среда, 11 декабря 2019 г.

How to Shape a Spiral Galaxy

Magnetic fields in NGC 1086, or M77, are shown as streamlines over a visible light and X-ray composite image of the galaxy from the Hubble Space Telescope, the Nuclear Spectroscopic Array, and the Sloan Digital Sky Survey. The magnetic fields align along the entire length of the massive spiral arms — 24,000 light years across (0.8 kiloparsecs) — implying that the gravitational forces that created the galaxy’s shape are also compressing the its magnetic field. This supports the leading theory of how the spiral arms are forced into their iconic shape known as “density wave theory.” SOFIA studied the galaxy using far-infrared light (89 microns) to reveal facets of its magnetic fields that previous observations using visible and radio telescopes could not detect. Credits: NASA/SOFIA; NASA/JPL-Caltech/Roma Tre Univ. Hi-res image

Our Milky Way galaxy has an elegant spiral shape with long arms filled with stars, but exactly how it took this form has long puzzled scientists. New observations of another galaxy are shedding light on how spiral-shaped galaxies like our own get their iconic shape.

Magnetic fields play a strong role in shaping these galaxies, according to research from the Stratospheric Observatory for Infrared Astronomy, or SOFIA. Scientists measured magnetic fields along the spiral arms of the galaxy called NGC 1068, or M77. The fields are shown as streamlines that closely follow the circling arms.

“Magnetic fields are invisible, but they may influence the evolution of a galaxy,” said Enrique Lopez-Rodriguez, a Universities Space Research Association scientist at the SOFIA Science Center at NASA’s Ames Research Center in California’s Silicon Valley. “We have a pretty good understanding of how gravity affects galactic structures, but we’re just starting to learn the role magnetic fields play.”

The M77 galaxy is located 47 million light years away in the constellation Cetus. It has a supermassive active black hole at its center that is twice as massive as the black hole at the heart of our Milky Way galaxy. The swirling arms are filled with dust, gas and areas of intense star formation called starbursts.

SOFIA’s infrared observations reveal what human eyes cannot: magnetic fields that closely follow the newborn-star-filled spiral arms. This supports the leading theory of how these arms are forced into their iconic shape known as “density wave theory.” It states that dust, gas and stars in the arms are not fixed in place like blades on a fan. Instead, the material moves along the arms as gravity compresses it, like items on a conveyor belt.

The magnetic field alignment stretches across the entire length of the massive, arms — approximately 24,000 light years across. This implies that the gravitational forces that created the galaxy’s spiral shape are also compressing its magnetic field, supporting the density wave theory. The results are published in the Astrophysical Journal

“This is the first time we’ve seen magnetic fields aligned at such large scales with current star birth in the spiral arms,” said Lopez-Rodriquez. “It’s always exciting to have observational evidence that supports theories.”

Celestial magnetic fields are notoriously difficult to observe. SOFIA’s newest instrument, the High-resolution Airborne Wideband Camera-Plus, or HAWC+, uses far-infrared light to observe celestial dust grains, which align perpendicular to magnetic field lines. From these results, astronomers can infer the shape and direction of the otherwise invisible magnetic field. Far-infrared light provides key information about magnetic fields because the signal is not contaminated by emission from other mechanisms, such as scattered visible light and radiation from high-energy particles. SOFIA’s ability to study the galaxy with far infrared light, specifically at the wavelength of 89 microns, revealed previously unknown facets of its magnetic fields.

Further observations are necessary to understand how magnetic fields influence the formation and evolution of other types of galaxies, such as those with irregular shapes.

SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a Boeing 747SP jetliner modified to carry a 106-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is maintained and operated from NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. The HAWC+ instrument was developed and delivered to NASA by a multi-institution team led by the Jet Propulsion Laboratory in Pasadena, California.


Media Contact


Felicia Chou
NASA Headquarters, Washington
202-358-0257

felicia.chou@nasa.gov

Editor: Kassandra Bell

Source: NASA/SOFIA




* This article was originally published here

Outlook for the polar regions in a 2-degrees-warmer world


With 2019 on pace as one of the warmest years on record, a major new study from the University of California, Davis, reveals how rapidly the Arctic is warming and examines global consequences of continued polar warming.

Outlook for the polar regions in a 2-degrees-warmer world
Greenland, July 2008. The Arctic has already reached the 2 degrees Celsius warming milestone
during some months of the year [Credit: Eric Post, UC Davis]
The study, published in the journal Science Advances reports that the Arctic has warmed by 0.75 degrees C in the last decade alone. By comparison, the Earth as a whole has warmed by nearly the same amount, 0.8 degrees C, over the past 137 years.


"Many of the changes over the past decade are so dramatic they make you wonder what the next decade of warming will bring," said lead author Eric Post, a UC Davis professor of climate change ecology. ""If we haven't already entered a new Arctic, we are certainly on the threshold."

What 2 degrees means for the poles

The comprehensive report represents the efforts of an international team of 15 authors specializing in an array of disciplines, including the life, Earth, social, and political sciences. They documented widespread effects of warming in the Arctic and Antarctic on wildlife, traditional human livelihoods, tundra vegetation, methane release, and loss of sea- and land ice. They also examined consequences for the polar regions as the Earth inches toward 2 degrees C warming, a commonly discussed milestone.

Outlook for the polar regions in a 2-degrees-warmer world
An arctic fox in Siberia [Credit: Jeff Kerby]
"Under a business-as-usual scenario, the Earth as a whole may reach that milestone in about 40 years," said Post. "But the Arctic is already there during some months of the year, and it could reach 2 degrees C warming on an annual mean basis as soon as 25 years before the rest of the planet."


The study illustrates what 2 degrees C of global warming could mean for the high latitudes: up to 7 degrees C warming for the Arctic and 3 C warming for the Antarctic during some months of the year.

The authors say that active, near-term measures to reduce carbon emissions are crucial to slowing high latitude warming, especially in the Arctic.

