вторник, 2 октября 2018 г.

Platelets Start Here They may look like sparkling, precious…

Platelets Start Here

They may look like sparkling, precious jewels, but these glowing gems are actually platelets forming inside the bone marrow. The smallest cellular component in blood, platelets are tiny cellular fragments that bud off from much larger cells known as megakaryocytes. Although they may be small, these little biological bags are real life-savers. Once activated at the site of a wound, platelets spring into action, clumping together to form a stable blood clot to stop the flow. But while platelets are vital for stopping dangerous bleeding when we’re injured, they can also cause trouble by creating unwanted clots inside blood vessels, leading to potentially fatal heart attacks and strokes. Researchers are taking a closer look at platelets to find out why they make clots when they shouldn’t, pointing towards life-saving new prevention strategies, and also investigating what happens when they fail to work properly in people with rare uncontrollable bleeding disorders.

Written by Kat Arney

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Mountains create biodiversity

Mountains are among the most biodiverse places on Earth, but scientists have struggled to fully understand why they are so important in creating high species richness. An international research team, including four scientists from the University of Amsterdam, has now shed new light on answering this long-standing question.

Mountains create biodiversity
The Serra Geral, Brazil [Credit: Edward Paine]

The team found that mountain building, through a process of uplift and erosion, continuously reshapes the landscape and is responsible for creating habitat heterogeneity in an elevational gradient. “The complex interplay between growing mountains and climate generates plenty of opportunities for the creation of new species,” says Carina Hoorn, senior author of the paper. “Although climate and ruggedness of the terrain were previously thought to be the principal cause for mountain biodiversity, our global synthesis now makes clear that geological history plays a paramount role in this process,” explains Hoorn.
The team reached this conclusion by applying statistical models to biological, geological and climatological datasets from across the globe. “In our models, we related the species richness of birds, mammals and amphibians to global datasets of temperature, precipitation, erosion rates, relief and soil composition,” says Daniel Kissling who conducted the statistical analyses of the paper. “I was surprised to find not only the usual correlations with climate, but a significant relation between biodiversity, erosion history, relief and number of soil types,” continues Kissling. While the study shows that this is evident globally, it also revealed that the relationship can vary depending on which mountain system is considered. “This regional variation in the importance of geological drivers was really unexpected,” says Kissling.

The study further showed that geographic position (e.g. whether a mountain intercepts atmospheric currents or not) and the duration of mountain building process (young or old) are also important processes influencing biodiversity in mountains. On shorter geological time scales, Quaternary climatic fluctuations can also promote the creation of new species in mountains. “We suggests that the waxing and waning of glaciers, which has strongly reshaped the landscape and repeatedly connected and disconnected animal and plant populations, has played an important role for the creation of new mountain species,” says Suzette Flantua who studied the effects of Quaternary climate change on mountain biodiversity in Latin America for her Ph.D. at the University of Amsterdam.

The advances in geological methods and the increasingly complete global data sets on climate, soils, erosion history, and species richness only now have made it possible to gain such comprehensive insights into the relation between mountain building and biodiversity. The scientists are optimistic that with the new methods and datasets, further insights into the complex relationship between biodiversity, climate and mountain building can be expected in the near future.

The study is published in Nature Geoscience.

Source: University of Amsterdam [October 01, 2018]



Set in amber, fossil ants help reconstruct evolution of fungus farming

Some 50 million years before humans figured it out, agriculture arrived in the world in a seemingly unlikely place: an ant hill.

Set in amber, fossil ants help reconstruct evolution of fungus farming
A fungus-farming ant is covered in white symbiotic bacteria, which the ant relies on to produce
 antibiotics to protect its garden from a parasitic fungus [Credit: Alex Wild]

Eschewing wheat or rice for feathery white fungus, the ants cultivated their fungal crop, providing it with care in exchange for nourishment. But like their human counterparts who would come after them, the ants faced the perennial problem of crop disease, in this case a parasitic fungus, which threatened to wipe out their harvests.

So the ant farmers evolved another partnership. They offered safe harbor and nutrition to a certain group of bacteria — the Actinobacteria — that in turn produced antibiotics capable of keeping the parasite at bay. To help the bacteria stick around, the ants’ exoskeletons evolved specialized pockets that protected and fed their partners.

These structures seemed so intricate that scientists believed they only had the chance to evolve once as the original fungal farmers eventually diverged into the 250-some ant farming species we find today. But writing in the Proceedings of the National Academy of Sciences, University of Wisconsin-Madison researchers reveal that these bacteria-harboring structures evolved independently three times.

The results make it clear that the constant threat of crop parasites repeatedly pushed evolution in strikingly similar directions, creating structures that helped the ants reinforce their partnership with bacteria. And their successful use of protective antibiotics for eons suggests the ants may have lessons for human medicine, which has quickly come up against resistance by pathogens to our most important antibiotics.

