about 75,000 light years across. NGC 1672, which appears toward the constellation of the Dolphinfish (Dorado), is being studied to find out how a spiral bar contributes to star formation in a galaxy’s central regions.

∞ Source: apod.nasa.gov/apod/ap181009.html

HiPOD (21 September 2018): A Small Crater on North Polar Layered…

HiPOD (21 September 2018): A Small Crater on North Polar Layered Deposits 

   – Even at HiRISE resolution, it’s difficult to spot in black and white, but the color enhanced picture at full resolution tells a different story. (317 km above the surface. Black and white is less than 5 km across; enhanced color is less than 1 km.)

NASA/JPL/University of Arizona

HiPOD (22 September 2018): Up Above the Dust CloudsWhen much of…

HiPOD (22 September 2018): Up Above the Dust Clouds

When much of Mars was enshrouded by a recent massive dust storm, HiRISE captured this clear view of the surface because of the target’s unique location.

Olympus Mons is the biggest volcano in the Solar System, reaching a height of nearly 25 kilometers, almost 3 times taller than Mount Everest on Earth. This view of the western flank of Olympus Mons shows the surface at an elevation of 21.3 kilometers, far above the swirling dust clouds. In this picture, we can see details of the flows that erupted over millions of years to form the enormous shield volcano.

A similar situation unfolded in the early days of Mars exploration, when NASA’s Mariner 9 spacecraft reached orbit around Mars in 1971 and was soon joined by two Soviet space probes, Mars 2 and Mars 3. Mars was blanketed at the time by a global dust storm that persisted for months and completely obscured the surface of the planet. As the storm ended and the dust began to settle out of the atmosphere, the tops of the giant volcanoes were the first portions of the surface to be seen.

Unfortunately the missions of the Soviet probes ended before the rest of the planet was clearly visible. Mariner 9 was able to wait out the dust storm and discover the surface features (such as the Valles Marineris canyon system, named after Mariner 9) that had previously been hidden beneath the dust clouds.

NASA/JPL/University of Arizona

HiPOD (23 September 2018): Sustained Bright Patches at the…

HiPOD (23 September 2018): Sustained Bright Patches at the Margins of North Polar Layered Terrain 

   – 320 km above the surface. (NASA/JPL/University of Arizona)

HiPOD (24 September 2018) Clays in a Well-Preserved Impact…

HiPOD (24 September 2018) Clays in a Well-Preserved Impact Crater in Acidalia Planitia 

   – 291 km above the surface. Black and white is 5 km across; enhanced color is less than 1 km.

NASA/JPL/University of Arizona

HiPOD (25 September 2018): A Clay Outcrop Near Maja Valles …

HiPOD (25 September 2018): A Clay Outcrop Near Maja Valles

   – Maja Valles is a large, ancient outflow channel in the Lunae Palus quadrangle on Mars. The name is a Nepali word for “Mars”, and Pparts of the system have been partially buried by thin volcanic debris. (283 km above the surface. Black and white is 5 km across; enhanced color is less than 1 km.)

NASA/JPL/University of Arizona

HiPOD (26 September 2018): Knobs on the Rim of a Circular…

HiPOD (26 September 2018): Knobs on the Rim of a Circular Feature

   – And there might be clays on this cluster of knobs which as a unit, look very interesting. (298 km above the surface. Black and white is 5 km across; enhanced color is less than 1 km.)

NASA/JPL/University of Arizona

HiPOD (27 September 2018): That Crazy Terrain   – This is the…

HiPOD (27 September 2018): That Crazy Terrain

   – This is the floor of a crater in Utopia Planitia. (298 km above the surface. Black and white is 5 km across; enhanced color is less than 1 km)

NASA/JPL/University of Arizona

HiPOD (28 September 2018): Simply Classical   – Ah, the joy of a…

HiPOD (28 September 2018): Simply Classical

   – Ah, the joy of a simple and well-preserved bowl-shaped impact crater in Idaeus Fossae. (298 km above the surface, less than 5 km across.)

