четверг, 10 января 2019 г.

Gaia reveals how Sun-like stars turn solid after their demise

ESA – Gaia Mission patch.

10 January 2019

Data captured by ESA’s galaxy-mapping spacecraft Gaia has revealed for the first time how white dwarfs, the dead remnants of stars like our Sun, turn into solid spheres as the hot gas inside them cools down.

This process of solidification, or crystallisation, of the material inside white dwarfs was predicted 50 years ago but it wasn’t until the arrival of Gaia that astronomers were able to observe enough of these objects with such a precision to see the pattern revealing this process.

Crystallised white dwarf core

“Previously, we had distances for only a few hundreds of white dwarfs and many of them were in clusters, where they all have the same age,” says Pier-Emmanuel Tremblay from the University of Warwick, UK, lead author of the paper describing the results, published today in Nature.

“With Gaia we now have the distance, brightness and colour of hundreds of thousands of white dwarfs for a sizeable sample in the outer disc of the Milky Way, spanning a range of initial masses and all kinds of ages.”

It is in the precise estimate of the distance to these stars that Gaia makes a breakthrough, allowing astronomers to gauge their true brightness with unprecedented accuracy.

Stellar evolution

White dwarfs are the remains of medium-sized stars similar to our Sun. Once these stars have burnt all the nuclear fuel in their core, they shed their outer layers, leaving behind a hot core that starts cooling down.

These ultra-dense remnants still emit thermal radiation as they cool, and are visible to astronomers as rather faint objects. It is estimated that up to 97 per cent of stars in the Milky Way will eventually turn into white dwarfs, while the most massive of stars will end up as neutron stars or black holes.

The cooling of white dwarfs lasts billions of years. Once they reach a certain temperature, the originally hot matter inside the star’s core starts crystallising, becoming solid. The process is similar to liquid water turning into ice on Earth at zero degrees Celsius, except that the temperature at which this solidification happens in white dwarfs is extremely high – about 10 million degrees Celsius.

In this study, the astronomers analysed more than 15 000 stellar remnant candidates within 300 light years of Earth as observed by Gaia and were able to see these crystallising white dwarfs as a rather distinct group.

Gaia data

“We saw a pile-up of white dwarfs of certain colours and luminosities that were otherwise not linked together in terms of their evolution,” says Pier-Emmanuel.

“We realised that this was not a distinct population of white dwarfs, but the effect of the cooling and crystallisation predicted 50 years ago.”

The heat released during this crystallisation process, which lasts several billion years, seemingly slows down the evolution of the white dwarfs: the dead stars stop dimming and, as a result, appear up to two billion years younger than they actually are. That, in turn, has an impact on our understanding of the stellar groupings these white dwarfs are a part of.

“White dwarfs are traditionally used for age-dating of stellar populations such as clusters of stars, the outer disc, and the halo in our Milky Way,” explains Pier-Emmanuel.

“We will now have to develop better crystallisation models to get more accurate estimates of the ages of these systems.”

Gaia spacecraft

Not all white dwarfs crystallise at the same pace. More massive stars cool down more rapidly and will reach the temperature at which crystallisation happens in about one billion years. White dwarfs with lower masses, closer to the expected end stage of the Sun, cool in a slower fashion, requiring up to six billion years to turn into dead solid spheres.

The Sun still has about five billion years before it becomes a white dwarf, and the astronomers estimate that it will take another five billion years after that to eventually cool down to a crystal sphere.

“This result highlights the versatility of Gaia and its numerous applications,” says Timo Prusti, Gaia project scientist at ESA.

“It’s exciting how scanning stars across the sky and measuring their properties can lead to evidence of plasma phenomena in matter so dense that cannot be tested in the laboratory.”

Notes for editors:

“Core crystallisation in evolving white dwarf stars from a pile up in the cooling sequence” by P.-E. Tremblay et al is published in Nature: https://doi.org/10.1038/s41586-018-0791-x

Explore the Gaia Data Release 2 archive here: http://www.esa.int/%20[EB1]https://www.cosmos.esa.int/web/gaia/data-release-2

ESA’s Gaia: http://www.esa.int/Our_Activities/Space_Science/Gaia

Images, Text, Credits: ESA/Markus Bauer/Timo Prusti/University of Warwick/Pier-Emmanuel Tremblay.

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Female penguins are getting stranded along the South American coast

Every year, thousands of Magellanic penguins are stranded along the South American coast–from northern Argentina to southern Brazil–1,000 kilometers away from their breeding ground in northern Patagonia. Now researchers reporting in Current Biology have new evidence to explain the observation that the stranded birds are most often female: female penguins venture farther north than males do, where they are apparently more likely to run into trouble.

Female penguins are getting stranded along the South American coast
Magellanic penguins [Credit: Takashi Yamamoto]

“Anthropogenic threats have been considered to threaten wintering Magellanic penguins along the coasts of northern Argentina, Uruguay, and southern Brazil; these include water pollution caused by oil development and marine transport as well as fishery-associated hazards, such as bycatch and depletion of prey species,” says Takashi Yamamoto of the Institute of Statistical Mathematics in Tokyo. “Our results suggest that the northward spatial expansion likely increases the probability to suffer these risks, and particularly so in females.”
Researchers knew that penguins stranded along the South American coast were three times as likely to be females. The question was: why?