The work was led by UW-Madison Professor of Bacteriology Cameron Currie and Hongjie Li, a postdoctoral researcher in the Currie lab. They partnered with colleagues at Arizona State University, the University of Sao Paulo, Harvard Medical School and the Smithsonian.

“This work provides fascinating insights into an animal using bacteria to provide antibiotics over a long period of time,” says Currie, who has researched the dynamics of farming ants for 20 years.

The researchers performed an exhaustive survey of 69 ant species, sourcing diverse ant samples from the collections at Arizona State University and the Smithsonian. The research team reconstructed the ants’ evolutionary tree using pieces of their genomic sequences. The resulting tree suggested that the partnership between ants and bacteria evolved soon after the ants began farming.

Further evidence for the ancient origin of the ant-bacteria relationship came from a handful of fungus-farming ants fortuitously frozen in amber from what is now the Dominican Republic. Through the hardened tree sap, the researchers could spot the telltale signs of bacteria clinging to the ants’ bodies. With the amber dated to between 15 and 20 million years old, Currie’s team could validate their genomic data and show that the ant-bacteria symbiosis was at least as old as the amber samples.

Earlier work had hinted at the early evolution of the ant-bacteria partnership, says Li, but “this paper provides much more evidence that this is an ancient system.”

Using ultra-high-magnification electron microscopy, the researchers examined the ants for the specialized structures housing bacteria, known as crypts. The microscopic images showed that most living species of farming ants had crypts and related structures that could support Actinobacteria. But a number of ant species were missing these structures.

When they mapped the crypt data over the reconstructed evolutionary tree, Currie’s team saw that crypts had evolved not once, but three separate times during the evolution of farming ants.

But the crypts were not ubiquitous. Some species have lost any obvious structures for supporting bacteria. The researchers showed that ants that have done away with crypts have also lost any trace of symbiotic Actinobacteria.

Currie and Li venture that ants that now farm in more arid areas no longer contend with the constant threat of the parasitic fungal disease. Since harboring and feeding the bacteria can use up to a quarter of an ant’s energy, it became more advantageous for the ants to part ways with their erstwhile partners.

Apparently not content to mimic the ant’s farming lifestyle, humans would later turn to the same group of bacteria, the Actinobacteria, for most of our clinical antibiotics. That the ants have, for millions of years, used similar antibiotics to protect their fungal gardens from pests suggests that we might learn from their success.

“I strongly believe there are mechanisms here that reduce the emergence of antibiotic resistance,” says Currie.

Discovering what those mechanisms are might just help us extend the useful life of our own antibiotics.

Author: Eric Hamilton | Source: University of Wisconsin-Madison [October 01, 2018]



Palaeontology: A way of reaching into the past to build lessons for the present

South Africa has an unparalleled fossil record of prehistoric life. It also holds a key position within the African nursery of humankind. And so, the country’s palaeontology tells the story not just of those who live in it, but of every person living on earth.

Palaeontology: A way of reaching into the past to build lessons for the present
The fossilised skull of a young Australopithecus africanus, known as the Taung Child,
is among South Africa’s most famous fossils [Credit: PAST]

Public and private investment has been crucial in driving some of South Africa’s most important fossil finds of the last few decades. Take the story of Little Foot. She’s a near-complete 3.67 million year old skeleton; a pre-human adult found, excavated and reconstructed over the last 20 years in the Sterkfontein Caves near Johannesburg. Little Foot is the country’s oldest fossil hominid. She is also by far the most complete skeleton of an Australopithecus ever found.

But she may never have been discovered without major financial investments into palaeontological research. With major funding from PAST, Little Foot was discovered and excavated by Ronald J. Clark of the University of the Witwatersrand.

PAST was created in 1994 to raise corporate support for research at Sterkfontein, which was on the verge of shutting down because it didn’t have enough funding.

Since then, the government, universities and PAST’s corporate and foundation sponsors have invested a growing amount of money into the study of South Africa’s fossil heritage.

Some may question why money is being spent on exploring the past – especially in a country that faces so many pressing challenges. But this sort of work is about more than just supporting an academic exercise in chronicling ancient events. It offers lessons that can change attitudes and responses to the most fundamental issues facing South Africa and societies everywhere. These lessons relate to discrimination, particularly that based on race, and the rapid, human-induced loss of natural environments and biodiversity.

Our shared heritage provides an essential tool for securing a just and sustainable future. Palaeontology teaches us that we are all from one. Ignoring lessons from the 3.8 billion years of life’s prehistory, which preceded the brief 5,200 years of written history, would be an astonishing folly. Seeking further knowledge about our ancient heritage today is an investment in leaving a legacy of prosperity for future generations.

Shared origins

The lessons from our distant past are based on two facts. First, all of humankind shares a common origin in Africa. Second, all living beings – including humans – share a common origin. These facts are conclusive. They have been demonstrated by tens of thousands of fossil finds and corroborated independently by genetic studies of extant species.