NASA/JPL/University of Arizona

HiPOD (29 September 2018): The Wall of East Candor Chasma   –…

HiPOD (29 September 2018): The Wall of East Candor Chasma

   – The science rationale for this observation: “We would like to check whether a feature observed in a Context Camera image is or not a 50-meter thick dyke. HiRISE resolution will reveal if this feature has structures typical of dyke margins. If It is a dyke, then because of its thickness, its associated stress field is an important constraint for the evolution of this part of Valles Marineris. If it is not a dyke, then it could be another type of fracture that could also inform us about the formation of Candor Chasma.” (266 km above the surface, less than 5 km across)

NASA/JPL/University of Arizona

Newly detected microquasar gamma-rays ‘call for new ideas’

The first-ever detection of highly energetic radiation from a microquasar has astrophysicists scrambling for new theories to explain the extreme particle acceleration. A microquasar is a black hole that gobbles up debris from a nearby companion star and blasts out powerful jets of material.

Newly detected microquasar gamma-rays 'call for new ideas'
The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, located 13,500 feet above sea level
on the slopes of Mexico in the Volcan Sierra Negra [Credit: LANL]

“What’s amazing about this discovery is that all current particle acceleration theories have difficulties explaining the observations,” said Hui Li, a theorist in Los Alamos National Laboratory’s Theoretical Division who served on the team. “This surely calls for new ideas on particle acceleration in microquasars and black hole systems in general.”

The team’s observations, described in the journal Nature, strongly suggest that particle collisions at the ends of the microquasar’s jets produced the powerful gamma rays. Scientists think that studying messages from this microquasar, dubbed SS 433, may offer a glimpse into more extreme events happening at the centers of distant galaxies.

The team gathered data from the High-Altitude Water Cherenkov Gamma-Ray Observatory (HAWC), which is a mountain-top detector in Mexico that observes gamma ray emission from supernova remnants, rotating dense stars called pulsars, and quasars. Los Alamos, funded by Department of Energy Office of High-Energy Physics, helped build HAWC, which was completed in 2015.

Now, the team has studied one of the most well-known microquasars, which is about 15,000 light years away.

Quasars are massive black holes that suck in material from the centers of galaxies, rather than feeding on a single star. They actively emit radiation visible across the universe. But most are so far away that the majority of the detected quasars must have their jets aimed at Earth, making them easier to spot, like looking directly into a flashlight. In contrast, SS 433’s jets are oriented away from Earth, which makes them more difficult to observe. However, HAWC was able to detect similarly energetic light when viewed from the side, allowing the full length of the jet to be visible.”

“The new findings improve our understanding of particle acceleration in jets of microquasars, which also sheds light on jet physics in much larger and more powerful extragalactic jets in quasars,” said Hao Zhao, of Los Alamos National Laboratory’s Physics Division.

HAWC, located roughly 13,500 feet above sea level near the Sierra Negra volcano in Mexico, catches the fast-moving rain of particles with a detector composed of more than 300 tanks of water, each about 24 feet in diameter. When the particles strike the water, they produce a shock wave of blue light, called Cherenkov radiation. Cameras in the tanks detect this light, allowing scientists to compile the origin story of the gamma rays.

The HAWC collaboration examined data taken from more than 1,017 days of observation and saw evidence that gamma rays were coming from the ends of the microquasar’s jets, rather than the central part of the star system. Based on their analysis, the researchers concluded that electrons in the jets attain energies that are about 1,000 times higher than can be achieved using earth-bound particle accelerators, such as the Large Hadron Collider. The jet electrons collide with the low-energy microwave background radiation that permeates space, resulting in gamma ray emission. This is a newly observed mechanism for getting high-energy gamma rays out of this kind of system and is different from what scientists have observed when the jets are aimed at earth.

