воскресенье, 1 декабря 2019 г.

Kalmott Prehistoric Ring Cairn, Oddendale, Shap, Cumbria, 30.11.19.

Kalmott Prehistoric Ring Cairn, Oddendale, Shap, Cumbria, 30.11.19.



* This article was originally published here

Planets around a black hole?


Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun. They proposed the possibility of thousands of planets around a supermassive black hole.

Planets around a black hole?
Artist's impression of planets orbiting a supermassive black hole
[Credit: Kagoshima University]
"With the right conditions, planets could be formed even in harsh environments, such as around a black hole," says Keiichi Wada, a professor at Kagoshima University researching active galactic nuclei which are luminous objects energized by black holes.


According to the latest theories, planets are formed from fluffy dust aggregates in a protoplanetary disk around a young star. But young stars are not the only objects that possess dust disks. In a novel approach, the researchers focused on heavy disks around supermassive black holes in the nuclei of galaxies.

"Our calculations show that tens of thousands of planets with 10 times the mass of the Earth could be formed around 10 light-years from a black hole," says Eiichiro Kokubo, a professor at the National Astronomical Observatory of Japan who studies planet formation. "Around black holes there might exist planetary systems of astonishing scale."

Some supermassive black holes have large amounts of matter around them in the form of a heavy, dense disk. A disk can contain as much as a hundred thousand times the mass of the Sun worth of dust. This is a billion times the dust mass of a protoplanetary disk.


In a low temperature region of a protoplanetary disk, dust grains with ice mantles stick together and evolve into fluffy aggregates. A dust disk around a black hole is so dense that the intense radiation from the central region is blocked and low temperature regions are formed. The researchers applied the planet formation theory to circumnuclear disks and found that planets could be formed in several hundred million years.

Currently there are no techniques to detect these planets around black holes. However, the researchers expect this study to open a new field of astronomy.

The study is published in The Astrophysical Journal.

Author: Hitoshi Yamaoka | Source: National Astronomical Observatory of Japan [November 25, 2019]



* This article was originally published here

Cawfields Roman Milecastle and Hadrian’s Wall, Haltwhistle, Northumberland, 30.11.19.

Cawfields Roman Milecastle and Hadrian’s Wall, Haltwhistle, Northumberland, 30.11.19.



* This article was originally published here

Climate change is reshaping communities of ocean organisms


Climate change is reshaping communities of fish and other sea life, according to a pioneering study on how ocean warming is affecting the mix of species.

Climate change is reshaping communities of ocean organisms
This is a black and yellow rockfish (Sebastes chrysomelas) in the Channel Islands National Marine
Sanctuary off Southern California [Credit: Claire Fackler/CINMS, NOAA]
The study, published in the journal Nature Climate Change, covers species that are important for fisheries and that serve as food for fish, such as copepods and other zooplankton.

"The changes we're observing ripple throughout local and global economies all the way to our dinner plates," said co-author Malin Pinsky, an associate professor in the Department of Ecology, Evolution, and Natural Resources in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick.


"We found dramatic evidence that changing temperatures are already reshaping communities of ocean organisms," Pinsky said. "We found that warm-water species are rapidly increasing and cold-water marine species are decreasing as the global temperature rises. Changes like this are often disrupting our fisheries and ocean food chains."

An international team of scientists also found evidence that species in some places can avoid declines by seeking refuge in cooler, deeper water - like plants on land that move to higher elevations to avoid heat, Pinsky said.

The scientists compiled the most comprehensive assessment of how ocean warming is affecting the mix of species in our oceans. They looked at fishes, invertebrates such as crabs and other crustaceans and plankton in the North Atlantic and North Pacific, across two continents and two oceans. They analyzed three million records of thousands of species from 200 ecological communities across the globe from 1985 to 2014.


Regions with stable temperatures (the Northeast Pacific and Gulf of Mexico, for example) show little change in species dominance, while warming areas (the North Atlantic, for example) are experiencing strong shifts toward the dominance of warm-water species, the study says.

Temperature is a fundamental driver for change in marine systems, with restructuring of communities in the most rapidly warming areas. Still, the data "suggest a strong prognosis of resilience to climate change for these communities," the study says.

