четверг, 12 декабря 2019 г.

Mars Express tracks the phases of Phobos

ESA - Mars Express Mission patch.

Dec. 12, 2019

ESA’s Mars Express has captured detailed views of the small, scarred and irregularly shaped moon Phobos from different angles during a unique flyby.


Mars has two moons: Phobos and the smaller and more distant Deimos, named after the Greek mythological personifications of fear (Phobos – hence ‘phobia’) and terror (Deimos).

Mars Express has explored this duo since it began observing the Red Planet in 2004: it has viewed Phobos with the beautiful rings of Saturn in the background, skimmed past the moon at a distance of just 45 km, used its High Resolution Stereo Camera to take incredibly detailed 360-degree images of Phobos and its intriguingly marked surface, and approached Deimos to produce an array of images and pin down the moon's location and motions.

A new image sequence from Mars Express now captures Phobos’ motions and surface in detail. The movie comprises 41 images taken on 17 November 2019, when Phobos passed Mars Express at a distance of 2400 km. Mars Express is currently the only spacecraft capable of close encounters with Phobos.

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Travelling back in time through smart archaeology

The British explorer George Dennis once wrote, "Vulci is a city whose very name … was scarcely remembered, but which now, for the enormous treasures of antiquity it has yielded, is exalted above every other city of the ancient world." He's correct in assuming that most people do not know where or what Vulci is, but for explorers and historians—including Duke's Bass Connections team Smart Archaeology—Vulci is a site of enormous potential.

Travelling back in time through smart archaeology
The team at work in Vulci [Credit: Duke Research Blog]
Vulci, Italy, was an ancient Etruscan city, the remains of which are situated about an hour outside of Rome. The Etruscan civilization originated in the area roughly around Tuscany, western Umbria, northern Lazio, and in the north of Po Valley, the current Emilia-Romagna region, south-eastern Lombarty, southern Veneto, and some areas of Campania. The Etruscan culture is thought to have emerged in Italy around 900 BC and endured through the Roman-Etruscan Wars and coming to an end with the establishment of the Roman Empire.

As a dig site, Vulci is extremely valuable for the information it can give us about the Etruscan and Roman civilizations—especially since the ruins found at Vulci date back beyond the 8th century B.C.E. On November 20th, Professor Maurizio Forte, of the Art, Art History and Visual Studies departments at Duke as well as Duke's Dig@Lab, led a talk and interactive session. He summarized the Smart Archaeology teams' experience this past summer in Italy as well as allowing audience members to learn about and try the various technologies used by the team. With Duke being the first university with a permit of excavation for Vulci in the last 60 years, the Bass Connections team set out to explore the region, with their primary concerns being data collection, data interpretation, and the use of virtual technology.

Travelling back in time through smart archaeology
An example of one of the maps created by the team 
[Credit: Duke Research Blog]
The team, lead by Professor Maurizio Forte, Professor Michael Zavlanos, David Zalinsky, and Todd Barrett, sought to be as diverse as possible. With 32 participants ranging from undergraduate and graduate students to professionals, as well as Italian faculty and student members, the team flew into Italy at the beginning of the summer with a research model focused on an educational approach of practice and experimentation for everyone involved. With a naturally interdisciplinary focus ranging from classical studies to mechanical engineering, the team was divided, with people focusing on excavation in Vulci, remote sensing, haptics, virtual reality, robotics, and digital media.

So what did the team accomplish? Well, technology was a huge driving force in most of the data collected. For example, with the use of drones, photos taken from an aerial view were patched together to create bigger layout pictures of the area that would have been the city of Vulci. The computer graphics created by the drone pictures were also used to create a video and aided in the process of creating a virtual reality simulation of Vulci. VR can be an important documentation tool, especially in a field as ever-changing as archaeology. And as Professor Forte remarked, it's possible for anyone to see exactly what the researchers saw over the summer—and "if you're afraid of the darkness of a cistern, you can go through virtual reality instead."

Travelling back in time through smart archaeology
Processed image of Vulci [Credit: Katherine McCusker 
and the Smart Archaeology team]
In addition, the team used sensor technology to get around the labor and time it would take to dissect the entire site—which by the team's estimate would take 300 years! Sensors in the soil, in particular, can sense the remnants of buildings and archaeological features up to five meters below ground, allowing researchers to imagine what monuments and buildings might have looked like.

One of the biggest takeaways from the data the team collected based on discovering remnants of infrastructure and layout of the city was of the Etruscan mastery of water, developing techniques that the Romans also used. More work was also done on classification of Etruscan pottery, tools, and materials based on earlier work done by previous researchers. Discovering decorative and religious artifacts was also impactful for the team, because as Professor Forte emphasized, these objects are the "primary documentation of history."

Travelling back in time through smart archaeology
The team at work in Vulci [Credit: Duke Research Blog]
But the discoveries won't stop there. The Smart Archaeology team is launching their 2019-2020 Bass Connections project on a second phase of their research—specifically focusing on identifying new archaeological sites, analyzing the landscape's transformation and testing new methods of data capturing, simulation and visualization. With two more years of work on site, the team is hopeful that research will be able to explain in even greater depth how the people of Vulci lived, which will certainly help to shine a light on the significance of the Etruscan civilization in global history.