Until now, instruments have not seen such detailed information about SS 433 because, according to the existing sky maps, this microquasar is tucked up into a bright supernova remnant that also emits gamma rays. But HAWC’s wide field of view and long baseline looks at the whole sky every night. This feature enabled the detector, analogous to a camera with a long exposure and wide-angle lens, to resolve the microquasar’s distinct features, even though it is obscured by the surroundings.

Source: DOE/Los Alamos National Laboratory [October 04, 2018]



Surprising chemical complexity of Saturn’s rings changing planet’s upper...

Political humorist Mark Russel once joked, “The scientific theory I like best is that the rings of Saturn are composed entirely of lost airline luggage.”

Surprising chemical complexity of Saturn's rings changing planet's upper atmosphere
During Cassini’s ‘Grand Finale’ plunge into Saturn’s innermost ring and upper atmosphere in 2017, the mass spectrometer
 aboard the probe sampled chemicals at altitudes between Saturn’s rings and atmosphere [Credit: NASA]

Well, there’s no luggage, it turns out. But a new study appearing in Science based on data from the final orbits last year of NASA’s Cassini spacecraft shows the rings of Saturn — some of the most visually stupendous objects in the universe — are far more chemically complicated than previously was understood.

Furthermore, the paper shows the innermost D ring of the gas giant is hurling dust grains coated in its chemical cocktail into the planet’s upper atmosphere at an extraordinary rate as it spins. Over long timescales, the researchers say this infalling material may change the carbon and oxygen content of the atmosphere.

“This is a new element of how our solar system works,” said Thomas Cravens, professor of physics & astronomy at the University of Kansas and a co-author of the new paper. “Two things surprised me. One is the chemical complexity of what was coming off the rings — we thought it would be almost entirely water based on what we saw in the past. The second thing is the sheer quantity of it — a lot more than we originally expected. The quality and quantity of the materials the rings are putting into the atmosphere surprised me.”

Cravens is a member of Cassini’s Ion and Neutral Mass Spectrometer (INMS) team. During Cassini’s “Grand Finale” plunge into Saturn’s innermost ring and upper atmosphere in 2017, the mass spectrometer aboard the probe sampled chemicals at altitudes between Saturn’s rings and atmosphere.

More than simply water, the INMS found the rings to be composed of water, methane, ammonia, carbon monoxide, molecular nitrogen and carbon dioxide.

“What the paper is describing is the environment in the gap between the inner ring and upper atmosphere, and some of the things found were expected, such as water,” Cravens said. “What was a surprise was the mass spectrometer saw methane — no one expected that. Also, it saw some carbon dioxide, which was unexpected. The rings were thought to be entirely water. But the innermost rings are fairly contaminated, as it turns out, with organic material caught up in ice.”

Surprising chemical complexity of Saturn's rings changing planet's upper atmosphere
The new paper in Science, shows the innermost D ring of the gas giant is hurling dust grains coated in its chemical cocktail into the planet’s upper atmosphere at an extraordinary rate as it spins. Over long timescales, the researchers say this infalling material may change the carbon and oxygen content of the atmosphere [Credit: NASA]

A further new finding from Cassini’s mass spectrometer showed large amounts of the chemical brew from Saturn’s D ring is flung into the planet’s upper atmosphere by the ring spinning faster than the planet’s atmosphere itself.

“We saw it was happening even though it’s not fully understood,” the KU researcher said. “What we saw is this material, including some benzine, was altering the uppermost atmosphere of Saturn in the equatorial region. There were both grains and dust that were contaminated.”

Cravens said the findings could cast new light on mechanisms underpinning our solar system as well as other solar systems and exoplanets — and also prompt a host of new scientific questions.

“This could help us understand, how does a planet get rings? Some do, some don’t,” he said. “What’s the lifetime of a ring? And what’s replenishing the rings? Was there a time when Saturn didn’t have rings? How did that composition get into there in the first place? Is it left over from the formation of our solar system? Does it date back to proto pre-solar nebula, the nebula that collapsed out of interstellar media that formed the sun and planets?”