While data were lacking, there wasn’t any evidence to suggest that males and females split up for the winter. Now, Yamamoto and his colleagues find that in fact they do. The researchers recorded the migratory and diving behavior of 14 Magellanic penguins (eight males and six females) during the non-breeding period in 2017 using LAT 2500 geolocators (Lotek Wireless, Inc.).

Female penguins are getting stranded along the South American coast
Magellanic penguin [Credit: Takashi Yamamoto]

The Magellanic penguins finished breeding in late February. Afterward, they began their migration through April, returning to the breeding grounds in September or October. During the wintering period, the tracking data show that females reached more northern areas than males did. Females showed other differences too. For example, they didn’t dive as deep under the water.
The researchers suggest that these behavioral differences between sexes in winter might be related to competition for food resources or other factors related to differences in size (males are larger and heavier than females). They also suggest that penguins traveling farther to the north may be at greater risk to a wide range of threats, leading them to become stranded more often.

Whatever the reasons, the greater loss of females from the breeding population could have serious consequences for the viability of the population. So, Yamamoto says, the new findings highlight “the necessity of gaining a better understanding of the long-term spatial utilizations of species throughout their annual cycle, including any differences within a population, in order to facilitate dynamic and adaptive conservation practices.”

Female penguins are getting stranded along the South American coast
Magellanic penguin [Credit: Takashi Yamamoto]

Yamamoto also notes that juvenile penguins are stranded more often than adults are. To further explore, they’d like to track movements of juveniles from the time they leave the place of their birth until they return to breed for the first time. “Information during this period is totally missing,” he says.

Source: Cell Press [January 07, 2019]



Evolution used same genetic formula to turn animals monogamous

Why are some animals committed to their mates and others are not? According to a new study led by researchers at The University of Texas at Austin that looked at 10 species of vertebrates, evolution used a kind of universal formula for turning non-monogamous species into monogamous species — turning up the activity of some genes and turning down others in the brain.

Evolution used same genetic formula to turn animals monogamous
In many non-monogamous species, females provide all or most of the offspring care. In monogamous species, parental
care is often shared. In these frogs, parental care includes transporting tadpoles one by one after hatching to small pools
of water. In the non-monogamous strawberry poison frog (Oophaga pumilio, left) moms perform this task; however,
 in the monogamous mimic poison frog (Ranitomeya imitator, right) this is dad’s job
[Credit: Yusan Yan and James Tumulty]

“Our study spans 450 million years of evolution, which is how long ago all these species shared a common ancestor,” said Rebecca Young, research associate in UT Austin’s Department of Integrative Biology and first author of the study published today in the journal Proceedings of the National Academy of Sciences.
The authors define monogamy in animals as forming a pair bond with one mate for at least one mating season, sharing at least some of the work of raising offspring and defending young together from predators and other hazards. Researchers still consider animals monogamous if they occasionally mate with another.

The researchers studied five pairs of closely related species — four mammals, two birds, two frogs and two fish — each with one monogamous and one non-monogamous member. These five pairs represent five times in the evolution of vertebrates that monogamy independently arose, such as when the non-monogamous meadow voles and their close relatives the monogamous prairie voles diverged into two separate species.

Evolution used same genetic formula to turn animals monogamous
At least five times during the past 450 million years, evolution used a kind of universal formula for turning animals
monogamous — turning up the activity of some genes (red) and turning down others (blue) in the brain. Researchers
studied five pairs of closely related species – four mammals, two birds, two frogs and two fish — each with
one monogamous and one non-monogamous member. They found 24 genes with similar expression
 patterns in monogamous males [Credit: University of Texas at Austin]

The researchers compared gene expression in male brains of all 10 species to determine what changes occurred in each of the evolutionary transitions linked to the closely related animals. Despite the complexity of monogamy as a behavior, they found that the same changes in gene expression occurred each time. The finding suggests a level of order in how complex social behaviors come about through the way that genes are expressed in the brain.

This study covers a broader span of evolutionary time than had been explored previously. Other studies have looked at genetic differences related to evolutionary transitions to new traits, but they typically focus on animals separated by, at most, tens of millions of years of evolution, as opposed to the hundreds of millions of years examined with this study.

“Most people wouldn’t expect that across 450 million years, transitions to such complex behaviors would happen the same way every time,” Young said.

The paper’s other UT Austin authors are senior author professor Hans Hofmann and professor Steven Phelps. Researchers examined gene activity across the genomes of the 10 species, using RNA-sequencing technology and tissue samples from three individuals of each species. The scientists detected gene-activity patterns across species using bioinformatics software and the Texas Advanced Computing Center’s Wrangler data-intensive supercomputer. Arranging genes from distantly related species — such as a fish and a mammal — into groups based on sequence similarities, the team was able to identify the common evolutionary formula that led to pair bonds and co-parenting in the five species that behave monogamously.

Source: University of Texas at Austin [January 07, 2019]



A little squid sheds light on evolution with bacteria

Bacteria, which are vital for the health of all animals, also played a major role in the evolution of animals and their tissues. In an effort to understand just how animals co-evolved with bacteria over time, researchers have turned to the Hawaiian bobtail squid, Euprymna scolopes.

A little squid sheds light on evolution with bacteria
Scientists led by UConn biologist Spencer Nyholm have found clues to the origin and evolution of symbiotic organs
in animals from the genome of the Hawaiian bobtail squid [Credit: Sarah McAnulty/UConn]

In a new study published this week in the Proceedings of the National Academy of Sciences, an international team of researchers, led by UConn associate professor of molecular and cell biology Spencer Nyholm, sequenced the genome of this little squid to identify unique evolutionary footprints in symbiotic organs, yielding clues about how organs that house bacteria are especially suited for this partnership.