Author: Meghna Datta | Source: Duke Research Blog, Duke University [December 10, 2019]

* This article was originally published here

ALMA Spots Most Distant Dusty Galaxy Hidden in Plain Sight

ALMA radio image of the dusty star-forming galaxy called MAMBO-9. The galaxy consists of two parts, and it is in the process of merging. Credit: ALMA (ESO/NAOJ/NRAO), C.M. Casey et al.; NRAO/AUI/NSF, B. Saxton. Hi-Res File

Artist impression of what MAMBO-9 would look like in visible light. The galaxy is very dusty and it has yet to build most of its stars. Credit: NRAO/AUI/NSF, B. Saxton. Hi-Res File

#WAWUA - ALMA is a timemachine! from NRAO Outreach on Vimeo.
The light from MAMBO-9 travelled about 13 billion years to reach ALMA’s antennas. That means that we can see what the galaxy looked like in the past. Watch this video to learn how ALMA works as a time-machine. Credit: María Corrêa-Mendes et al. - ALMA (ESO/NAOJ/NRAO)

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have spotted the light of a massive galaxy seen only 970 million years after the Big Bang. This galaxy, called MAMBO-9, is the most distant dusty star-forming galaxy that has ever been observed without the help of a gravitational lens.

Dusty star-forming galaxies are the most intense stellar nurseries in the universe. They form stars at a rate up to a few thousand times the mass of the Sun per year (the star-forming rate of our Milky Way is just three solar masses per year) and they contain massive amounts of gas and dust. Such monster galaxies are not expected to have formed early in the history of the universe, but astronomers have already discovered several of them as seen when the cosmos was less than a billion years old. One of them is galaxy SPT0311-58, which ALMA observed in 2018.

Because of their extreme behavior, astronomers think that these dusty galaxies play an important role in the evolution of the universe. But finding them is easier said than done. “These galaxies tend to hide in plain sight,” said Caitlin Casey of the University of Texas at Austin and lead author of a study published in The Astrophysical Journal. “We know they are out there, but they are not easy to find because their starlight is hidden in clouds of dust.”

MAMBO-9’s light was already detected ten years ago by co-author Manuel Aravena, using the Max-Planck Millimeter BOlometer (MAMBO) instrument on the IRAM 30-meter telescope in Spain and the Plateau de Bure Interferometer in France. But these observations were not sensitive enough to reveal the distance of the galaxy. “We were in doubt if it was real, because we couldn’t find it with other telescopes. But if it was real, it had to be very far away,” says Aravena, who was at that time a PhD student in Germany and is currently working for the Universidad Diego Portales in Chile.

Thanks to ALMA’s sensitivity, Casey and her team have now been able to determine the distance of MAMBO-9. “We found the galaxy in a new ALMA survey specifically designed to identify dusty star-forming galaxies in the early universe,” said Casey. “And what is special about this observation, is that this is the most distant dusty galaxy we have ever seen in an unobstructed way.” The light of distant galaxies is often obstructed by other galaxies closer to us. These galaxies in front work as a gravitational lens: they bend the light from the more distant galaxy. This lensing effect makes it easier for telescopes to spot distant objects (this is how ALMA could see galaxy SPT0311-58). But it also distorts the image of the object, making it harder to make out the details.

In this study, the astronomers saw MAMBO-9 directly, without a lens, and this allowed them to measure its mass. “The total mass of gas and dust in the galaxy is enormous: ten times more than all the stars in the Milky Way. This means that it has yet to build most of its stars,” Casey explained. The galaxy consists of two parts, and it is in the process of merging.

Casey hopes to find more distant dusty galaxies in the ALMA survey, which will give insight into how common they are, how these massive galaxies formed so early in the universe, and why they are so dusty. “Dust is normally a by-product of dying stars,” she said. “We expect one hundred times more stars than dust. But MAMBO-9 has not produced that many stars yet and we want to find out how dust can form so fast after the Big Bang.”

“Observations with new and more capable technology can produce unexpected findings like MAMBO-9,” said Joe Pesce, National Science Foundation Program Officer for NRAO and ALMA. “While it is challenging to explain such a massive galaxy so early in the history of the universe, discoveries like this allow astronomers to develop an improved understanding of, and ask ever more questions about, the universe.”

The light from MAMBO-9 travelled about 13 billion years to reach ALMA’s antennas (the universe is approximately 13.8 billion years old today). That means that we can see what the galaxy looked like in the past (Watch this video to learn how ALMA works as a time-machine). Today, the galaxy would probably be even bigger, containing one hundred times more stars than the Milky Way, residing in a massive galaxy cluster.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Media contact:

Iris Nijman
News and Public Information Manager
National Radio Astronomy Observatory (NRAO)
+1 (434) 296-0314

Science contact:

Caitlin Casey
Assistant Professor of Astronomy
University of Texas at Austin
+1 (512) 471-3405


“Physical characterization of an unlensed dusty star-forming galaxy at z = 5.85,” C.M. Casey et. al., The Astrophysical Journal. DOI: 10.3847/1538-4357/ab52ff

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East refereAsia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

* This article was originally published here

Prehistoric Pottery Photoset 1, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Prehistoric Pottery Photoset 1, Tullie House Museum and Gallery, Carlisle, 8.12.19.

* This article was originally published here

Oxygen shaped the evolution of the eye

Convergent origins of new mechanisms to supply oxygen to the retina were directly linked to concurrent enhancements in the functional anatomy of the eye.