According to Cravens, the higher-than-expected rate of material being expelled from Saturn’s D Ring into the planet’s upper atmosphere, or ionosphere, is sufficient that astronomers now think the lifespan of the ring may be briefer than previously estimated.

“Because of this data, we now have shortened the lifetime of inner rings because of the quantity of material being moved out — it’s much more than we thought before,” Cravens said. We know that it’s bumping material out of the rings at least 10 times faster than we thought. If it’s not being replenished, the rings aren’t going to last — you’ve got a hole in your bucket. Jupiter probably had a ring that evolved into the current wispy ring, and it could be for similar reasons. Rings do come and go. At some point they gradually drain away unless somehow they’re getting new material.”

A video clip to animate the trajectory of a charged nanograin ejected from Saturn’s main rings under the influence 

of Saturn’s gravity and magnetic field [Credit: H.-W. Hsu and the Cassini Cosmic Dust Analyser team]

Assisted by KU graduate and undergraduate students, a first stage of Cravens’ work involved sorting and cleaning raw data from Cassini’s INMS instrument.

“The raw data came through from our instrument on Cassini to deep-space antennas to NASA’s Jet Propulsion Laboratory and then to computers at the Southwest Research Institute in San Antonio where Hunter Waite, the first author, is based,” he said.

But Cravens’ main contribution involved interpreting that data with a focus on how materials from the rings are altering Saturn’s ionosphere. Cravens and his colleagues report the influx of chemicals from the rings change Saturn’s equatorial ionospheric chemistry by converting the hydrogen ions and triatomic hydrogen ions into heavier molecular ions, depleting the planet’s ionospheric density.

“My interest was in the ionosphere, the charged-particle environment, and that’s what I focused on,” Cravens said. “This gunk coming in chews up a lot of the ionosphere, affects its composition and causes observable effects — that’s what we’re trying to understand now. The data are clear, but explanations are still being modeled and that will take a while. The material is coming into Saturn at high speeds because the rings are moving faster than the atmosphere quite a bit. It doesn’t just drop in gently. It comes flying in there like a satellite re-entering our own planet. These dust grains moving at satellite speed, depositing energy that can dissociate the atmosphere. Per atom, it’s pretty energetic stuff because of the speed differentiation between the rings and the atmosphere. We think it may be heating the upper atmosphere, changing its composition.”

Source: University of Kansas [October 04, 2018]



More wet and dry weather extremes projected with global warming

Global warming is projected to spawn more extreme wet and dry weather around the world, according to a Rutgers-led study.

More wet and dry weather extremes projected with global warming
Drought-stricken corn in Texas in December 2016
[Credit: Bob Nichols/USDA]

Those extremes include more frequent dry spells in the northwestern, central and southern United States and in Mexico, and more frequent heavy rainfall events in south Asia, the Indochinese Peninsula and southern China.

One reason – subtropical stationary waves in northern summers, according to the study in the Journal of Climate. These planet-spanning waves are composed of persistent high-pressure systems over the North Pacific and North Atlantic and persistent low-pressure systems over Eurasia and North America, the study says. The high-pressure systems provide persistent conditions for dry weather, while the low-pressure systems fuel wet weather.

The intensity of subtropical stationary waves during northern summers increased from 1979 to 2013, and projections suggest the increase will accelerate as climate warms, the study says.

“Increasingly strong subtropical stationary waves play an important role in explaining the increase in extremely dry weather in North America and extremely wet weather in south and southeast Asia,” said study lead author Jiacan Yuan, a post-doctoral associate in the Department of Earth and Planetary Sciences at Rutgers University-New Brunswick and the Rutgers Institute of Earth, Ocean, and Atmospheric Sciences.

Subtropical stationary waves may serve as an important link connecting regional droughts and extreme rainfall events with global warming, the study says. Such extremes, which have increased significantly in recent decades because of a warming climate, can cause enormous economic losses and threaten lives.