The first squid genome was sequenced by Nyholm, along with Jamie Foster of the University of Florida, Oleg Simakov of the University of Vienna, and Mahdi Belcaid of the University of Hawaii. The team found several surprises, for instance, that the Hawaiian bobtail squid’s genome is 1.5 times the size of the human genome.

By comparing the genome of E. scolopes to its cousin, the octopus, the researchers show that the common ancestor of both the octopus and the Hawaiian bobtail squid went through a major genetic makeover, reorganizing and increasing the genome size. This “upgrade” likely gave the cephalopods opportunities for increased complexity, including new organs like the ones that house bacteria.

“The Hawaiian bobtail squid has served as a model organism for studying symbiosis for over 30 years,” notes Nyholm. “Having the genome will help researchers who study these interactions, as well as those studying diverse areas of biology, such as animal development and comparative evolution.”

A little squid sheds light on evolution with bacteria
Hawaiian bobtail squid. UConn researcher Spencer Nyholm and his colleagues were the first
to sequence this squid’s genome [Credit: Mattias Ormestad, www.kahikai.com]

Many animals have organs that house bacteria. The human gut houses trillions of bacteria that play important roles in digestion, immune function, and overall health. Understanding how these relationships are maintained by identifying genes that help animals cooperate with bacteria lays the groundwork for furthering knowledge of the human body. The Hawaiian bobtail squid is an excellent model for identifying these genes because of its symbiotic relationships with beneficial microbes, and its use by a number of scientists to study communication between bacteria and animals.

The Hawaiian bobtail squid has two different symbiotic organs, and researchers were able to show that each of these took different paths in their evolution. This particular species of squid has a light organ that harbors a light-producing, or bioluminescent, bacterium that enables the squid to cloak itself from predators. At some point in the past, a major “duplication event” occurred that led to repeat copies of genes that normally exist in the eye. These genes allowed the squid to manipulate the light generated by the bacteria.

Another finding was that in the accessory nidamental gland, a female reproductive organ, there was an enrichment of genes that are “orphan genes” or genes that have only been found in the bobtail squid and not in other organisms.

“Squid and octopus showed very unique genome structure, unlike in any other animals,” says Simakov, “corroborating previous reports of their unusual nature and complexity.”

Foster notes that teasing out these unusual and complex details is directly applicable to the study of other bacteria/animal relationships.

“Microbes are major drivers of the evolution of animals and their tissues,” she says. “The results of our study have helped identify the ‘origin story’ of those tissues that house an animal’s microbes, and will help tease apart the genetic processes by which these different types of innovation can happen in animals.”

Source: University of Connecticut [January 07, 2019]



Fossil of prehistoric deer found in Argentina

The well-preserved fossil of a prehistoric deer has been discovered just to the north of Buenos Aires, the La Matanza University revealed on Monday.

Fossil of prehistoric deer found in Argentina
Almost 70 percent of the fossilised bones of the Morenelaphus prehistoric deer were found
[Credit: Museo Paleontologico/AFP]

The fossil—which hasn’t yet been given a definitive age—included almost 70 percent of the animal, including its spine, extremities and teeth.
The discovery came from a site where 24 fossils of mammals and reptiles have been found in the last 17 years.

“It’s amazing to see how its spine and neck remained in the ‘life position’,” said Jose Luis Aguilar, director of the Paleontological Museum of San Pedro, in the north of Buenos Aires province.

Fossil of prehistoric deer found in Argentina
The deer’s complete spine and neck was found in the fossil remains of an animal that could have lived
up to two and a half million years ago [Credit: Museo Paleontologico/AFP]

As well as an almost complete set of teeth and its spine, the skeleton also included more than 20 ribs, the pelvic bone, a rear leg and a part of a femur.

This species of deer, from the Morenelaphus genus of which only fragmentary remains had been found until now, could reach up to 200 kilograms (440 pounds).

“This little animal has come to give us details about a moment in our prehistory when the environment they lived in was quite different to now,” said Aguilar, who made the discovery.

Tests are due to be carried out to determine the fossil’s age but the Morenelaphus is from the Pleistocene era that lasted from 2.5 million years ago until around 12,000 years ago.

Source: AFP [January 07, 2019]



From dreams to fire: How Aboriginal Australians shaped biodiversity

For many wild species, Aboriginal Australians shaped their diversity and distribution and even helped them thrive.

From dreams to fire: How Aboriginal Australians shaped biodiversity
Humans have used fire to manipulate Australian landscapes for thousands of years
[Credit: CSIRO]

Humans have been influencing their surroundings since prehistoric times. They’ve changed the land, established crops, hunted and raised animals and collected plants from the wild. Humans are also blamed for the extinction of many species.

But for some species, human intervention was actually a good thing. It helped them thrive and spread across Australia.

Trees on the move

For a long time, the first inhabitants of this country have been considered hunter-gatherers. They weren’t thought to be involved with the spread of other species, but the current distribution of some Australian native plants is hard to explain by natural processes.

Take the iconic boab tree. This tree is currently found in the Kimberley region of northwestern Australia. In a recent study, Associate Professor Haripriya Rangan found little genetic difference between boabs from different sites across the Kimberley. This meant that the boabs were moving around somehow.