These facts offer a compelling and profound way to think about and act on human diversity and our place in nature.

Physical differences among people from different places have been used to divide humans into races. To many, these groupings are presumed to be biologically superior or inferior to one another. Yet our shared origins have resulted in a remarkably strong – 99.9% – similarity between any two people’s genetic makeup. That’s regardless of their appearance and where they come from.

The few traits that differentiate regional populations often reflect adaptations to the new environments encountered during humankind’s prehistoric expansion out of Africa. For example, variations in skin colour result from adaptation to mainly latitude-dependent differences in ultraviolet radiation from the sun. This forms a continuum that can only divide people into arbitrary categories.

Humans and nature

Just as all people share a relatively recent origin, all living beings share a far more ancient origin. All have inherited – with modifications – DNA from the single-celled Last Universal Common Ancestor (referred to as LUCA) that lived over three billion years ago.

A growing tree is a useful way to envision the origin and diversification of life on earth: LUCA is positioned at the base of the primeval seedling; the leaves of the mature Tree of Life represent the millions of extant species, and their twigs and then branches retrace lines of descent as they coalesce toward and on to the trunk and LUCA.

As part of this tree, humans owe our existence to the same natural processes as any other species. In no way do we have dominion or supremacy over it.

But we have the power, intelligence, technology and large numbers to severely deplete biodiversity on a global scale. This understanding has perhaps never been more important given our current rates of destruction.

Palaeontology reveals that natural catastrophes have resulted in five worldwide mass extinctions over the last 540 million years. The most recent, 66 million years ago, claimed the non-avian dinosaurs and about three-quarters of all other species.

Today’s extinction rates are higher than in the aeons since the dinosaurs’ demise. We are on pace to reach the 75% species-loss threshold for a sixth mass extinction in as little as three human lifetimes.

Author: Robert Blumenschine | Source: The Conversation [October 01, 2018]



Siberian paleontologists discovered the oldest macro-skeleton remains

The oldest skeleton remains known to fossil chronicle of the Earth belonged to the microorganisms that lived 700-650 million years ago. International research team proved that a larger organisms of the same period, such as Palaeopascichnus linearis up to 20 centimeters long, also had a skeleton. The research is published in Precambrian Research.

Siberian paleontologists discovered the oldest macro-skeleton remains
Palaeopascichnus linearis from the khatyspyt formation in Siberia
[Credit: Anton Kolesnikov]

Palaeopascichnus resembles a series of spheres or ellipsoids, which are placed one by one and called chambers. They have been known for a long time and can be found all across the world since for that time period they were one of the most widespread living organisms. Palaeopascichnus was considered as fossil traces of life activity for a while: someone described them as traces on the surface of a substrate or sediment left by animal migration in search of food, someone – as petrified chains of feces, someone – as the algae remains.

Researchers from Institute of Petroleum Geology and Geophysics SB RAS and Novosibirsk State University together with their colleagues from Great Britain and France for the first time managed to prove that in fact Palaeopascichnus was a skeletal organism. The scientists found out that Palaeopascichnus has much in common with modern giant protozoa: deep-sea single-cell xenophyphores. For example, Palaeopascichnus agglutinated exoskeleton by staying motionless at the bottom and gluing around itself particles of rocks and sediment from the surrounding space. As a modern example of the agglutination caddisflies can be named, even though they are moving.

“The material was collected in the Arctic at the Olenek uplift of the northeast of the Siberian platform, where a very large accumulation of organisms was found,” says one of the researchers Anton Kolesnikov, member of Institute of Petroleum Geology and Geophysics SB RAS and Doctor of the University of Lille. “When we made a thin cut through the Palaeopascichnus across the chamber, we saw that there is a certain wall composed of a material that is more coarse in comparison to the host rocks.”

A set of diverse methods was used in this research: the scientists made thin saw cuts, or slides, studied them under microscope, conducted tomography studies, used scanning electron microscope and so for. Afterwards the researchers started to look at additional materials from the White Sea, Ukraine, Australia, Canada, and all these samples confirmed the existence of a skeleton.

Siberian paleontologists discovered the oldest macro-skeleton remains
These are agglutinated walls in Palaeopascichnus linearis from the khatyspyt formation under the scanning electron
microscope. (B, C) are magnified images showing the wall, the internal filling and the surrounding rock.
White arrowheads mark the outer limit of the rim [Credit: Anton Kolesnikov]

Through statistical calculations of rock grains size in the Palaeopascichnus wall and the surrounding space, the scientists also found that these organisms preferred to collect large particles to construct the skeleton rather than everything around them.

Palaeopascichnus turned out to be more lucky than other creatures of that time, such as Ediacaran biota, which almost disappeared approximately ten million years before the Cambrian. Palaeopascichnus lived up to the beginning of the Cambrian, and theoretically modern xenophyphores might be their distant descendants.