Oxygen shaped the evolution of the eye
Vascular networks in the retina of a goldfish. The retinal vasculature is divided into the separate layers. Capillaries on
the outer side of the retina (red and pink), capillaries on the inner side of the retina (purple and blue), and capillaries
 inside the retina (not found in the goldfish). For more details, see the interactive model of the goldfish vasculature
on Supplementary File 4 https://doi.org/10.7554/eLife.52153 - Supplementary File 4.
[Credit: Henrik Lauridsen, AU]
In his On the Origin of Species, Darwin used the complexity of the eye to argue his theory of natural selection and the eye has continued to fascinate and trouble evolutionary biologists ever since.

In a paper published in eLife, researchers from Aarhus University teamed up with scientists from eight international institutions to explore the physiological requirements for the evolution of improved eyesight.

They argue that the evolution of high-acuity vision in ancestral animals was constrained by the ability to deliver sufficient amounts of oxygen to cells in the retina. Their study uncovered a fascinating pattern of mechanisms to improve retinal oxygen supply capacity that evolved in concert with enhanced retinal morphology to improve vision.

The model fits across all bony vertebrates from fish through to birds and mammals. These findings add an additional component to our understanding of the evolution eye, which has fascinated and troubled evolutionary biologists for centuries.

The rises and falls of retinal oxygen supply

The study took advantage of the diversity in the physiology and anatomy among eyes from 87 animal species, including fishes, amphibians and mammals. By placing these species on the tree of life, the authors unravelled the evolutionary history of the eye from a 425 million-year-old extinct ancestor of modern vertebrates to current day animals.

Oxygen shaped the evolution of the eye
The evolution of the size of the eye (A) and retina (B). The evolution of structures to supplement retinal oxygen supply
to tightly coupled to the evolution of large eyes and a thick retina. The pectens oculi is a vascular structure found
in the eyes of birds, the choroid rete mirabile is a gas-gland found in the eyes of fishes, and intra-retinal
capillaries are found in some mammals, including humans [Credit: Christian Damsgaard, AU]
They identified three distinct physiological mechanisms for retinal oxygen supply that are always associated with improved vision. Thus, in fishes, mutations in haemoglobin were associated with the ability to deliver oxygen to the retina at exceptional high oxygen partial pressures to overcome the significant diffusion distance to the retinal cells.

The authors show that the origin of this mechanism around 280 million years ago was associated with a dramatic increase in eye size and retinal thickness that directly links to improved light sensitivity and spatial resolution. This mechanism in hemoglobin was subsequently lost several times, possibly to avoid oxidative damage and gas bubble formation in the eye.

Warm blooded dinosaurs shaped the vision of mammals

The authors show that increased reliance on vision in mammals was associated with the evolution of capillary beds inside the retina despite the potential trade-off to visual acuity imposed by the bending of light by red blood cells.

Retinal capillaries in mammals originated around 100 million years ago when dinosaurs evolved endothermy. Endothermy allowed these Mesozoic dinosaurs to hunt at night, which forced the previously nocturnal mammals into a diurnal lifestyle with an increased reliance of vision.

The new model on eye evolution shows that the evolution of intra-retinal capillaries coincided precisely with the improvements in vision around 100 million years ago. Further, it shows that some mammals lost retinal capillaries when they became less reliant on vision (e.g., echolocating bat).

Oxygen and vision go hand in hand

Overall, this analysis shows that the functional morphology of the eye has changed dynamically throughout animal evolution. It shows that eye morphology goes hand in hand with parallel changes in retinal oxygen supply, and they are likely driven by different tradeoffs to retinal oxygen supply. These tradeoffs appear acceptable in place of the improved visual acuity available when the thickness of the retina was allowed to increase.

Overall, this study shows that adaptations to ensure oxygen delivery to the retina was a physiological prerequisite for the functional evolution of the eye.

Source: Aarhus University [December 10, 2019]

* This article was originally published here

Roman Message Fragment to Britannia, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Roman Message Fragment to Britannia, Tullie House Museum and Gallery, Carlisle, 8.12.19.

* This article was originally published here

Wide Range of Space Research Keeping Crew Busy Today

ISS - Expedition 61 Mission patch.

December 11, 2019

The International Space Station is a hive of science activity today as the Expedition 61 crew and mission controllers initiate a variety of space research.

Inside the orbiting lab, mice are being scanned to study how their bones change in microgravity. Astronauts Jessica Meir and Christina Koch placed the rodents in a new bone densitometer and imaged their bones. The new Rodent Research-19 study is investigating two proteins that may prevent muscle and bone loss in space.

Image above: NASA astronauts Andrew Morgan and Jessica Meir conduct research operations inside the Japanese Kibo lab module’s Life Sciences Glovebox. Image Credit: NASA.

NASA Flight Engineer Andrew Morgan and ESA Commander Luca Parmitano were in the Columbus lab module exploring how they grip and manipulate objects in space. Insights may help future astronauts adjust to long-term missions farther into space and possibly planetary exploration.

Mission controllers on the ground today commanded the Canadarm2 robotic arm to reach into the back of the SpaceX Dragon resupply ship and extract the new HISUI experiment device. HISUI, or Hyperspectral Imagery Suite, is a unique Earth imaging system that can benefit agriculture, forestry and other environmental areas. HISUI will be installed on the outside of the Kibo lab module to scan the Earth’s surface using high spectral resolution.

International Space Station (ISS). Animation Credit: NASA

In the Russian segment of the station, the cosmonauts focused on docking port inspections and life science. Oleg Skripochka photographed internal and external docking gear and continued unpacking cargo from the Progress 74 resupply ship. Alexander Skvortsov finalized a 24-hour monitoring of his heart activity then contributed to a study observing how space crews interact with mission controllers.