“Genetic data alone did not provide an answer,” says Haripriya.

From dreams to fire: How Aboriginal Australians shaped biodiversity
Boab trees are distinctive on the Kimberley horizon. But how did they spread across the region?
[Credit: Summerdrought]

So rather than just focusing on genes, Haripriya and her team decided to focus on language. They compared genetic data with the geographic locations of indigenous words used for boabs.

“When we combined our genetic results with the geographic location of different words used to describe boabs, we were amazed. They matched perfectly,” Haripriya says.

“This indicated that ancient Aboriginal groups from northwest coastal Kimberley were carrying the boab fruit with them as they moved inland and to other parts of the Kimberley. In the process, they were sharing the names for boabs with other Aboriginal groups they encountered,” Haripriya adds.

The boab is not the only case. Another interesting case involves toxic beans and songs. The black bean or bean tree is a large evergreen tree found in Queensland and New South Wales that grows up to 40m high.

From dreams to fire: How Aboriginal Australians shaped biodiversity
The black bean tree has distinctive flowers… [Credit: Tatters]

Black bean seeds are normally transported by water to new locations, which means the trees are commonly found close to the coast. Oddly, some populations of this tree occur deep in the Australian rainforest—far from the coast and at considerable altitude.

Maurizio Rossetto from the Royal Botanic Garden in Sydney thinks that, just like with the boab trees, humans may have played a role in their movement.

The seeds of the black bean are poisonous but also highly nutritious. Aboriginal groups have figured out ways to use them for food without getting sick. They make a tasty bread out of the seeds.

To test whether Aboriginal groups moved the trees for food, Maurizio and a team of researchers used a combination of genetic data with traditional knowledge about this tree. They even interviewed five Aboriginal knowledge custodians about the use of black bean trees.

From dreams to fire: How Aboriginal Australians shaped biodiversity
…and seed pods that float [Credit: Arthur Chapman]

“Our genetic analyses showed very little variation between all the trees from NSW. This suggests that all black bean populations from NSW originated from one or a small number of very closely related trees,” he says.

Their review of literature and interviews revealed extensive use of black bean by Aboriginal groups since historical times. They even found a songline that told the story of a spirit called Nguthungulli. According to the song, the spirit carried and left “bean tree” seeds as he journeyed inland from the east coast to the western ranges.

But plants aren’t the only group whose distribution has been influenced by humans. Humans and their use of fire has also played a role in the life of some animals.

Fire and humans

Aboriginal people have been harvesting plant and animal species for thousands of years using traditional techniques that help ensure long-term use. Some of these techniques involve the use of fire.

One study, led by Rebecca Bliege Bird at Penn State University in the USA, found that Gould’s goannas actually do better under an Aboriginal burning approach.

“Our work has shown that burning is important for many species, especially those that are significant as subsistence resources,” says Rebecca.

The study focused on the burning practices of the Martu people. The Martu traditionally lived in the Little Sandy and Great Sandy Deserts of Western Australia. Historically, Gould’s goannas have been an important hunting prize for Martu women. They spend half of their hunting time looking for this half-kilo sand monitor.

Rebecca found that there were higher populations of these lizards in areas where they were more heavily hunted. But how is that possible?

It turns out the burning technique used by the Martu to hunt the lizards has a positive effect on their habitat. The burning increases the diversity of vegetation patches across the landscape. In places not influenced by the Martu, natural fires are usually caused by lightning. This leads to more extensive damage and lower diversity of plants.

“Perhaps they gain access to a wider set of different types of prey found in more diverse landscapes, or perhaps, they benefit from having an easier time finding protection from predators,” Rebecca says.

Now Rebecca plans to continue her research on the role of burning on other species, such as wild tomatoes.

From dreams to fire: How Aboriginal Australians shaped biodiversity
Gould’s sand monitors are important hunting prizes for Martu women
[Credit: Jean and Fred]

“There’s been some work in Australia already suggesting that the lack of Aboriginal burning and seed dispersal may be causing the decline of some wild tomato species.”

All in all, these studies show that the actions of ancient Aboriginal tribes have not only benefited humans but also other species.

Author: Karl Gruber | Source: Particle [January 07, 2019]



Medical scanner helps to unlock the mysteries of a giant prehistoric marine reptile

A nearly metre-long skull of a giant fossil marine ichthyosaur found in a farmer’s field more than 60 years ago has been studied for the first time.

Medical scanner helps to unlock the mysteries of a giant prehistoric marine reptile
Life reconstruction of ichthyosaur skull [Credit: Thinktank, Birmingham Science Museum]

Using cutting-edge computerised tomography (CT) scanning technology, the research reveals new information including details of the rarely preserved braincase.
The almost 200 million year old fossil, which was found in 1955 at Fell Mill Farm in Warwickshire, had never formally been studied prior to this research.

Now, thanks to data collected from CT scans, the research team were able to digitally reconstruct the entire skull in 3-D. It is the first time a digital reconstruction of a skull and mandible of a large marine reptile has ever been made available for research purposes and to the public.

Medical scanner helps to unlock the mysteries of a giant prehistoric marine reptile
Thinktank ichthyosaur skull [Credit: Thinktank, Birmingham Science Museum]

Although thousands of ichthyosaur fossils have been unearthed in the UK, this specimen is particularly important and unusual because it is three-dimensionally preserved and contains bones of the skull that are rarely exposed.
In 2014, as part of a project at Thinktank Science Museum, Birmingham, palaeontologists Dean Lomax, from The University of Manchester, and Nigel Larkin began to study the skull and its incomplete skeleton for the first time and were soon convinced of its importance.