Apart from Palaeopascichnus’ potential descendants, the paleontologists discovered their ancient relatives. “The thing is that there are plenty organisms like Palaeopascichnus,” Anton Kolesnikov notes. “For instance, genus Orbesiana, which was discovered in the well drilled near Moscow by a famous scientist, founder of the Ediacaran biota study, Boris Sokolov. He described the fossils that he found as the ancient macroscopic algae, and after that this material got lost for a while. Recently, the family of Boris Sokolov offered us his archives and we found the original material with detailed explanatory note.”

The researchers managed to use the most advanced equipment, and with the help of British and French colleagues they showed that Orbesiana was far from being an algae. More likely, they were close to Palaeopascichnus and might be placed in one group of the oldest macro-skeletal organisms. “Palaeopascichnus preferred to build their skeleton of single row chambers, while Orbesiana used multiple raw building as they either created spirals and foam-like clusters of irregular shape or simply were two- and multi-row,” explains Anton Kolesnilov.

For the next step of the research the paleontologists plan to further examine organisms, that could be attributed to this group. In other words, the researchers have to deeply understand the taxonomy of these first macro-skeletal creatures of the Ediacaran biota.

Source: AKSON Russian Communication Association [October 01, 2018]



Eighth-century skeleton unearthed on the island of Torcello in Venice

On the island of Torcello, at the Ca’ Foscari University of Venice excavation site, some protagonists of the island’s thousand-year history have begun to emerge. A tomb datable to around 700 A.D. has recently been unearthed by the site’s team of scholars, who hail from universities throughout Italy, under the scientific direction of archaeologist Diego Calaon (a Marie Curie Fellow).

Eighth-century skeleton unearthed on the island of Torcello in Venice
This is the skeleton discovered during the excavation in Torcello Island, Venice, Italy
[Credit: Ca’ Foscari University of Venice]

“The subject is a young adult, whose burial – not far from the area we imagine was used as a cemetery adjacent to the Basilica during the Early Middle Ages – maintained nearly the entire skeleton intact, with the exception of the head. We mustn’t be misled, however: the discovery of the residual parts of the right side of the skull and of the perforation coming from above (probably due to a construction pole) which occurred during modern times, indicate that the burial was complete and that the defects we see today resulted from activities which occurred later on in the area”.
The discovery is an important one: during the archaeological digs that took place on Torcello in the 1960s and 70s, cemetery sites were excavated, but for the most part only relatively modern ones pertaining to the High Middle Ages. Being able to analyze the biometric data of those who lived on Torcello from the sixth to ninth century presents a unique opportunity. Who were the ancient island residents who lived in the well-constructed wooden houses that were densely present in the area? Free workers? Slaves? Was this a community which already had deeply Christian roots, or not? If the burial site was isolated, or not connected directly to the Church, multiple hypotheses may arise: DNA and biometric analyses will reveal important interpretative data.

The burial has been excavated in an area which is particularly interesting in terms of stratigraphy: we are at the head of an ancient lagoon canal that separated the island of the Ancient Church of Saint Mary from the inhabited area of the medieval settlement: over time, the channel was fortified with hundreds of wooden poles, indicative of a “hunger for space” on the part of homes and craft businesses that required the enlargement and creation of new living spaces.

As the excavation has expanded, it has revealed how the eighth and ninth century were significant and demonstrative of the island’s population explosion: the presence of dense wooden houses, docks, fireplaces and production facilities, proven by hundreds of ceramic fragments from kitchen pottery (including many covering basins, the dishes of yesteryear for cooking breads and cakes in fireplaces on the ground), amphorae for oil and wine, and soapstone vessels for cooking soups and stews.

The inhabited area includes a large number of warehouses, constructed and active in the two previous centuries, from 500-600 A.D.: “Torcello became a hub of movement within the lagoon precisely at this moment. Altino was no longer feasible as a port, and the warehouses that we are excavating on the island,” explains Diego Calaon, “are revealing that long before the ‘imagined’ or ‘legendary’ barbaric destruction occurred, the local elite had fully invested in creating an efficient ship yard precisely in the littoral area of the time. Warehouses were built with reused Roman bricks, some with markings on them, fashioned with stones taken from ancient Rome. The porticoed harbor warehouse visible on Torcello nowadays is exceptionally well preserved: we will be able to clean up the interiors within 5/10 days of work”. Thanks to the Torcello Abitata project and archaeology talks also attended by the citizenry, inhabitants as well as external interested parties will be able to discover more.

Meanwhile, there is another project underway at a different location where a construction of large dimensions (more than 25 meters in length), which may be interpreted as a boat garage and warehouse datable to the fourteenth century, is currently undergoing excavation and study. The structure, with a solid stone foundation (again, “pieces” from Altino which were salvaged for use here in the lagoon) sits opposite a very old and sturdy stone-laid riverbank, which was subsequently reinforced by an outward-facing jetty reaching where the Sile river used to flow. Between the riverbank and the warehouse, the obvious and abundant characteristics of a medieval shipyard for organizing and holding boats, probably for fishing, with traces of poles for hauling, for lateral mooring and, probably, for preparing pitches.

