суббота, 18 мая 2019 г.

Long March-3C launches BeiDou-2 GEO-8 satellite

BeiDou Navigation Satellite System logo.

May 18, 2019

Long March-3C launches BeiDou-2 GEO-8 satellite. Image Credit: Xinhua

A Long March-3C launch vehicle launched the BeiDou-2 GEO-8 navigation satellite from the Xichang Satellite Launch Center, Sichuan Province, China, on 17 May2019, at 15:48 UTC (23:48 local time).

Long March-3C launches BeiDou-2 GEO-8 satellite

The new satellite is the fourth BeiDou-2 backup satellite and the 45th satellite of the BeiDou satellite family. According to official sources, the satellite entered its designated orbit. Long March 3C rocket launches a satellite for the country’s Beidou navigation network toward geostationary orbit.

Render of a BeiDou-3 satellite by J. Huart

The MEO satellites are the Medium Earth Orbit component of the 3rd phase of the Chinese Beidou (Compass) satellite navigation system. The satellites are part of a fleet that will expand the system to a global navigation coverage.

The Beidou Phase III system includes the migration of its civil Beidou 1 or B1 signal from 1561.098 MHz to a frequency centered at 1575.42 MHz – the same as the GPS L1 and Galileo E1 civil signals – and its transformation from a quadrature phase shift keying (QPSK) modulation to a multiplexed binary offset carrier (MBOC) modulation similar to the future GPS L1C and Galileo’s E1.

Image above: BeiDou Constellation Overview (Compass Navigation Satellite System). Image Credit: CASC.

The Radio Navigation Satellite Service (RNSS) is very similar to that provided by GPS and Galileo and is designed to achieve similar performances.

For more information about Beidou navigation system: http://www.beidou.gov.cn/

For more information about China Aerospace Science and Technology Corporation (CASC): http://english.spacechina.com/n16421/index.html

Images (mentioned), Video, Text, Credits: CASC/Beidou/China Central Television (CCTV)/SciNews/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.chArchive link

Asteroid Apophis 2029 It’s Coming Very Close to the Earth

Asteroid Watch.

May 18, 2019

Asteroids are out there, even if you can’t always see them.

Image above: Artist illustration of the asteroid Apophis making a close flyby of Earth. Image Credit: European Space Agency (ESA).

Want some naked-eye proof? It’s coming, in the form of a mountain of space rock named Apophis, for the Egyptian god of chaos; his task is to prevent the sun from rising.

Stretching three-and-a-half football fields long, Apophis will cruise within 19,000 miles of Earth—the closest this large an asteroid has come in recorded history. Apophis will swing inside our ring of geosynchronous satellites on April 13, 2029.

And yes, that is a Friday.

Animation above: This animation shows the distance between the Apophis asteroid and Earth at the time of the asteroid’s closest approach in 2029. The blue dots are manmade satellites orbiting our planet, and the pink represents the International Space Station. Animation Credits: NASA/JPL-Caltech.

But don’t worry, NASA has it all figured. Any bad luck that may befall you on that day won’t come from Apophis—probably. An earlier worst-case prediction that gave a 2.7 percent chance of Apophis striking the Earth has since been downgraded to practically nil. Actually, that’s an upgrade.

Apophis is a Sparkle in NASA’s Eye

In fact, NASA scientists look forward to Apophis’ near miss. Given a decade to prepare, NASA might even send a robotic probe to rendezvous with the rock. At minimum, it’s an incredible opportunity to make close-up observations of a large asteroid. Apophis is large enough, and will be close enough, to see with our bare eyes, so Earth-based optical and radio telescopes will have an unprecedented view of the spectacle.

Image above: Astronomers discovered asteroid Apophis on June 19, 2004. At first, when its orbit was not well understood, there was brief concern it had the potential to strike Earth in this century. Image Credits: UH/IA/NASA.

At the 2019 Planetary Defense Conference held in Maryland this April, scientists brainstormed all the possible ways to take advantage of a flyby that others might see only as a narrowly averted disaster.

NASA has used radio telescopes before to produce rudimentary images of some passing asteroids, though these were either smaller ones or much farther away. The last time any rock this size passed close to Earth was in 2001, the asteroid 2017 VW13. That one is estimated to have passed within 76,000 miles, a third of the distance to the moon. And, since it wasn’t discovered until 2017, no one even noticed it fly by!

God of Chaos

Apophis is classified today as a «Potentially Hazardous Asteroid» (PHA). This means that it periodically crosses Earth’s orbital path, and is large enough to do some major damage if it were to hit us.

Far from being an infrequent visitor from deep space as many comets are, coming around only every few decades or centuries, Apophis is a denizen of the inner solar system. Its 324-day orbit carries it from just outside Earth’s orbit at its farthest point from the sun, almost to the orbit of Venus at its closest.

Image above: Diagram showing the orbits of the planets of the inner solar system, and the asteroid Apophis. Image Credits: NASA/JPL.

You might think that because Apophis crosses Earth’s orbit more than once each year, the chance of collision is an ever-present threat.

However, most of the time when Apophis crosses our path, Earth is at a different point in its orbit. It’s only those times when our orbital positions sync up that there’s any chance of bumping into each other. Think of a carnival carousel and that brass ring you try to grab each time your horse passes by it. You only have a shot at getting that ring if it swings close when you pass—and even then there’s no guarantee.

April 13, 2029 is one of those match-ups, and scientists are keenly eyeing the brass ring of new discovery that will be briefly within their reach.

What Are the Chances?

While small objects pass close to Earth on a routine basis, and even collide with us more often than you might think, most go unnoticed. Three quarters of them fall over open ocean, most of the rest over sparsely populated land. And those that don’t break up in the atmosphere have limited effects when they hit the water or the ground anyway.

Larger, more dangerous rocks make appearances with far less frequency—and the bigger they are, the rarer the encounter.