Dean, the lead author and one of the world’s leading ichthyosaur experts, explains: “The first time I saw this specimen I was puzzled by its excellent preservation.

Medical scanner helps to unlock the mysteries of a giant prehistoric marine reptile
Thinktank ichthyosaur skull – CT-scanning [Credit: Thinktank, Birmingham Science Museum]

Ichthyosaurs of this age (Early Jurassic) are usually ‘pancaked’, meaning that they are squished so that the original structure of the skull is either not preserved or is distorted or damaged. So to have a skull and portions of the skeleton of an ichthyosaur of this age preserved in three dimensions, and without any surrounding rock obscuring it, is something quite special.”
The ichthyosaur was originally identified as a common species called Ichthyosaurus communis, but after studying it closer, Dean was convinced it was a rarer species. Based on various features of the skull, he identified it as an example of an ichthyosaur called Protoichthyosaurus prostaxalis. With a skull almost twice as long as any other specimen of Protoichthyosaurus, this is the largest specimen so far known of the species.

Co-author Nigel Larkin added: “Initially, the aim of the project was to clean and conserve the skull and partially dismantle it to rebuild it more accurately, ready for redisplay at the Thinktank Museum. But we soon realised that the individual bones of the skull were exceptionally well preserved in three dimensions, better than in any other ichthyosaur skull we’d seen. Furthermore, that they would respond well to CT scanning, enabling us to capture their shape digitally and to see their internal details. This presented an opportunity that couldn’t be missed”

Medical scanner helps to unlock the mysteries of a giant prehistoric marine reptile
Thinktank ichthyosaur skull – micro CT-scanning with Dean Lomax (left), Nigel Larkin (centre pointing
at screen) and Dr Laura Porro (right) at the University of Cambridge
[Credit: Nigel Larkin, the University of Cambridge]

The skull isn’t quite complete, but several bones of the braincase—which are rarely preserved in ichthyosaurs—are present. To unlock information contained in the skull, these bones were micro-CT scanned at Cambridge University in 2015 by expert palaeontologist and co-author, Dr. Laura Porro of University College London (UCL).
The fossil only preserved bones from the left side of the braincase; however, using CT scans these elements were digitally mirrored and 3-D printed at life size to complete the braincase. Finally, the entire skull was CT scanned at the Royal Veterinary College (RVC) using a scanner typically reserved for horses and other large animals.

Dr. Porro added: “CT scanning allows us to look inside fossils—in this case, we could see long canals within the skull bones that originally contained blood vessels and nerves. Scans also revealed the curation history of the specimen since its discovery in the ’50s. There were several areas reconstructed in plaster and clay, and one bone was so expertly modelled that only the scans revealed part of it was a fake. Finally there is the potential to digitally reconstruct the skull in 3-D. This is hard (and risky) to do with the original, fragile and very heavy fossil bones; plus, we can now make the 3-D reconstruction freely available to other scientists and for education.”

Thinktank ichthyosaur skull – CT-scanning [Credit: Nigel Larkin, taken at Royal Veterinary College, London]

The use of modern technologies, such as medical scanners, have revolutionised the way in which palaeontologists are able to study and describe fossils.

Dean added: “It’s taken more than half a century for this ichthyosaur to be studied and described, but it has been worth the wait. Not only has our study revealed exciting information about the internal anatomy of the skull of this animal, but our findings will aid other palaeontologists in exploring its evolutionary relationship with other ichthyosaurs.”

The findings are published in PeerJ.

Source: University of Manchester [January 08, 2019]



2019 January 10 Vela Supernova Remnant Mosaic Image Credit…

2019 January 10

Vela Supernova Remnant Mosaic
Image Credit & Copyright: Robert Gendler, Roberto Colombari, Digitized Sky Survey (POSS II)

Explanation: The plane of our Milky Way Galaxy runs through this complex and beautiful skyscape. Seen toward colorful stars near the northwestern edge of the constellation Vela (the Sails), the 16 degree wide, 200 frame mosaic is centered on the glowing filaments of the Vela Supernova Remnant, the expanding debris cloud from the death explosion of a massive star. Light from the supernova explosion that created the Vela remnant reached Earth about 11,000 years ago. In addition to the shocked filaments of glowing gas, the cosmic catastrophe also left behind an incredibly dense, rotating stellar core, the Vela Pulsar. Some 800 light-years distant, the Vela remnant is likely embedded in a larger and older supernova remnant, the Gum Nebula. Objects identified in this broad mosaic include emission and reflection nebulae, star clusters, and the remarkable Pencil Nebula.

∞ Source: apod.nasa.gov/apod/ap190110.html

Archaeological dig unravels secrets to Ribchester’s Roman past

A team from the University of Central Lancashire have spent their fourth year digging at a site in Ribchester during the summer.

Archaeological dig unravels secrets to Ribchester's Roman past
The team from UCLan digging at the site in Ribchester [Credit: Lancashire Telegraph]

This year’s four-week long dig revealed items from the Roman fort’s earliest existence, the remains of a wooden well, almost 2,000 years old.

The well would have been one of several in the fort which would have been used by the 500 men and 700 horses that would have lived there at the time.

