четверг, 30 января 2020 г.

Driven by Earth's orbit, climate changes in Africa may have aided human migration

In 1961, John Kutzbach, then a recent college graduate, was stationed in France as an aviation weather forecaster for the U.S. Air Force. There, he found himself exploring the storied caves of Dordogne, including the prehistoric painted caves at Lascoux.

Driven by Earth's orbit, climate changes in Africa may have aided human migration
An aerial view of northern Africa, the Arabian Peninsula and the Mediterranean Basin. A new study led by University
 of Wisconsin–Madison’s John Kutzbach shows that changes in Earth’s orbit, greenhouse gases, and ice sheets
influenced the planet’s climate over the last 140,000 years and may have provided wetter, greener corridors
at times that permitted human migration out of Africa and into the Middle East
[Credit: Google Earth]
Thinking about the ancient people and animals who would have gathered in these caves for warmth and shelter, he took up an interest in glaciology. "It was interesting to me, as a weather person, that people would live so close to an ice sheet," says Kutzbach, emeritus University of Wisconsin-Madison professor of atmospheric and oceanic sciences and the Nelson Institute for Environmental Studies.

Kutzbach went on to a career studying how changes in Earth's movements through space - the shape of its orbit, its tilt on its axis, its wobble - and other factors, including ice cover and greenhouse gases, affect its climate. Many years after reveling at Ice Age cave art, today he's trying to better understand how changes in Earth's climate may have influenced human migration out of Africa.

In a recent study published in the Proceedings of the National Academy of Sciences, Kutzbach and a team of researchers trace changes in climate and vegetation in Africa, Arabia and the Mediterranean going back 140,000 years to aid others studying the influences underlying human dispersal.

The study describes a dynamic climate and vegetation model that explains when regions across Africa, areas of the Middle East, and the Mediterranean were wetter and drier and how the plant composition changed in tandem, possibly providing migration corridors throughout time.

"We don't really know why people move, but if the presence of more vegetation is helpful, these are the times that would have been advantageous to them," Kutzbach says.

The model also illuminates relationships between Earth's climate and its orbit, greenhouse gas concentrations, and its ice sheets.

For instance, the model shows that around 125,000 years ago, northern Africa and the Arabian Peninsula experienced increased and more northerly-reaching summer monsoon rainfall that led to narrowing of the Saharan and Arabian deserts due to increased grassland. At the same time, in the Mediterranean and the Levant (an area that includes Syria, Lebanon, Jordan, Israel and Palestine), winter storm track rainfall also increased.

These changes were driven by Earth's position relative to the sun. The Northern Hemisphere at the time was as close as possible to the sun during the summer, and as far away as possible during the winter. This resulted in warm, wet summers and cold winters.

"It's like two hands meeting," says Kutzbach. "There were stronger summer rains in the Sahara and stronger winter rains in the Mediterranean."

Given the nature of Earth's orbital movements, collectively called Milankovitch cycles, the region should be positioned this way roughly every 21,000 years. Every 10,000 years or so, the Northern Hemisphere would then be at its furthest point from the sun during the summer, and closest during winter.

Indeed, the model showed large increases in rainfall and vegetation at 125,000, at 105,000, and at 83,000 years ago, with corresponding decreases at 115,000, at 95,000 and at 73,000 years ago, when summer monsoons decreased in magnitude and stayed further south.

Between roughly 70,000 and 15,000 years ago, Earth was in a glacial period and the model showed that the presence of ice sheets and reduced greenhouse gases increased winter Mediterranean storms but limited the southern retreat of the summer monsoon. The reduced greenhouse gases also caused cooling near the equator, leading to a drier climate there and reduced forest cover.

These changing regional patterns of climate and vegetation could have created resource gradients for humans living in Africa, driving migration outward to areas with more water and plant life.

For the study, the researchers, including Kutzbach's UW-Madison colleagues Ian Orland and Feng He, along with researchers at Peking University and the University of Arizona, used the Community Climate System Model version 3 from the National Center for Atmospheric Research. They ran simulations that accounted for orbital changes alone, combined orbital and greenhouse gas changes, and a third that combined those influences plus the influence of ice sheets.

It was Kutzbach who, in the 1970s and 1980s, confirmed that changes in Earth's orbit can drive the strength of summer monsoons around the globe by influencing how much sunlight, and therefore, how much warming reaches a given part of the planet.

Forty years ago, there was evidence for periodic strong monsoons in Africa, but no one knew why, Kutzbach says. He showed that orbital changes on Earth could lead to warmer summers and thus, stronger monsoons. He also read about periods of "greening" in the Sahara, often used to explain early human migration into the typically-arid Middle East.

"My early work prepared me to think about this," he says.

His current modeling work mostly agrees with collected data from each region, including observed evidence from old lake beds, pollen records, cave features, and marine sediments. A recent study led by Orland used cave records in the Levant to show that summer monsoons reached into the region around 125,000 years ago.

"We get some things wrong (in the model)," says Kutzbach, so the team continues to refine it. For instance, the model doesn't get cold enough in southern Europe during the glacial period and not all vegetation changes match observed data. Computing power has also improved since they ran the model.

"This is by no means the last word," Kutzbach says. "The results should be looked at again with an even higher-resolution model."

