среда, 25 июля 2018 г.

Skeleton of extinct rhinoceros species discovered in Spain

Researchers from the Quaternary Research Group (GRQ-SERP) of the University of Barcelona (UB) have discovered in Castelldefels a rhinoceros skeleton some 160,000 years old, belonging to an extinct species, Stephanorhinus hundsheimensis, which would have been similar to the current African black rhinoceros. The discovery took place in the so-called Rhinoceros cave, a site where two skeletons of this animal species had already been found by 2015.

Skeleton of extinct rhinoceros species discovered in Spain
Skeleton of the rhinoceros discovered in Castelldefels [Credit: Universitat de Barcelona]

The remains include the two front extremities of the animal, the ribs, part of the spine and the skull with the both jaws. Researchers assume that the animal probably fell accidentally into the Rhinoceros cave, where it died when trapped. The teeth would indicate that it was a young specimen, about seven years old, as it still has some of its milk teeth.

The Rhinoceros cave is an archaeological site with a long chronological sequence, ranging from 200,000 to 80,000 years old. In the Mediterranean basin there are very few sites from this period with such a complete stratigraphic sequence. In the deposit there is a large quantity of faunal remains in an excellent state of preservation. In 2012, a skeleton of an elephant calf was discovered, and in 2015, two skeletons of young rhinoceroses were also found. Apparently, the cave was as a natural trap for many different types of animals, especially the younger, inexperienced creatures that fell into it. Several lithic remains have also been recovered at this site.

The cavity is currently transected vertically due to the mining activity of the ca n’Aymerich quarry in Castelldefels. The extraction of limestone has greatly disfigured the original terrain and destroyed most of the cave, as well as the original entrance. For this reason, the cavity is now accessible via a scaffold that allows archaeological work to be carried out.

The remains will be removed from the cave this summer and will then be studied by researchers. Castelldefels Town Council plans to organise an exhibition in the municipality on the site of the cave in which part of the skeletons found in the archaeological excavations will be displayed.

The archaeological excavations are part of the project “Climate change during the Upper Pleistocene on the central Catalan coast and the impact on Neanderthal populations and anatomically modern humans”, carried out by the Quaternary Research Group (GRQ-SERP) of the University of Barcelona, headed by researchers Joan Daura (University of Barcelona) and Montserrat Sanz (Complutense University of Madrid). The excavations are financed by the Castelldefels Town Council and the Archaeology and Paleontology Service of the Generalitat de Cataluña.

Source: La Vanguardia [July 21, 2018]




Large Frentani necropolis excavated in Central Italy

In the Autumn of 2015 the Archaeological Superintendence of Fine Arts and Landscape of Abruzzo, with the support of the Archeoclub of Crecchio, started the first archaeological investigations in the district of S. Maria Cardetola bringing to light precious ancient materials in the same area where, in 1855, the famous stele with an Oscan inscription was discovered.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

During the excavations numerous artefacts belonging to a large votive deposit were brought to light and identified, including black painted pottery, numerous terracotta statuettes depicting animals, female priests and divinities, clay plaques depicting a mysterious face of a woman flanked by a torch, testifying to an ancient Italic cult evidently attributable to a cthonic goddess, perhaps Keres or Kardea who, with Greek iconographic attributes typical of Demeter or Persephone, was venerated by the Frentanians.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

Almost 100 burials have been excavated so far, dating from the end of the sixth to the fourth centuries BC. The richness of the necropolis and the variety of grave goods unearthed is remarkable, especially from this latter period.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

The discovery of two unique bronze helmets, one of Montefortino type (T.52) and one of Negau type (T.53), is particularly exceptional. The first of the two is very well preserved, an important fact considering that of the forty or so helmets discovered in Abruzzo so far only 4-5 come from specific archaeological contexts.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

In one tomb (T.13), in addition to the abundant pottery, a bronze band that widened on the forehead of the deceased to form a circular phalera or cameo was recovered, a discovery so far unparalleled in Abruzzo or neighbouring regions, and which is thought to be a sign of the high social status of the deceased, perhaps a magistrate or a priest.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

In some of the male tombs there are rarer items, which illustrate the evolution of military weapons in Italy during and after the Samnite wars, including several narrow and long javelin points (T.52) similar the Roman ‘pilum’ or the ‘saunion’ of the Samnites and two short swords (Tombs 21 and 52), possible forerunners of the Roman ‘gladii’.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

Other finds in male burials include 8 bronze waist bands, a symbol of citizenship that Samnite warriors wore with pride. Another 3 waist bands belonging to infants have also been recovered. Funeral banquets is testified by the frequent presence of complete cooking utensils, including knives and skewers of various types and sizes.