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Bone densitometer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?

Rodent Research-19: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8075

Columbus lab module: https://www.nasa.gov/mission_pages/station/structure/elements/europe-columbus-laboratory

Grip and manipulate objects: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1188

Canadarm2: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

SpaceX Dragon resupply ship: https://go.nasa.gov/2Po0qjn

HISUI: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7476

Kibo lab module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Progress 74 resupply ship: https://orbiterchspacenews.blogspot.com/2019/12/russian-space-freighter-docks.html

Heart activity: https://www.energia.ru/en/iss/researches/human/12.html

How space crews interact with mission controllers: https://www.energia.ru/en/iss/researches/human/20.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

* This article was originally published here

Breathing new life into the rise of oxygen debate

New research strongly suggests that the distinct 'oxygenation events' that created Earth's breathable atmosphere happened spontaneously, rather than being a consequence of biological or tectonic revolutions.

Breathing new life into the rise of oxygen debate
Credit: University of Leeds
The University of Leeds study, published in the journal Science, not only shines a light on the history of oxygen on our planet, it gives new insight into the prevalence of oxygenated worlds other than our own.

The early Earth had no oxygen in its atmosphere or oceans until roughly 2.4 billion years ago when the first of three major oxygenation events occurred. The reasons for these 'stepwise' increases of oxygen on Earth have been the subject of ongoing scientific debate.

In a new study, Leeds researchers modified a well-established conceptual model of marine biogeochemistry so that it could be run over the whole of Earth history, and found that it produced the three oxygenation events all by itself.

Their findings suggest that beyond early photosynthetic microbes and the initiation of plate tectonics - both of which were established by around three billion years ago - it was simply a matter of time before oxygen would reach the necessary level to support complex life. This new theory drastically increases the possibility of high-oxygen worlds existing elsewhere.

Study lead author Lewis Alcott, a postgraduate researcher in the School of Earth and Environment at Leeds, said: "This research really tests our understanding of how the Earth became oxygen rich, and thus became able to support intelligent life.

"Based on this work, it seems that oxygenated planets may be much more common than previously thought, because they do not require multiple - and very unlikely - biological advances, or chance happenings of tectonics."

The first "Great Oxidation Event" occurred during the Paleoproterozoic era - roughly 2.4 billion years ago. The subsequent wholesale oxygenation events occurred in the Neoproterozoic era around 800 million years ago and finally in the Paleozoic Era roughly 450 million years ago, when atmospheric oxygen rose to present day levels.

Breathing new life into the rise of oxygen debate
Transitions are driven by the marine phosphorus cycle's response to changing oxygen levels
[Credit: G. Mannaerts]
Large animals with high energy demands require high levels of oxygen, and evolved soon after the last of these steps, ultimately evolving into dinosaurs and mammals.

Currently, the two prevailing theories suggest the drivers of these oxygenation events were either major steps in biological revolutions - where the evolution of progressively more complex lifeforms essentially "bioengineered" oxygenation to higher levels - or tectonic revolutions - where oxygen rose due to shifts in the style of volcanism or make-up of the crust.

The new study instead highlights a set of feedbacks that exist between the global phosphorus, carbon and oxygen cycles, which are capable of driving rapid shifts in ocean and atmospheric oxygen levels without requiring any 'stepwise' change in either tectonics or biology.

Study co-author Professor Simon Poulton, also from the School of Earth and Environment at Leeds said: "Our model suggests that oxygenation of the Earth to a level that can sustain complex life was inevitable, once the microbes that produce oxygen had evolved."

Their 'Earth system' model of the feedbacks reproduces the observed three-step oxygenation pattern when driven solely by a gradual shift from reducing to oxidizing surface conditions over time. The transitions are driven by the way the marine phosphorus cycle responds to changing oxygen levels, and how this impacts photosynthesis, which requires phosphorus.

Senior author Dr Benjamin Mills, who leads the biogeochemical modelling group at Leeds, said: "The model demonstrates that a gradual oxygenation of Earth's surface over time should result in distinct oxygenation events in the atmosphere and oceans, comparable to those seen in the geological record.

"Our work shows that the relationship between the global phosphorus, carbon and oxygen cycles is fundamental to understanding the oxygenation history of the Earth. This could help us to better understand how a planet other than our own may become habitable."

Source: University of Leeds [December 10, 2019]

* This article was originally published here

2019 December 12 Decorating the Sky Image Credit &...

2019 December 12

Decorating the Sky
Image Credit & Copyright: Leonardo Julio (Astronomia Pampeana)

Explanation: Bright stars, clouds of dust and glowing nebulae decorate this cosmic scene, a skyscape just north of Orion’s belt. Close to the plane of our Milky Way galaxy, the wide field view spans about 5.5 degrees. Striking bluish M78, a reflection nebula, is on the right. M78’s tint is due to dust preferentially reflecting the blue light of hot, young stars. In colorful contrast, the red sash of glowing hydrogen gas sweeping through the center is part of the region’s faint but extensive emission nebula known as Barnard’s Loop. At lower left, a dark dust cloud forms a prominent silhouette cataloged as LDN 1622. While M78 and the complex Barnard’s Loop are some 1,500 light-years away, LDN 1622 is likely to be much closer, only about 500 light-years distant from our fair planet Earth.

∞ Source: apod.nasa.gov/apod/ap191212.html

* This article was originally published here

Roman Blank Gravestone for Engraving, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Roman Blank Gravestone for Engraving, Tullie House Museum and Gallery, Carlisle, 8.12.19.