"We're now trying to understand how the changes we see in the ocean compare with those on land and in freshwater ecosystems," said Pinsky, who is also a sabbatical professor at the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig.

Source: Rutgers University [November 25, 2019]



* This article was originally published here

Горные козы скалолазы



The incredible ibex defies gravity and climbs a dam | Forces of Nature with Brian Cox - BBC

Спасение



  Медведица не могла спасти медвежат из холодной воды, но то, что случилось дальше  

Roman Temple of Mithras, Carrawburgh Roman Fort, Hexham, 30.11.19.

Roman Temple of Mithras, Carrawburgh Roman Fort, Hexham, 30.11.19.



* This article was originally published here

Changes in oxygen concentrations in our ocean can disrupt fundamental biological cycles


New research led by scientists at the University of Bristol has shown that the feedback mechanisms that were thought to keep the marine nitrogen cycle relatively stable over geological time can break down when oxygen levels in the ocean decline significantly.

Changes in oxygen concentrations in our ocean can disrupt fundamental biological cycles
On Aug. 11, 2015, a NASA satellite captured this false-color image of a large bloom of cyanobacteria (Nodularia)
swirling in the Baltic Sea. These cyanobacteria fix inorganic atmospheric nitrogen (N2) into a form available to Life,
 a process fundamental for marine ecosystems. In our paper we show that nitrogen fixation becomes even more
important when the state of oxygenation of the ocean declines [Credit: NASA Earth Observatory/USGS]
The nitrogen cycle is essential to all forms of life on Earth - nitrogen is a basic building block of DNA.

The marine nitrogen cycle is strongly controlled by biology and small changes in the marine nitrogen cycle have major implications on life. It is thought that the marine nitrogen cycle has stayed relatively stable over geological time due to a range of different feedback mechanisms.

These feedback mechanisms are called 'the nitrostat'. However, exactly how the global marine nitrogen cycle and the associated feedback mechanisms responded to past severe changes in marine oxygenation is not well understood.


The team used a data-constrained earth system model to show show that under these deoxygenated conditions the ocean can become extremely depleted in nitrogen as the total bioavailable nitrogen inventory collapses relative to phosphorous.

At the same time the ocean transitions from an oxic-nitrate ocean to an anoxic ammonium ocean. The substantive reduction in the ocean bioavailable-N inventory in response to change in marine oxygenation may represent a key biogeochemical vulnerability.

Lead author Dr David Naafs from the University of Bristol's School of Earth Sciences, said: "Our results demonstrate that changing the amount of oxygen in the ocean can have disastrous effects on vital biogeochemical cycles such as the nitrogen cycle, which is essential for all forms of Life."

Co-author Dr Fanny Monteiro, from Bristol's School of Geographical Sciences, added: "Our modelling results are in agreement with the sparsely available proxy data from the geological past."


Co-author Professor Ann Pearson from Harvard University, said: "Our modelling results show the impact of changes in ocean oxygenation on the marine nitrogen cycle for places and time periods for which we do not (yet) have sufficient proxy data."

The strength and state of the marine nitrogen cycle and biological pump in the ocean are highly susceptible to disruptions in the level of oceanic oxygen.

As oxygen levels in the oceans are currently declining and expected to decline significantly more in the coming decades due to anthropogenic activities, the results indicate that the marine nitrogen cycle might be significantly disrupted in the future.

Their findings are published in the journal Proceedings of the National Academy of Sciences.

Source: University of Bristol [November 25, 2019]



* This article was originally published here

Aquatic microorganisms offer important window on the history of life


The air, earth and water of our planet are pulsating with living things. Yet, a vast and diverse web of life exists, about which almost nothing is known. This is the world of flagellates, tiny organisms that persist in staggering numbers in many diverse ecosystems around the world.

Aquatic microorganisms offer important window on the history of life
The graphic shows a tree of life for complex forms known as Eukaryotes, that arose mysteriously around 1.2-2 billions
years ago from a progenitor known as LECA (for Last Eukaryote Common Ancestor.) Jeremy Wideman and his
colleagues used a new method to sequence mitochondrial DNA for around 100 species of flagellates--tiny aquatic
organisms that populate many branches of the tree. These are seen on the graphic as red dots marking
the particular lineages these flagellates belong to [Credit: Shireen Dooling]
According to Jeremy Wideman, a researcher at the Biodesign Center for Mechanisms in Evolution at Arizona State University, we have a great deal to learn from these delicate and wildly varied creatures. Among other surprises, flagellates could provide valuable clues about a shadowy event that may have occurred 1.5-2 billion years ago, (no one is really sure of the timing), with the arrival of a new type of cell.