Of particular importance, given the agrarian economy of the territory, is the information provided by the excavations for the consumption of wine, evidenced in the burials by the deposition of cups, large olla or wine jars, bronze sieves or strainers, and graters used to aromatize wine with spices. Resin residues found in one wine jar (T.33) were still perceptible by smell at the time of excavation, and may reveal interesting palaeobotanical evidence.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

Numerous bronze vases, including cauldrons and a rare patera with an omega hook (T.53), were also found, perhaps imported from Magna Graecia or the Tyrrhenian Sea; other imports include painted Daunian ceramic vases from northern Apulia.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

The combination of internment and incineration burials, a practice almost unknown among the Italic tribes in Abruzzo, and various foreign items like the Greek strigil, bear witness to important cultural changes that occurred after the Samnite Wars with the opening of these territories to the larger Mediterranean world. Likewise, the discovery of three chamber tombs with a descending dromos is also typical of the Hellenistic Mediterranean, from Puglia to the Middle East.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

The numerous female tombs are also characterized by rich grave goods, and typically include iron or bronze fibulae placed on the shoulders of the deceased on which precious imported objects were hung, testifying not only to a display of wealth but also to the commercial contacts that probably took place through the nearby port of Ortona, which was certainly already active in the fourth century BC.

Large Frentani necropolis excavated in Central Italy

Credit: SABAP Abruzzo

Other objects found in the female burials include bronze pendants of various shapes, precious yellow and red Baltic amber, discs made of ivory from North Africa, necklaces of beads made of blue glass paste, simple or adorned with eyes, of clear Punic origin, gold decorations that once adorned clothing, and fibulas of silver, perhaps of Tarantine origin.

Large Frentani necropolis excavated in Central Italy
Credit: SABAP Abruzzo

The tombs identified so far were located at a considerable depth, ranging between 1 and 4 metres, and filled with stones and rubble sometimes exceeding a ton of weight, which fortunately made it difficult for illegal excavators to find them.

The surveillance of the area by the local authorities has allowed and still allows work to be carried out on this valuable site, the discovery of which represents an important opportunity for the development of the local economy.

Source: Fame di Sud [July 22, 2018]




Fortification wall of the Ibero-Roman city of Isturgi found

Over the last few weeks the Andújar Town Council has been conducting archaeological excavations at the Los Villares site. The aim is to identify the ancestors of the inhabitants of the ancient town of Isturgi. The chronology of the remains of the site ranges from the 7th century BC to the 3rd/4th centuries AD. “Between these two periods we are going to find the remains of a thriving city, with a very strong presence”, says archaeologist Pablo Ruiz, part of the University of Granada team working in the area.

Fortification wall of the Ibero-Roman city of Isturgi found
Credit: Ayuntamiento de Andújar

The team of archaeologists from the University of Granada has just brought to light the first remains of one of the most significant sites in the province of Jaén, the Ibero-Roman city of Isturgi, an area declared a Site of Cultural Interest in 2016.

Excavations have revealed not only the remnants of the wall that defines the perimetre of the city, but also a glass manufacturing workshop from the later period and two ovens associated with it, one of the few examples of this type of industry that are preserved throughout the peninsula.

Both discoveries, as reported by the department in a statement, are only the tip of the iceberg of a site that, according to previous studies, hides a major settlement where some significant remains of frescoes have also appeared and whose architecture is in a good state of preservation.

These finds also confirm the importance of Isturgi as an economic and commercial enclave in the Roman province of Betica, given its strategic location along the Via Augusta and the River Guadalquivir.

The excavations began on 25 June and form part of the “ISTVRGI Project”, conducted by the Archaeology Department of the University of Granada, directed by Professor Mª Isabel Fernández García and researchers Mª Victoria Peinado Espinosa and Pablo Ruiz Montes, for the excavation and enhancement of the site that is being developed within the framework of a collaboration agreement between the Andújar City Council and the university.

Following approval by the Andalusian Regional Government in 2012, a topographical study was carried out in 2014 and a magnetometer survey was undertaken in 2016 as a preliminary step to this third phase of excavation, which is now underway.

From the 1970s until now, excavations in Isturgi had been confined to the artisan quarter of the city, where the workshops for the manufacture of sigillata ceramics were located. The recent findings confirm the intense production activity of its inhabitants, whose products were exported to other parts of the Empire.