* This article was originally published here

Isotope analysis from 1,400-year-old Maya mass grave of Uxul points to prisoners of war

Several years ago, Maya archaeologists from the University of Bonn found the bones of about 20 people at the bottom of a water reservoir in the former Maya city of Uxul, in what is now Mexico. They had apparently been killed and dismembered about 1,400 years ago. Did these victims come from Uxul or other regions of the Maya Area? Dr. Nicolaus Seefeld, who heads the project that is funded by the Gerda Henkel Foundation at the University of Bonn, is now one step further: A strontium isotope analysis by the National Autonomous University of Mexico (UNAM) showed that some of the dead grew up at least 95 miles (150 kilometers) from Uxul.

Isotope analysis from 1,400-year-old Maya mass grave of Uxul points to prisoners of war
After the bodies had been dismembered, the body parts were placed at the bottom of an artificial
water reservoir and covered with large stone blocks [Credit: Nicolaus Seefeld]
Strontium is ingested with food and stored like calcium in bones and teeth. The isotope ratios of strontium vary in rocks and soils, which is why different regions on earth have their own characteristic signatures. "As the development of tooth enamel is completed in early childhood, the strontium isotope ratio indicates the region where a person grew up," says Dr. Nicolaus Seefeld, who heads a project at the University of Bonn on the mass grave of Uxul and the role of ritualized violence in Maya society.

Together with researchers from the Isotope Geochemistry Laboratory of the Geophysics Institute at the National Autonomous University of Mexico (UNAM), Seefeld took tiny samples of tooth enamel from a total of 13 individuals early this summer. "Unfortunately it was not possible to examine the strontium isotope ratio of the remaining individuals, because the teeth were too decayed and the result would have been distorted," reports Seefeld.

The victims apparently had a high social status

The results of the isotope analysis show that most of the victims grew up at least 95 miles (150 kilometers) from Uxul in the southern lowlands, in what is now Guatemala. "However, at least one adult and also one infant were local residents from Uxul," says the researcher. They were apparently mostly people of high social status, as eight of the individuals had elaborate jade tooth jewelry or engravings in their incisors.

Isotope analysis from 1,400-year-old Maya mass grave of Uxul points to prisoners of war
Overview of body parts during the excavations of the Mass Grave o Uxul
[Credit: N. Seefeld]
In 2013, Seefeld was investigating the water supply system of the former Maya city of Uxul when he discovered a well, in which the remains of about 20 people had been buried during the seventh century AD. The excavations of this mass grave were carried out as part of the Uxul archaeological project by the Department for the Anthropology of the Americas at the University of Bonn, which was headed by Prof. Dr. Nikolai Grube during the research period from 2009 to 2015. The investigations of the mass grave have been under the leadership of Dr. Seefeld and funded by the Gerda Henkel Foundation since January 2018.

Detailed investigations revealed that, in addition to at least 14 men and one woman, the mass grave contained the remains of several adolescents and an 18-month-old infant. Nearly all the bones showed marks of cuts and injuries by stone blades. Their regular distribution clearly shows that the individuals had been systematically and deliberately dismembered. The victims were killed and decapitated outside the water reservoir, then dismembered and the body parts placed at the bottom of the reservoir.

Isotope analysis from 1,400-year-old Maya mass grave of Uxul points to prisoners of war
Cut marks show that skin, muscles and tendons were removed from the limbs
[Credit: Nicolaus Seefeld]
Heat marks on the bones showed that the bodies were exposed to fire - presumably so that skin and muscles could be removed more easily. However, there were no human bite marks on the bones that would indicate cannibalism. After dismemberment, body parts that were originally connected were deliberately placed as far apart from each other as possible. "This clearly demonstrates the desire to destroy the physical unity of the individuals," says Seefeld.

Killing and dismemberment as a demonstration of power

The latest results of the strontium isotope analysis and the anthropological investigations now allow more precise conclusions about the identity of the victims and the possible reasons for the killings. It is known from pictorial representations of ritual violence of the Classic Maya that the beheading and dismemberment of humans mostly occurred in the context of armed conflicts.

Isotope analysis from 1,400-year-old Maya mass grave of Uxul points to prisoners of war
Close-up view of cutting marks on the rib of an individual buried
in the Mass Grave of Uxul [Credit: N. Seefeld]
These representations often show victorious rulers who chose to take the elites of the defeated city as prisoners of war and later publicly humiliate and kill them. "The documented actions in Uxul should therefore not be regarded as a mere expression of cruelty or brutality, but as a demonstration of power," says Seefeld.

The most plausible explanation for the current evidence is that the majority of the victims were prisoners of war from a city in the southern Maya lowlands, who were defeated in a military confrontation with Uxul. These formerly powerful individuals were then brought to Uxul and killed. Seefeld recently presented his findings at the Archaeological Conference of Central Germany in Halle and at the conference "Investigadores de la Cultura Maya" in Campeche in Mexico.

Source: University of Bonn [December 11, 2019]

* This article was originally published here

Native British Non-Roman Deity Carvings, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Native British Non-Roman Deity Carvings, Tullie House Museum and Gallery, Carlisle, 8.12.19.

* This article was originally published here

Roscosmos - Soyuz-2.1b launches new GLONASS-M navigation satellite

Glonass Navigation Satellites patch.

Dec. 11, 2019

Soyuz-2.1b launches new GLONASS-M navigation satellite. Image Credit: ROSCOSMOS

A Soyuz-2.1b rocket launched a new GLONASS-M satellite from the Plesetsk Cosmodrome, Russia, on 11 December 2019, at 08:54 UTC (11:54 local time).