Beyond the polar regions

Post emphasizes that major consequences of projected warming in the absence of carbon mitigation are expected to reach beyond the polar regions. Among these are sea level rise resulting from rapid melting of land ice in the Arctic and Antarctic, as well as increased risk of extreme weather, deadly heat waves, and wildfire in parts of the Northern Hemisphere.

"What happens in the Arctic doesn't stay in the Arctic," said co-author Michael Mann, a distinguished professor of atmospheric sciences at Penn State. "The dramatic warming and melting of Arctic ice is impacting the jet stream in a way that gives us more persistent and damaging weather extremes."

Author: Kat Kerlin | Source: UC Davis [December 04, 2019]



* This article was originally published here

Meteorite-loving microorganism


Chemolithotrophic microorganisms derive their energy from inorganic sources. Research into the physiological processes of these organisms - which are grown on meteorite - provides new insights into the potential of extraterrestrial materials as a source of accessible nutrients and energy for microorganisms of the early Earth. Meteorites may have delivered a variety of essential compounds facilitating the evolution of life, as we know it on Earth.

Meteorite-loving microorganism
Meteorite dust fragments colonized and bioprocessed by M. sedula
[Credit: Tetyana Milojevic]
An international team around astrobiologist Tetyana Milojevic from the University of Vienna explored the physiology and metal-microbial interface of the extreme metallophilic archaeon Metallosphaera sedula, living on and interacting with extraterrestrial material, meteorite Northwest Africa 1172 (NWA 1172).


Assessing the biogenicity based on extraterrestrial materials provides a valuable source of information for exploring the putative extraterrestrial bioinorganic chemistry that might have occurred in the Solar System.

Archaeon prefers meteorites

Cells of M. sedula rapidly colonize the meteoritic material, much faster than the minerals of terrestrial origin. "Meteorite-fitness seems to be more beneficial for this ancient microorganism than a diet on terrestrial mineral sources. NWA 1172 is a multimetallic material, which may provide much more trace metals to facilitate metabolic activity and microbial growth. Moreover, the porosity of NWA 1172 might also reflect the superior growth rate of M. sedula", says Tetyana Milojevic.


Investigations on nanometer scale

The scientists traced the trafficking of meteorite inorganic constituents into a microbial cell and investigated iron redox behavior. They analyzed the meteorite-microbial interface at nanometer scale spatial resolution.

Meteorite-loving microorganism
The trafficking of meteorite inorganic constituents into a microbial cell investigated
by elemental ultrastructural analysis of M. sedula grown on NWA 1172
[Credit: Tetyana Milojevic]
Combining several analytical spectroscopy techniques with transmission electron microscopy, the researchers revealed a set of biogeochemical fingerprints left upon M. sedula growth on the NWA 1172 meteorite.

"Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry", concludes Milojevic.

The findings are published in Scientific Reports.

Source: University of Vienna [December 03, 2019]



* This article was originally published here

What's driving erosion worldwide?


Soil erosion is a global problem that threatens food security and the functioning of ecosystems. It has an adverse effect on water and air and, of course, on the soil itself. It also produces a number of harmful knock-on effects; farmers, for example, have to compensate for the loss of natural soil productivity by increasing their use of fertiliser. As things stand, soil is being lost at a significantly greater rate than it is being created. Given that the agriculture and forestry industries simply cannot function without soil, many governments are trying to combat the erosion in their countries.

What's driving erosion worldwide?
The border between Haiti and the Dominican Republic is easily recognizable by the vegetation cover
[Credit: UNEP—United Nations Environmental Programme]
Soil erosion has a whole host of causes, many of which are still not well understood. We still don't know, for example, whether and indeed how different countries influence the erosion of their soils. Research so far has focussed on identifying reciprocal relationships known as correlations, such as the fact that erosion is more severe in poor countries than in rich ones. Identifying causal effects, on the other hand, has been and remains very difficult.

Remote sensing and modelling of soil erosion

David Wuepper and Robert Finger from the Group for Agricultural Economics and Policy at ETH Zurich and Pasquale Borrelli from the University of Basel have now employed satellite imagery and numerous other data sources to investigate the socio-economic causes of soil erosion around the world.


On the basis of high-resolution remote sensing data and numerous other data sources, the researchers created an erosion map of the world. With the help of a statistical model, the researchers then investigated whether the erosion rate is generally changing continuously through space but "jumps" abruptly at country borders. Such abrupt "jumps" at political borders reveal the influence of the countries that are left and right of the borders.

On a second map, the researchers also modelled the potential natural erosion rate. This enabled them to see how great the difference between current and natural erosion is and whether there are natural discontinuities in the erosion rate at the political borders.

National borders reveal where erosion is unnaturally high

It was through this approach that Wuepper and Finger were able to identify the "country effect" as a cause of soil erosion. The researchers present their findings in a study recently published in the journal Nature Sustainability.

What's driving erosion worldwide?
The natural (left) erosion on the whole of Hispaniola would be almost the same.
Currently the erosion is rising at the border [Credit: Wupper et al., 2019]
This country effect is most visible along political borders as these areas offer the best basis for comparing observations. "The rate at which soils erode strongly depends on which side of a border, and accordingly, in which country the soil lies," says lead author David Wuepper.

To illustrate their approach, the researchers use the island of Hispaniola, home to Haiti and the Dominican Republic, as an example. In its natural form, Hispaniola would be uniformly covered with dense tropical forest and natural erosion would be very low because this vegetation would protect the soil from rain.


In reality, however, the researchers found that along the border, Haiti's soils lose 50 tonnes more per year and per hectare than those of the Dominican Republic. Wuepper explains that if Hispaniola had not been subject to human intervention and were still in its natural state, there would be no sharp increase in soil erosion along the border. "But the presence of such a rise points to political entities, not natural borders," he says.

The differential erosion along the border of the two Caribbean states is extremely high: 30 times higher than the global average, which -- according to the researchers' calculations -- stands at 1.4 tonnes per year and hectare of arable land. By comparison, the rate of erosion in Germany is 0.2 tonnes lower than that of neighbouring countries.