Image above: A model of the shape of asteroid Apophis, generated from its light curve and assuming that all areas of the asteroid have a similar albedo and reflectivity, via the Database of Asteroid Models from Inversion Techniques (DAMIT) and and Wikimedia Commons.

Notable impacts in recent history include the Tunguska comet or meteorite impact in Siberia in 1908, and the Chelyabinsk event in Russia in 2013. Both were smaller than Apophis, but were relatively large objects: between 200 and 600 feet across in the case of Tunguska, and about 66 feet for Chelyabinsk. They exploded in Earth’s atmosphere, producing significant effects on the ground below, though no known fatalities.

Larger collisions with greater regional and even global effects can be found in prehistoric times, such as the impact that formed Barringer Crater (aka «Meteor Crater») in Arizona 50,000 years ago.

To find a «dinosaur killer» impact event you’d have to look all the way back to, well, the dinosaur killer impact, 66 million years ago. The asteroid that contributed to ending the dinosaurs’s long reign on Earth, which struck the northern end of the Yucatan Peninsula near Chicxulub, Mexico, was probably six miles across.

Image above: Diagram detailing the remnants of the Chicxulub impact crater on the Yucatan Peninsula. Though now buried under jungle and ocean sediment, evidence of the crater can be found through radar imaging and mineral analysis of rock samples. Image Credits: NASA/JPL-Caltech/David Fuchs.

Defending Against Near Earth Objects

Fortunately, we aren’t completely in the dark about the dangers posed by Near-Earth Objects. We’re also not completely helpless when it comes to defending our planet from them.

For years now, an international coalition of observers and researchers have collaborated to find, measure, and track Near-Earth Objects. The data they collect are used to calculate the probability of a collision, and to predict the level of damage in the event of a hit. (Related articles links).

Ultimately, a major asteroid impact with Earth is a matter of when, not if. But the good news is that none are predicted in the foreseeable future.

Asteroid impact on Earth

The current approach to planetary defense hinges on the idea that the further in advance we can predict an impact, the more time we have to do something about it. If we know it’s coming years before the fact, a tiny «nudge» to the asteroid’s trajectory can make the difference between a catastrophic impact and a harmless near miss.

What About Apophis’ Next Flyby?

The probability of Apophis hitting the Earth in 2029 has been practically ruled out. Its close passage through Earth’s gravitational field, though, will result in a change in its orbital path, so careful observations of the flyby will yield more than scientific discovery, it will let us make more precise collision predictions for future encounters.

As things stand now, Apophis will make another close encounter with Earth in 2036, but will come no closer than 14 million miles. Beyond that, the chance of it hitting us anytime between 2060 and 2105 is 1 in 110,000.

Astronomers will be watching!

For more information about asteroids and near-Earth objects, visit: https://www.jpl.nasa.gov/asteroidwatch. Updates about near-Earth objects are also available by following AsteroidWatch on Twitter at https://www.twitter.com/asteroidwatch.

Bottom line: Astronomers met on April 30, 2019, at the Planetary Defense Conference to discuss plans to observe asteroid 99942 Apophis, a relatively large asteroid that’ll sweep past Earth safely – but rather closely – a decade from now.

Related articles:

NASA’s First Planetary Defense Technology Demonstration to Collide with Asteroid in 2022

Earth vs. asteroids: humans strike back

Work begins on ESA’s part of planetary defence test

Related links:

2019 Planetary Defense Conference: http://pdc.iaaweb.org/

Potentially Hazardous Asteroid» (PHA): https://cneos.jpl.nasa.gov/about/neo_groups.html

Near-Earth Objects: https://cneos.jpl.nasa.gov/ca/

Images (mentioned), Animation, Text, Credits: NASA/KQED Science/Ben Burress/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.chArchive link

Australian islands home to 414 million pieces of plastic pollution

A survey of plastic pollution on Australia’s Cocos (Keeling) Islands has revealed the territory’s beaches are littered with an estimated 414 million pieces of plastic debris.

Australian islands home to 414 million pieces of plastic pollution
A Cocos island beach. The world may be seriously underestimating the amount of plastic waste
along its coastlines, according to new research [Credit: Silke Struckenbrock/AFP]

The study led by IMAS researcher Dr Jennifer Lavers and published in the journal Scientific Reports estimated beaches on the Indian Ocean islands are littered with 238 tonnes of plastic, including 977,000 shoes and 373,000 toothbrushes.

Dr Lavers’ research made headlines around the world when in May 2017 she revealed that beaches on remote Henderson Island in the South Pacific had the highest density of plastic debris reported anywhere on Earth.

While the density of plastic debris on Cocos (Keeling) Islands beaches is lower than on Henderson Island, the total volume dwarfs the 38 million pieces weighing 17 tonnes found on the Pacific island.

Dr Lavers said remote islands which don’t have large human populations depositing rubbish nearby are an indicator of the amount of plastic debris circulating in the world’s oceans.

«Islands such as these are like canaries in a coal mine and it’s increasingly urgent that we act on the warnings they are giving us,» Dr Lavers said.

«Plastic pollution is now ubiquitous in our oceans, and remote islands are an ideal place to get an objective view of the volume of plastic debris now circling the globe.

Australian islands home to 414 million pieces of plastic pollution
This University of Tasmania photo shows the extent of the problem on the Cocos Islands
[Credit: Jennifer Lavers/AFP]

«Our estimate of 414 million pieces weighing 238 tonnes on Cocos (Keeling) is conservative, as we only sampled down to a depth of 10 centimetres and couldn’t access some beaches that are known debris ‘hotspots’.

«Unlike Henderson Island, where most identifiable debris was fishing-related, the plastic on Cocos (Keeling) was largely single-use consumer items such as bottle caps and straws, as well as a large number of shoes and thongs,» Dr Lavers said.

Co-author Dr Annett Finger from Victoria University said global production of plastic continues to increase, with almost half of the plastic produced over the past 60-years manufactured in the last 13-years.