It is a history rich with elements which is a marvel to discover from one day to the next.

Source: Università Ca’ Foscari Venezia [October 01, 2018]



Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea

A unique ivory statuette depicting the god Harpokrates was discovered by archaeologists from the Bosporos Archaeological Expedition of the Research Centre for History and Archaeology of Crimea, the Crimean Federal University in Vernadsky and the Centre for Archaeological Research Foundation Demeter.

Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea
Credit: Crimea Press

The statuette, which is exceptionally well preserved, was discovered during the excavations of the ancient city of Tyritake (Greek Diya) located in the southern part of modern Kerch.
Dating from the first century BC the statuette is believed to depict  the child god Harpokrates, “with a cornucopia, as well as two satyrs and a goose,” said Alexander Aybabin, director of the Research Centre for History and Archaeology of Crimea.

Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea

Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea
Credit: Crimea Press

Harpokrates was the god of silence, secrets and confidentiality in the Hellenistic religion developed in Ptolemaic Alexandria (and also an embodiment of hope, according to Plutarch). Harpokrates was adapted by the Greeks from the Egyptian child god Horus.
The head of the expedition, Viktor Zinko, added that this year work was carried out in two areas in the ancient city. Investigations focussed on the northern fortress wall of the ancient city, which in the second half of the fourth and early third centuries BC served as a powerful defensive structure.

Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea

Unique ivory statuette of Graeco-Egyptian god Harpokrates unearthed in Crimea
Credit: Crimea Press

In 2018, scientists began researching the residential quarter to the south of the city wall, where they found an early medieval building with a large stone stove in its upper cultural layers.
In the central part of the city, the western city wall and the buildings adjacent to it were also investigated. This part of the city fortification wall was built at the end of the 6th century BC. During the course of excavations, a number of structures dating from the sixth to first centuries BC were discovered.

“In addition to the statuette of the god Harpokrates, various amphorae, pottery and bronze coins were also found,” said Viktor Zinko.

Source: Crimea Press [October 01, 2018]



Gaia spots stars flying between galaxies

ESA – Gaia Mission patch.

2 October 2018

A team of astronomers using the latest set of data from ESA’s Gaia mission to look for high-velocity stars being kicked out of the Milky Way were surprised to find stars instead sprinting inwards – perhaps from another galaxy.

In April, ESA’s stellar surveyor Gaia released an unprecedented catalogue of more than one billion stars. Astronomers across the world have been working ceaselessly over the past few months to explore this extraordinary dataset, scrutinising the properties and motions of stars in our Galaxy and beyond with never before achieved precision, giving rise to a multitude of new and intriguing studies..

Sprinting stars in the Milky Way

The Milky Way contains over a hundred billion stars. Most are located in a disc with a dense, bulging centre, at the middle of which is a supermassive black hole. The rest are spread out in a much larger spherical halo.

Stars circle around the Milky Way at hundreds of kilometres per second, and their motions contain a wealth of information about the past history of the Galaxy. The fastest class of stars in our Galaxy are called hypervelocity stars, which are thought to start their life near the Galactic centre to be later flung towards the edge of the Milky Way via interactions with the black hole.

Only a small number of hypervelocity stars have ever been discovered, and Gaia’s recently published second data release provides a unique opportunity to look for more of them.

Several groups of astronomers jumped into the brand-new dataset in search of hypervelocity stars immediately after the release. Among them, three scientists at Leiden University, the Netherlands, were in for a big surprise.

For 1.3 billion stars, Gaia measured positions, parallaxes – an indicator of their distance – and 2D motions on the plane of the sky. For seven million of the brightest ones, it also measured how quickly they move towards or away from us.

All-sky view from Gaia’s second data release

“Of the seven million Gaia stars with full 3D velocity measurements, we found twenty that could be travelling fast enough to eventually escape from the Milky Way,” explains Elena Maria Rossi, one of the authors of the new study.

Elena and colleagues, who had already discovered a handful of hypervelocity stars last year in an exploratory study based on data from Gaia’s first release, were pleasantly surprised, as they were hoping to find at most one star breaking loose from the Galaxy among these seven million. And there is more.

“Rather than flying away from the Galactic centre, most of the high velocity stars we spotted seem to be racing towards it,” adds co-author Tommaso Marchetti.

“These could be stars from another galaxy, zooming right through the Milky Way.”

It is possible that these intergalactic interlopers come from the Large Magellanic Cloud, a relatively small galaxy orbiting the Milky Way, or they may originate from a galaxy even further afield.

If that is the case, they carry the imprint of their site of origin, and studying them at much closer distances than their parent galaxy could provide unprecedented information on the nature of stars in another galaxy – similar in a way to studying martian material brought to our planet by meteorites.