What's driving erosion worldwide?
The soil of this olive grove in Italy is exposed to erosion without any protection
[Credit: Artemi Cerda]


The researchers consider this to be very positive because it suggests that erosion is also fairly low in the countries that border Germany. "Our findings illustrate how inconsistent the pattern observed around the world is," Wuepper says. A country's strongest influence on soil erosion is its agriculture and the way that farmers cultivate the soil there. The income level in a particular country, however, has no influence.

High potential

In addition to highlighting failures and shortcomings in soil protection, the study also shows that there is clear potential for countries to improve their soil protection and how they go about it. Finger explains that before the study, nobody realised the huge leverage that the country effect would offer. In the past, soil erosion had been seen as a predominantly local problem. "Now we've shown that larger-scale factors also strongly influence erosion in a given country," he says.

In addition, the ETH Zurich researchers' method can be used to determine whether measures that countries take to improve soil protection are effective or not. One such measure, for example, is introducing economic incentives to encourage greater soil cover or reduced tillage. However, measures to protect against erosion can also result in new conflicts of interest if, for example, reduced tillage leads to increased use of pesticides for weed control. "The basis for good policy-making in this respect is to identify and quantify these conflicting goals," Finger says.

Author: Peter Ruegg | Source: ETH Zurich [December 04, 2019]



* This article was originally published here

2019 December 11 N63A: Supernova Remnant in Visible and X-ray...



2019 December 11

N63A: Supernova Remnant in Visible and X-ray
Image Credit: NASA, ESA, Hubble, Chandra; Processing & License: Judy Schmidt

Explanation: What has this supernova left behind? As little as 2,000 years ago, light from a massive stellar explosion in the Large Magellanic Cloud (LMC) first reached planet Earth. The LMC is a close galactic neighbor of our Milky Way Galaxy and the rampaging explosion front is now seen moving out - destroying or displacing ambient gas clouds while leaving behind relatively dense knots of gas and dust. What remains is one of the largest supernova remnants in the LMC: N63A. Many of the surviving dense knots have been themselves compressed and may further contract to form new stars. Some of the resulting stars may then explode in a supernova, continuing the cycle. Featured here is a combined image of N63A in the X-ray from the Chandra Space Telescope and in visible light by Hubble. The prominent knot of gas and dust on the upper right – informally dubbed the Firefox – is very bright in visible light, while the larger supernova remnant shines most brightly in X-rays. N63A spans over 25 light years and lies about 150,000 light years away toward the southern constellation of Dorado.

∞ Source: apod.nasa.gov/apod/ap191211.html



* This article was originally published here

Birds are shrinking as the climate warms


Every day in the spring and fall since 1978, scientists and volunteers at Chicago's Field Museum have gotten up as early as 3:30 in the morning to collect fallen birds that have crashed into nearby buildings' windows. One scientist, Dave Willard, has measured every single one of the dead birds and recorded the data by hand into a ledger. That meticulous note-keeping paid off: scientists analyzed the data and learned that over the last forty years, migratory birds have been getting smaller--a change likely linked with climate change.

Birds are shrinking as the climate warms
One scientist, Dave Willard, took the measurements of the 70,716 bird specimens in this study and recorded
them by hand into ledgers like this. This photo shows one of Willard's ledgers, his measuring tools,
 and a Tennessee Warbler [Credit: Field Museum, Kate Golembiewski]
"When we began collecting the data analyzed in this study, we were addressing a few simple questions about year-to-year and season-to-season variation in birds. The phrase 'climate change' as a modern phenomenon was barely on the horizon. The results of this study highlight how essential long-term data sets are for identifying and analyzing trends caused by changes in our environment," says Willard, a collections manager emeritus at the Field Museum and one of the authors of a new study in Ecology Letters presenting these findings, along with lead author Brian Weeks and senior author Ben Winger from the University of Michigan.

Every night during the spring and fall migration seasons, nocturnal birds making their way through Chicago run into the windows of big buildings. Many of the birds hit the hulking glass McCormick Place, North America's largest convention center. And since McCormick Place is just over a mile away from the Field, Willard headed down there one morning in 1978 to see what he could find.


"It started as a very casual study--someone mentioned that birds sometimes run into McCormick Place, and I was curious, so I went for a walk around the building one morning," recalls Willard. "I found a couple dead birds and I brought them back to the museum--I've always wondered if there had been no birds that morning whether I would have ever bothered to go back."

Over the years, Willard and volunteers with the Chicago Bird Collision Monitors collected over 100,000 birds that had hit McCormick Place and other buildings in downtown Chicago--they now make up 20% of the Field's bird collections. Willard began to notice subtle changes in the birds' measurements over time, but it wasn't clear that statistically significant change was happening. "It's a matter of millimeters, tenths of millimeters--it's not something you know is happening until the analysis," says Willard. The Ecology Letters study's senior author, Ben Winger, began working on statistical analyses of the birds' sizes when he was still a University of Chicago graduate student working at the Field Museum; now, he's an assistant professor of ecology and evolutionary biology at the University of Michigan and an assistant curator at the U-M Museum of Zoology.

Birds are shrinking as the climate warms
Some of the thousands of birds in the Field Museum's collections that collided
with city windows [Credit: Field Museum, Ben Marks]
The team analyzed the measurements of 70,716 bird specimens representing 52 species; they found that the sizes of all of these species declined between 1978 and 2016. The birds' body masses, lower leg bone lengths, and overall body sizes all went down--the leg bone length decreased by 2.4% across species. Meanwhile, the birds' wingspans increased by 1.3%. The researchers suspect that these changes in body size are related to climate change.

Animals' body sizes are often tied to the climate they live in--within a species, individuals that live in cold climates tend to be bigger than their counterparts in warmer areas. This trend, called Bergmann's rule, helps animals in cold places stay warm. Since temperatures have crept up in the last forty years in the birds' summer breeding grounds north of Chicago, the researchers believe that the incredible shrinking birds might be due to climate change. Smaller bodies hold on to less heat; meanwhile, the birds' wingspans may have increased so that the birds are still able to make their long migrations, even with smaller bodies to produce the energy needed for flight.