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A new early whale, Aegicetus gehennae, and the evolution of modern whale locomotion

A newly discovered fossil whale represents a new species and an important step in the evolution of whale locomotion, according to a study published in the open-access journal PLOS ONE by Philip Gingerich of the University of Michigan and colleagues.

A new early whale, Aegicetus gehennae, and the evolution of modern whale locomotion
Cervical and thoracic vertebrae of Aegicetus. Compared with earlier whales, Aegicetus has a more elongated body
and tail and smaller back legs, and it lacks a firm connection between the hind legs and the spinal column.
These adaptations indicate an animal that was more fully aquatic and less of a foot-powered swimmer
than its ancestors [Credit: Gingerich et al., 2019]

The fossil record of whale evolution tracks the transition from land-dwelling ancestors to ocean-dwelling cetaceans. Protocetids are a group of early whales known from the Eocene Epoch of Africa, Asia, and the Americas. While modern whales are fully aquatic and use their tails to propel themselves through the water, most protocetids are thought to have been semi-aquatic and swam mainly with their limbs. In this study, Gingerich and colleagues describe a new genus and species of protocetid, Aegicetus gehennae.

The new whale was discovered in 2007 in the Wadi Al Hitan World Heritage Site in the Western Desert of Egypt. It is the youngest-known protocetid, dating to around 35 million years ago, and is known from one exceptionally complete skeleton and a partial second specimen, making it among the best-preserved ancient whales. Compared with earlier whales, it has a more elongated body and tail, smaller back legs, and lacks a firm connection between the hind legs and the spinal column. These adaptations indicate an animal that was more fully aquatic and less of a foot-powered swimmer than its ancestors.

The body shape of Aegicetus is similar to that of other ancient whales of its time, such as the famous Basilosaurus. These animals appear to be well-adapted for swimming through undulation of the mid-body and the tail, somewhat as crocodiles swim today. The authors suggest that an undulatory swimming style might represent a transitional stage between the foot-powered swimming of early whales and the tail-powered swimming of modern whales.

The authors add: "Early protocetid whales living 47 to 41 million years ago were foot-powered swimmers, and later basilosaurid and modern whales -- starting about 37 million years ago -- were tail-powered swimmers. The late protocetid Aegicetus was intermediate in time and form, and transitional functionally in having the larger and more powerful vertebral column of a tail-powered swimmer."

Source: Public Library of Science [December 11, 2019]

* This article was originally published here

Blue Origin - New Shepard Mission NS-12

Blue Origin logo.

Dec. 11, 2019

New Shepard Mission NS-12 lift off

The New Shepard reusable launch system was launched and landed at Blue Origin’s West Texas Launch Site, on 11 December 2019, at 17:53 UTC (11:53 CST). This was the 6th mission, launch and landing, for this New Shepard launch vehicle. Audio commentary by Ariane Cornell, Director of Astronaut & Orbital Sales, Blue Origin.

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Birdoswald Roman Fort, Hadrian’s Wall, Brampton, 8.12.19.

Birdoswald Roman Fort, Hadrian’s Wall, Brampton, 8.12.19.

* This article was originally published here

Deciphering the equations of life

Research led by the University of Arizona has resulted in a set of equations that describes and predicts commonalities across life despite its enormous diversity.

Deciphering the equations of life
Elephants are an example of organisms that have few, but large, offspring. Elephants also put more energy into
rearing their offspring than many animals, such as fish, which lay their eggs and leave them behind
[Credit: University of Arizona]
"Our study develops a general theory to study the extraordinary diversity of life using simple rules common to all species. We can further apply these rules to predict specific traits of species that we might know a lot less about," said Joseph 'Robbie' Burger, an ecology and evolutionary biology postdoctoral fellow in the Institute of the Environment and the Bridging Biodiversity and Conservation Science program at the University of Arizona. These specific traits, include the timing of an organism's reproduction and death, called an organism's life history.

Burger is lead author on a paper, published in the journal Proceedings of the National Academy of Sciences, which also included collaborators from Missouri University Science and Technology and the University of New Mexico.

"When thinking about the enormous varieties of lifeforms, it would seem that life is very complicated and wouldn't be that predictable," he said. But whether you're as large as a whale or as tiny as plankton, or whether you're a giant clam that lays millions of eggs at once or an elephant that births a few 250-pound calves in a lifetime, all species have evolved to reproduce, grow, survive and replace within universal biophysical constraints.

"If you impose these constraints on the mathematical model, then certain unifying patterns fall out," Burger said.

One of the constraints is demography. Regardless of the number of offspring produced in a lifetime, on average, only two survive to replace the parents. Another constraint is mass-energy balance. Living things allocate energy to bodily maintenance, growth and reproduction, all of which must balance in a lifecycle.

Imposing these constraints explains two fundamental tradeoffs in how organisms reproduce: the tradeoff between number and size of offspring, and between parental investment in offspring and offspring growth.

"What's so cool about these equations is that to solve it, all you have to know are two values - the size of the offspring at independence and the adult size," Burger said. "If you plug that into the equation, you get the number of offspring an organism will produce in a lifetime and myriad other life history characteristics."

To arrive at this new understanding of how organisms allocate energy to growth, reproduction and survival, Burger and his colleagues compiled published data on the life histories of a diverse array of wild animals in stable populations.