Known as LECA, it was a sort of primal egg out of which the astonishing profusion of complex life--from flagellate organisms, fungi and plants, to insects, zebra, and humans, exploded and spread over the earth.


In new research published in the journal Nature Microbiology, Wideman and his colleagues, including Prof. Thomas Richards at the University of Exeter describe a new method for investigating the genomes of eukaryotic flagellate organisms, which have been notoriously tricky to pinpoint and sequence.

Specifically, they explored samples of mitochondrial DNA, sequencing around 100 such genomes for previously undocumented flagellates. The new technique could help scientists like Wideman begin to fill in the largely blank region of the eukaryotic puzzle, where flagellate life flourishes.

Cellular worlds

Wideman, originally a traditional cell biologist, became frustrated with the many unaddressed questions in the field, recently joining the emerging discipline of evolutionary cell biology. This rapidly advancing research area uses cells as fundamental units for the study of evolutionary processes and imports concepts from evolutionary biology to better understand how cells work. "I'm literally a cell biologist that wants to know more about things we know nothing about," he says.

Evolutionary cell biology is a profoundly transdisciplinary endeavor, fusing evolutionary theory, genomics and cell biology with quantitative branches of biochemistry, biophysics, and population genetics.

Flagellates include many parasites implicated in human disease, from the intestinal bug Giardia to more damaging trypanosomes, and leishmania. Flagellates also perform more benevolent tasks. As the major consumers of bacteria and other protists in aquatic ecosystems, they help ensure the recycling of limiting nutrients.


Single-celled eukaryotic organisms, which include flagellates, constitute the overwhelming majority of eukaryotic diversity, vastly outpacing the more familiar multicellular plants, animals, and fungi. Despite their importance and ubiquity across the globe, flagellates are, as Wideman stresses, an almost entirely unknown inhabitant of the living world and one of the most enigmatic. When viewed under a microscope, their often science fiction-like appearance is markedly distinct from the kinds of eukaryotic cells commonly described in biology textbooks. Their emergence from comparatively rudimentary prokaryotes marks the most momentous transition in the history of life on earth.

"Novel lineages of heterotrophic flagellates are being discovered at an alarming, rate," Wideman says. "In the last two years 2 kingdom level lineages have been discovered (see here and here), meaning lineages that have been evolving independently of animals and fungi for over a billion years." Nevertheless, researchers have barely scratched the surface of this astonishing diversity and new methods must be brought to bear to speed up the quest. (Heterotrophs are organisms that cannot synthesize their own food, relying instead on other organisms for nutrition.)

Microbial safari

Any drop of pond, lake or ocean water is likely to contain many flagellates, but separating them from a multitude of non-flagellates and accurately reading their genomes by conventional means has been slow and painstaking work. Only a minute fraction of extant flagellates have known genomic sequences and it's even possible that the overwhelming majority have never actually been seen. According to Wideman, flagellate life forms represent the 'dark matter' of the eukaryotic universe.

"Heterotrophic flagellates are the target," Wideman says. "They're not a lineage. They're many, many lineages that are from all over the tree of life. LECA, the Last Eukaryotic Common Ancestor, was a heterotrophic flagellate, which means, that every major lineage (of eukaryotes) evolved from some sort of heterotrophic flagellate."


To access the elusive flagellate mitochondrial DNA, the researchers exploited a feature common to all flagellates and from which they take their name--the existence of flagella, which, unlike in animal sperm are on the front of cells and are often used to pull them forward like a microscopic breast stroke but are also involved in sensation, feeding, and perhaps other, as-yet unknown functions.

Flagella are rich in a particular protein known as tubulin. The new method for identifying flagellates and distinguishing them from their aquatic neighbors--primarily algae and bacteria--capitalizes on this fact by applying a selective stain to flagella-bearing organisms, activated by their high tubulin content. (Algal cells are naturally marked by their chloroplasts, which the flagellates of interest in the new study lack.)