Large Magellanic Cloud

“Stars can be accelerated to high velocities when they interact with a supermassive black hole,” Elena explains.

“So the presence of these stars might be a sign of such black holes in nearby galaxies. But the stars may also have once been part of a binary system, flung towards the Milky Way when their companion star exploded as a supernova. Either way, studying them could tell us more about these kinds of processes in nearby galaxies.”

An alternative explanation is that the newly identified sprinting stars could be native to our Galaxy’s halo, accelerated and pushed inwards through interactions with one of the dwarf galaxies that fell towards the Milky Way during its build-up history. Additional information about the age and composition of the stars could help the astronomers clarify their origin.

“A star from the Milky Way halo is likely to be fairly old and mostly made of hydrogen, whereas stars from other galaxies could contain lots of heavier elements,” says Tommaso.

“Looking at the colours of stars tells us more about what they are made of.”

Gaia mapping the Milky Way

New data will help nail down the nature and origin of these stars with more certainty, and the team will use ground-based telescopes to find out more about them. In the meantime, Gaia continues to make observations of the full sky, including the stars analysed in this study.

While investigating the nature of these possible stellar interlopers, the team is also busy digging into the full dataset from Gaia’s second release, searching for more high-speed stars and looking forward to the future. At least two more Gaia data releases are planned in the 2020s, and each will provide both more precise and new information on a larger set of stars.

“We eventually expect full 3D velocity measurements for up to 150 million stars,” explains co-author Anthony Brown, chair of the Gaia Data Processing and Analysis Consortium Executive.

“This will help find hundreds or thousands of hypervelocity stars, understand their origin in much more detail, and use them to investigate the Galactic centre environment as well as the history of our Galaxy,” he adds.

“This exciting result shows that Gaia is a true discovery machine, providing the ground for completely unexpected discoveries about our Galaxy,” concludes Timo Prusti, Gaia project scientist at ESA.

Notes for editors:

“Gaia DR2 in 6D: Searching for the fastest stars in the Galaxy” by T. Marchetti et al is published in Monthly Notices of the Royal Astronomical Society: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/sty2592/5104415

Related link:

Gaia: http://www.esa.int/Our_Activities/Space_Science/Gaia

Related article:

Counting stars with Gaia: https://orbiterchspacenews.blogspot.com/2015/07/counting-stars-with-gaia.html

Gaia’s first year of scientific observations: https://orbiterchspacenews.blogspot.com/2015/08/gaias-first-year-of-scientific.html

The billion-pixel camera:

Images, Text, Credits: ESA (artist’s impression and composition); Marchetti et al 2018 (star positions and trajectories); NASA/ESA/Hubble (background galaxies), CC BY-SA 3.0 IGO/ESA/Gaia/DPAC/ATG medialab; background: ESO/S. Brunier.

Best regards, Orbiter.chArchive link

20-million-year-old elephant tusks unearthed in Iran

The remnants of two Proboscidean fossils including two elephant tusks have been unearthed in Iran’s northwestern city of Ardabil, said the General Director of Ardabil’s Department of Environment.

20-million-year-old elephant tusks unearthed in Iran
Credit: IFP

Mohammad Khodaparast said the remnants date back to the Miocene, the first geological epoch of the Neogene period, from about 23 to 5.3 million years ago.
The two fossil pieces were discovered in the site of the Ardabil-Mianeh railroad project, passing through Kowsar town.

The fossils include two one-metre elephant tusks which most likely belong to the Proboscidea from the Miocene with an about 20-million-year history.

According to Khodaparast, the fossil pieces were unearthed during a three-day excavation operation and transferred to the natural history museum of Ardabil province for additional studies.

He also underlined that over the past two years, a number of other fossil pieces have been discovered in the same site and officially registered. They included a number of fossil teeth, jawbone and foot bone remained from various species.

Kowsar is about 80 km southwest of Ardabil.

Source: Iran Front Page [October 01, 2018]



Two sandstone stele discovered in Egypt’s Aswan

Egyptian archaeologists have discovered two ancient sandstone stele in Upper Egypt’s province of Aswan, Egyptian Ministry of Antiquities said Sunday.

Two sandstone stele discovered in Egypt's Aswan
Stele of Seti I [Credit: Egyptian Ministry of Antiquities]

This discovery was made by the Egyptian archaeological mission at the Kom Ombo Temple in Aswan.
According to Mostafa Waziri, head of Egypt’s Supreme Council of Antiquities, the first stele belongs to Seti I of the 19th Dynasty, who ruled Egypt from 1290 to 1279 BC, while the other one belongs to Ptolemy IV who ruled Egypt from 221 to 204 BC.

Two sandstone stele discovered in Egypt's Aswan
Seti stele inscription detail [Credit: Egyptian Ministry of Antiquities]

The first stele is 2.3 metres long and 1 metre wide, while the other is 3.25 metres long and 1.15 metres wide. Both measure 30 cm thick, Waziri said.
The first stele was found broken into two pieces but the drawings and inscriptions were still in good condition, he noted.