Author: Kelly April Tyrrell | Source: University of Wisconsin-Madison [January 27, 2020]

* This article was originally published here

James Mallory and Oleg Balanovsky

Here's a quote from a new paper on the impact of genetics, and especially ancient DNA, on archeology and linguistics co-authored by archeologist James Mallory and geneticist Oleg Balanovsky: Just as the genetic evidence for a steppe homeland appeared to weaken a popular theory (among archaeologists more than linguists) that the Indo-European languages spread from an Anatolian homeland with the

* This article was originally published here

Seeing Stars in 3D: The New Horizons Parallax Program

Color images of the Wolf 359 (top) and Proxima Centauri star fields, obtained in late 2019. The large proper motions of both stars (at the center of each image) will cause them to shift by over an arcsecond by April 2020, when NASA's New Horizons spacecraft, nearly five billion miles (8 billion kilometers) from Earth, will image them. A green circle provides a rough estimate of where both stars will appear in the New Horizons images. (Credit: William Keel/University of Alabama/SARA Observatory)

NASA's Pluto-Kuiper Belt mission invites public participation in a record-setting astronomical measurement

Have a good-sized telescope with a digital camera? Then you can team up with NASA's New Horizons mission this spring on a really cool – and record-setting -- deep-space experiment.

In April, New Horizons, which by then will be more than 46 times farther from the Sun than Earth, nearing 5 billion miles (8 billion kilometers) from home, will be used to detect "shifts" in the relative positions of nearby stars as compared with the way they appear to observers on Earth.

The technique is called parallax, and it has been used by astronomers for nearly two centuries to measure the distances of faraway stars; see the accompanying sidebar article for more detail.

On April 22 and 23, New Horizons will take images of two of the very nearest stars, Proxima Centauri and Wolf 359. When combined with Earth-based images made on the same dates, the result will be a record-setting parallax measurement yielding 3D images of these stars popping out of their background star fields that the New Horizons project will share with the public.

The mission team is coordinating the use of astronomical observatories and a public observing campaign to image the same stars on the same day to demonstrate the "parallax" effect.parallax effect

"These exciting 3D images, which we'll release in May, will be as if you had eyes as wide as the solar system and could detect the distance of these stars yourself," said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. "It'll be a truly vivid demonstration of the immense distance New Horizons has traveled, and a cool way to take advantage of the spacecraft's unique vantage point out on the very frontier of our solar system!"

New Horizons' two target stars can be observed by anyone with a camera-equipped, 6-inch or larger telescope. Once New Horizons sends its images to Earth, the mission team will provide them for comparison to images obtained with amateur telescopes. Wolf 359 and Proxima Centauri will appear to shift in position between the Earth-based and space-based images.

In addition, working with New Horizons participating scientist and Queen guitarist Brian May – an astrophysicist himself – the New Horizons team will create and release 3D images showing these two stars.

"For all of history, the fixed stars in the night sky have served as navigation markers," said Tod Lauer, a New Horizons science team member from the National Science Foundation's National Optical-Infrared Astronomy Research Laboratory. "As we voyage out of the solar system and into interstellar space, how the nearer stars shift can serve as a new way to navigate. We will see this for the first time with New Horizons."

Get more details on the New Horizons Parallax program – including background info on the target stars and the best times to take images – at http://pluto.jhuapl.edu/Learn/Get-Involved.php#Parallax-Program.

New Horizons is the first mission to explore Pluto and distant Kuiper Belt. The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, manages the New Horizons mission for NASA's Science Mission Directorate. Alan Stern, of the Southwest Research Institute (SwRI) is the principal investigator and leads the mission; SwRI also leads the science team, payload operations, and encounter science planning, data analyses and archiving. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. APL designed, built and operates the New Horizons spacecraft.

For more information, visit www.nasa.gov/newhorizons and http://pluto.jhuapl.edu.

What's a Parallax?

The "parallax effect" is when an object appears to shift in position with respect to more distant objects. This is how our sense of depth perception works: each eye has a slightly different perspective, and the brain uses this to figure out which objects are close and which are far away. You can check this by holding up a finger, blinking with each eye, and noting how your finger it jumps back and forth against more distant background objects. You also see a parallax when you rock from side to side to see around someone blocking your view of a more distant object.

In traditional "stellar parallax" measurements, astronomers use Earth's own back-and-forth rocking motion, as it orbits the Sun, to deduce distances to nearby stars. Earth's orbit is about 186 million miles in diameter, so in half a year – the time it takes Earth to go from one side of its orbit to the other – its vantage point to nearby stars will change by that much. The orbit thus serves as a "baseline" for measuring distances. The bigger the baseline, the bigger the parallaxes.

As they wondered how far away the stars were, astronomers in the early 1700s predicted that nearer stars should shift in position more than distant stars as Earth moved around its orbit. Because distances to even the nearest stars are almost a half-million times greater than the baseline provided by Earth's orbit, the effect is subtle. It took until 1838 for Friedrich Bessel to obtain the first parallax observations by observing semi-annual shifts in the position of the star 61 Cygni.

Accurate stellar parallaxes allow us to survey distances to stars throughout our own Milky Way galaxy, and in doing so anchor our ability to measure distances to other galaxies and determine the overall size of the universe itself! The work to obtain ever more precise parallaxes continues today, with data from the European Space Agency's Gaia mission.