Samples of sea water collected in 2014 off the coast of California provided a test case. Using the technique, the researchers gathered a windfall of mitochondrial sequence data, significantly expanding the catalog of flagellates identified by molecular means. Indeed, they doubled the existing mitochondrial DNA library for flagellate organisms. "We got many, many different kinds of organisms. So it was a very rich sample and very few were identical," Wideman says.

In search of LECA

Apart from the mystery of life's origin, the puzzle of where eukaryotes came from and how the LECA event transpired is the most important and vexing unanswered question in all of biology. (It has been dubbed the black hole at the heart of the living world.)

Correctly establishing the sequence of events underlying the crucial innovations within eukaryotes, from whence all complex life sprang, will take much more research in unexplored regions of the existing eukaryotic domain, particularly, the flagellates. Wideman believes the rapid advance of techniques for identifying and sequencing these organisms, such as the one outlined in the new study, offer hope such questions may one day find answers.

Author: Richard Harth | Source: Arizona State University [November 25, 2019]



* This article was originally published here

2019 December 1 Starburst Galaxy M94 from Hubble Image Credit...



2019 December 1

Starburst Galaxy M94 from Hubble
Image Credit & Copyright: ESA/Hubble & NASA

Explanation: Why does this galaxy have a ring of bright blue stars? Beautiful island universe Messier 94 lies a mere 15 million light-years distant in the northern constellation of the Hunting Dogs (Canes Venatici). A popular target for Earth-based astronomers, the face-on spiral galaxy is about 30,000 light-years across, with spiral arms sweeping through the outskirts of its broad disk. But this Hubble Space Telescope field of view spans about 7,000 light-years across M94’s central region. The featured close-up highlights the galaxy’s compact, bright nucleus, prominent inner dust lanes, and the remarkable bluish ring of young massive stars. The ring stars are all likely less than 10 million years old, indicating that M94 is a starburst galaxy that is experiencing an epoch of rapid star formation. The circular ripple of blue stars is likely a wave propagating outward, having been triggered by the gravity and rotation of a oval matter distributions. Because M94 is relatively nearby, astronomers can better explore details of its starburst ring.

∞ Source: apod.nasa.gov/apod/ap191201.html



* This article was originally published here

World's oldest comma shrimp was way ahead of the curve


Scientists have discovered the world's oldest "comma" shrimp, a tiny crustacean shaped like its punctuation namesake. The 90-million-year-old creature fills in a major evolutionary gap for a family of marine animals now found in abundance around the planet, according to researchers from Yale and the University of Alaska. The discovery appears in the journal Proceedings of the Royal Society B.

World's oldest comma shrimp was way ahead of the curve
Eobodotria muisca [Credit: Javier Luque]
The fossilized shrimp, named Eobodotria muisca, comes from Mesozoic rocks in tropical South America. Researchers found exceptionally well-preserved fossils representing more than 500 individuals between 6 and 8 millimeters long, with features that are rarely preserved in fossil crustaceans: mouthparts, the gut, tiny hairs, and small compound eyes.

"We are amazed by how similar Eobodotria muisca is to today's species," said Yale paleontologist Javier Luque, lead author of the study. "There are eight families or main groups of living comma shrimp, and none of them have a confirmed fossil occurrence. This means we had no idea when modern comma shrimp evolved, until now."


The only previous record of a modern-looking comma shrimp is a 160-million-year-old fossil from Europe, Luque said. Although that shrimp fit within the range of comma shrimp body forms, it couldn't be linked to any of the main modern families of comma shrimp.

Eobodotria muisca, on the other hand, belongs to the Bodotriidae family of living comma shrimp, Luque said, extending the fossil record of that family of shrimp by nearly 100 million years.

The new species lived during the mid-Cretaceous period, when a long, narrow inland sea covered a large part of what is today the Eastern and Central Andes of Colombia. Luque found the fossils together with fossils of the crab Callichimaera perplexa. Eobodotria muisca is named after the Muisca native Americans who lived in the Colombian Andes.

Live 3-D model of Eobodotria muisca [Credit: Yale University]

Luque said that the similarity between Eobodotria muisca and its modern relatives suggests that the rates of external anatomical changes over millions of years in this group was low compared to other crustacean groups found in the same location. He also noted that the new cache of fossils is the first of its kind in northern South America.