"We had good reason to expect that increasing temperatures would lead to reductions in body size, based on previous studies. The thing that was shocking was how consistent it was. I was incredibly surprised that all of these species are responding in such similar ways," says the study's lead author, Brian Weeks, an assistant professor at the University of Michigan School for Environment and Sustainability.

"Periods of rapid warming are followed really closely by periods of decline in body size, and vice versa," Weeks says. "Being able to show that kind of detail in a morphological study is unique to our paper, as far as I know, and it's entirely due to the quality of the dataset that David Willard generated."

"It's really been a herculean effort on the part of Dave and others at the Field Museum, including co-author Mary Hennen, to get such valuable data from birds that might otherwise have been discarded after they died from building collisions," Winger adds.

Willard, however, turns praise back on Winger and Weeks: "I want to celebrate that there was someone out there who saw the dataset's value and was willing to do the work to see if it had anything to say or not."

Source: Field Museum [December 04, 2019]



* This article was originally published here

Prehistoric Decorated Stone Slab, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Prehistoric Decorated Stone Slab, Tullie House Museum and Gallery, Carlisle, 8.12.19.



* This article was originally published here

New life support system cleans air during full-house Space Station













ISS - International Space Station logo.

Dec. 10, 2019

In October the International Space Station was even more busy than usual with nine astronauts living and working in humankind’s outpost in Earth orbit. With three more astronauts, the Station’s life support systems worked overtime to provide enough air and water recycling for the crew, and ESA’s new Advanced Closed Loop System (ACLS) stepped in to help scrub the extra carbon dioxide in the air.

A flock of astronauts

The Station is designed to house six astronauts but regularly receives additional visitors for brief periods of time. The extra humans need extra food, water and oxygen, but also create extra waste such as carbon dioxide exhaled from the lungs which puts extra strain on the Station’s life support systems.

n October 2018, ESA launched a new regenerative life support system made by Airbus in Friedrichshafen, Germany. The ACLS is capable of recycling carbon dioxide. Three major steps in the recycling process are currently being tested and worked on in order.

Advanced Close Loop System infographics

One element of the system takes water and separates it into oxygen and hydrogen. A second part captures carbon dioxide from the air and keeps carbon dioxide within acceptable levels using a unique amine process developed by ESA. The recycling step takes place in a ‘Sabatier reactor’. Hydrogen and carbon dioxide react with steam and pass over a catalyst to form water and methane.

The water is condensed to be recycled into oxygen and hydrogen while the methane is vented into space, together with excess carbon dioxide. The element that captures and concentrates carbon dioxide in the three-step system was used extensively when ESA astronaut Luca Parmitano and his six crewmates were joined by three additional astronauts for a few days, boosting existing carbon dioxide scrubbing systems.

Life support rack installed

Though regulating carbon dioxide is only one feature of the ACLS, testing on the Space Station has proven its ability to control CO2 concentrations. The technology used in ACLS is especially suitable for operation at low carbon dioxide levels. This is a major goal for long duration missions in order to increase crew health and comfort.

Full house on the Space Station

“We are very happy to have contributed to Space Station life support operations, especially in such a critical area as the air astronauts breathe,” says Johannes Witt, project manager at ESA, “it is an amazing feeling for the team to consider that the work we invested over years into ACLS is now helping to produce clean air for astronauts in space.”

Table for nine

The system will continue to be tested step-by-step, as some teething problems encountered along the way mean that it is not yet fully operational.

“We knew that designing and testing a life-support system that is the size of a single bed would be a challenge,” explains Johannes.

Space bubble

“Systems with fluids and gases behave differently in microgravity. Air bubbles and particles in the condensate which is used by ACLS posed a much bigger challenge than expected. This is exactly why we developed and are testing the life support system close to home on the International Space Station where problems can be solved relatively easily. Farther away from Earth you need high reliability because repairs are much more difficult.”

The European technology behind the ACLS will be hugely beneficial in exploring farther beyond our planet and engineers, astronauts and ground control are rigorously working on getting the system fully operational.

Advanced Close Loop System life support rack

New parts and filters arrived by cargo ferry and the team is optimistic that the system will be fully operational by early 2020.

Related links:

Human and Robotic Exploration: http://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration

Science & Exploration: http://www.esa.int/Science_Exploration

International Space Station (ISS): http://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/International_Space_Station

Aniation, Images, Text, Credits: ESA / NASA.

Greetings, Orbiter.ch

* This article was originally published here

Untangling the branches in the mammal tree of life


The mammal tree of life is a real leaner. Some branches are weighed down with thousands of species -- we're looking at you, rodents and bats -- while others hold just a few species. Now we may have a better idea why.

Untangling the branches in the mammal tree of life
A North American pronghorn antelope, whose closest genetic relatives are giraffes
and okapi from all the way in Africa [Credit: Yale University]
In a new study published in the journal PLOS Biology, researchers at Yale University unveil a complete overhaul of the way species data is brought together and analyzed to construct an evolutionary tree of life for mammals. It's aimed at giving scientists, conservation managers, policymakers, and environmentalists more accurate, comprehensive information about species diversity and relationships, past and present.

"The fossil and genomic data we use are often fragmentary and messy, but the reality is we are reconstructing events that occurred millions of years ago in long-extinct mammals," said Nathan Upham, a Yale postdoctoral associate in ecology and evolutionary biology and first author of the study.


Of the roughly 6,000 species of living mammals, most of them are rodents (42%) or bats (24%), while common mammals such as cows, pigs, sheep, cats, raccoons, and monkeys consist of relatively few species. Yet up to this point, attempts to formulate a tree of life for mammals have been unable to explain this unevenness of species diversity.

Upham and senior author Walter Jetz, professor of ecology and evolutionary biology at Yale, took a new approach. They reconstructed the evolutionary relationships of species by creating "patches" of smaller, more accurate evolutionary trees that were then linked to a carefully developed "backbone" representing the deep divergences in the tree. This resulted in 10,000 big trees -- designed so they can be studied individually or together -- that also point out the remaining gaps in data for the overall mammal tree of life.