As fundamental as stellar parallaxes are to astronomy, however, they are difficult to demonstrate simply because the shifts are typically smaller than the scales on which telescope can easily resolve, so they require exceedingly careful measurement techniques to be accurately detected. An additional complication: all stars have their own random drifts as they orbit around our galaxy, which means that as we wait several months for Earth's movement to provide the parallaxes, the stars are not staying put. The drifts, known as "proper motions," often cause shifts in a star's position larger than its parallax. The solution is to measure the stellar positions over a few years, so that the change in their positions due to Earth's orbit can be recognized and separated from their constant proper motions. This means parallaxes are evident only with careful numerical analysis applied to years of observations.

The great distance of New Horizons from Earth provides a baseline that is 23 times larger than that previously used to measure parallaxes, thus the shifts of the stars seen in comparison of Earth and New Horizons images will be visually obvious. And, because New Horizons and Earth-based observers can image the same fields at the same time, proper motions over time are irrelevant – meaning we can obtain parallaxes instantly!

* This article was originally published here

Archaeologists analyze the composition of a Roman-era 'makeup case'

A study carried out by researchers from the Merida Consortium, the University of Granada (UGR) and the Institute of Cultural Heritage of Spain has analysed the contents of a scallop shell discovered in a 1st century AD grave and found traces of makeup.

Archaeologists analyze the composition of a Roman-era 'makeup case'
Image of the scallop with pigment residues 
[Credit:University of Granada]
First discovered in 2000 during excavations of a funerary complex in the former capital of the Lusitania, Augusta Emerita (present-day Merida) the 'make-up case' was uncovered in a deposit of cremated remains alongside ceramic cups, bone spindles, nails, glassware and the remains of a detachable bone box.

The make-up case is made from a bivalve malacological mollusk specimen of pecten maximus (viera). Once the shell was opened, it was possible to document the cosmetic remains, specifically, a small ball of a “pinkish” powdery conglomerate via a combination of X-ray diffraction (XRD), electron microscopy and chromatographic analysis.

Archaeologists analyze the composition of a Roman-era 'makeup case'
The study revealed that the pinkish deposit was composed of a granite lacquer, mixed with a rose madder 
to obtain the colouration and then an astringent compound was used as a fixative agent 
[Credit: University of Granada]

The use of the mollusk as a cosmetic container is a practice that dates back thousands of years across various civilisations. One of the earliest examples is tiny shells in the Sumerian city of Ur from 2500 BC that contained pigments used for cosmetics.

The study revealed that the pinkish deposit was composed of a granite lacquer, mixed with a rose madder to obtain the coloration and then an astringent compound was used as a fixative agent.

The results of the study have been published in the latest issue of Saguntum.

Source: University of Granada [January 24, 2020]

* This article was originally published here

2020 January 30 Two Clusters and a Comet Image Credit &...

2020 January 30

Two Clusters and a Comet
Image Credit & Copyright: Rolando Ligustri (CARA Project, CAST)

Explanation: This lovely starfield spans some four full moons (about 2 degrees) across the heroic northern constellation of Perseus. In telescopic exposures made during the nights of January 24, 26, and 28 it holds the famous pair of open or galactic star clusters h and Chi Persei with comet PanSTARRS (C/2017 T2) captured each night as it swept left to right across the field of view. Also cataloged as NGC 869 (right) and NGC 884, both star clusters are about 7,000 light-years away and contain stars much younger and hotter than the Sun. Separated by only a few hundred light-years, the clusters are both 13 million years young based on the ages of their individual stars, evidence that they were likely a product of the same star-forming region. Discovered in 2017 while still beyond the orbit of Saturn, Comet PanSTARRs is a new visitor to the inner solar system and just over 13 light-minutes from planet Earth. Always a rewarding sight in binoculars, the Double Cluster is even visible to the unaided eye from dark locations. C/2017 T2 could remain a telescopic comet though. One of the brightest comets anticipated in 2020 it makes its closest approach to the Sun in early May.

∞ Source: apod.nasa.gov/apod/ap200130.html

* This article was originally published here

Corbridge Roman Lion Statue, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

Corbridge Roman Lion Statue, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

* This article was originally published here

Shocking truth behind Takabuti’s death revealed

Takabuti, the famous ancient Egyptian mummy on display at the Ulster Museum, suffered a violent death from a knife attack, a team of experts from National Museums NI, University of Manchester, Queen’s University Belfast and Kingsbridge Private Hospital have revealed.

Shocking truth behind Takabuti’s death revealed
Takabuti mummy case, ca. 660 BC [Credit: University of Manchester]
The team, whose findings are made public on the 185 year anniversary of Takabuti’s unwrapping in 1835, also show that her DNA is more genetically similar to Europeans rather than modern Egyptian populations.

The team show Takabuti had an extra tooth - 33 instead of 32 - something which only occurs in 0.02% of the population and an extra vertebrae, which only occurs 2% of the population.

And Takabuti’s heart, previously thought to have been missing, was identified by the state of the art technology used by the researchers as intact and perfectly preserved.

The scans show she was stabbed in the upper back near her left shoulder and that it was the cause of her death.

The findings finally solve the mystery of the mummy which has intrigued Egyptologists - and the public - since she was first unwrapped in Belfast in 1835. It transforms our understanding of Takabuti’s life in ancient Egypt and her journey into the afterlife.

The project was supported by funding from Friends of the Ulster Museum. Kingsbridge Private Hospital facilitated the work by providing their expertise and use of a portable x-ray machine to aid sampling for DNA work.