Sarah Gerken of the University of Alaska-Anchorage is co-author of the study.

Gerken and Luque said most of the Eobodotria muisca fossils they found were adult males. Large aggregations of males usually happen in the water column when they are searching for females by means of their large antennae for smelling and their flappy tail appendages for swimming—both features that females lack, the researchers explained.

One possible explanation for this unusual accumulation of adult males is that they could have died suddenly in the water column while swarming in search of females, and then sunk down to the soft bottom where they fossilized, Gerken and Luque said.

The researchers said the discovery not only helps paleontologists understand the origin of the comma shrimp's curved body, it also can be used to help understand the origins of related crustaceans on the evolutionary family tree.

Author: Jim Shelton | Source: Yale University [November 26, 2019]



* This article was originally published here

Black hole nurtures baby stars a million light years away


Black holes are famous for ripping objects apart, including stars. But now, astronomers have uncovered a black hole that may have sparked the births of stars over a mind-boggling distance, and across multiple galaxies.

Black hole nurtures baby stars a million light years away
Credit: X-ray: NASA/CXC/INAF/R. Gilli et al.; Radio NRAO/VLA; Optical: NASA/STScI
If confirmed, this discovery, made with NASA's Chandra X-ray Observatory and other telescopes, would represent the widest reach ever seen for a black hole acting as a stellar kick-starter. The black hole seems to have enhanced star formation more than one million light-years away. (One light-year is equal to 6 trillion miles.)

"This is the first time we've seen a single black hole boost star birth in more than one galaxy at a time," said Roberto Gilli of the National Institute of Astrophysics (INAF) in Bologna, Italy, lead author of the study describing the discovery. "It's amazing to think one galaxy's black hole can have a say in what happens in other galaxies millions of trillions of miles away."


A black hole is an extremely dense object from which no light can escape. The black hole's immense gravity pulls in surrounding gas and dust, but particles from a small amount of that material can also get catapulted away instead at nearly the speed of light. These fast-moving particles form two narrow beams or "jets" near the poles of the black hole.

The supermassive black hole scientists observed in the new study is located in the center of a galaxy about 9.9 billion light-years from Earth. This galaxy has at least seven neighboring galaxies, according to observations with the European Southern Observatory's Very Large Telescope (VLT) and the Large Binocular Telescope (LBT).

Using the National Science Foundation's Karl Jansky Very Large Array, scientists had previously detected radio-wave emission from a jet of high-energy particles that is about a million light-years long. The jet can be traced back to the supermassive black hole, which Chandra detected as a powerful source of X-rays produced by hot gas swirling around the black hole. Gilli and colleagues also detected a diffuse cloud of X-ray emission surrounding one end of the radio jet. This X-ray emission is most likely from a gigantic bubble of hot gas heated by the interaction of the energetic particles in the radio jet with surrounding matter.


As the hot bubble expanded and swept through four neighboring galaxies, it could have created a shock wave that compressed cool gas in the galaxies, causing stars to form. All four galaxies are approximately the same distance, about 400,000 light-years, from the center of the bubble. The authors estimate that the star formation rate is between about two to five times higher than typical galaxies with similar masses and distance from Earth.

"The story of King Midas talks of his magic touch that can turn metal into gold," said co-author Marco Mignoli, also of INAF in Bologna, Italy. "Here we have a case of a black hole that helped turn gas into stars, and its reach is intergalactic."

Astronomers have seen many cases where a black hole affects its surroundings through "negative feedback"—in other words, curtailing the formation of new stars. This can occur when the black hole's jets inject so much energy into the hot gas of a galaxy, or galaxy cluster, that the gas can't cool down enough to make large numbers of stars.


In this newly discovered collection of galaxies, astronomers have found a less common example of "positive feedback," where the black hole's effects increase star formation. Moreover, when astronomers previously encountered positive feedback, it either involved increases in the star formation rate of 30% or less, or it occurred over scales of only about 20,000 to 50,000 light-years on a nearby companion galaxy. Whether the feedback is positive or negative depends on a delicate balance between the heating rate and cooling rate of a cloud. That is because clouds that are initially cooler when hit by a shock wave are more prone to experience positive feedback, and form more stars.