Untangling the branches in the mammal tree of life
Species-level relationships and tempo of diversification across mammals
[Credit: Upham et al., 2019]
"We're calling it a 'backbone-and-patch' approach," Jetz said. "For the first time, we're able to characterize the genetic relationships of essentially all living mammals while transparently relaying the parts that remain uncertain. It should enable advances in a variety of fields, including comparative biology, ecology, and conservation."


The completeness and accuracy of this information is important, Jetz added, as evolutionary distinctiveness is increasingly used to determine conservation priorities. Therefore, it can be useful for researchers and policymakers in the U.S. to know that the closest genetic relatives of the pronghorn antelope in the U.S. are not nearby mammal species, but giraffes and okapi in Africa.

The researchers also developed an interactive tool for exploring the mammal tree of life. The interface, which is downloadable, lets users examine information both at the species level and also more broadly.

Upham said further research will use the new information to look at how the uneven distribution of species in the mammal tree of life is related to geographic isolation among mammal populations, which can lead to higher rates of speciation -- the evolutionary process of forming new species -- and extinction.

Author: Jim Shelton | Source: Yale University [December 04, 2019]



* This article was originally published here

Two Rovers to Roll on Mars Again: Curiosity and Mars 2020














NASA - Mars Science Laboratory (MSL) logo / NASA - Mars 2020 Rover logo.

Dec. 10, 2019


Image above: Illustrations of NASA's Curiosity and Mars 2020 rovers. While the newest rover borrows from Curiosity's design, each has its own role in the ongoing exploration of Mars and the search for ancient life. Image Credits: NASA/JPL-Caltech.

Curiosity won't be NASA's only active Mars rover for much longer. Next summer, Mars 2020 will be headed for the Red Planet. While the newest rover borrows from Curiosity's design, they aren't twins: Built and managed by NASA's Jet Propulsion Laboratory in Pasadena, California, each has its own role in the ongoing exploration of Mars and the search for ancient life. Here's a closer look at what sets the siblings apart.

The Missions

Landing in 2004 to "follow the water," the twin rovers Spirit and Opportunity discovered evidence that the planet once hosted running water before becoming a frozen desert. But when did this happen and why?

NASA launched the supersized Curiosity rover to learn more. Since landing in 2012, Curiosity has been roaming Gale Crater, which, it discovered, contained a lake billions of years ago and an environment that could have supported microbial life. The rover is still hunting for clues related to this environment as it ascends the 3-mile-tall (5-kilometer-tall) Mount Sharp, which sits within Gale Crater and was partially formed by water.

Some 3,760 miles (6,050 kilometers) away, Mars 2020 will also explore a landscape shaped by water: Jezero Crater, the site of an ancient delta. But 2020 will take the next scientific step: It will look for actual signs of past life, or biosignatures, capturing samples of rocks and soil that could be retrieved by future missions and returned to Earth for in-depth study.


Image above: NASA's Mars 2020 rover looks virtually the same as Curiosity, but there are a number of differences. One giveaway to which rover you're looking at is 2020's aft cross-beam, which looks a bit like a shopping cart handle. Image Credits: NASA/JPL-Caltech.

The Tools

Mars 2020's chassis, or body, is about five inches longer than Curiosity's. It's also heavier, checking in at 2,260 pounds (1,025 kilograms), compared with Curiosity's 1,982 pounds (899 kilograms). The weight difference has to do with the tools each carries.

Start with the robotic arms: Curiosity's extends 7 feet (2.2 meters) and wields a rotating 65-pound (30-kilogram) turret equipped with a scientific camera, chemical analyzer and drill. The roving science lab pulverizes rock samples and pours the powder into its chassis, where two laboratories can determine the rocks' chemical and mineral makeup.

Mars 2020's arm has the same reach as Curiosity's, but its turret weighs more — 99 pounds (45 kilograms) — because it carries larger instruments and a larger drill for coring. The drill will cut intact rock cores, rather than pulverizing them, and they'll be placed in sample tubes via a complex storage system.

The Eyes and Ears

All of NASA's Mars missions have allowed the public to ride along as scientists and engineers explore the planet. Curiosity has been doing that with 17 cameras on its Mast, or head, and body; four of them are color cameras.

Mars 2020 has 23 cameras, most of them color. The new rover also includes "ears" — two microphones to capture not only the first sounds of a Mars landing, but also Martian wind and the rover's chemical-analyzing laser zaps. Mastcam-Z, an improved version of Curiosity's Mast Camera, has a zoom capability and will take high-definition video and panoramas.

The Wheels

Curiosity has prepared Mars 2020's team for "off-roading" on the Red Planet. When holes began appearing in the veteran rover's aluminum wheels, engineers realized that sharp rocks cemented on the Martian surface exert more pressure on the wheels than expected. Careful drive planning, along with a software upgrade, will keep them in shape for the rest of Curiosity's journey up Mount Sharp.

While Mars 2020's wheels are made from the same materials, they're slightly bigger and narrower, with skins that are almost a millimeter thicker. Instead of Curiosity's chevron-pattern treads, or grousers, Mars 2020 has straighter ones and twice as many per wheel (48 versus 24). Extensive testing in JPL's Mars Yard has shown these treads better withstand the pressure from sharp rocks but work just as well on sand.

The Brains

Mars rovers don't drive themselves. Teams of scientists and engineers beam meticulously programmed task lists to them at the beginning of each Mars day, or sol. Rover drivers on Earth then wait for the vehicle to report back before planning the next drive. The more a rover can do on its own, the more time drivers have to program new commands.

After Curiosity landed, it took an average of 19 hours for the rover's team to analyze a day's data, build and test commands, then send those commands back to the rover. Years of honing operations shrunk the time it takes to develop each day's plan to seven hours, and a limited degree of auto-navigation has enabled Curiosity to take some cautious steps on its own.

