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.

#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).