«An estimated 12.7 million tonnes of plastic entered our oceans in 2010 alone, with around 40 per cent of plastics entering the waste stream in the same year they’re produced,» Dr Finger said.

«As a result of the growth in single-use consumer plastics, it’s estimated there are now 5.25 trillion pieces of ocean plastic debris.

«Plastic pollution is a well-documented threat to wildlife and its potential impact on humans is a growing area of medical research.

«The scale of the problem means cleaning up our oceans is currently not possible, and cleaning beaches once they are polluted with plastic is time consuming, costly, and needs to be regularly repeated as thousands of new pieces of plastic wash up each day.

«The only viable solution is to reduce plastic production and consumption while improving waste management to stop this material entering our oceans in the first place,» Dr Finger said.

Source: University of Tasmania [May 16, 2019]



A global map to understand changing forests

An international collaboration of hundreds of scientists—led in part by the Forest Advanced Computing and Artificial Intelligence (FACAI) Laboratory in Purdue’s Department of Forestry and Natural Resources—has developed the world’s first global map of tree symbioses. The map is key to understanding how forests are changing and the role climate plays in these shifts.

A global map to understand changing forests
The Global Forest Biodiversity Initiative developed the first map of global tree symbioses. The map will help
answer questions about environmental impacts associated with forest changes, forest management
and biological conservation [Credit: Leonhard Steinacker]

The findings, reported in the journal Nature, come from the Global Forest Biodiversity Initiative (GFBI), a consortium of forest scientists and practitioners of which the FACAI Lab is a key hub and global center. Jingjing Liang, a Purdue University assistant professor of quantitative forest ecology, is co-supervisor the FACAI Lab, coordinator and cofounder of the GFBI and co-lead author of the paper. Mo Zhou, a Purdue assistant professor of forest economics and management, is a senior author of the paper, co-supervisor of the FACAI lab and lead economist of the GFBI.

Purdue’s FACAI lab employs artificial intelligence and machine learning to study global, regional and local forest resource management and biodiversity conservation. For this research, FACAI compiled species abundance data from 55 million tree records in 1.2 million forest sample plots spanning 110 countries. The organization of the data was integral to developing the global map.

«The map and underlying global forest inventory database will serve as the foundation for research on the environmental impacts of forest changes, biological conservation and forest management,» Liang said.

The map identifies the types of mycorrhizal fungi associated with trees in a particular forest. These fungi attach to tree roots, extending a tree’s ability to reach water and nutrients while the tree provides carbon necessary for the fungi’s survival. The two most common types of mycorrhizae are arbuscular, which grow inside the tissues of tree roots and are associated with tree species such as maple, ash and yellow poplar, and ectomycorrhizal, which live on the outside of roots and are associated with tree species such as pine, oak, hickory and beech.

Those associations are important because the mycorrhizae affects the trees’ ability to access nutrients, sequester carbon and withstand the effects of climate change.

«Managing forests for climate change mitigation and sustainable development, therefore, should go well beyond managing only trees,» Zhou said.

The authors found that climate is the most significant factor affecting the distribution of mycorrhizae. A warming climate is reducing the abundance of ectomycorrhizal tree species by as much as 10 percent. That change is altering forests’ ecological and economic footprints, especially along the boreal-temperate ecotone, the border areas between colder and warmer forest. Losses to ectomycorrhizal species have implications for climate change since these fungi increase the amount of carbon stored in soil.

«Knowing the species composition in the forested area across the world is an important start,» Liang said. «There are many fundamental and socioeconomic questions we can answer now with GFBI data and cutting-edge machine learning techniques.»

The FACAI lab is currently developing collaborations to explore questions about ecology and economics, including self-learning forest models, innovative approaches to biodiversity valuation, locating unknown forest resources and space exploration.

Author: Brian Wallheimer | Source: Purdue University [May 16, 2019]



Bedbugs evolved more than 100 million years ago

Bedbugs — some of the most unwanted human bed-mates — have been parasitic companions with other species aside from humans for more than 100 million years, walking the earth at the same time as dinosaurs.

Bedbugs evolved more than 100 million years ago
Bedbugs are older than bats — a mammal that people had previously believed to be their first host
50-60 million years ago. Bedbugs in fact evolved around 50 million years earlier
[Credit: Mark Chappell, University of Cailfornia, Riverside]

Work by an international team of scientists, including the University of Sheffield, compared the DNA of dozens of bedbug species in order to understand the evolutionary relationships within the group as well as their relationship with humans.

The team discovered that bedbugs are older than bats — a mammal that people had previously believed to be their first host 50-60 million years ago. Bedbugs in fact evolved around 50 million years earlier.

Bedbugs rank high among the list of most unwanted human bedfellows but until now, little was known about when they first originated.

Experts have now discovered that the evolutionary history of bed bugs is far more complex than previously thought and the critters were actually in existence during the time of dinosaurs. More research is needed to find out what their host was at that time, although current understanding suggests it’s unlikely they fed on the blood of dinosaurs. This is because bed bugs and all their relatives feed on animals that have a «home» — such as a bird’s nest, an owl’s burrow, a bat’s roost or a human’s bed — a mode of life that dinosaurs don’t seem to have adopted.

The team spent 15 years collecting samples from wild sites and museums around the world, dodging bats and buffaloes in African caves infected with Ebola and climbing cliffs to collect from bird nests in South East Asia.

Professor Mike Siva-Jothy from the University of Sheffield’s Department of Animal and Plant Sciences, who was part of the team, said: «To think that the pests that live in our beds today evolved more than 100 million years ago and were walking the earth side by side with dinosaurs, was a revelation. It shows that the evolutionary history of bed bugs is far more complex than we previously thought.»

Dr Steffen Roth from the University Museum Bergen in Norway, who led the study, added: «The first big surprise we found was that bedbugs are much older than bats, which everyone assumed to be their first host. It was also unexpected to see that evolutionary older bedbugs were already specialised on a single host type, even though we don’t know what the host was at the time when T. rex walked the earth.»