But Mars 2020 has even more self-driving smarts, allowing it to calculate a path five times faster than Curiosity can. That self-driving will be key to condensing the amount of time it takes for the 2020 team to plan each day's operations. The new mission intends to eventually condense daily operations to just five hours. The faster pace will allow it to cover more ground and gather more samples over the course of its prime mission. Mars 2020 won't move faster than its older sibling, but more automation means that it can potentially drive farther and collect more science without having to wait for engineers back on Earth.

The Landing

Curiosity transformed Mars landings with the seemingly radical "sky crane maneuver." Mars 2020 will rely on the same process but also features an important new technology: Terrain Relative Navigation. An onboard computer matches surface images from a camera to a map to keep the spacecraft on target. Meanwhile, the Range Trigger lets the rover get miles closer to an ideal site before firing a parachute.

The Humans to Come

NASA's Artemis program aims to return astronauts to the Moon by 2024, preparing for future exploration of Mars. Helping pave the way for humans, Curiosity carries instruments that study the Martian environment, like surface radiation and weather.

Besides studying the weather, Mars 2020 will carry spacesuit samples, allowing scientists to study how they degrade. An oxygen generator will test technology for astronauts to make their own rocket fuel from the Martian atmosphere. A subsurface radar like the one on the rover could someday be used to find buried water ice.

Related links:

Mastcam-Z: https://mars.nasa.gov/mars2020/mission/instruments/mastcam-z/

Terrain Relative Navigation: https://www.jpl.nasa.gov/news/news.php?feature=7442

Artemis program: https://www.nasa.gov/what-is-artemis

For more information about Curiosity and Mars 2020, visit:

https://mars.nasa.gov/msl/home/

https://mars.nasa.gov/mars2020/

Images (mentioned), Text, Credits: NASA/Tony Greicius/Alana Johnson/JPL/Andrew Good.

Greetings, Orbiter.ch

* This article was originally published here

Bronze Age Decorated Gold Torc Piece, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Bronze Age Decorated Gold Torc Piece, Tullie House Museum and Gallery, Carlisle, 8.12.19.



* This article was originally published here

3-D printing is helping museums in repatriation and decolonization efforts


Manchester Museum recently returned items taken from Australia more than 100 years ago to Aboriginal leaders, the latest move in an ongoing debate over calls to "repatriate" museum artifacts to their countries of origin.

3-D printing is helping museums in repatriation and decolonization efforts
Credit: David Herraez Calzada/Shutterstock
It's part of a wider discussion over to what degree museums need to reform and "decolonize" away from displaying collections that were gathered or stolen from other countries during the colonial era, in a way that portrays foreign cultures as strange or inferior and other nations as unsuitable possessors of the world's cultural heritage and knowledge. Major institutions including the British Museum and the Victoria & Albert Museum have been caught up in the debate.


One way forward may be found in digital technologies that can enable people to access representations of other cultures in fair, interesting ways, without cultural institutions needing to hold on to controversial artifacts. For example, with 3-D imaging and 3-D printing we can produce digital and physical copies of artifacts, allowing visitors to study and interact with them more closely than ever before.

Copying artifacts

Copying artifacts has a surprisingly long history. Many ancient Greek statues that we have today are actually Roman copies made hundreds of years after the originals. Famous Renaissance artists' workshops regularly produced copies of artwork. In the 19th century, museums produced copies through processes that involved making a mold of the original item, such as casting and electrotyping. The famous diplodocus skeleton "Dippy" actually exists as a number of copies in museums all over the world.

3-D printing is helping museums in repatriation and decolonization efforts
Copy of Myron’s Discobolus at the Vatican Museums in Rome 
[Credit: Leomudde, WikiCommons]
Today, digital technology has democratized the art of copying so it isn't limited to big museums with generous budgets or top experts with specialist knowledge. Accessible digitization technologies, such as photogrammetry and 3-D scanning, can digitally record the shape of objects to a good degree of accuracy. And 3-D printing and cutting machines can physically reproduce this digital information at an affordable cost.


3-D copies can be touched and handled by visitors and can also be customized in shape, material and size. What's more, digital files of artifacts can be shared online and replicas can be printed in other parts of the world. And most importantly, physically printing a copy from a digital image doesn't depend on whether the original artifact still exists or not.


Some governments and institutions have supported the creation of copies by adopting these technologies. These include, just to name a few, the prehistoric cave engravings in Lascaux IV in France, Jackson Pollock's 3-D poured painting Alchemy, and the 900-year-old Signing Oak Tree from Windsor Great Park near London.

Democratising and repatriating heritage

Once the digital information from an artifact is produced and shared, the knowledge the artifact represents is no longer locked up in a single museum and can potentially be accessed by many more people. Sceptics might argue that the value of the artifact cannot be reproduced by these means. But 3-D technologies open up the possibility for democratizing cultural heritage and creating alternative meanings by different groups of people.


3-D technologies can also support museums to adapt to changing social, political, financial, environmental and other challenges. For instance, creating physical copies allows museums to repatriate artifacts to their communities of origin, or to display objects without having to transport them across the world. It can also be a starting point for talking to different communities about repatriation and decolonization. All these actions can support museums through their transformation from colonial institutions to more modern and open organizations, helping them to become less bound to "original" artifacts.


For example, the Smithsonian National Museum of Natural History in the US has worked closely with the Tlingit native community of southeast Alaska, which requested the repatriation of several objects that were sacred to them. One of the most important objects was the Killer Whale clan crest hat, which the museum digitized and made an accurate replica of, before returning the original to the community.


3-D copies have even been deployed in repatriation activism without the official involvement of museums or their approval. For the project Nefertiti Hack, artists Nora Al-Badri and Jan Nikolai Nelles claimed that they secretly scanned the bust of Egyptian queen Nefertiti, held by the Neues Museum in Berlin, and freely released the 3-D data online. A 3-D replica of Nefertiti's bust was also 3-D printed and exhibited in Cairo. The artists argued their intention was to return Nefertiti to her homeland and criticized the colonialist practices of Western museums.


Moving forward

The repatriation debate is forcing museums to rethink what and who they are for and how they can best serve society.