The well is believed to have been constructed around 72 to 74 AD, when the fort’s first wooden structures were built.

Other findings included pieces of leather.

Archaeological dig unravels secrets to Ribchester's Roman past
A 1st century wicker wood lined Roman well being excavated on site
[Credit: Lancashire Telegraph]

Dr Jim Morris, a lecturer in archaeology at the university, who led the team, said the findings were unique.

He said: “We are pleased with the results because these sorts of materials are perishable and usually disintegrate.

“The well was lined with wattle, which had lots of pieces of wood weaved together to make it strong.

“It’s a great find, we have found pieces of the fort from when it was originally built as a wooden fort, almost 2,000 years ago.”

Archaeological dig unravels secrets to Ribchester's Roman past
Remains of a Roman shoe being excavated by the team [Credit: Lancashire Telegraph]

The fort is one of specific interest as its one of the last so-called areas of Roman civilisation before the Lake District, which was described as ‘wild lands’.

The dig also revealed there had been people living in Ribchester before the first known settlers, contrary to what archaeologists originally believed.

A dig has taken place at the site every summer since 2015, with finds including pieces of pottery and cloth, along with broken ladles and lead weights. More than 20 coins were dug up in a trench in the northern area of the fort during the digs.

He said: “Every year we generate a lot of interest and we have students from the university, the USA, Australia and primary school children from Ribchester coming down to look at what we are doing.

“We’re open to the public when we’re digging and we want to encourage young people to take an interest in the history on their doorstep.”

Author: Neil Athey | Source: Lancashire Telegraph [December 28, 2018]



5,000-year-old house in central China to get renovated

The foundations of a Neolithic house that has stood for over 5,000 years in central China’s Henan Province will be examined and reinforced 46 years after they were unearthed.

5,000-year-old house in central China to get renovated
The foundations of a Neolithic house that has stood for over 5,000 years in central China’s Henan Province
will be examined and reinforced 46 years after they were unearthed. The four-bedroom home is part
of the Neolithic Yangshao culture, dating back 7,000 years [Credit: Xinhua/Li An]

The four-bedroom home that covers nearly 50 square meters in Zhengzhou, capital of Henan, is located in the Dahe Village relic site that is part of the Neolithic Yangshao culture, dating back 7,000 years.
The roof is long gone, but the one-meter-high walls still stand, providing a complete spatial layout of the house. Specialists use tools such as brushes and bamboo knives to clean the dust and dead moss accumulated on the surface and inside small cracks before they are reinforced.

5,000-year-old house in central China to get renovated

5,000-year-old house in central China to get renovated

5,000-year-old house in central China to get renovated

5,000-year-old house in central China to get renovated
The foundation of a Neolithic house in the Dahe Village relic site museum in Zhengzhou,
capital of central China’s Henan Province [Credit: Xinhua/Li An]

The Yangshao Culture, widely known for its advanced pottery-making technology, originated on the middle reaches of the Yellow River and is considered an important stream of Chinese civilization.
The house was built with wood as its “bones,” hay as “muscles,” and clay that covered the walls. Fire was then used to burn the entire building, similar to firing pottery, to make it strong enough to stand for thousands of years, according to Hu Jizhong, curator of the relic site museum.

5,000-year-old house in central China to get renovated
Replica of a pottery ware in the Dahe Village relic site museum in Zhengzhou,
capital of central China’s Henan Province [Credit: Xinhua/Li An]

More than 50 utensils, including 20 pottery ware were found in the house, along with a can of carbonized food grains. Experts said the four rooms had living and sleeping functions, demonstrating that private ownership and family had budded at the time.

The renovation will last about one year.

Source: Xinhua [December 28, 2018]



Ancient lead sarcophagus unveiled to public in Jerash

The Jerash Department of Antiquities on Thursday unveiled a “unique” lead sarcophagus that dates back to the early Byzantine era.

Ancient lead sarcophagus unveiled to public in Jerash
The Jerash Directorate of Antiquities on Thursday unveiled a 4th century sarcophagus containing carvings
of Christian symbols and Greek mythological stories [Credit: Ahmed Bani Mustafa]

During an unveiling ceremony held at  the Jerash Archaeological Museum, Director of the General Department of Antiquities Yazeed Hashem said that the coffin represents one of the most important discoveries in the Middle East, as it is unique in terms of material, size and carvings.

“It is the one of only two lead sarcophagi found in Jordan. The other was found in Umm Qais, and it reflects the wealth of Jerash during that time,” Hashem said.

The coffin is thought to have been made in Jerusalem or Sidon in Lebanon and was carried all way to Jerash, which tells researchers that the person inside must have been an important social or religious figure, stakeholders said.

The sarcophagus was found accidentally, in Jerash’s Wadi Addeir Gharbi region in 2003, Jerash Director of Antiquities Ziad Ghunaimat, told The Jordan Times during the event.

It has funerary art carved on its outer walls, which depict Christian symbols and Greek mythological subjects, such as the myths of Prometheus and Hades, Abdulrahman Serouji, a professor from Yarmouk University who supervised the restoration process, said.

The sarcophagus is thought to have held the body of a priest or a high-profile person during the 4th century, according to a study from Masters student Belal Borini, who wrote his thesis on the finding.

Burial in such a coffin was expensive and, thus, done mainly by rich families during the Byzantine era, who expanded into Jordan from 324 to 636AD, according to Borini

This discovery, in addition to a number of marble statues of Zeus, Aphrodite and the muses, are important for the tourism sector of the Kingdom and Jerash, Director of Jerash Tourism Department Bassam Tobat said.