The findings made in Isturgi supplement the recent discovery of the Arch of Janus in Mengibar as well as the remains that continue to come to light at the Cástulo site in Linaro, thus making the province of Jaén one of the most important and promising territories in Spain for understanding the Ibero-Roman period.

Source: Lacontradejaén [July 22, 2018]




Fans and Valleys   An impact crater approximately 23 kilometers…

Fans and Valleys

   An impact crater approximately 23 kilometers across is home to fan-shaped deposits that extend from the rim and sit on the interior crater floor.

Thick beds with varying tone are exposed along the edge of the fan. Shallow valleys that carve into the smooth upland surfaces outside of the crater may provide clues regarding the formation of the deposits. Many boulder-sized blocks sit on the interior crater floor beyond the toe (distal edge) of the deposits.

This fan-hosting crater is located near the boundary between Tempe Terra and Acidalia Planitia in the Northern Hemisphere of Mars. (302 km above the surface; enhanced color is less than 1 km across.)

NASA/JPL/University of Arizona


2018 July 25 The Edge-On Spindle Galaxy Image Credit &…

2018 July 25

The Edge-On Spindle Galaxy
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation: What kind of celestial object is this? A relatively normal galaxy – but seen from its edge. Many disk galaxies are actually just as thin as NGC 5866, pictured here, but are not seen edge-on from our vantage point. A perhaps more familiar galaxy seen edge-on is our own Milky Way Galaxy. Cataloged as M102 and NGC 5866, the Spindle galaxy has numerous and complex dust lanes appearing dark and red, while many of the bright stars in the disk give it a more blue underlying hue. The blue disk of young stars can be seen extending past the dust in the extremely thin galactic plane. There is evidence that the Spindle galaxy has cannibalized smaller galaxies over the past billion years or so, including multiple streams of faint stars, dark dust that extends away from the main galactic plane, and a surrounding group of galaxies (not shown). In general, many disk galaxies become thin because the gas that forms them collides with itself as it rotates about the gravitational center. The Spindle galaxy lies about 50 million light years distant toward the constellation of the Dragon (Draco).

∞ Source: apod.nasa.gov/apod/ap180725.html


I’ve just posted a poem; please follow the link!

I’ve just posted a poem; please follow the link!Source link


Aquamarine and Fluorite on Muscovite | #Geology #GeologyPage…

Aquamarine and Fluorite on Muscovite | #Geology #GeologyPage #Mineral

Locality: Nagar, Hunza valley, Gilgit District, Northern Areas, Pakistan

Size: 7.7 x 4.3 x 5 cm

Photo Copyright © Saphira Minerals

Geology Page



Opal Var. “Boulder Opal” in Ironstone | #Geology #GeologyPage…

Opal Var. “Boulder Opal” in Ironstone | #Geology #GeologyPage #Mineral

Locality: Quilpie, Queensland, Australia, Oceania

Dimensions: 9.4 × 8.8 × 3.6 cm

Photo Copyright © Crystal Classics

Geology Page



Erbenochile erbeni Trilobite | #Geology #GeologyPage #Fossil…

Erbenochile erbeni Trilobite | #Geology #GeologyPage #Fossil #Trilobite

Name: Erbenochile erbeni (Alberti, 1981)

Age: Devonian

Location: Timrhanrhart Formation, Jebel Issomour, Morocco

Size: 6 cm

Photo Copyright © American Museum of Natural History

Geology Page



Finding a planet with a 10 year orbit in just a few months

To discover and confirm the presence of a planet around stars other than the Sun, astronomers wait until it has completed three orbits. However, this very effective technique has its drawbacks since it cannot confirm the presence of planets at relatively long periods (it is ideally suited for periods of a few days to a few months). To overcome this obstacle, a team of astronomers under the direction of the University of Geneva (UNIGE) have developed a method that makes it possible to ensure the presence of a planet in a few months, even if it takes 10 years to circle its star: this new method is described for the first time in the journal Astronomy & Astrophysics.

Finding a planet with a 10 year orbit in just a few months
Artist’s conception of Kepler Space Telescope [Credit: NASA]

The method of transits, consisting of detecting a dip in the luminosity of the host star at the time the planet passes, is a very effective technique to search for exoplanets. It makes it possible to estimate the radius of the planet, the inclination of the orbit and can be applied to a large number of stars at the same time. However, it has a significant limitation: since it is necessary to wait at least three passes in front of the star to confirm the existence of a planet, it is currently only suitable to detect planets with rather short orbital periods (typically from a few days to a few months). We would indeed have to wait more than 30 years to detect a planet similar to Jupiter which needs 11 years to make the full tour).