Shocking truth behind Takabuti’s death revealed
Takabuti's mummified remains [Credit: University of Manchester]
According to the team, the mysterious object in her body cavity, previously thought to be her heart, was in fact material used to pack the knife wound.

Takabuti lived over 2,600 years ago and died in her 20s. Experts say she was probably a married woman because she was a leading woman living - or mistress – who lived in a Thebes house - where Luxor is today.

She was acquired in Thebes by Thomas Greg from Holywood, County Down and brought to Belfast in 1834.

The scientific team consisted of Professor Rosalie David, Drs Bart van Dongen, Konstantina Drosou, Sharon Fraser, Professor Tony Freemont, Ds Roger Forshaw, Robert Loynes and Keith White from The University of Manchester

It also included Professors Eileen Murphy and Paula Reimar from Belfast University; Professor Caroline Wilkinson and Dr Sarah Shrimpton from Liverpool John Moores University; and Dr David Tosh from the Ulster Museum.

Dr Greer Ramsey, Curator of Archaeology at National Museums NI, says advances in scientific techniques have made the new findings possible.

Shocking truth behind Takabuti’s death revealed
Detail of Takabuti's head with auburn coloured wig deliberately set after death
[Credit: University of Manchester]
He said: “There is a rich history of testing Takabuti since she was first unwrapped in Belfast in 1835. But in recent years she has undergone x-rays, CT scans, hair analysis and radio carbon dating. The latest tests include DNA analysis and further interpretations of CT scans which provides us with new and much more detailed information.

“The significance of confirming Takabuti’s heart is present cannot be underestimated as in ancient Egypt this organ was removed in the afterlife and weighed to decide whether or not the person had led a good life. If it was too heavy it was eaten by the demon Ammit and your journey to the afterlife would fail.”

The tests and examination of Takabuti were carried out over a period of months by the team using the latest scanning technologies, leading to new insights into Egyptian high society in the 25th dynasty.

Professor Rosalie David, an Egyptologist from The University of Manchester said: “This study adds to our understanding of not only Takabuti, but also wider historical context of the times in which she lived: the surprising and important discovery of her European heritage throws some fascinating light on a significant turning-point in Egypt’s history.

“This study, which used cutting-edge scientific analysis of an ancient Egyptian mummy - demonstrates how new information can be revealed thousands of years after a person’s death. Our team - drawn from institutions and specialisms – was in a unique position to provide the necessary expertise and technology for such a wide-ranging study.”

Professor Eileen Murphy, a Bioarchaeologist from Queen’s University Belfast’s School of Natural and Built Environment, said: “It has been an incredible privilege to have been involved in modern research that has really helped enlighten us about Takabuti’s life and death. The latest research programme has provided some astounding results. It is frequently commented that she looks very peaceful lying within her coffin but now we know that her final moments were anything but and that she died at the hand of another.

Shocking truth behind Takabuti’s death revealed
Takabuti's opened coffin [Credit: University of Manchester]
“Trawling the historical records about her early days in Belfast it is clear that she caused quite a media sensation in 1835 – she had a poem written about her, a painting was made of her prior to her ‘unrolling’ and accounts of her unwrapping were carried in newspapers across Ireland. Research undertaken ten years ago gave us some fascinating insights, such as how her auburn hair was deliberately curled and styled. This must have been a very important part of her identity as she spurned the typical shaven-headed style. Looking at all of these facts, we start to get a sense of the petite young woman and not just the mummy.”

Retired Orthopaedic Surgeon and currently honorary lecturer in the University of Manchester's KNH Centre for Biomedical Egyptology, Dr Robert Loynes who performed the CT analysis and biopsy retrieval of material for a DNA and other analyses said: “The CT scan reveals that Takabuti sustained a severe wound to the back of her upper left chest wall. This almost certainly caused her rapid death. However, the CT scan also reveals unusual and rare features of her embalming process.”

Geneticist Dr Konstantina Drosou said “Takabuti’s genetic footprint H4a1 is relatively rare as it has not been found to my knowledge in any ancient or modern Egyptian population. My results agree with previous studies about ancient Egyptians being more genetically similar to Europeans than modern day Arabs.”

A book is currently being produced by the project team and supported by the Engaged Research Fund, Queen’s University Belfast, and the KNH Centre for Biomedical Egyptology, The University of Manchester. The book will bring together all of the research findings to date on Takabuti.

Details of the new findings can be found in the Ancient Egypt gallery in the Ulster Museum where Takabuti is currently on display. Admission is free.

Source: University of Manchester [January 27, 2020]

* This article was originally published here

Roman Casting Mould showing a Warrior God with Shield and Club, Corbridge Roman Town,...

Roman Casting Mould showing a Warrior God with Shield and Club, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

* This article was originally published here

Large 15th century merchant vessel being put back together piece by piece

"Reassembling a 600-year-old ship from its original timbers is like doing a 3D jigsaw puzzle with 2,500 pieces, without the picture on the box" - that's how Bob Evans, chairman of the Friends of the Newport Ship, describes the work being carried out on a fascinating historical find. The ship is the best example of its kind in the world.

Large 15th century merchant vessel being put back together piece by piece
Newport Ship during excavation in 2002 [Credit: Rob Norman/WalesOnline]

It is the best preserved large 15th century ship found anywhere in the world and is currently hidden away in an industrial unit on the south side of Newport.