Examples of extreme events include catastrophic floods in South Asia during the 2017 monsoon season, when about 1,300 people died and more than 45 million people were affected, according to a United Nations Children’s Fund report. A severe drought afflicted Texas in 2011, with direct agricultural losses estimated at $5.2 billion by the Texas AgriLife Extension Service.

Source: Rutgers University [October 04, 2018]



Amazon rainforest conservation victories spill losses to neighbours

New research suggests that protecting the Amazon rainforest from deforestation may just be shifting the damage to a less renowned neighbour. The unintended consequences are profound.

Amazon rainforest conservation victories spill losses to neighbours
Brazil’s savannah is a biodiveristy hotspot, but doesn’t command the conservation attention the rainforests garner
[Credit: Ramon Felipe Bicudo da Silva, Michigan State University]

Efforts to rein in agriculture activities in the Amazon have led to an 80 percent reduction in rainforest destruction between the early 2000s to 2015. Yet in this month’s Journal of Geographic Sciences Michigan State University (MSU) researchers show that farming and ranching have caused 6.6 times more destruction of natural vegetation in the nearby Tocantins State of the Cerrado in central Brazil, without a corresponding uprising of concern.

“We are not saying reducing rainforest destruction in the Amazon shouldn’t get attention,” said Yue Dou, a research associate in MSU’s Centers for Systems Integration and Sustainability (CSIS). “But attention has to be paid in the major destruction of another area which also has significant biodiversity.”

Cerrado is a Brazilian savanna of varied, wooded grasslands that cover more than 20 percent of the country. Amazon’s rainforest terrain of towering, ancient broadleaf trees, has a wide appeal and international fascination. The Cerrado, though a global biodiversity hotspot, hasn’t commanded the same attention. Both areas of Brazil have been farmed aggressively. Two supply-chain agreements placed bans on purchasing soybeans grown on Amazonian lands after 2006 or beef raised on Amazon land deforested after 2009 vastly slowed deforestation. Researchers calculated that the policies reduced deforestation from 22,766 square miles to 11,013 square miles in the Amazon.

Yet destruction in the Cerrado surged as soybean farmers and cattle ranchers sought new places to produce highly demanded foods. In the state of Tocantins alone the conversion to agricultural land increased from 465 square miles to 3,067 square miles from 2007 to 2015.

The authors of “Spillover effect offsets the conservation effort in the Amazon” note that the reasons behind the hidden impacts are complex and can be difficult to understand – so it’s hard to realize success in one part of the country can be spilling over with setbacks in a neighbouring area. Colonization, road building, available infrastructure and effectiveness of law enforcement are among the many moving parts that cause people to cut down natural vegetation and farm. Comparing rainforest to Cerrado also is challenging.

That’s why scientists worked with the telecoupling framework capable of examining many different factors. Telecoupling framework integrates many different scientific disciplines to allow scientists to holistically understand ecological and socioeconomic interactions over distances.

“In our increasingly complex world, we need to look at problems in new ways that can reflect subtleties and truths that are counterintuitive,” said Jianguo “Jack” Liu, CSIS director and co-author. “Progress in sustainability must be genuine and we can’t allow ourselves to be blinded by success in one place at the expense of invisible impacts on other places. The telecoupling framework helps to bring together many different kinds of information to fully understand important change in our telecoupled world.”

Source: Michigan State University [October 04, 2018]



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Apatite | #Geology #GeologyPage #Mineral

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Size: 6.3 x 6.1 x 4.2

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Wulfenite | #Geology #GeologyPage #Mineral

Locality: Ahmad Abad Mine, Bahabad, Yazd Province, Iran

Size: 13.3 x 11.2 x 9.2 cm

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Indicolite | #Geology #GeologyPage #Mineral

Locality: Santa Rosa Mine, Itambacuri, Doce Valley, Minas Gerais, Brazil

Size: 16 x 1.9 x 1.6 cm

Photo Copyright © Anton Watzl Minerals

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https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...