To overcome this obstacle, a team of astronomers led by researcher Helen Giles, from the Astronomy Department at the Faculty of Science of UNIGE and a member of the NCCR PlanetS, has developed an original method. By analysing data from the space telescope K2, one star showed a significant long-duration temporary decrease of luminosity, the signature of a possible transit, in other words, the passage of a planet in front of its star. “We had to analyse hundreds of light curves” explains the astronomer, to find one where such a transit was unequivocal.

Finding a planet with a 10 year orbit in just a few months
This is data from the light curve of the EPIC248847494 star. The transit is clearly visible,
on the upper right part of the image [Credit: © UNIGE]

Helen Giles consulted recent data from the Gaïa mission to determine the diameter of the star referenced as EPIC248847494 and its distance, 1500 light-years away from the planet Earth. With that knowledge and the fact that the transit lasted 53 hours, she found that the planet is located at 4.5 times the distance from the Sun to the Earth, and that consequently it takes about 10 years to orbit once. The key question left to answer was whether it was a planet and not a star. The Euler telescope of the UNIGE in Chile would provide the answer. By measuring the radial velocity of the star, which makes it possible to deduce the mass of the planet, she was able to show that the mass of the object is less than 13 times that of Jupiter — well below the minimum mass of a star (at least 80 times the mass of Jupiter).

“This technique could be used to hunt habitable, Earth-like planets around stars like the Sun” enthuses Helen Giles, “we have already found Earths around red dwarf stars whose stellar radiation may have consequences on life which are not exactly known.” With her method it will no longer be necessary to wait many years to know whether the detected single transit is due to the presence of a planet. “In the future, we could even see if the planet has one or more moons, like our Jupiter,” she concludes.

Source: Université de Genève [July 19, 2018]




Deep-diving scientists say shallow reefs can’t rely on twilight zone systems for...

New findings suggest that out-of-sight deep reefs are unique habitats in need of protection. A team of highly trained scientific divers — led by researchers from the California Academy of Sciences — explored Pacific and western Atlantic reefs to test a widely held hypothesis that climate-stressed life from shallow reefs can take refuge at mesophotic depths (100 — 500 feet beneath the ocean’s surface). The results are clear: deep and shallow reefs are actually different systems with their own species, and deep reefs are just as threatened by climate impacts, storms, and pollution as their shallow counterparts. Their work, published in Science, represents a major shift in thinking for scientists, conservation managers, and members of the public hoping to give coral reefs a fighting chance.

Deep-diving scientists say shallow reefs can't rely on twilight zone systems for recovery
Credit: Luiz A. Rocha – California Academy of Sciences

“We have hope for coral reefs around the world,” says Dr. Luiz Rocha, Academy Ichthyology Curator and Hope for Reefs initiative co-leader. “Rather than take that hope away, these findings show us the critical importance of protecting twilight zone reefs in places we don’t normally look. We can’t ignore the deep while we throw our collective might behind protecting and restoring shallow coral reefs. Reefs — in the light and in the dark — need our urgent attention.”

Nearly 75 percent of the world’s coral reefs are currently threatened by the combined impacts of overfishing, habitat destruction, water pollution, and climate change. Though coral reefs provide human societies with vital goods and services worth an estimated several hundred billion dollars per year, very little is known about shallow reefs’ deeper counterparts — the species they shelter, the threats they face, or the refuge they’ve been thought to provide.

Charting life in the deep

Rocha is part of a deep-diving research team that explores these mesophotic reefs, the mysterious coral habitats stretching across a narrow band of ocean 100 — 500 feet beneath the surface. In these deep reefs, animals live in partial darkness — beyond recreational diving limits, yet above the deep trenches patrolled by submarines and ROVs. As part of its Hope for Reefs initiative, the Academy team is exploring this unknown frontier with the help of high-tech equipment like closed-circuit rebreathers that allow scientists to extend their research time underwater. Many species observed in the twilight zone are new scientific discoveries — but determining if and how deep and shallow reefs are connected required a much closer look at reefs around the world.

“Exploring the twilight zone is a scientific adventure we take very seriously,” says Bart Shepherd, Senior Director of the Academy’s Steinhart Aquarium and Hope for Reefs co-leader. “One reason we know so little about them is because it’s hard to complete the dives safely. From the Philippines to the Bahamas, we took careful visual surveys of the life we encountered during these long, amazing, difficult dives. The results are a call to action — deep reefs are not the refuge some thought they were.”