Their new theory refines old understandings about life history tradeoffs. Past assumptions were that offspring size and number increased or decreased at the same rate. For example, elephants have relatively large calves, so they have few in a lifetime, while tuna produce millions of tiny eggs. It turns out that the relationship is not so straightforward, a realization that inspired Burger's work.

"We now need to put these equations to practice by developing user-friendly programming tools, collaborating with field scientists refine ecosystem models and informing management decisions," he said.

Source: University of Arizona [December 11, 2019]

* This article was originally published here

Revealing the Physics of the Sun with Parker Solar Probe

NASA - Parker Solar Probe patch.

Dec. 11, 2019

Nearly a year and a half into its mission, Parker Solar Probe has returned gigabytes of data on the Sun and its atmosphere. Following the release of the very first science from the mission, five researchers presented additional new findings from Parker Solar Probe at the fall meeting of the American Geophysical Union on Dec. 11, 2019. Research from these teams hints at the processes behind both the Sun's continual outflow of material — the solar wind — and more infrequent solar storms that can disrupt technology and endanger astronauts, along with new insight into space dust that creates the Geminids meteor shower.

The young solar wind

The solar wind carries the Sun's magnetic field with it, shaping space weather throughout the solar system as it flows out from the Sun at around a million miles per hour. Some of Parker Solar Probe's primary science goals are to pinpoint the mechanisms that send the solar wind streaming out into space at such high speeds.

Animation above: Animation of data from the WISPR instrument on Parker Solar Probe. The Sun is at the left of the animation, and Jupiter is highlighted in red. Image Credits: Naval Research Laboratory/Johns Hopkins Applied Physics Lab.

One clue lies in disturbances in the solar wind that could point to the processes that heat and accelerate the wind. These structures — pockets of relatively dense material — have been glimpsed in data from earlier missions spanning decades. They are several times the size of Earth's entire magnetic field, which stretches tens of thousands of miles into space — meaning these structures can compress Earth's magnetic field on a global scale when they crash into it.

"When structures in the solar wind reach Earth, they can drive dynamics in Earth's magnetosphere, including particle precipitation from Earth's radiation belts," said Nicholeen Viall, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who presented new findings on solar wind structures from Parker Solar Probe at the AGU meeting. Particle precipitation can cause a range of effects, like setting off the aurora and interfering with satellites.

Near the Sun, Parker Solar Probe made better-than-ever measurements of these solar wind structures, using both imagers to take pictures from afar and in situ instruments to measure the structures as they pass over the spacecraft. To get a more complete picture of these solar wind structures, Viall went one step further, combining observations from Parker, satellites near Earth, and NASA's STEREO-A spacecraft to examine these structures from multiple angles.​

Animation above: NASA's STEREO-A spacecraft, with its unique vantage point away from Earth, observed the Sun's outer atmosphere as Parker Solar Probe flew through it in November 2018, giving scientists another perspective on structures in this region. Image Credits: NASA/STEREO/Angelos Vourlidas.

STEREO-A carries an instrument called a coronagraph, which uses a solid disk to block out the bright light of the Sun, letting the camera capture images of the relatively faint outer atmosphere, the corona. From its vantage point about 90 degrees away from Earth, STEREO-A could see the regions of the corona that Parker was flying through — allowing Viall to combine the measurements in a novel way and get a better view of solar wind structures as they flowed out from the Sun. Alongside Parker Solar Probe's images, scientists now have a better view of magnetic disturbances in the solar wind.​

Parker's instruments are also shedding new light on the invisible processes in the solar wind, revealing a surprisingly active system near the Sun.

"We think of the solar wind — as we see it near Earth — as very smooth, but Parker saw surprisingly slow wind, full of little bursts and jets of plasma," said Tim Horbury, a lead researcher on Parker Solar Probe's FIELDS instruments based at Imperial College London.

Animation above: Parker Solar Probe measured sudden reversals in the Sun's magnetic field. These events, called "switchbacks," may provide clues to the processes that heat the Sun's outer atmosphere to millions of degrees. Image Credits: NASA/GSFC/CIL/Adriana Manrique Gutierrez.

Horbury used data from Parker Solar Probe's FIELDS instruments — which measure the scale and shape of electric and magnetic fields near the spacecraft — to examine in detail one particularly odd event: magnetic "switchbacks," sudden clusters of events when the solar magnetic field bends back on itself, first described with Parker Solar Probe's initial results on Dec. 4, 2019.​

The exact origin of the switchbacks isn't certain, but they may be signatures of the process that heats the Sun's outer atmosphere, the corona, to millions of degrees, hundreds of times hotter than the visible surface below. The cause of this counterintuitive jump in temperature is a longstanding question in solar science — referred to as the coronal heating mystery — and is closely related to questions about how the solar wind is energized and accelerated.

"We think the switchbacks are probably related to individual energetic energy releases on the Sun — what we call jets," said Horbury. "If these are jets, there must a very large population of small events happening on the Sun, so they would contribute a large fraction of the total energy of the solar wind."

A look inside solar storms

Along with the solar wind, the Sun also releases discrete clouds of material called coronal mass ejections, or CMEs. Denser and sometimes faster than the solar wind, CMEs can also trigger space weather effects on Earth, or cause problems for satellites in their path.

CMEs are notoriously hard to predict. Some of them are simply not visible from Earth or from STEREO-A — the two positions where we have instruments capable of seeing CMEs from afar —  because they erupt from parts of the Sun out of view of both spacecraft. Even when they are spotted by instruments, it's not always possible to predict which CMEs will disturb Earth's magnetic field and trigger space weather effects, as the magnetic structure within the cloud of material plays a crucial role.