It's a unique piece of history; 60 years older than the Mary Rose and about three quarters of her size, she was a merchant ship of about 400 tons displacement and over 30 metres in length. Clearly it's impressive, but it's more than that - it's an amazing piece of history.

"In her time the Newport Ship was one of the biggest vessels afloat," explained Mr Evans. "She was a merchant vessel, not a warship and she is an important part of Newport’s heritage as an historic port and maritime centre.

Large 15th century merchant vessel being put back together piece by piece
The ship was found in the banks of the Usk in 2002
[Credit: Friends of the Newport Ship]

"It is important to remember that the ship was saved by actions of the local Newport community and there is nothing like her anywhere else in the world. There are no other surviving vessels from the early 15th century; a time when ship design was developing rapidly and we have much to learn from the way in which she was built and how she would have sailed".

Mr Evans added: "We know nothing of her history but everything we have learned from our research suggests that our ship traded with Portugal and the Iberian peninsula and was engaged in the wine trade. She could carry up to 200 tonnes of wine in one voyage – that’s 50,000 gallons or around 200,000 bottles - truly a 15th century wine supertanker." 

It's thought the ship was probably built in the Basque country around 1449 and sailed the North Atlantic until about 1469 when she entered an inlet on the river Usk in Newport and never emerged.

Large 15th century merchant vessel being put back together piece by piece
Newport Ship hull in situ [Credit: Friends of the Newport Ship]

The ship was discovered in 2002 during the building of the Riverfront Theatre and was recovered piece by piece. Around 2,000 timbers were recovered and the last 15 years have been spent preserving and freeze drying timbers.

Since then, the idea of the ship has become something of an inspiration for the people of Newport; Monusk Tapas say their menus draw on the food eaten along the ship's route, while local brewery Anglo-Oregon Brewing have produced a stout called Newport Ship.

The timbers and associated artefacts are currently undergoing conservation and study at the Ship Centre in Queensway Meadows, Newport. But it's no easy task, the efforts to recreate the impressive vessel are painstaking and Mr Evans stresses that it's a slow process.

Large 15th century merchant vessel being put back together piece by piece
Dried ship timbers [Credit: Friends of the Newport Ship]

"We have received two further shipments of dried timbers during the year so that we now have around three quarters of the recovered timbers preserved and ready for reassembly," explained Mr Evans.

"We aim to have the remaining timbers back at the Newport Ship Centre by the end of 2020. The latest shipment includes some of the big framing timbers which are very impressive in terms of their size and the high standard of carpentry they exhibit. We intend to have some of them on display when we reopen the centre for 2020."

The information displays at the site have been completely redesigned too, with new museum-standard display boards and a new set of posters and images. It will include a specially commissioned set of images by a prominent young designer showing the ship under construction.

Large 15th century merchant vessel being put back together piece by piece
Timbers undergoing conservation [Credit: Friends of the Newport Ship]
"In the meantime," Mr Evans adds, "we are preparing for the reassembly phase, even though we only have some 40% of the hull remaining, the timbers in total weigh over 25 tons and will require a sophisticated and high technology cradle to support them. We are working with Swansea University, who are acknowledged experts in this type of structural engineering, to design a suitable structure and specify the right materials for the job. Reassembling a 600 year old ship from its original timbers is like doing a 3D jigsaw puzzle with 2,500 pieces, without the picture on the box."

He added: "We do not want to put it together in the wrong way or have to take it apart again, so we must be certain that we know exactly how each timber fits together before we start. Work continues on finding a building in the Newport area which is big enough to house the Ship and we hope to make an announcement on this in a few months’ time."

The centre is due to reopen in spring 2020, and it's usually open on Fridays, Saturdays and Bank Holiday Mondays. Admission is free.

Author: Joshua Knapman | Source: Wales Online [January 20, 2020]

* This article was originally published here

Astronomers Detect Large Amounts of Oxygen in Ancient Star’s Atmosphere

Artistic image of the supernova explosions of the first massive stars that formed in the milky way. the star j0815+4729 was formed from the material ejected by these first supernovae. Credit: Gabriel Pérez Díaz, SMM (IAC)

Maunakea, Hawaii – An international team of astronomers from the University of California San Diego, the Instituto de Astrofísica de Canarias (IAC), and the University of Cambridge have detected large amounts of oxygen in the atmosphere of one of the oldest and most elementally depleted stars known – a “primitive star” scientists call J0815+4729.

This new finding, which was made using W. M. Keck Observatory on Maunakea in Hawaii to analyze the chemical makeup of the ancient star, provides an important clue on how oxygen and other important elements were produced in the first generations of stars in the universe.

The results are published in the January 21, 2020 edition of the The Astrophysical Journal Letters.

“This result is very exciting. It tells us about some of the earliest times in the universe by using stars in our cosmic back yard,” said Keck Observatory Chief Scientist John O’Meara. “I look forward to seeing more measurements like this one so we can better understand the earliest seeding of oxygen and other elements throughout the young universe.”

Oxygen is the third most abundant element in the universe after hydrogen and helium, and is essential for all forms of life on Earth, as the chemical basis of respiration and a building block of carbohydrates. It is also the main elemental component of the Earth’s crust. However, oxygen didn’t exist in the early universe; it is created through nuclear fusion reactions that occur deep inside the most massive stars, those with masses roughly 10 times the mass of the Sun or greater.