The researchers conducted visual counts of reef species by laying out transects (an easy-to-follow path made from a 20-meter tape measure) and counting which species appear at different depths. By comparing the data from the field with results in peer-reviewed literature, the team presents evidence contradicting the two major assumptions of the “refuge hypothesis”: One, that there is substantial species overlap in deep and shallow reefs (there isn’t), and two, that deep reefs are protected from local and global threats (they’re not).

Twilight zone reefs “feel it all”

Study results published today describe the unique communities — with several endemic species — found in deep reefs. Species that share shallow and deep coral reefs usually have strong preferences for specific depth zones — meaning there are few shallow reef residents comfortable moving between light-filled reefs and shadowy twilight zones. Even top predators — key players in the marine ecosystem, like sharks, groupers, and snappers — that move between shallow and deep reefs each day do most of their feeding in the light and aren’t likely to take refuge in the deep. Shallow and deep reef populations appear disconnected.

Mesophotic coral reefs are, in reality, also susceptible to human and natural impacts (like hurricanes and tropical storms). In 2016, several members of the research team chased Hurricane Matthew’s destructive path through the Bahamas, capturing a rare look at powerful storms’ impacts at mesophotic depths. The team observed that powerful storms can impact even the deepest coral reef ecosystems, choking live corals and harming marine life with sand, silt, and natural debris like tree branches. Trash — including plastic bags, cups, aluminum cans, and fishing gear — also appear to reach deep reefs.

“Deep reefs feel it all,” says Rocha, referring to the evidence of mesophotic vulnerability they’ve documented across two oceans. “Besides storm impacts, we saw the familiar signs of heavy fishing, sedimentation, coral bleaching, and invasive species in deep reefs. If real refuges for shallow reefs exist, we think they’re mostly far away from humans. Climate impacts can still reach them, but we’re really seeing the undersea consequences of human population expansion and increased demand for food and natural resources. Reef troubles don’t stop at 100 feet deep.”

A light in the dark

The Academy’s commitment to studying and restoring global coral reefs will continue alongside several visionary partners in years to come. This August, the institution’s twilight zone researchers will explore deep Pacific reefs in the Marshall Islands.

Hope for Reefs — the Academy initiative behind this study — supports expeditions to Earth’s most remote and unknown reefs for deeper study and understanding. Visitors to the Academy in San Francisco’s Golden Gate Park can learn more about these precious ecosystems in Twilight Zone: Deep Reefs Revealed, a first-of-its-kind exhibit that showcases the mysterious underwater realm so few get to witness. Visitors can also experience the museum’s newest original planetarium show Expedition Reef — featuring immersive visualizations of deep reefs and shallow reef restoration work with SECORE International — under a world-class planetarium dome.

“In a time of global crisis for coral reefs, learning more about unexplored reef habitats is critical to our understanding of how to protect them,” says Rocha. “Deep reefs are important environments that are rarely included in marine protected areas or sanctuaries. We aim to highlight the ocean’s vast and unexplored wonders and inspire a new generation of sustainability champions.”

Source: California Academy of Sciences [July 19, 2018]




From cradle to grave: Model identifies factors that shaped evolution

Understanding the many factors that have played into shaping the biodiversity within Earth’s ecosystems can be daunting. In a major step to that end, an international team of researchers built a computer simulation that takes into account many of the fundamental factors that drive evolutionary adaptation and extinction.

From cradle to grave: Model identifies factors that shaped evolution
Engraving of South America, 1700 [Credit: DeAgostini/Getty Images]

Their study, published in Science, brings us closer to knowing the complex interactions between topography and climate change, and how these factors influence the evolutionary histories and biodiversity of species in natural ecosystems.

The model created by researchers at the University of Connecticut, the Federal University of Goiás in Brazil, and The Open University in the U.K., details biogeographical cradles, museums, and graves. Cradles are areas where new species form; museums, areas where species persist; and graves, areas where extinctions take place.

“We had hoped to be able to model in the simulation the most fundamental processes that shape the geography of life on Earth,” says Robert Colwell, emeritus professor of ecology and evolutionary biology at the University of Connecticut, who led the research with Brazilian colleague Thiago F. Rangel, in collaboration with Neil Edwards and Philip Holden in the UK.

To find these answers, the researchers looked to the most climatically and biologically diverse continent on earth, South America, to develop and test their model. As the Andes mountain range began to develop 25 million years ago, it created a varied landscape that would give rise to a rich biodiversity, and the perfect setting to study the ecology and evolution of biodiversity.