The study also reveals that a new species of bedbug conquers humans about every half a million years: moreover that when bedbugs changed hosts, they didn’t always become specialised on that new host and maintained the ability to jump back to their original host. This demonstrates that while some bedbugs become specialised, some remain generalists, jumping from host to host.

Professor Klaus Reinhardt, a bedbug researcher from Dresden University in Germany, who co-led the study, said: «These species are the ones we can reasonably expect to be the next ones drinking our blood, and it may not even take half a million years, given that many more humans, livestock and pets that live on earth now provide lots more opportunities.»

The team also found that the two major bedbug pests of humans — the common and the tropical bedbug — are much older than humans. This contrasts with other evidence that the evolution of ancient humans caused the split of other human parasites into new species.

Professor Mike Siva-Jothy from the University of Sheffield, added: «These findings will help us better understand how bedbugs evolved the traits that make them effective pests — that will also help us find new ways of controlling them.»

The researchers hope the findings will help create an evolutionary history of an important group of insects, allowing us to understand how other insects become carriers of disease, how they evolve to use different hosts and how they develop novel traits. The aim is to help control insects effectively and prevent the transmission of insect-vectored disease.

The research has been published in Current Biology.

Source: University of Sheffield [May 16, 2019]



3-D Earth in the making

A thorough understanding of the ‘solid Earth’ system is essential for deciphering the links between processes occurring deep inside Earth and those occurring nearer the surface that lead to seismic activity such as earthquakes and volcanic eruptions, the rise of mountains and the location of underground natural resources. Thanks to gravity and magnetic data from satellites along with seismology, scientists are on the way to modelling inner Earth in 3-D.

3-D Earth in the making
Top left: Earth’s topography; bottom: gravity gradients as measured by ESA’s GOCE satellite.
Right: depth slices through LithoRef18 (Afonso et al.). Colours represent density variation
 in crust and upper mantle, where blue represents denser material and red represents
less dense material. The animation is not to scale [Credit: Density values from
 LithoRef18 (Afonso et al.) and gravity gradients from Bouman et al. (2016)]

Solid Earth refers to the crust, mantle and core. Because these parts of our world are completely hidden from view, understanding what is going on deep below our feet can only be done by using indirect measurements.

New results, based on a paper published recently in Geophysical Journal International and presented at this week’s Living Planet Symposium, reveal how scientists are using a range of different measurements including satellite data along with seismological models to start producing a global 3-D Earth reference model.

The model will make a step change in being able to analyze Earth’s lithosphere, which is the rigid outer shell, and the underlying mantle to understand the link between Earth’s structure and the dynamic processes within.

Juan Carlos Afonso, from Australia’s Macquarie University and Norway’s Centre for Earth Evolution and Dynamics, said, «We are realising the new global model of Earth’s lithosphere and upper mantle by combining gravity anomalies, geoid height, and gravity gradients complemented with seismic, thermal, and rock information.»

3-D Earth in the making
ESA’s GOCE mission will measure high-accuracy gravity gradients and provide global models of the Earth’s gravity
 field and of the geoid. The geoid (the surface of equal gravitational potential of a hypothetical ocean at rest)
serves as the classical reference for all topographical features. The accuracy of its determination is important
 for surveying and geodesy, and in studies of Earth interior processes, ocean circulation, ice motion
 and sea-level change [Credit: AOES Medialab]

Wolfgang Szwillus from Kiel University, added, «Data from ESA’s GOCE satellite mission served as input for the inversion. It is the first time that gravity gradients have been inverted on a global scale in such an integrated framework.»

While this is just a first step, 3-D Earth offers tantalizing insights into the deep structure of our world. For example, the new models of the thickness of the crust and the lithosphere are important for unexplored continents like Antarctica.

Jorg Ebbing from Kiel University, noted, «This is just a first step so we have more work to do, but we plan to release the 3-D Earth models in 2020.»

The 3-D Earth research, which involves scientists from nine institutes in six European countries, is funded through ESA’s Science for Society programme. ESA’s GOCE gravity mission and Swarm magnetic field mission are key to this research.

Source: European Space Agency [May 16, 2019]



Precursors of a catastrophic collapse

On the morning of the 13th of March 1888, the inhabitants of the Finschhafen trading post on the east coast of New Guinea were awakened by a dull rumbling sound. An eyewitness later reported that the water in the port had receded at the same time. A short time later, several two- to three-metre high waves hit the coast. It was a tsunami on that fateful morning that devastated the surrounding coasts. Several thousand people probably died in New Guinea and the Bismarck Archipelago.

Precursors of a catastrophic collapse
The research vessel SONNE in front of Ritter Island during the expedition SO252 in autumn 2016
[Credit: Christian Berndt/GEOMAR]

The cause of the tsunami was quickly discovered: the largest part of the volcanic island of Ritter Island, 150 kilometres from Finschhafen, had slipped into the sea in a single catastrophic collapse. However, some questions about the exact course of the landslide remained unanswered.
In the international journal Earth and Planetary Science Letters, researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel together with colleagues from the University of Birmingham, the University of Malta, the University of London and the German Research Centre for Geosciences, have now published a study showing that the volcanic slope of Ritter Island had already slipped before the catastrophe of 13 March 1888 — but much more slowly. «These new findings help us to better assess the hazard potential of other volcanic islands,» says Dr Jens Karstens of GEOMAR, first author of the study.

The study is based on the expedition SO252 of the German research vessel SONNE to Ritter Island in Autumn 2016. With seismic methods, the international team led by Prof. Dr. Christian Berndt (GEOMAR) precisely measured the traces of the disaster of 1888. They found evidence that the flank of the island had moved sporadically over a long period of time before 1888. This is indicated by corresponding deformation of the subsurface at a smaller volcanic cone off the coast of Ritter Island.