Two sandstone stele discovered in Egypt's Aswan
Stele of Seti I [Credit: Egyptian Ministry of Antiquities]

“The second one was found broken into several pieces but our restoration team at the ministry repaired and assembled them,” Waziri added.
The first stele shows Seti I standing in front of ancient Egyptian gods Horus and Sobek, with the sun above as a symbol of protection. As for the second, it portrays Ptolemy IV, his wife and Egyptian deities.

Two sandstone stele discovered in Egypt's Aswan
Ptolemy stele inscription detail [Credit: Egyptian Ministry of Antiquities]

On Sept. 16, Egypt announced the discovery of a sandstone Sphinx statue during an excavation at the Kom Ombo Temple.

Two days later, it revealed the discovery of a sandstone sarcophagus with a mummy inside near Aga Khan Mausoleum on the west bank of Aswan.

Over past years, Egypt has witnessed several big archaeological discoveries, including pharaonic tombs, statues, coffins, mummies, burial sites and funerary gardens.

Source: Xinhua [October 01, 2018]



Humans delayed the onset of the Sahara desert by 500 years

Humans did not accelerate the decline of the ‘Green Sahara’ and may have managed to hold back the onset of the Sahara desert by around 500 years, according to new research led by UCL.

Humans delayed the onset of the Sahara desert by 500 years
Credit: Chris Ford/Flickr

The study by a team of geographers and archaeologists from UCL and King’s College London, published in Nature Communications, suggests that early pastoralists in North Africa combined detailed knowledge of the environment with newly domesticated species to deal with the long-term drying trend.

It is thought that early pastoralists in North Africa developed intricate ways to efficiently manage sparse vegetation and relatively dry and low fertility soils.

Dr Chris Brierley (UCL Geography), lead author, said: “The possibility that humans could have had a stabilising influence on the environment has significant implications. We contest the common narrative that past human-environment interactions must always be one of over-exploitation and degradation.

“The fact that societies practising ‘pastoralism’ persisted in this region for so long and invested both economically and ideologically in the local landscape, does not support the scenario of over-exploitation. Our study shows that increasing human population and sustainable pastoralism did not accelerate – and may even have delayed – the decline of the ‘Green Sahara’.”

Around 8,000 years ago, the Sahara wasn’t desert, but instead was a vibrant ecosystem that supported hunter-gatherers and fisherfolk. The ‘Green Sahara’ –   the colloquial term for the African Humid Period – was the period in which North Africa became much wetter than it is today thanks to a series of monsoons.

As the Earth’s orbit slowly changed, the rain started to reduce, and the vegetation started to die back. Around 5,500 years ago, the ecosystem in the Sahara went into a terminal decline towards the desert we have today.

Pastoralism (nomadic or semi-nomadic cattle-herders) blossomed in the Sahara from around 1000 years before that collapse. Previous studies have put the blame for the collapse of the ‘Green Sahara’ onto these nomads who have often been marginalised in history, but this latest studies dispels that myth.

The study uses a novel climate-vegetation model to determine whether the end of the African Humid Period occurred earlier than expected. The model keeps track of variables such as vegetation and rainfall, and other processes such as the amount of energy coming from the sun, and the amount of carbon dioxide in the atmosphere.

The model found that the ‘Green Sahara’ should have collapsed earlier than it did. This suggests that pastoralists lasted longer than expected and the techniques they used helped them to adapt to the environmental changes.

Dr Brierley added: “Those places where pastoralists last longer are where there are more resources. It’s a good adaptation to the climate change taking place at the time. There is now work today looking at what we can learn from nomadic pastoralists, such as selective grazing strategies, which can be applied to sustainable adaption to desertification that we expect from future climate change.”

Dr Katie Manning (King’s College London), concluded: “Despite the largely inhospitable conditions of the Sahara today, it is not hard to find evidence of human occupation from the last 11,000 years. Thousands of rock art sites illustrate a lush environment, large-game hunting and livestock herding. The spread of domestic animals across the Sahara occurred at a time of increasing climatic instability, and yet, these pastoralist populations thrived.

“It is likely that strategies used by contemporary traditional herders, such as seasonal movement and selective grazing, were also used by these early pastoralists, helping to maintain an otherwise deteriorating ecosystem.”

Source: University College London [October 01, 2018]



2018 October 2 Supernumerary Rainbows over New Jersey Credit…

2018 October 2

Supernumerary Rainbows over New Jersey
Credit & Copyright: John Entwistle

Explanation: Yes, but can your rainbow do this? After the remnants of Hurricane Florence passed over Jersey Shore, New Jersey, USA last month, the Sun came out in one direction but something quite unusual appeared in the opposite direction: a hall of rainbows. Over the course of a next half hour, to the delight of the photographer and his daughter, vibrant supernumerary rainbows faded in and out, with at least five captured in this featured single shot. Supernumerary rainbows only form when falling water droplets are all nearly the same size and typically less than a millimeter across. Then, sunlight will not only reflect from inside the raindrops, but interfere, a wave phenomenon similar to ripples on a pond when a stone is thrown in. In fact, supernumerary rainbows can only be explained with waves, and their noted existence in the early 1800s was considered early evidence of light’s wave nature.