“The Andes are the longest mountain range on Earth, and the only trans-tropical one. They sit right beside the Amazon, the planet’s largest tropical rainforest and river basin. This is the reason South America has such exuberant biodiversity,” says Rangel.

Collaborators at The Open University built a model of the ancient climate of South America. Combining conventional and statistical approaches to climate modeling, the researchers were able to model, for the first time, the changing climate in detail over hundreds of millennia, far longer than would otherwise have been possible. The model spans a time scale of 800,000 years, to the earliest ice-core records, and estimates temperature and precipitation at 500-year intervals during repeated cycles of glaciation and thawing in a period called the late Quaternary climate cycles.

Speciation, or the evolution of new species from ancestral species, is a process made complicated by various factors, such as the changing climate, geographical, and topographical features. These factors can all lead to the splitting or isolation of populations and the establishment of new species. Over time, new species arise, persist, expand to new areas, or go extinct, and the reasons as to why any of those events occur are not always clear.

Through computer simulation, the team was able to estimate the lifetime trajectory of species, starting with origination and ending at one of three points: when the species splits into daughter species, when the species ended in extinction, or the species persisted.

At each time step of the simulation, the geographical range — the location — of each species was recorded. The team found that the trajectories were driven by the glacial cycles, leading to episodes of origination and extinction caused by changes in species ranges in the complex topography of the continent, allowing the researchers to map cradles and graves of diversity.

Surprisingly, the model was able to reproduce maps of biodiversity that closely resemble maps of present-day species of birds, mammal, and plants, despite accounting for only the most fundamental of processes and having no specific target pattern of biodiversity, according to Colwell.

“The majority of living species in South America are more ancient than 800,000 years, but our results suggest that even the ancient species have been moved around in the same way as younger species, all contributing the same patterns of species richness,” says Colwell.

The researchers think the most likely explanation is the strong influence of changing climate during the glacial cycles, as it interacts with the topography of the landscape. Changes in temperature and precipitation will have profound impact on species ranges, fragmenting, shuffling, and eliminating ranges, regardless of the species’ age.

“Our results demonstrate how intimately the evolution of life depends on the changing physical environment,” says Neil Edwards of The Open University modeling team.

This model comes at a crucial time, one of unprecedented climate change. While the simulation is based on a different time period, it shows the dynamic power of climate change and the ways it shapes life on Earth.

“The current pace of human driven climate change is much, much faster than anything in our model, but the same processes are happening in terms of species’ range shifts today,” says Colwell.

Author: Elaina Hancock | Source: University of Connecticut [July 19, 2018]




The Andromeda galaxy cannibalized the Milky Way’s ‘sibling’ 2 billion...

Scientists at the University of Michigan have deduced that the Andromeda galaxy, our closest large galactic neighbor, shredded and cannibalized a massive galaxy two billion years ago.

The Andromeda galaxy cannibalized the Milky Way's 'sibling' 2 billion years ago
In this image, the Andromeda galaxy shreds the large galaxy M32p, which eventually resulted in M32
and a giant halo of stars [Credit: Richard D’Souza. Image of M31 courtesy of Wei-Hao Wang/
Image of stellar halo of M31 courtesy of AAS/IOP]

Even though it was mostly shredded, this massive galaxy left behind a rich trail of evidence: an almost invisible halo of stars larger than the Andromeda galaxy itself, an elusive stream of stars and a separate enigmatic compact galaxy, M32. Discovering and studying this decimated galaxy will help astronomers understand how disk galaxies like the Milky Way evolve and survive large mergers.

This disrupted galaxy, named M32p, was the third-largest member of the Local Group of galaxies, after the Milky Way and Andromeda galaxies. Using computer models, Richard D’Souza and Eric Bell of the University of Michigan’s Department of Astronomy were able to piece together this evidence, revealing this long-lost sibling of the Milky Way. Their findings were published in Nature Astronomy.

Scientists have long known that this nearly invisible large halo of stars surrounding galaxies contains the remnants of smaller cannibalized galaxies. A galaxy like Andromeda was expected to have consumed hundreds of its smaller companions. Researchers thought this would make it difficult to learn about any single one of them.

Using new computer simulations, the scientists were able to understand that even though many companion galaxies were consumed by Andromeda, most of the stars in the Andromeda’s outer faint halo were mostly contributed by shredding a single large galaxy.