Some museums have taken decisions to return artifacts to their homeland, others to organize exhibitions dedicated to indigenous voices. Yet, in most cases, these efforts are scattered, or one-off events still infused with colonialist spirit. A more concerted effort to use 3-D copying technologies could help overcome this.

3-D printing is helping museums in repatriation and decolonization efforts
3-D printed copy of Pot Oiseau produced for research at the University of Brighton. The original edition
of Pot Oiseau by Pablo Picasso is exhibited at the Brighton Museum & Art Gallery
[Credit: Myrsini Samaroudi & Karina Rodriguez Echavarria]
Some might argue that original artifacts have an "aura" that is impossible to recreate, and that looking at a copy just isn't the same. But simply visiting a museum or a cultural heritage site is an authentic experience in its own way. And this doesn't always have to depend on seeing "original" objects, as long as the museum is honest about its exhibitions and purposes. In future, museums will focus more on the experience of cultural heritage, while promoting universal values, regardless of where the artifacts are.

Author: Myrsini Samaroudi & Karina Rodriguez Echavarria | Source: The Conversation [December 04, 2019]



* This article was originally published here

Advanced Biology Research Taking Place on Station Today













ISS - Expedition 61 Mission patch.

December 10, 2019

Advanced space research is in full gear aboard the International Space Station today. The Expedition 61 crew is activating new science gear and continuing long-running experiments to benefit humans on and off the Earth.

Rodents delivered aboard the SpaceX Dragon resupply ship are now being housed inside the U.S. Destiny laboratory module. They are being studied for ways to prevent muscle and bone loss in microgravity. NASA astronauts Jessica Meir and Andrew Morgan have been setting up the habitats and stocking them with food and water to support the mice.


Image above: The SpaceX Dragon resupply ship approaches the International Space Station as both spacecraft were orbiting 257 miles above Egypt. Image Credit: NASA.

A specialized 3-D printer aboard the orbiting lab is testing printing cellular structures in space due to the detrimental effects of Earth’s gravity. NASA Flight Engineer Christina Koch has been operating the Bio-Fabrication Facility this week using “bio-inks” with more success than on the ground. The device is dedicated to manufacturing human organs, producing food and personalizing pharmaceuticals.

Koch and Meir also partnered together today to set up and calibrate a new bone densitometer in Japan’s Kibo lab module. The biology research gear will measure and image bone density in the mice living aboard the station.

Morgan and Commander Luca Parmitano are participating this week in a pair of motion coordination experiments sponsored by the European Space Agency. In the first study, the astronauts are exploring how weightlessness affects gripping and manipulating objects with implications for exploring planetary bodies. The second investigation explores how the brain adapts to the lack of traditional up-and-down cues in space.

International Space Station (ISS). Image Credit: NASA

Cosmonaut Oleg Skripochka continues to unload the nearly three tons of cargo just delivered on the Progress 74 cargo craft. Russian Flight Engineer Alexander Skvortsov attached a sensor to himself to measure his cardiac activity before spending the rest of the day on lab maintenance.

Related links:

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

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

Muscle and bone loss: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8075

Habitats: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1096

Bio-Fabrication Facility: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7599

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

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

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

How the brain adapts: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2038

Progress 74 cargo craft: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1096

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

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

Best regards, Orbiter.ch

* This article was originally published here

Prehistoric Pottery Patterns, Tullie House Museum and Gallery, Carlisle, 8.12.19.

Prehistoric Pottery Patterns, Tullie House Museum and Gallery, Carlisle, 8.12.19.



* This article was originally published here

Investigating the rise of oxygenic photosynthesis


About 2.4 billion years ago, at the end of the Archean Eon, a planet-wide increase in oxygen levels called the Great Oxidation Event (GOE) created the familiar atmosphere we all breathe today. Researchers focused on life's origins widely agree that this transition event was caused by the global proliferation of photosynthetic microbes capable of splitting water to make molecular oxygen (O2). However, according to Tanja Bosak, associate professor in MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS), researchers don’t know how long before the GOE these organisms evolved.

Investigating the rise of oxygenic photosynthesis
Biomineralization of dolomite and manganese oxide minerals on the cell surfaces
of Chlorobium sp. [Credit: Mirna Daye]
Bosak’s new research, published this week in Nature, suggests it might now be even harder to pin down the emergence of oxygen-producing microbes in the geologic record.

A signal in the rocks

The first microbes to make oxygen did not leave a diary behind, so scientists must search for subtle clues of their emergence that could have survived the intervening few billion years. Complicating things further, while evidence of the GOE is found all over the Earth, these early colonies of oxygen-producing organisms would likely have first existed in small ponds or bodies of water. Any record of them would be geographically isolated.


Some scientists consider localized evidence of the mineral manganese oxide in ancient sediments to be an indicator (or proxy) for the existence of oxygen-producing organisms. This is because manganese oxidation was only thought to be possible in the presence of significant amounts of O2, more than normally existed in the atmosphere pre-GOE. Thus, finding evidence of manganese oxide in sediments predating the GOE would suggest oxygen-producing organisms had evolved by that time and were active in the area. But it turns out there’s more than one way to oxidize manganese.

Anaerobic microbes change the game

As described in the new paper, Bosak and her former postdoc, Mirna Daye, discovered that colonies of modern microbes can perform this process in anaerobic environments typical of the late Archean Eon. Unlike the organisms that caused the GOE, Daye and Bosak’s microbes use sulfide, instead of water, to perform photosynthesis, so they do not create molecular oxygen as a byproduct. Most scientists think that this type of anaerobic photosynthesis emerged as a precursor system to the more familiar oxygenic photosynthesis that ushered in the GOE, and Daye and Bosak’s microbes contain genetic machinery similar to what is thought to have existed before the evolution of bacteria capable of making oxygen.

Investigating the rise of oxygenic photosynthesis
Biomineralization of dolomite and manganese oxide minerals on the cell surfaces
of Chlorobium sp. [Credit: Mirna Daye]
The Bosak group’s demonstration of manganese oxidation in an anaerobic environment means that evidence of ancient manganese oxide may not be a reliable proxy for the local evolution of oxygen-producing life. It could just be a signal for the presence of other organisms already thought to be widespread at that time.