"Black holes have a well-earned reputation for being powerful and deadly, but not always," said co-author Alessandro Peca, formerly at INAF in Bologna and now a Ph.D. student at the University of Miami. "This is a prime example that they sometimes defy that stereotype and can be nurturing instead."

The researchers used a total of six days of Chandra observing time spread out over five months.

"It's only because of this very deep observation that we saw the hot gas bubble produced by the black hole," said co-author Colin Norman of the Johns Hopkins University in Baltimore, Maryland. "By targeting objects similar to this one, we may discover that positive feedback is very common in the formation of groups and clusters of galaxies."

A paper describing these results has been published in the most recent issue of the journal Astronomy and Astrophysics.

Source: Chandra X-ray Center [November 26, 2019]



* This article was originally published here

Moor Divock Bronze Age Sites Video Clip, including Cist Cairns and The Cockpit Stone Circle, Moor...

Moor Divock Bronze Age Sites Video Clip, including Cist Cairns and The Cockpit Stone Circle, Moor Divock, Cumbria, 30.11.19.



* This article was originally published here

Impact crater data analysis of Ryugu asteroid illuminates complicated geological history


Analysis of the impact craters on Ryugu using the spacecraft Hayabusa 2's remote sensing image data has illuminated the geological history of the Near-Earth asteroid.

Impact crater data analysis of Ryugu asteroid illuminates complicated geological history
Individual images of each identified crater on Ryugu
[Credit: Kobe University]
A research group led by Assistant Professor Naoyuki Hirata of the Department of Planetology at Kobe University's Graduate School of Science revealed 77 craters on Ryugu. Through analyzing the location patterns and characteristics of the craters, they determined that the asteroid's eastern and western hemispheres were formed at different periods of time.

It is hoped that the collected data can be used as a basis for future asteroid research and analysis. These results were first published in the scientific journal Icarus.

Introduction

The Japan Space Agency (JAXA)'s Hayabusa 2 has been used to carry out various missions to increase our understanding of the spinning top-shaped, Near-Earth asteroid Ryugu. Since arriving in June 2018, the unmanned spacecraft has taken samples and a great number of images of the asteroid. It is hoped that these can reveal more about Ryugu's formation and history.


This research group focused on using the image data to determine the number and location of impact craters on the asteroid. Impact craters are formed when a smaller asteroid or a comet hits the surface of the asteroid. Analyzing the spatial distribution and the number of impact craters can reveal the frequency of collisions and aid researchers in determining the age of different surface areas.

Research Methodology

First of all, the image data from Hayabusa 2 was analyzed. Hayabusa 2 has many different types of camera including Optical Navigation Cameras (ONC). The ONC team has been able to take around 5000 images of Ryugu, which have revealed many surface features- including impact craters. For this study, image data obtained from the 'ONC-T' camera between July 2018 and February 2019 was utilized.

Impact crater data analysis of Ryugu asteroid illuminates complicated geological history
Size and location of craters on Ryugu: The craters are numbered in order of size
[Credit: Kobe University]
The research group had to determine which of these images showed craters. 340 images were used for crater counting, with stereopair images making it easier to identify the craters. A global image mosaic map was constructed from the ONC images and rendered onto the computer model of Ryugu's shape. Small Body Mapping Tool software was then used to measure the size, latitude and longitude of the craters. A LiDAR (Light Detection and Ranging pulsed laser) was also utilized to determine the overall size of Ryugu.


The depressions identified on Ryugu were divided into four categories- depending on how evident their circular appearance was. Category I to III depressions were classified as distinct craters. Category IV depressions only had quasi-circular features, therefore it was hard to determine whether they were craters or not. Many craters were filled with boulders or lacked a distinct shape. Depressions that were too vague to determine were left out of the results.

Research Results

The research team were able to identify all impact craters over 10 to 20m in diameter on Ryugu's entire surface- a total of 77 craters. Furthermore, a pattern was discovered in their distribution. The section of the eastern hemisphere near the meridian was found to have the most craters. This is the area near the large crater named Cendrillon - which is one of Ryugu's biggest. In contrast, there are hardly any craters in the western hemisphere- suggesting that this part of the asteroid was formed later. The analysis also revealed that there are more craters at lower latitudes than at higher latitudes on Ryugu. In other words, there are very few craters in Ryugu's polar regions.