The Andromeda galaxy cannibalized the Milky Way's 'sibling' 2 billion years ago
This is a family portrait of our local neighborhood of galaxies, called the Local Group as it would have looked more
 than 2 billion years ago. The missing galaxy, M32p would have been the third largest galaxy in the Local Group
 after the Andromeda and Milky Way galaxies [Credit: Richard D’Souza; LMC, M33 and M31,
courtesy of Wei-Hao Wang; Milky Way, NASA/JPL; M64, NOAO/AURA/NSF]

“It was a ‘eureka’ moment. We realized we could use this information of Andromeda’s outer stellar halo to infer the properties of the largest of these shredded galaxies,” said lead author D’Souza, a postdoctoral researcher at U-M.

“Astronomers have been studying the Local Group — the Milky Way, Andromeda and their companions — for so long. It was shocking to realize that the Milky Way had a large sibling, and we never knew about it,” said co-author Bell, U-M professor of astronomy.

This galaxy, called M32p, which was shredded by the Andromeda galaxy, was at least 20 times larger than any galaxy which merged with the Milky Way over the course of its lifetime. M32p would have been massive, making it the third largest galaxy in the Local Group after the Andromeda and the Milky Way galaxies.

This work might also solve a long-standing mystery: the formation of Andromeda’s enigmatic M32 satellite galaxy, the scientists say. They suggest that the compact and dense M32 is the surviving center of the Milky Way’s long-lost sibling, like the indestructible pit of a plum.

The Andromeda galaxy cannibalized the Milky Way's 'sibling' 2 billion years ago
The larger disc in this image, galaxy M64, represents what astronomers suspect the M32p galaxy looked like before
 the Andromeda galaxy cannibalized it nearly 2 billion years ago. The smaller image at the top shows is the
M32p’s present-day remnant, the compact elliptical galaxy, M32 [Credit: University of Michigan]

“M32 is a weirdo,” Bell said. “While it looks like a compact example of an old, elliptical galaxy, it actually has lots of young stars. It’s one of the most compact galaxies in the universe. There isn’t another galaxy like it.”

Their study may alter the traditional understanding of how galaxies evolve, the researchers say. They realized that the Andromeda’s disk survived an impact with a massive galaxy, which would question the common wisdom that such large interactions would destroy disks and form an elliptical galaxy.

The timing of the merger may also explain the thickening of the disk of the Andromeda galaxy as well as a burst of star formation two billion years ago, a finding which was independently reached by French researchers earlier this year.

“The Andromeda Galaxy, with a spectacular burst of star formation, would have looked so different 2 billion years ago,” Bell said. “When I was at graduate school, I was told that understanding how the Andromeda Galaxy and its satellite galaxy M32 formed would go a long way towards unraveling the mysteries of galaxy formation.”

The method used in this study can be used for other galaxies, permitting measurement of their most massive galaxy merger, the researchers say. With this knowledge, scientists can better untangle the complicated web of cause and effect that drives galaxy growth and learn about what mergers do to galaxies.

Author: Morgan Sherburne | Source: University of Michigan [July 23, 2018]




More on Distinctive projectile point technology sheds light on peopling of the Americas

For decades, researchers believed the Western Hemisphere was settled by humans roughly 13,500 years ago, a theory based largely upon the widespread distribution of Clovis artifacts dated to that time. Clovis artifacts are distinctive prehistoric stone tools so named because they were initially found near Clovis, New Mexico, in the 1920s but have since been identified throughout North and South America.

More on Distinctive projectile point technology sheds light on peopling of the Americas
Stone tool assemblage recovered from the Gault Site [Credit: Produced by N Velchoff,
The Gault School of Archaeological Research]

In recent years, though, archaeological evidence has increasingly called into question the idea of “Clovis First.” Now, a study published by a team including DRI’s Kathleen Rodrigues, Ph.D. student, and Amanda Keen-Zebert, Ph.D., associate research professor, has dated a significant assemblage of stone artifacts to 16-20,000 years of age, pushing back the timeline of the first human inhabitants of North America before Clovis by at least 2,500 years.

Significantly, this research identifies a previously unknown, early projectile point technology unrelated to Clovis, which suggests that Clovis technology spread across an already well-established, indigenous population.

“These projectile points are unique. We haven’t found anything else like them,” said Tom Williams, Ph.D., Postdoctoral Research Associate in the Department of Anthropology at Texas State University and lead author of the study. “Combine that with the ages and the fact that it underlies a Clovis component, and the Gault site provides a fantastic opportunity to study the earliest human occupants in the Americas.”