Exhibiting the sarcophagus at the museum will contribute to efforts by stakeholders to lengthen the time tourists spend in Jerash, Tobat added.

Early Christian sarcophagi were the result of an abandonment of the cremation practices used by the Romans, and spread in the 2nd to 5th centuries, according to experts.

Author: Ahmed Bani Mustafa | Source: The Jordan Times [December 28, 2018]



Remains of 5,750-year-old infant found in Argentina

Archaeologists from the Natural Science Department of the National University of Cuyo have discovered the skeletal remains of a 5,700 year old infant in Ciudad de Mendoza, western Argentina.

Remains of 5,750-year-old infant found in Argentina
Excavation reveals infant remains in Mendoza, Argentina [Credit: UNCuyo]

According to the univiserity announcement, the researchers discovered the bones unexpectedly when looking for the sterile layer of a previous dig in the archaeological region known as the ‘Nino de las Cuevas’ (‘the child of the caves’), named after the remains of a young child between three and five years old were found there in 2015.

Alejandra Gasco from the archaeology team said they found the remains only 1,5 metres away from where they discovered the previous set of remains. “It is quite surprising that another child was buried in the same area,” he said.

“We came across something special: a circle with carbonaceous sediment, whose black colour and texture was markedly different from the reddish clay of the site. We managed to remove a couple of centimetres of sediment with brushes when we found fragments of a tiny jaw. We realized we had found the remains of a child. Following this, we asked for the necessary permissions from Juan Cornelio Moyano Nature and Anthropological Sciences Museum to continue excavation works,” Gasco said.

“Unlike the previous burial, which was found at the same site, here we were able to determine the funeral structure clearly, which has a circular shape of about 30 centimetres in diameter, that is to say very small, and which is on the red clay sediment, which is considered sterile in archaeological terms,” the researcher added.

“Until the beginning of these studies there was only archaeological information related to the period of Inca domination, especially on a sacrifice of a child that was deposited in a high sanctuary located in the Aconcagua”, says anthropologist Victor Duran, director of the research project.

Remains of 5,750-year-old infant found in Argentina
Detail of infant remains in funerary context [Credit: UNCuyo]

“Finding a skeleton was not expected by the group, since very few human skeletal remains had been discovered in high altitude environments. The result of the radiocarbon dating done on a fragment of one of its bones by AMS was also a surprise. The date obtained gives this individual an age of 5750 years. It is the oldest in the province of Mendoza and corresponds to a period in which the climatic conditions were more favourable to the current ones (a little warmer and wetter) in the mountain range according to pollen studies.”

Because the remains of the infant were found at the same layer as the child discovered in 2015, the archaeologists believe that the remains likely to date to around the same time.

“The regional archaeological information allows us to propose that the society from which this individual came had a hunter-gatherer economy and a band-like social organization. Surely it was small groups (between 30 and 50 people) that moved throughout the year, from lowlands to highlands and vice versa, to obtain the meat of animals that hunted (especially guanacos — Lama guanicoe) and vegetables that they collected.”

“Having found this infant burial, it can be ascertained that it was the entire family group that moved (men, women and children) and that it is likely that the mountain range where it was left was part of a larger territory, a space of seasonal occupation to which it recurred,” said Duran.

Knowing where these ancient mountaineers came from and specifying aspects of their way of life is one of the major challenges of the research group.

“This new finding will allow expanding the ongoing studies that have placed the town of Las Cuevas in a position of great importance within the archaeology of the province and the country”, concludes the anthropologist.

Source: National University of Cuyo [December 29, 2018]



Don’t judge a galaxy by its cover: Astronomers develop new tool to find merging...

Three galaxies observed by the SDSS MaNGA survey

The top row shows the galaxies’ images, while the bottom row shows the velocity of the stars within the galaxies; red means the stars are moving away from us and blue means towards us. The panel on the left shows an isolated spiral galaxy, not undergoing a merger. The middle panels show a spectacular pair of merging galaxies, obvious in both the image and the velocity map. The right panels show what appears in the image to be a single galaxy – but the velocity map reveals that it is actually a galaxy that has just merged. This is evident in the disturbed (counter-rotating) features in the velocity map. This example demonstrates the power of the team’s new method, which will identify merging galaxies using both imaging and kinematics. Image credit: Rebecca Nevin (University of Colorado Boulder) and the SDSS collaboration. Hi-res image

Don’t judge a book by its cover, and don’t judge a galaxy by its image alone.

Today, at the 233rd AAS meeting in Seattle, astronomers from the Sloan Digital Sky Survey (SDSS) announce that they have developed a new tool to find otherwise-hidden galaxy mergers in data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey of SDSS. These results show that by going beyond simple searches for merging galaxies based just on how they look, astronomers will now be able find more galaxy mergers than ever before.

“Merging galaxies are key to understanding galaxy evolution, but finding them can be tricky,” says Rebecca Nevin of the University of Colorado, the lead author of the study. Nevin is presenting this work this week as a Dissertation talk, as it formed the basis of her PhD thesis at Colorado with Professor Julie Comerford.