Tracing the early production of oxygen and other elements requires studying the oldest stars still in existence. J0815+4729 is one such star; it resides over 5,000 light years away toward the constellation Lynx.

“Stars like J0815+4729 are referred to as halo stars,” explained UC San Diego astrophysicist Adam Burgasser, a co-author of the study. “This is due to their roughly spherical distribution around the Milky Way, as opposed to the more familiar flat disk of younger stars that include the Sun.”

Halo stars like J0815+4729 are truly ancient stars, allowing astronomers a peek into element production early in the history of the universe.

The research team observed J0815+4729 using Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES) on the 10m Keck I telescope. The data, which required more than five hours of staring at the star over a single night, were used to measure the abundances of 16 chemical species in the star’s atmosphere, including oxygen.

“The primitive composition of the star indicates that it was formed during the first hundreds of millions of years after the Big Bang, possibly from the material expelled from the first supernovae of the Milky Way,” said Jonay González Hernández, Ramón y Cajal postdoctoral researcher and lead author of the study.

Keck Observatory’s HIRES data of the star revealed a very unusual chemical composition. While it has relatively large amounts of carbon, nitrogen, and oxygen – approximately 10, 8, and 3 percent of the abundances measured in the Sun – other elements like calcium and iron have abundances around one millionth that of the Sun.

This animation illustrates the earliest epoch of the universe, just after the Big Bang, when the first elements of hydrogen, helium, and lithium were created in the still hot cosmos. These atoms eventually collected to form the first generation of massive stars, which in turn produced heavier elements such as carbon, oxygen, and nitrogen. As these massive stars exploded as supernovae, they released these heavier elements into the universe, eventually collecting on next generation stars such as J0815+4729, with its unusually high abundance of oxygen. Credit: Gabriel Pérez Díaz, SMM (IAC)

“Only a few such stars are known in the halo of our galaxy, but none have such an enormous amount of carbon, nitrogen, and oxygen compared to their iron content,” said David Aguado, a postdoctoral researcher at the University of Cambridge and co-author of the study. 

The search for stars of this type involves dedicated projects that sift through hundreds of thousands of stellar spectra to uncover a few rare sources like J0815+4729, then follow-up observations to measure their chemical composition. 

This star was first identified in data obtained with the Sloan Digital Sky Survey (SDSS), then characterized by the IAC team in 2017 using the Grand Canary Telescope in La Palma, Spain. “Thirty years ago we started at the IAC to study the presence of oxygen in the oldest stars of the Galaxy; those results had already indicated that this element was produced enormously in the first generations of supernovae. However, we could not imagine that we would find a case of enrichment as spectacular as that of this star,” noted Rafael Rebolo, IAC director and co-author of the study.


The High-Resolution Echelle Spectrometer (HIRES) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many “stripes” of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding exoplanets. Astronomers also use HIRES to study important astrophysical phenomena like distant galaxies and quasars, and find cosmological clues about the structure of the early universe, just after the Big Bang.

About W. M. Keck Observatory

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two, 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems.

Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

* This article was originally published here

Roman Stone Slab Decoration, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

Roman Stone Slab Decoration, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

* This article was originally published here

New study debunks myth of Cahokia's Native American lost civilization

A University of California, Berkeley, archaeologist has dug up ancient human feces, among other demographic clues, to challenge the narrative around the legendary demise of Cahokia, North America's most iconic pre-Columbian metropolis.

New study debunks myth of Cahokia's Native American lost civilization
Painting of the Cahokia Mounds by William R. Iseminger
[Credit: Cahokia Mounds Historic State Site]
In its heyday in the 1100s, Cahokia -- located in what is now southern Illinois -- was the center for Mississippian culture and home to tens of thousands of Native Americans who farmed, fished, traded and built giant ritual mounds.

By the 1400s, Cahokia had been abandoned due to floods, droughts, resource scarcity and other drivers of depopulation. But contrary to romanticized notions of Cahokia's lost civilization, the exodus was short-lived, according to a new UC Berkeley study.

The study takes on the "myth of the vanishing Indian" that favors decline and disappearance over Native American resilience and persistence, said lead author A.J. White, a UC Berkeley doctoral student in anthropology.

"One would think the Cahokia region was a ghost town at the time of European contact, based on the archaeological record," White said. "But we were able to piece together a Native American presence in the area that endured for centuries."

The findings, just published in the journal American Antiquity, make the case that a fresh wave of Native Americans repopulated the region in the 1500s and kept a steady presence there through the 1700s, when migrations, warfare, disease and environmental change led to a reduction in the local population.

White and fellow researchers at California State University, Long Beach, the University of Wisconsin-Madison and Northeastern University analyzed fossil pollen, the remnants of ancient feces, charcoal and other clues to reconstruct a post-Mississippian lifestyle.

Their evidence paints a picture of communities built around maize farming, bison hunting and possibly even controlled burning in the grasslands, which is consistent with the practices of a network of tribes known as the Illinois Confederation.

Unlike the Mississippians who were firmly rooted in the Cahokia metropolis, the Illinois Confederation tribe members roamed further afield, tending small farms and gardens, hunting game and breaking off into smaller groups when resources became scarce.

New study debunks myth of Cahokia's Native American lost civilization
Credit: Herb Roe, University of California - Berkeley
The linchpin holding together the evidence of their presence in the region were "fecal stanols" derived from human waste preserved deep in the sediment under Horseshoe Lake, Cahokia's main catchment area.