More on Distinctive projectile point technology sheds light on peopling of the Americas
Soil layers (stratigraphy) identified at the Gault Site along with the cultural periods identified
[Credit: Produced by A Gilmer, The Gault School of Archaeological Research]

The research team identified the artifacts at the Gault Site in Central Texas, an extensive archaeological site with evidence of continuous human occupation. The presence of Clovis technology at the site is well-documented, but excavations below the deposits containing Clovis artifacts revealed well-stratified sediments containing artifacts distinctly different from Clovis.

To determine the ages of these artifacts, Rodrigues, Keen-Zebert, and colleagues used a process called optically simulated luminescence (OSL) dating to the ages of the surrounding sedimentary material. In OSL, researchers expose minerals that have long been buried under sediment layers to light or heat, which causes the minerals to release trapped potassium, uranium, and thorium electrons that have accumulated over time due to ambient, naturally occurring radiation. When the trapped electrons are released, they emit light which can be measured to determine the amount of time that has elapsed since the materials were last exposed to heat or sunlight.

“The fluvial nature of the sediments deposited at the Gault Site have created a poor environment for preservation of organic materials, so radiocarbon dating has not been a useful technique to apply in this region,” said Kathleen Rodrigues, graduate research assistant in DRI’s Division of Earth and Ecosystem Sciences. “This made luminescence dating a natural choice for dating the archaeological materials here. We are really pleased with the quality of the results that we have achieved.”

Source: Desert Research Institute [July 23, 2018]




Paleontologists discover largest dinosaur foot to date

As it turns out, “Bigfoot” was a dinosaur—a giant, plant-eating one. A new study based on fossils excavated in Wyoming reveals the largest dinosaur foot ever found and identifies it as a brachiosaur, a type of sauropod dinosaur that was among the largest land animals on Earth. The work, published in the journal PeerJ, also confirms that 150 million years ago brachiosaurs called a huge swath of North America home.

Paleontologists discover largest dinosaur foot to date
A photograph from the excavations in 1998, with the brachiosaur foot bones below a tail of a Camarasaurus.
University of Kansas expedition crew member as a scale [Credit: the KUVP archives]

“There are tracks and other incomplete skeletons from Australia and Argentina that seem to be from even bigger animals, but those gigantic skeletons were found without the feet. This beast was clearly one of the biggest that ever walked in North America,” said co-author Emanuel Tschopp, a Theodore Roosevelt Richard Gilder Graduate School postdoctoral fellow in the American Museum of Natural History’s Division of Paleontology and author on the new PeerJ study.

The foot was excavated in 1998 by an expedition team from the University of Kansas which included Anthony Maltese, now at the Rocky Mountain Dinosaur Resource Center in Woodland Park, Colorado.

Paleontologists discover largest dinosaur foot to date
This illustration shows a Brachiosaurus eating from an Araucaria tree. These dinosaurs had enormous necks
and relatively short tails. The animal to which the foot belongs was nearly 4 meters high at its hip
[Credit: © Davide Bonadonna, Milan, Italy]

“It was immediately apparent that the foot, nearly a meter wide, was from an extremely large animal, so the specimen was nicknamed ‘Bigfoot,'” said Maltese, lead author of the study.

Now, after thorough preparation and examination, Maltese, Tschopp, and collaborators have identified the foot as belonging to an animal very closely related to the long-necked, long-tailed sauropod Brachiosaurus, best known as the sauropod featured in the movie Jurassic Park. The researchers used 3-D scanning and detailed measurements to compare the specimen to feet from numerous dinosaur species. Their research confirms that this foot is the largest dinosaur foot discovered to date.

Paleontologists discover largest dinosaur foot to date
Researchers Anthony Romillo and Linda Pollard make silicon casts of sauropod tracks
 in the Dampier Peninsula, Western Australia [Credit: Steven Salisbury]

The study also shows that brachiosaurs inhabited a huge area from eastern Utah to northwestern Wyoming.

“This is surprising,” Tschopp said. “Many other sauropod dinosaurs seem to have inhabited smaller areas during that time.”

The rock outcrops that produced this fossil—the Black Hills region of Wyoming, famous today for tourist attractions like Deadwood and Mount Rushmore—hold many more fantastic dinosaur skeletons, says Maltese. The research team hopes to continue their studies on fossils from the Black Hills region.

Source: American Museum of Natural History [July 24, 2018]




Presaddfed Prehistoric Burial Chamber, Anglesey, North Wales,…

Presaddfed Prehistoric Burial Chamber, Anglesey, North Wales, 21.7.18.

This must be the first time I’ve ever been in this field and it was dry! Brilliant site but quite formidable and curious cattle in the field!

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