Precursors of a catastrophic collapse
3D visualization of Ritter Island and the surrounding seafloor with traces of the landslide of 1888
[Credit: Jens Karstens/GEOMAR]

It is unknown whether slow landslides at volcanic flanks are precursors of a catastrophic collapse, or even whether they might reduce the risk of such a collapse because they relieve tension from the volcanic system. «At Ritter Island, we now have evidence that sporadic, small landslides have preceded a much larger one,» explains Dr Karstens.
Both types of landslides were observed last year on active volcanoes. Last year’s eruption of Kilauea on Hawaii was accompanied by a landslide of the volcano flank, which caused a moderate earthquake. The eastern flank of Mount Etna in Sicily is also moving slowly towards the sea, as showed in a study published in Autumn 2018.

In December 2018, an eruption of the volcano Anak Krakatau caused a landslide that triggered a tsunami in the Sunda Strait (Indonesia) and killed more than 400 people. The events at Anak Krakatau are comparable to those that took place on the 13th of March 1888 at the Ritter Island Volcano. This demonstrates the relevance of the findings at Ritter Island for hazard assessments on volcanic islands all over the world.

«The better we know the dynamics of such events, the better we can asses the hazard for a given region. Ritter Island is a very good case study because the volcano resembles many other volcanic islands and because the eruption and the tsunami are well documented thanks to eyewitness accounts. Together with our modern research methods, we can get a more complete picture of the processes of 1888,» summarizes Dr. Karstens.

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR) [May 16, 2019]



Climate a driver of language diversity

A region’s climate has a greater impact than landscape on how many languages are spoken there, new research from The Australian National University (ANU) shows.

Climate a driver of language diversity
Credit: Sherrie Thai/Flickr

The research team mapped language diversity around the world and found areas with more productive climates tend to have more languages.

«We were able to show that despite popular belief, climatic factors have a stronger effect than landscape factors — like how mountainous it is, or how many rivers there are — when it comes to language diversity,» ANU biologist Professor Lindell Bromham said.

The researchers think this could have a lot to do with food production — another driver of language diversity.

«If an area can reliably support food production for more of the year it may allow human groups to persist in smaller areas, so you can pack more different cultures into one region, and therefore more languages,» Professor Bromham explained.

«If you’re up in a region with a shorter growing season, or less reliable food productivity, you might need to make sure you’ve got links with other groups so you can support each other. It might be harder to form a small, isolated, self-sufficient band.»

Professor Bromham said the study showed language diversity and biodiversity might both be affected by similar factors.

«Our results look a lot like a map of biodiversity,» Professor Bromham said. «You could overlay a map of language diversity and a map of biodiversity and they’d show some very similar patterns.

«For example, there’s more diversity around the equator, and less as you go towards the poles.

«If you’ve got an area where it’s hard for animals to live, it’s generally also hard for people to live there. So unsurprisingly, in those areas, there are less languages.»

As part of the study, the researchers pin-pointed areas where language diversity could not be easily explained by factors like climate and landscape alone. A few areas stood out.

The eastern Himalayas, west Africa and Papua New Guinea had far more unexplained language diversity than other parts of the world.

«Papua New Guinea is home to 10 per cent of the world’s languages, despite taking up just 0.5 per cent of the world’s land area. Incredibly, it not only has many languages, but languages that are fundamentally different from each other,» said study lead Dr Xia Hua.

«If we can understand what’s driving this, I think we’d understand a lot more about the drivers of cultural diversity in general.»

This could have extra significance in places like Australia that have experienced a high rate of language loss.

«Every language we lose is a rich source of information on the way languages have evolved. The more we lose, the harder it will be for us to understand language origins,» Professor Bromham said.

«Biologists face the same problem — when we lose species to extinction we lose information about the evolutionary process that created those species.»

The research has been published in Nature Communications.

Source: Australian National University [May 17, 2019]



Plugging Leaks When it comes to building barriers, nature…

Plugging Leaks

When it comes to building barriers, nature comes up trumps with the blood-brain barrier (BBB), a network of blood vessels supplying the brain which only allows select nutrients to pass through, blocking everything else. However, structures in the BBB called circumventricular organs (CVOs) are considerably leakier, allowing the brain to monitor blood changes and respond by triggering sensations such as thirst and hunger. Using mice and zebrafish, researchers investigated what happens when leaky CVO vessels are tightened up. Fluorescent microscopy of zebrafish brain blood vessels (red) revealed low levels of signalling molecules involved in BBB formation (green) in the zebrafish equivalent of the CVO (far left bottom region). Genetically altering mice to produce more of these molecules tightened up leaky CVO vessels but also impaired the ability of brain cells to correctly respond to water deprivation. These insights reveal more about how our most basic needs are controlled.

Written by Lux Fatimathas

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2019 May 18 Atlas, Daphnis, and Pan Image Credit: Cassini…

2019 May 18

Atlas, Daphnis, and Pan
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Atlas, Daphnis, and Pan are small, inner, ring moons of Saturn. They are shown at the same scale in this montage of images by the Cassini spacecraft that made its grand final orbit of the ringed planet in September 2017. In fact, Daphnis was discovered in Cassini images from 2005. Atlas and Pan were first sighted in images from the Voyager 1 and 2 spacecraft. Flying saucer-shaped Atlas orbits near the outer edge of Saturn’s bright A Ring while Daphnis orbits inside the A Ring’s narrow Keeler Gap and Pan within the A Ring’s larger Encke Gap. The curious equatorial ridges of the small ring moons could be built up by the accumulation of ring material over time. Even diminutive Daphnis makes waves in the ring material as it glides along the edge of the Keeler Gap.

∞ Source: apod.nasa.gov/apod/ap190518.html

The first step on Mars planned for 2039

Astronaut — From the Moon to Mars and Beyond logo.

May 18, 2019

On December 11, 2017, US President Donald Trump signed a directive ordering NASA to prepare the return of astronauts to the moon, «followed by human missions to Mars and other destinations.»