The equatorial ridge in the eastern hemisphere was determined to be a fossil structure. When asteroids like Ryugu rotate at high speeds, this can alter their shape. It is thought that this ridge formed in the distant past during a period when it only took Ryugu 3 hours to rotate. As the eastern hemisphere and western hemisphere were formed at different periods of the asteroid's history- this suggests that there have been at least two instances where Ryugu's rotational speed has increased.

Further Research

The results of this study were compiled into a global impact crater catalogue for Ryugu. It is hoped that this database can be used as a basis for future research and that comparing these results with those of a similar asteroid will lead to greater understanding about these astronomical objects.

Hayabusa2 is scheduled to drop the capsule containing samples of Ryugu's surface into Earth's atmosphere in late 2020. Analysis of these samples should provide further insight into the asteroid and how it was formed.

Source: Kobe University [November 27, 2019]



* This article was originally published here

Oddendale Prehistoric Stone Circle Video Clip, Oddendale, Shap, Cumbria, 30.11.19.

Oddendale Prehistoric Stone Circle Video Clip, Oddendale, Shap, Cumbria, 30.11.19.



* This article was originally published here

Hubble Detects Dynamic Galactic Duo












NASA - Hubble Space Telescope patch.

Nov. 30, 2019


Some galaxies are closer friends than others. While many live their own separate, solitary lives, others stray a little too close to a near neighbor and take their friendship even deeper.

The two galaxies in this image taken by the NASA/ESA Hubble Space Telescope, named NGC 6285 (left) and NGC 6286 (right), have done just that! Together, the duo is named Arp 293 and they are interacting, their mutual gravitational attraction pulling wisps of gas and streams of dust from them, distorting their shapes, and gently smudging and blurring their appearances on the sky — to Earth-based observers, at least.

Hubble has viewed a number of interacting pairs. These can have distinctive, beautiful, and downright odd shapes, ranging from sheet music to a spaceship entering a sci-fi-esque wormhole, a bouquet of celestial blooms and a penguin fiercely guarding its precious egg.

Arp 293 is located in the constellation of Draco (the Dragon) and lies over 250 million light-years from Earth.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation Credits: ESA/Hubble & NASA, K. Larson et al.

Greetings, Orbiter.ch

* This article was originally published here

Solving fossil mystery could aid quest for ancient life on Mars


Research which suggests that structures previously thought to be fossils may, in fact, be mineral deposits could save future Mars missions valuable time and resources.

Solving fossil mystery could aid quest for ancient life on Mars
A life-like structure created in the lab by chemical gardening
[Credit: Sean McMahon]
Microscopic tubes and filaments that resemble the remains of tiny creatures may have been formed by chemical reactions involving iron-rich minerals, the study shows. Previous research had suggested that such structures were among the oldest fossils on Earth.

The new findings could aid the search for extraterrestrial life during future missions to Mars by making it easier to distinguish between fossils and non-biological structures.

The discovery was made by a scientist from the University of Edinburgh who is developing techniques to seek evidence that life once existed on Mars.


Astrobiologist Sean McMahon created tiny formations in the lab that closely mimic the shape and chemical composition of iron-rich structures commonly found in Mars-like rocks on Earth, where some examples are thought to be around four billion years old.

Dr McMahon created the complex structures by mixing iron-rich particles with alkaline liquids containing the chemicals silicate or carbonate.

This process - known as chemical gardening - is thought to occur naturally where these chemicals abound. It can occur in hydrothermal vents on the seabed and when deep groundwater circulates through pores and fractures in rocks.


His findings suggest that structure alone is not sufficient to confirm whether or not microscopic life-like formations are fossils. More research will be needed to say exactly how they were formed.

The study, published in the journal Proceedings of the Royal Society B, was funded by the European Union's Horizon 2020 programme.

Dr Sean McMahon said: "Chemical reactions like these have been studied for hundreds of years but they had not previously been shown to mimic these tiny iron-rich structures inside rocks. These results call for a re-examination of many ancient real-world examples to see if they are more likely to be fossils or non-biological mineral deposits."

Source: University of Edinburgh [November 27, 2019]



* This article was originally published here

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