Fecal stanols are microscopic organic molecules produced in our gut when we digest food, especially meat. They are excreted in our feces and can be preserved in layers of sediment for hundreds, if not thousands, of years.

Because humans produce fecal stanols in far greater quantities than animals, their levels can be used to gauge major changes in a region's population.

To collect the evidence, White and colleagues paddled out into Horseshoe Lake, which is adjacent to Cahokia Mounds State Historical Site, and dug up core samples of mud some 10 feet below the lakebed. By measuring concentrations of fecal stanols, they were able to gauge population changes from the Mississippian period through European contact.

Fecal stanol data were also gauged in White's first study of Cahokia's Mississippian Period demographic changes, published last year in the Proceedings of the National Academy of Sciences. It found that climate change in the form of back-to-back floods and droughts played a key role in the exodus of Cahokia's Mississippian inhabitants.

But while many studies have focused on the reasons for Cahokia's decline, few have looked at the region following the exodus of Mississippians, whose culture is estimated to have spread through the Midwestern, Southeastern and Eastern United States from 700 A.D. to the 1500s.

White's latest study sought to fill those gaps in the Cahokia area's history.

"There's very little archaeological evidence for an indigenous population past Cahokia, but we were able to fill in the gaps through historical, climatic and ecological data, and the linchpin was the fecal stanol evidence," White said.

Overall, the results suggest that the Mississippian decline did not mark the end of a Native American presence in the Cahokia region, but rather reveal a complex series of migrations, warfare and ecological changes in the 1500s and 1600s, before Europeans arrived on the scene, White said.

"The story of Cahokia was a lot more complex than, 'Goodbye, Native Americans. Hello, Europeans,' and our study uses innovative and unusual evidence to show that," White said.

Author: Yasmin Anwar | Source: University of California - Berkeley [January 27, 2020]

* This article was originally published here

Roman Metal Cockrel, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

Roman Metal Cockrel, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

* This article was originally published here

Archaic building found at Asclepeion Sanctuary in ancient Epidaurus

The Asclepeion of Epidaurus on the Peloponnesian Peninsula is one of the most important ancient sites in the entire world.

Archaic building found at Asclepeion Sanctuary in ancient Epidaurus
The Tholos of Ancient Epidaurus in the process of restoration and the remains of the Archaic era
building that has just been discovered [Credit: Athens-Macedonian News Agency]
Today, it owes a great deal of its fame to the theatre, a wonder of acoustics which is still in operation today, but in ancient times it served as a medical sanctuary, and serious illnesses were healed there.

People from all over the Eastern Mediterranean region flocked to Epidaurus in antiquity to find cures for their various maladies. It was a spacious resort which included guesthouses, a gymnasium, a stadium and the famous theater, which served to “elevate the soul,” which ancient Greeks saw as the goal of all theatrical plays, both tragedies and comedies.

Along with its many luxurious facilities, the Asclepeion of Epidaurus offered beautiful, serene natural surroundings, with lush vegetation and stunning views of the surrounding mountaintops.

According to the poet Hesiod, who was active between 750 and 650 BC, Asclepius, the son of Apollo who was considered the ancient Greek god of medicine, was born in Epidaurus.

A new building found at Epidaurus’ Asclepeion area, which was dedicated to this god, gives new insight into the famous sanctuary, mainly concerning the early years of its creation.

The newly-uncovered building is a structure from the archaic era, whose function is currently unknown. It was built on a site adjacent to where the Tholos, or dome, the most iconic building of the Asclepeion, is situated.

The building, rectangular in plan, had a basement space corresponding to the ground floor, with mosaics placed in a peristyle form. According to the information gleaned so far from the excavation, which is still in progress, the building dates back to around the year 600 BC.

Archaic building found at Asclepeion Sanctuary in ancient Epidaurus
The theatre at Epidaurus [Credit: Geolines]
University of Athens Professor Vassilis Lamprinoudakis, head of the excavations in ancient Epidaurus, explained to the Athens-Macedonian News Agency “This means the worship of Asclepius appears to have begun earlier in the Asclepeion of Epidaurus. Until now, it was believed to have begun around 550 BC, i.e., in the middle of the sixth century BC.

“Now it is evident that the structures are earlier, and this is particularly important for the history of the sanctuary and for the history of Asclepius himself,” the archaeologist noted.

“At the place where the Tholos was later built, a part of a building, a ‘double’ building, with basement and ground floor has been found. Since there is a basement, like in the Tholos, we consider it to be a forerunner of this ‘mysterious’ building called the Tholos,” Lamprinoudakis stated.

“When it was decided to build the Tholos, this building was demolished. The empty space created by its basement was filled with relics from the old building, but also from other parts of the sanctuary. That is because (when) the great program of the 4th century BC began, some other buildings were also demolished, the material of which was buried with respect in the place,” he added.

The archaeologist explained that the name Tholos “was only given to the structure by the ancient traveler Pausanias in the second century AD. Its original name, as we know from the inscriptions of the 4th century BC, was ‘Thymeli.’ Thymeli was a kind of altar (used in sacrifice), in which offerings were made without blood.”

Lamprinoudakis continued, saying “Research tells us that the Tholos was a kind of underground house of Asclepius, where patients were treated by injection.” The patient who slept in this special place would dream of the god Asclepius to reveal to him the cure for his illness. “This former building had a function similar to that of the Tholos, that is, its basement served as the seat of Asclepius on earth,” the archaeologist explained.