The date fixed by NASA is 2024 for the Moon and 2033 for March, but among the experts and industrialists of the American space sector, the date of 2033 seems highly unlikely, unless a national effort Herculean, the magnitude of Apollo program in the 1960s.

This week, NASA boss Jim Bridenstine said: «The Moon is our test bed for our future mission to Mars at the seventh» People on Mars «conference in Washington. That’s why we go to the moon. «

Moon to Mars

Two days later, during a session at the same site devoted to surface operations on Mars, the head of the laboratory developing future space dwellings at Houston’s legendary Johnson Center explained that the problem was not technological.

«A lot of people want us to have an Apollo moment, a president get up like Kennedy and take the whole country behind him,» said Robert Howard. «With this impulse, we could go there in 2027. But I do not believe it. With our current approach, we will be lucky if we get there before 2037 «. «And if I was really pessimistic (…) I would say the 2060s,» he said.

Isolated humans

Everything remains to design, build, test and retest, rockets to vehicles through the method to grow salads.

The one-way trip will take six months at least, as opposed to three days for the moon. The whole mission could last two years, because Mars does not get close to the Earth until every 26 months: you have to sit on these windows.

It will be necessary to design protections for astronauts against solar and cosmic radiation for such a long time, said Julie Robinson, Chief Scientist for the International Space Station (ISS).

«A second problem is the feeding system,» she said. The concepts proposed so far «are not small enough to go to Mars». Not to mention the possibility of a medical emergency: the astronauts will have to learn how to manage any accident themselves, because the rescue will be too far away.

«One big topic is space suits,» said Jennifer Heldmann of NASA’s Ames Research Center. She recalls that the Apollo astronauts had complained a lot of gloves, too inflated and exhausting any manipulation.

New NASA Position to Focus on Moon’s Exploration, Mars and Worlds Beyond

In Houston, NASA is developing a new combination, the first in 40 years, called xEMU, but it will only be tested in the ISS in a few years. And Mars is not the moon. Dust will be a big problem. Apollo’s astronauts returned covered with lunar dust in their module. Blocking it will be crucial for those who will spend months or a year on the red planet.

The techniques of exploiting the resources of the Martian soil to extract the water, the oxygen and the fuels necessary for the humans do not exist yet — it should be tested on the Moon by the end of this decade.

Finally, there is the most fundamental question: how will some humans psychologically bear being confined and isolated for two years?

It will not be possible to communicate in real time with «mission control» in Houston: radio communications will take between 4 and 24 minutes between the two planets, one way. NASA is planning delayed communication exercises in the coming years in the ISS.

Artificial intelligence will also need to be developed to help and guide astronauts without ground intervention. One researcher studied in detail the feasibility of Mars landing in 2033, in a report for NASA in February. She declared the goal «unfeasible».

«It’s not just a budget issue,» said expert Bhavya Lal of the Science & Technology Policy Institute this week. «It’s a question of organizational capacity: how much can NASA do at the same time?» The most realistic date, according to her, is 2039.

Related article:

Sending American Astronauts to Moon in 2024: NASA Challenge Accepts

Related links:

National Aeronautics and Space Administration (NASA): https://www.nasa.gov/

Space Policy Directive-1: https://www.nasa.gov/press-release/new-space-policy-directive-calls-for-human-expansion-across-solar-system

Moon to Mars: https://www.nasa.gov/specials/moon2mars/

Images, Text, Credits: AFP/NASA/Orbiter.ch Aerospace/Roland Berga.

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Shedding light on white dwarfs – the future of stars like our Sun

ESA — Gaia Mission patch.

17 May 2019

ESA’s Gaia mission has been busy mapping our Milky Way galaxy since 2014, and just over one year ago released its second batch of data on more than one billion stars. Since then, astronomers have been exploring this catalogue to reveal a huge amount of new information about the cosmos. One type of object that has seen an abundance of new discoveries is white dwarfs.

Gaia white dwarf discoveries. Image Credits: ESA/Gaia/DPAC

White dwarfs are the remnants left behind when medium-sized stars like our Sun reach the end of their lives. These stellar relics are extremely dense, with masses comparable to the Sun’s confined to volumes comparable to that of Earth; just one cubic centimetre can weigh an incredible 1000 kilograms. Finding out more about white dwarfs gives us a peek into the future, showing us what the Sun will be like in five billion years’ time, once it has exhausted the fuel powering nuclear fusion reactions at its core.

White dwarfs were discovered in 1910, when astronomers observed some mysterious objects that didn’t fit with the then accepted model of stellar evolution. But it took almost 50 years to find as many as one hundred of them.

Until recently, just 30 000 white dwarfs had been discovered – a tiny number compared to the few hundred billion stars that are believed to exist within the Milky Way alone. And because they radiate only a small amount of lingering thermal energy as they slowly cool down, they are very faint and so it has been difficult to uncover much about them.

Image above: A size comparison between Earth and Sirius B, the closest white dwarf. Image Credits: ESA and NASA.

Enter the Gaia era

Now, thanks to the game-changing second batch of data from Gaia, 486 641 white dwarf candidates have been detected, with 260 000 of these being high-confidence candidates, as reported in a catalogue compiled by Nicola Pietro Gentile Fusillo and collaborators. Discovering more of these mysterious objects enables us to gain better knowledge of their properties, improving our understanding of how they fit into the overall picture of stellar evolution.

«Thanks to Gaia’s incredible ability to pinpoint the 3D position of huge numbers of stars, not only are we finding many more white dwarfs than we previously knew to exist, but our knowledge of their distances is hugely improving,» explains Gaia scientist Stefan Jordan of Astronomisches Rechen-Institut, Zentrum für Astronomie in Heidelberg, Germany. «This allows us to decipher other properties of these stars better than we ever could in the past.»

The motions of 230 000 white dwarfs

Video above: The motions of 230 000 white dwarfs. Video Credits: ESA/Gaia/DPAC.