∞ Source: apod.nasa.gov/apod/ap181002.html

Sixty Years of Exploration, Innovation, and Discovery!


Exactly sixty years ago today, we opened our doors for the first time. And since then, we have opened up a universe of discovery and innovation. 

There are so many achievements to celebrate from the past six decades, there’s no way we can go through all of them. If you want to dive deeper into our history of exploration, check out NASA: 60 Years and Counting

In the meantime, take a moonwalk down memory lane with us while we remember a few of our most important accomplishments from the past sixty years!


In 1958, President Eisenhower signed the National Aeronautics and Space Act, which effectively created our agency. We officially opened for business on October 1

To learn more about the start of our space program, watch our video: How It All Began. 


Alongside the U.S. Air Force, we implemented the X-15 hypersonic aircraft during the 1950s and 1960s to improve aircraft and spacecraft. 

The X-15 is capable of speeds exceeding Mach 6 (4,500 mph) at altitudes of 67 miles, reaching the very edge of space

Dubbed the “finest and most productive research aircraft ever seen,” the X-15 was officially retired on October 24, 1968. The information collected by the X-15 contributed to the development of the Mercury, Gemini, Apollo, and Space Shuttle programs. 

To learn more about how we have revolutionized aeronautics, watch our Leading Edge of Flight video. 


On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first humans to walk on the moon. The crew of Apollo 11 had the distinction of completing the first return of soil and rock samples from beyond Earth. 

Astronaut Gene Cernan, during Apollo 17, was the last person to have walked on the surface of the moon. (For now!)

The Lunar Roving Vehicle was a battery-powered rover that the astronauts used during the last three Apollo missions. 

To learn more about other types of technology that we have either invented or improved, watch our video: Trailblazing Technology.


Our long-term Earth-observing satellite program began on July 23, 1972 with the launch of Landsat 1, the first in a long series (Landsat 9 is expected to launch in 2020!) We work directly with the U.S. Geological Survey to use Landsat to monitor and manage resources such as food, water, and forests. 

Landsat data is one of many tools that help us observe in immense detail how our planet is changing. From algae blooms to melting glaciers to hurricane flooding, Landsat is there to help us understand our own planet better. 

Off the Earth, for the Earth.

To learn more about how we contribute to the Earth sciences, watch our video: Home, Sweet Home. 


Space Transportation System-1, or STS-1, was the first orbital spaceflight of our Space Shuttle program. 

The first orbiter, Columbia, launched on April 12, 1981. Over the next thirty years, Challenger, Discovery, Atlantis, and Endeavour would be added to the space shuttle fleet. 

Together, they flew 135 missions and carried 355 people into space using the first reusable spacecraft.


On January 16, 1978, we selected a class of 35 new astronauts–including the first women and African-American astronauts. 

And on June 18, 1983, Sally Ride became the first American woman to enter space on board Challenger for STS-7. 

To learn more about our astronauts, then and now, watch our Humans in Space video.


Everybody loves Hubble! The Hubble Space Telescope was launched into orbit on April 24, 1990, and has been blowing our minds ever since. 

Hubble has not only captured stunning views of our distant stars and galaxies, but has also been there for once-in-a-lifetime cosmic events. For example, on January 6, 2010, Hubble captured what appeared to be a head-on collision between two asteroids–something no one has ever seen before.

In this image, Hubble captures the Carina Nebula illuminating a three-light-year tall pillar of gas and dust. 

To learn more about how we have contributed to our understanding of the solar system and beyond, watch our video: What’s Out There?


Cooperation to build the International Space Station began in 1993 between the United States, Russia, Japan, and Canada. 

The dream was fully realized on November 2, 2000, when Expedition 1 crew members boarded the station, signifying humanity’s permanent presence in space!

Although the orbiting lab was only a couple of modules then, it has grown tremendously since then! 

To learn more about what’s happening on the orbiting outpost today, visit the Space Station page.


We have satellites in the sky, humans in orbit, and rovers on Mars. Very soon, we will be returning humankind to the Moon, and using it as a platform to travel to Mars and beyond.

And most importantly, we bring the universe to you

What are your favorite NASA moments? We were only able to share a few of ours here, but if you want to learn about more important NASA milestones, check out 60 Moments in NASA History or our video, 60 Years in 60 Seconds

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Cairnholy II Prehistoric Burial Chamber, nr. Carsluith, Dumfries and Galloway, Scotland,...

Cairnholy II Prehistoric Burial Chamber, nr. Carsluith, Dumfries and Galloway, Scotland, 30.9.18.

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