“The new building, however, also gives important clues to the topography of the sanctuary. It explains the orientation of some other constructions that follow,” Lamprinoudakis concluded.

The archaeological dig at the sanctuary of Asclepius of Epidaurus, which has been carried out by the Department of History and Archeology of the University of Athens since 2016, continues today.

The excavations, carried out with the support of the Ephorate of Antiquities of Argolis, were funded by the organization “Asclipiades” in 2016-2017 and by the Stavros Niarchos Foundation in the years 2018-2019.

Author: Philip Chrysopoulos | Source: Athens-Macedonian News Agency via Greek Reporter [January 29, 2020]

* This article was originally published here

Roman Military Armour, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

Roman Military Armour, Corbridge Roman Town, Hadrian’s Wall, Northumberland, 26.1.20.

* This article was originally published here

Siberian Neanderthals were intrepid nomads

A new study, published online today in the Proceedings of the National Academy of Sciences, reveals that Neanderthals made an intercontinental trek of more than 3000 km to reach Siberia's Altai Mountains, equipped with a distinctive toolkit used to kill and butcher bison and horses.

Siberian Neanderthals were intrepid nomads
Excavation work in Chagyrskaya Cave
[Credit: Richard Roberts]
Neanderthals are our nearest evolutionary cousins and survived until around 40,000 years ago in western Europe. Their legacy lives on today in the DNA of all people with European or Asian ancestry.

Neanderthal fossils were first reported from the Altai Mountains—the easternmost outpost of their known geographic range—in 2007. Nestled in the foothills, Chagyrskaya Cave has yielded 74 Neanderthal fossils, more than any other site in the region, as well as almost 90,000 stone tools and numerous bone tools made by Neanderthals.

The multi-disciplinary team of researchers from Russia, Australia, Ukraine, Poland, Germany and Canada, including University of Wollongong geochronologist Professor Richard "Bert' Roberts, carried out detailed investigations of the site to discover new clues about the history of these Siberian Neanderthals.

The 3.5 meter-thick cave deposits were first excavated in 2007. Dating of the sediments and the bones of butchered bison indicated that Neanderthals lived in the cave sometime between 59,000 and 49,000 years ago—shortly before modern humans first entered this region.

Siberian Neanderthals were intrepid nomads
Excavation of archaeological deposits in Chagyrskaya Cave
[Credit: IAET]
"The most surprising discovery was how closely the Chagyrskaya stone tools resemble Micoquian tools from archaeological sites in central and eastern Europe," project leader Dr. Kseniya Kolobova from the Russian Academy of Science's Institute of Archaeology and Ethnography in Novosibirsk said.

Using a variety of statistical tests, Dr. Kolobova and her team of archaeologists compared the distinctive stone tools found at Chagyrskaya Cave with those recovered from Micoquian sites in Europe and central Asia. They identified the region between the Crimea and the northern Caucasus as the likely ancestral homeland of the Chagyrskaya toolmakers.

"This part of eastern Europe is 3000 to 4000 kilometers from Chagyrskaya Cave, the equivalent of walking from Sydney to Perth or from New York to Los Angeles—a truly epic journey," co-author Professor Roberts from UOW's Centre for Archaeological Science said.

Analysis of animal and plant remains extracted from the Chagyrskaya Cave deposits showed that the Neanderthals were skilled at hunting bison and horses in the cold, dry and treeless environment, while microscopic study of the sediments yielded additional clues about the living conditions they had to endure.

Siberian Neanderthals were intrepid nomads
Siberian Neanderthals were intrepid nomads
Micoquian stone tools used as a meat knife by Neanderthals at Chagyrskaya Cave
about 54,000 years ago [Credit: IAET, Alexander Fedorchenko]
"Neanderthals were supremely adapted to life on steppe and tundra-steppe landscapes, and could have reached the Altai Mountains from eastern Europe by going around the Caspian Sea and then east along the steppe belt," co-author and geoarchaeologist Dr. Maciej Krajcarz from the Institute of Geological Sciences in the Polish Academy of Sciences said.

The new archaeological evidence indicates at least two separate migrations of Neanderthals into southern Siberia, and is independently supported by whole-genome studies of ancient DNA obtained from Neanderthal fossils.

The first migration occurred more than 100,000 years ago, blazing a trail to the nearby site of Denisova Cave—famous as the home of the enigmatic Denisovans, a sister group to Neanderthals, who also occupied the cave at times. A more recent migration event—originating in eastern Europe possibly about 60,000 years ago—led to the arrival of Neanderthals at Chagysrkaya Cave, armed with their distinctive Micoquian toolkit.

DNA studies confirm a link between Neanderthals living in Europe and at Chagyrskaya Cave after 100,000 years ago. Despite the geographic proximity of Chagyrskaya and Denisova Caves, the Chagyrskaya Neanderthal genome is more similar to those of European Neanderthals than it is to the 110,000 year-old Neanderthal from Denisova Cave.

Siberian Neanderthals were intrepid nomads
Chagyrskaya Cave in southern Siberia’s Altai Mountains
[Credit: IAET]
"By combining these new insights from archaeology and genetics, we can start to piece together the intriguing story of the easternmost Neanderthals and the events that shaped the history of our ancient human relatives," Dr. Kolobova said.

Source: University of Wollongong [January 28, 2020]

* This article was originally published here


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