The huge number of newly-discovered white dwarfs also means that many new classes and configurations have been revealed that didn’t appear in the original 30 000. These include the first triple white dwarf system described in a paper by Marti Perpinyà-Vallès and colleagues: the triplet features three white dwarfs of the same age, which is strange if we consider that these objects are the relics of dead stars and therefore should all have formed at different times.

The Gaia catalogue includes lots of particularly cool white dwarfs, usually difficult to spot because they are so dim, as reported in studies led by Gustavo Ourique, Rodrigo González Peinado and Simon Blouin.

One of the most interesting discoveries to come out of this data release, made by Pier-Emmanuel Tremblay and collaborators, was the revelation that the cores of white dwarfs turn solid as they cool down, effectively forming extremely giant cosmic diamonds that are a million times denser than the Earth-based diamonds we are used to. This phenomenon was predicted 50 years ago by Hugh van Horn but little was understood about the process until Gaia data indicated white dwarfs release latent heat as they transform into crystals, slowing down the cooling process temporarily. The results suggest that after the Sun becomes a white dwarf in five billion years, it will take another five billion years for its core to turn solid.

Image above: Artist’s impression of a solidifying white dwarf. Image Credits: Mark Garlick; University of Warwick; European Research Council.

Image above: White dwarf cooling sequence and crystallization. Image Credits: Courtesy of Pier-Emmanuel Tremblay et al. (2018).

White dwarfs inside out

The majority of white dwarfs are made up of mostly one element – typically hydrogen or helium, and in rare cases, carbon. But some have thick atmospheres, which can be polluted with heavier elements such as calcium, magnesium and iron. The new data contains information on previously-unknown polluted white dwarfs, the first of them announced in a research note by Carl Melis and collaborators; these objects are interesting because the polluting elements are thought to come from surrounding dusty disks or even unseen exoplanets or asteroids that have merged with the white dwarfs’ outer layers.

Dusty disks can also lead to variability in the amount of infrared radiation that we receive from these stellar relics. One study led by Siyi Xu looked at Gaia observations of two white dwarfs that show such variability, suggesting that exoplanets could be disrupting the dusty disk.

Gaia. Animation Credit: ESA

Many new extremely low-mass white dwarfs have also been discovered in the new catalogue, as described in a paper by Ingrid Pelisoli and colleagues. The origin of these low-mass white dwarfs remains a mystery, and they don’t fit with current models of stellar evolution. Finding more of them could help us better understand stars overall.

Furthermore, Gaia is enabling astronomers to study pulsating white dwarfs in greater detail. This special variety of white dwarf allows astronomers to carry out ‘asteroseismology’ research and study their interiors, just like seismology on Earth is used to understand the interior of our planet. Robert A. Stiller and collaborators used data from Gaia’s second release to investigate the interaction between a pulsating white dwarf and its red-dwarf companion. Another study, led by Mukremin Kilic, looked for pulsations in white dwarf companions to millisecond pulsars, which are rapidly rotating, highly magnetised neutron stars – the endpoint of massive stars – and found pulsating emission from one such pair.

Near and far – white dwarfs across the Galaxy

The closest known white dwarf to Earth is Sirius B, companion of the brightest star in the night sky, Sirius A, only eight light years away. The Gaia data contained new information about Sirius A’s dim companion, which were used by Simon R. G. Joyce and collaborators to improve our knowledge of the fundamental relationship between the mass and radius of white dwarfs.

Image above: An artist’s impression of Sirius A and B. Image Credits: NASA, ESA and G. Bacon (STScI).

White dwarfs are also advancing our understanding of the Milky Way as a whole. Because they cool at specific rates, they are good indicators of the age of different parts of the Galaxy. Using information from Gaia on more than 150 000 of the coolest and faintest white dwarfs, Mukremin Kilic and colleagues estimated the halo of stars surrounding the Milky Way to be about 11 billion years old, helping to pin down the evolutionary history of our galaxy.

Gaia is also providing new insight into the progenitors of white dwarfs. In particular, two papers led respectively by Jeffrey D. Cummings and Kareem El-Badry used the data to investigate the relationship between the mass of a star and the mass of the white dwarf that it eventually morphs into. It is expected that future releases of Gaia data will clarify this further, helping us predict the Sun’s future in greater detail.

In a different study, Ken Shen and colleagues exploited Gaia’s information not only on the position and distance of stars but also on their velocities across the Milky Way to find three white dwarfs that are zipping through our Galaxy at very high speeds. One possible interpretation sees these hyper-velocity white dwarfs as the survivors of a particular type of thermonuclear explosion, known as a type-Ia supernova. These explosions happen when a white dwarf pulls matter from a stellar companion in a binary system; in this particular case, the astronomers believe that the explosion happened in a system of two white dwarfs, causing one of the two stellar remnants to disappear and throwing the other away at speeds over 1000 kilometres per second. Gaia data on the motion of one of these speedy white dwarfs even hints at the existence of a supernova remnant.

The hyper-velocity white dwarf D6-2

Video above: The hyper-velocity white dwarf D6-2. Image Credits: ESA/Gaia/DPAC.

More excitement awaits white dwarf researchers. Based on Gaia data, Peter McGill and collaborators predicted that on 11 November 2019 a nearby white dwarf will pass in front of a more distant star. The white dwarf’s gravity will deflect and magnify the background star’s light, acting as a gravitational lens: this unique opportunity will allow astronomers to determine the white dwarf’s mass. Until and after then, scientists will keep working with existing data from Gaia and other surveys to slowly but surely unveil the many mysteries of white dwarfs.

«Since Gaia was designed with ‘galactic archaeology’ as its main priority, we always expected that the mission would make ground-breaking discoveries in a diverse range of areas in astronomy,» concludes ESA’s Gaia deputy project scientist, Jos de Bruijne. «It is extremely rewarding to witness such a large contribution to white dwarf science from this latest data release.»

A huge amount remains to be discovered about white dwarfs, but with Gaia, we are deciphering these fascinating objects one step at a time.