Our best shot at understanding the magnetic properties of any given CME relies on pinpointing the region on the Sun from which the CME exploded — meaning that one type eruption called a stealth CME poses a unique challenge for space weather forecasters.

Stealth CMEs are visible in coronagraphs — instruments that look only at the Sun's outer atmosphere — but don't leave clear signatures of their eruption in images of the Sun's disk, making it difficult to ascertain from where, exactly, they lifted off.

But during Parker Solar Probe's first solar flyby in November 2018, the spacecraft was hit by one of these stealth CMEs.

"Flying close to the Sun, Parker Solar Probe has a unique chance to see young CMEs that haven't been processed from traveling tens of millions of miles," said Kelly Korreck, head of science operations for Parker's SWEAP instruments, based at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. "This was the first time we were able to stick our instruments inside one of these coronal mass ejections that close to the Sun."

In particular, Korreck used data from Parker's FIELDS and SWEAP instruments to get a snapshot of the internal structure of the CME. SWEAP, the mission's solar wind instruments, measures characteristics like velocity, temperature, and electron and proton densities of the solar wind. These measurements not only provide one of the first looks inside a CME so close to the Sun, but they may help scientists learn to trace stealth CMEs back to their sources.

Another type of solar storm consists of extremely energetic particles moving near the speed of light. Though often related to CME outbursts, these particles are subject to their own acceleration processes — and they move much faster than CMEs, reaching Earth and spacecraft in a matter of minutes. These particles can damage satellite electronics and endanger astronauts, but their speed makes them more difficult to avoid than many other types of space weather. 

Animation above: Parker Solar Probe observed how coronal mass ejections — which are outlined in black in this computer simulation — can act as "snowplows" for previously-released solar particles, contributing to energetic particle events. Animation Credits: Nathan Schwadron, et al.

These bursts of particles often, but not always, accompany other solar events like flares and CMEs, but predicting just when they'll make an appearance is difficult. Before particles reach the near-light speeds that makes them hazardous to spacecraft, electronics and astronauts, they go through a multi-stage energization process — but the first step in this process, near the Sun, hadn't been directly observed.

As Parker Solar Probe traveled away from the Sun in April 2019, after its second solar encounter, the spacecraft observed the largest-yet energetic particle event seen by the mission. Measurements by the energetic particle instrument suite, ISʘIS, have filled in one missing link in the processes of particle energization.

"The regions in front of coronal mass ejections build up material, like snowplows in space, and it turns out these 'snowplows' also build up material from previously released solar flares," said Nathan Schwadron, a space scientist at the University of New Hampshire in Durham. 

Understanding how solar flares create populations of seed particles that feed energetic particle events will help scientists better predict when such events might happen, along with improving models of how they move through space. 

Asteroid fingerprints

Parker Solar Probe's WISPR instruments are designed to capture detailed images of the faint corona and solar wind, but they also picked up another difficult-to-see structure: a 60,000-mile-wide dust trail following the orbit of the asteroid Phaethon, which created the Geminids meteor shower. In 2019, the Geminids meteor shower peaks on the night of Dec. 13-14.

This trail of dust grains peppers Earth's atmosphere when our planet intersects with Phaethon's orbit each December, burning up and producing the spectacular show we call the Geminids. Though scientists have long known that Phaethon is the parent of the Geminids, seeing the actual dust trail hasn't been possible until now. Extremely faint and very close to the Sun in the sky, it has never been picked up by any previous telescope, despite several attempts — but WISPR is designed to see faint structures near the Sun. WISPR's first-ever direct view of the dust trail has given new information about its characteristics.​

Image above: Parker Solar Probe's WISPR instruments captured the first-ever view of a dust trail in the orbit of asteroid Phaethon. This dust trail creates the Geminids meteor shower, visible each December. Image Credits: Brendan Gallagher/Karl Battams/NRL.

"We calculate a mass on the order of a billion tons for the entire trail, which is not as much as we’d expect for the Geminids, but much more than Phaethon produces near the Sun," said Karl Battams, a space scientist at the U.S. Naval Research Lab in Washington, D.C. "This implies that WISPR is only seeing a portion of the Geminid stream – not the entire thing – but it’s a portion that no one had ever seen or even knew was there, so that’s very exciting!”

With three orbits under its belt, Parker Solar Probe will continue its exploration of the Sun over the course of 21 progressively-closer solar flybys. The next orbit change will occur during the Venus flyby on Dec. 26, bringing Parker to about 11.6 million miles from the Sun's surface for its next close approach to the Sun on Jan. 29, 2020. With direct measurements of this never-before-measured environment — closer to the Sun than ever before — we can expect to learn even more about these phenomena and uncover entirely new questions.

Parker Solar Probe is part of NASA’s Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. Johns Hopkins APL designed, built and operates the spacecraft.

Related article (First results):

NASA's Parker Solar Probe Sheds New Light on the Sun

Related links:

Parker Solar Probe: https://www.nasa.gov/solarprobe

Geminids meteor shower: https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/geminids/in-depth/

NASA's STEREO-A spacecraft: https://www.nasa.gov/mission_pages/stereo/main/index.html

American Geophysical Union: http://nasa.gov/agu

Images (mentioned), Animations (mentioned), Text, Credits: NASA/Lina Tran/Goddard Space Flight Center, by Sarah Frazier.

Greetings, Orbiter.ch

* This article was originally published here


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