A pair of merging galaxies is one of the most beautiful sights in astronomy, with giant tidal streams of stars and unusual shapes sometimes resembling animals (e.g. the Antennae, Mice, Tadpole, or Penguin galaxies). However, these beautiful visible features are visible are only found in a small fraction of merging galaxies – and even then only for a small part of the billions of years it takes for two galaxies to fully merge into one. Some galaxies that otherwise look “normal” may still be in the process of merging.

Astronomers have developed a way to find these hidden mergers. They created a method that uses simulations of merging galaxies to predict both how the mergers would look and how the stars in the galaxies would move. By comparing their results with observations of galaxies from the SDSS’s Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, astronomers will be able to do much better at identifying merging galaxies in the wild.

“These simulations allow us to predict the more subtle signs of merging galaxies, so we can find mergers in SDSS data that were previously hidden,” explains Laura Blecha (University of Florida), another key member of the team.

This montage of six images from the Hubble Space Telescope shows six real galaxies in different stages of the merger process. For more information about these galaxies, see the image description at the Hubble Space Telescope website.  Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

What the team is presenting today is the part of their method that analyzes galaxy images. They have essentially made a galactic photo album, including pictures of galaxies in all stages of merging. In the past, astronomers’ “photo albums” of galaxy mergers were sparse, including only galaxies in the stage of merging where they looked like spectacular mergers. 

“Nowadays, it would be totally unthinkable to take only one or two selfies every year,” said Nevin. “We have modernized the galaxy merger photo album – now it’s like taking one galaxy merger selfie a day for years.”

The astronomers plan to make these extensive photo albums publicly available to everyone. Astronomers will use them to study how galaxies change as they undergo mergers.

The team’s work so far is already a giant step forward in merger identification, but they are already taking the next step. They have already begun to incorporate data on how the stars move in the galaxies from the SDSS MaNGA survey. This will allow the team to identify even more mergers – those where the galaxy looks completely “normal.”

The key to this new analysis is to incorporate data from MaNGA on how stars within galaxies are moving. “By going beyond images alone and incorporating stellar kinematics, we will find many more merging galaxies,” says Karen Masters of Haverford College, the Spokesperson for SDSS. “We’ll be able to learn how the merger process impacts how galaxies in our Universe evolve.”

These stellar kinematics are revealed in the maps created by the SDSS’s MaNGA survey. Because the spectra that MaNGA observes come from the light of all the stars in a particular part of a galaxy, stars, the spectra are slightly shifted by the Doppler Effect – blueshifted for the parts of a galaxy that are moving toward Earth and redshifted for the parts moving away from Earth. These subtle shifts reveal how the stars are moving around the galaxy.

When galaxies merge, the stars in them almost never collide, but they are thrown all around, creating dramatic distortions in the pattern of how stars move around the galaxy – patterns that astronomers refer to as “stellar kinematics.” In a typical, non-merging spiral galaxy, the stars rotate in a simple, predictable pattern. But if such a galaxy is undergoing a merger, that simple pattern becomes chaotic, creating wild (but predictable) arrangements of stellar motion. When a galaxy’s patterns of stellar motion have become distorted by a merger, the stellar kinematics data from MaNGA provides direct evidence of the merger. Nevin’s team, which includes astronomers from the University of Colorado Boulder, the University of Florida, and Princeton University, is beginning to add stellar kinematics data into their work.

This animation shows one of the galaxy merger simulations the team created. The first 38 seconds shows the simulation running, covering 2.5 billion years of history. From each step of the simulation, the team figures out what the galaxy would look like when viewed from Earth by the Sloan Digital Sky Survey (shown from 0:39 to 1:06). The last part of the video (1:06-1:30) shows a collection of simulated images and how they are used to create a classification method that can then be applied to real SDSS images. Image credit: Rebecca Nevin (University of Colorado), Laura Blecha (University of Florida), and the SDSS collaboration. 

“As we improve our machine learning algorithms to incorporate the stellar kinematics of merging galaxies, we are able to identify different stages of the merger. The disturbances in the stars can last longer than imaging signatures of a merger like faint tidal tails, which fade much quicker. This means we can identify later stages in the merger, when in the imaging the galaxies look just like normal galaxies. This is a powerful new technique in the study of merging galaxies.”

Understanding mergers is not only important to astronomers like Nevin’s team; this understanding can help us predict the future of our own Galaxy. The Milky Way will merge with the Large and Small Magellanic Clouds in about 2.5 billion years – and is then predicted to merge with the much more massive Andromeda galaxy in five billion years, combining to form a single super-galaxy, which some dub “Milkdromeda.” This event might throw the Sun out of the galaxy, but it won’t matter to future inhabitants of Earth, which will have been swallowed by the Sun as it turns into a red giant star at around the same time. But maybe our descendants will see this for themselves as they travel among the stars.

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Wide Field Camera 3 Anomaly on Hubble Space Telescope

NASA – Hubble Space Telescope patch.

Jan. 9, 2019

 Hubble Space Telescope in orbit. Image Credit: NASA

At 17:23 UTC on Jan. 8, the Wide Field Camera 3 on the Hubble Space Telescope suspended operations due to a hardware problem. Hubble will continue to perform science observations with its other three active instruments, while the Wide Field Camera 3 anomaly is investigated. Wide Field Camera 3, installed during Servicing Mission 4 in 2009, is equipped with redundant electronics should they be needed to recover the instrument.

Hubble Space Telescope (HST): https://www.nasa.gov/mission_pages/hubble/main/index.html

Image (mentioned), Text, Credits: NASA/Rob Garner.

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