Related links:

Dwarf catalogue: https://ui.adsabs.harvard.edu/abs/2019MNRAS.482.4570G

Siyi Xu study: https://ui.adsabs.harvard.edu/abs/2018ApJ…866..108X

Mukremin Kilic study: https://ui.adsabs.harvard.edu/abs/2018MNRAS.479.1267K

ESA Gaia: http://sci.esa.int/gaia/ and http://www.esa.int/Our_Activities/Space_Science/Gaia

Images (mentioned), Animation (mentioned), Videos (mentioned), Text, Credits: European Space Agency (ESA).

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NASA Testing Method to Grow Bigger Plants in Space

ISS — Veggie Mission patch.

May 17, 2019

Image above: NASA astronaut Christina Koch initiates the Veg-PONDS-02 experiment on the International Space Station within Veggie by filling the upper reservoir on April 25, 2019. Image Credits: NASA/David Saint-Jacques.

In an effort to increase the ability to provide astronauts nutrients on long-duration missions as the agency plans to sustainably return to the Moon and move forward to Mars, the Veg-PONDS-02 experiment is currently underway aboard the International Space Station.

The present method of growing plants in space uses seed bags, referred to as pillows, that astronauts push water into with a syringe. Using this method makes it difficult to grow certain types of “pick and eat” crops beyond lettuce varieties. Crops like tomatoes use a large amount of water, and pillows don’t have enough holding capacity to support them.

As an alternative to the pillows, 12 passive orbital nutrient delivery system (PONDS) plant growth units are being put through their paces. The PONDS units are less expensive to produce, have more water holding capacity, provide a greater space for root growth and are a completely passive system—meaning PONDS can provide air and water to crops without extra power.

The 21-day experiment is a collaboration between NASA, Techshot, Inc., the Tupperware Brands Corporation, fluids experts at NASA’s Glenn Research Center and Mark Weislogel at Portland State University. As a U.S. National Laboratory, the space station provides commercial companies and government agencies with the ability to test the experiment in a microgravity environment.

“There comes a point where you have longer and longer duration missions, and you reach a cost benefit point where it makes sense to grow your own food,” said Howard Levine, chief scientist of NASA’s Utilization and Life Sciences Office at the agency’s Kennedy Space Center.

After Levine developed the PONDS prototype, it was passed on to Dave Reed, Techshot’s Florida operations director, and his team to re-engineer and make it capable of withstanding spaceflight. PONDS tested well on the ground, but when the system first arrived at the space station last year for testing in a microgravity environment, it pumped too much water to the lettuce seeds.

“We took a step back, evaluated different aspects of the design, and together with water fluid experts from NASA, we came up with three alternative designs, each of which had a number of components we wanted to test in space,” said Levine.

Image above: The Veg-PONDS-02 experiment sits in the International Space Station’s two Veggie chambers. The 21-day experiment consists of 12 plant growth units in three different design configurations available for testing. Image Credits: NASA/Christina Koch.

On April 19, 2019, the Veg-PONDS-02 payload arrived at the orbiting laboratory via Northrop Grumman’s 11th Commercial Resupply mission, containing 12 PONDS units in the three new design configurations. Six of the units have a clear design to allow researchers to observe the performance of water in the units during the experiment. All units contain red romaine lettuce seeds and have been placed in the two space station vegetable production systems, known as Veggie, to test growth performance.

NASA astronaut Christina Koch initiated the experiment by filling the upper reservoir on April 25. Canadian Space Agency (CSA) astronaut David Saint-Jacques filled the PONDS unit lower reservoir on May 2 and documented how water behaved in the system.

Reed and his team worked closely with material scientists and mechanical engineers with Tupperware to design and mold components that make up the PONDS-02 units.

“We needed something that was molded well, molded precisely and molded out of plastics that were compatible with edible material,” said Reed. “They brought all this huge body of knowledge to us.”

This experiment is a way to test the performance of the three alternative design methods in space to see if the water management issue initially discovered during the first PONDS experiment has been adequately addressed.

“I look at this as a normal part of the process,” said David Brady, assistant program scientist in the International Space Station Program Science Office at NASA’s Johnson Space Center. “You find what works and what doesn’t work, and you adapt and change it. The fact that Howard and his team have been able to do that is progress.”

International Space Station (ISS). Animation Credit: NASA

On May 16, the final day of the experiment, the plants will be harvested. Six of the PONDS units will be returned to Earth on SpaceX’s 17th Commercial Resupply Services mission for further analysis. Reed’s team will take the successful components and combine them into one final PONDS design, which will pave the way for the agency to truly begin testing the growth capability of crop varieties beyond leafy greens.

“PONDS was an opportunity to do something that no one else has done before,” said Reed. “People have been growing plants in space since the Apollo era, but not like this.”

The Space Life and Physical Sciences Research and Applications Division (SLPSRA) of NASA’s Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington is sponsoring the Veg-PONDS-02 investigation as part of its mission to conduct research that enables human spaceflight exploration.

Related links:

Veg-PONDS-02: https://twitter.com/NASAedu/status/1126882906331160581

PONDS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7581

U.S. National Laboratory: https://www.nasa.gov/mission_pages/station/research/nlab/index.html

Northrop Grumman’s 11th Commercial Resupply mission: https://youtu.be/y9TJVLdIqp0

SpaceX’s 17th Commercial Resupply Services mission: https://www.nasa.gov/mission_pages/station/research/news/spx17-research

SLPSRA: https://www.nasa.gov/directorates/heo/slpsra

Canadian Space Agency (CSA): http://www.asc-csa.gc.ca/eng/missions/expedition58/default.asp

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

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

Images (mentioned), Animation (mentioned), Text, Credits: NASA/KSC/Danielle Sempsrott.

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Models and Recreations of Roman London, The Museum of London, 20.4.19.

Models and Recreations of Roman London, The Museum of London, 20.4.19.

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