Bosak’s co-authors include associate professor of geobiology Gregory Fournier, along with former postdocs Mirna Daye and Mihkel Pajusalu of MIT’s EAPS department; Vanja Klepac-Ceraj, Sophie Rowland, and Anna Farrell-Sherman of Wellesley College; Nicolas Beukes of the University of Johannesburg; and Nobumichi Tamura of Berkley National Laboratory.

Questioning ancient manganese

“Discovering new mechanisms by which manganese oxide might be created in the Archean environments, before the rise of oxygen, is tremendously interesting because many of the proxies that we have [used] for the presence of oxygen [and therefore, microbes capable of producing it] in the environment in the first half of Earth’s history are … actually proxies for the presence of manganese oxide,” says Ariel Anbar, professor at the Arizona State University School of Earth and Space Exploration, who was not involved in the research. “That forces us to think more deeply about the proxies that we're using and whether they really are indicative of O2 or not.”

The study of the ancient Earth has always been challenging, as evidence gets recycled by geological processes and otherwise lost to the wear and tear of time. Researchers have only fragmented and inferred data that they can use to develop theories.

“What we are finding is not necessarily saying that these people who are interpreting these blips of oxygen before the GOE [are] wrong. It just gives me huge pause,” says Bosak, “The fact that we threw in some microbes and found these processes that were just never considered tells us that we really don't understand a lot about how life and the environment coevolved.”

Author: Kate Petersen | Source: Massachusetts Institute of Technology [December 05, 2019]



* This article was originally published here

How to Shape a Spiral Galaxy













NASA & DLR - SOFIA Mission patch.

Dec. 10, 2019

Our Milky Way galaxy has an elegant spiral shape with long arms filled with stars, but exactly how it took this form has long puzzled scientists. New observations of another galaxy are shedding light on how spiral-shaped galaxies like our own get their iconic shape.

Magnetic fields play a strong role in shaping these galaxies, according to research from the Stratospheric Observatory for Infrared Astronomy, or SOFIA. Scientists measured magnetic fields along the spiral arms of the galaxy called NGC 1068, or M77. The fields are shown as streamlines that closely follow the circling arms.


Image above: Magnetic fields in NGC 1086, or M77, are shown as streamlines over a visible light and X-ray composite image of the galaxy from the Hubble Space Telescope, the Nuclear Spectroscopic Array, and the Sloan Digital Sky Survey. The magnetic fields align along the entire length of the massive spiral arms — 24,000 light years across (0.8 kiloparsecs) — implying that the gravitational forces that created the galaxy’s shape are also compressing the its magnetic field. This supports the leading theory of how the spiral arms are forced into their iconic shape known as “density wave theory.” SOFIA studied the galaxy using far-infrared light (89 microns) to reveal facets of its magnetic fields that previous observations using visible and radio telescopes could not detect. Image Credits: NASA/SOFIA; NASA/JPL-Caltech/Roma Tre Univ.

“Magnetic fields are invisible, but they may influence the evolution of a galaxy,” said Enrique Lopez-Rodriguez, a Universities Space Research Association scientist at the SOFIA Science Center at NASA’s Ames Research Center in California’s Silicon Valley. “We have a pretty good understanding of how gravity affects galactic structures, but we’re just starting to learn the role magnetic fields play.”

The M77 galaxy is located 47 million light years away in the constellation Cetus. It has a supermassive active black hole at its center that is twice as massive as the black hole at the heart of our Milky Way galaxy. The swirling arms are filled with dust, gas and areas of intense star formation called starbursts.

SOFIA’s infrared observations reveal what human eyes cannot: magnetic fields that closely follow the newborn-star-filled spiral arms. This supports the leading theory of how these arms are forced into their iconic shape known as “density wave theory.” It states that dust, gas and stars in the arms are not fixed in place like blades on a fan. Instead, the material moves along the arms as gravity compresses it, like items on a conveyor belt.

The magnetic field alignment stretches across the entire length of the massive, arms — approximately 24,000 light years across. This implies that the gravitational forces that created the galaxy’s spiral shape are also compressing its magnetic field, supporting the density wave theory. The results are published in the Astrophysical Journal.

Boeing 747SP jetliner modified to carry a 106-inch diameter telescope (SOFIA)

“This is the first time we’ve seen magnetic fields aligned at such large scales with current star birth in the spiral arms,” said Lopez-Rodriquez. “It’s always exciting to have observational evidence that supports theories.”

Celestial magnetic fields are notoriously difficult to observe. SOFIA’s newest instrument, the High-resolution Airborne Wideband Camera-Plus, or HAWC+, uses far-infrared light to observe celestial dust grains, which align perpendicular to magnetic field lines. From these results, astronomers can infer the shape and direction of the otherwise invisible magnetic field. Far-infrared light provides key information about magnetic fields because the signal is not contaminated by emission from other mechanisms, such as scattered visible light and radiation from high-energy particles. SOFIA’s ability to study the galaxy with far infrared light, specifically at the wavelength of 89 microns, revealed previously unknown facets of its magnetic fields.

Further observations are necessary to understand how magnetic fields influence the formation and evolution of other types of galaxies, such as those with irregular shapes.

SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a Boeing 747SP jetliner modified to carry a 106-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is maintained and operated from NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. The HAWC+ instrument was developed and delivered to NASA by a multi-institution team led by the Jet Propulsion Laboratory in Pasadena, California.

Related links:

SOFIA’s newest instrument: https://www.nasa.gov/ames/image-feature/one-of-a-kind-camera-added-to-sofia

SOFIA: http://www.nasa.gov/mission_pages/SOFIA/index.html

Galaxies: https://www.nasa.gov/subject/6894/galaxies

Image (mentioned), Animation, Text, Credits: NASA/Kassandra Bell/Felicia Chou.

Greetings, Orbiter.ch

* This article was originally published here

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