пятница, 20 июля 2018 г.

Blue Origin Mission 9: Safe Escape In Any Phase of Flight


Blue Origin logo.


July 20, 2018


New Shepard flew for the ninth time on July 18, 2018. During this mission, known as Mission 9 (M9), the escape motor was fired shortly after booster separation. The Crew Capsule was pushed hard by the escape test and we stressed the rocket to test that astronauts can get away from an anomaly at any time during flight. The mission was a success for both the booster and capsule. Most importantly, astronauts would have had an exhilarating ride and safe landing.



Blue Origin Mission 9 landing

This isn’t the first time we’ve done this type of extreme testing on New Shepard. In October of 2012, we simulated a booster failure on the launch pad and had a successful escape. Then in October of 2016, we simulated a booster failure in-flight at Max Q, which is the most physically strenuous point in the flight for the rocket, and had a completely successful escape of the capsule.



Replay of Mission 9 Webcast

This test on M9 allowed us to finally characterize escape motor performance in the near-vacuum of space and guarantee that we can safely return our astronauts in any phase of flight.


Also on M9, New Shepard carried science and research payloads from commercial companies, universities and space agencies.


Learn more about the payloads on board: https://www.blueorigin.com/news/news/payload-manifest-on-mission-9


For more information about Blue Origin, visit: https://www.blueorigin.com/


Image, Video, Text, Credit: Blue Origin.


Greetings, Orbiter.chArchive link


https://xissufotoday.space/2018/07/blue-origin-mission-9-safe-escape-in-any-phase-of-flight/

HiPOD (20 July 2018): Portion of a Lobe Flow off the West Flank…


HiPOD (20 July 2018): Portion of a Lobe Flow off the West Flank of Arsia Mons


   – 259 km above the surface. Black and white is less than 5 km across.


NASA/JPL/University of Arizona


https://xissufotoday.space/2018/07/hipod-20-july-2018-portion-of-a-lobe-flow-off-the-west-flank/

Gravitational Microlens Detection from Spitzer




Hubble Space Telescope images of a microlens system. The image on the left was taken 3.7 years after an observed microlensing event; the one on the right was taken 8.9 years later after the moving foreground (lensing) source had changed position. The lens and source components (A and B) are clearly resolved in the later image. Credit: NASA/Hubble





The path of light from a star as it passes by a massive body, like an exoplanet, will be bent and an observer looking towards the star will see its image distorted. Like an object seen through the stem of a wineglass, the stellar image could even be deformed into two bright peaks. That mass could influence light in this way was first confirmed in 1919, but some of the more subtle effects have only been detected in the past twenty-five years. In one such process, microlensing, a flash of light is produced when the path of a moving cosmic body (perhaps otherwise unknown) passes fortuitously in front of a star and briefly increases the intensity of its light. 


The Spitzer Space Telescope circles the Sun in an Earth-trailing orbit, and it is currently 1.66 astronomical units away from Earth (one AU is the average distance of the Earth form the Sun). Scientists had predicted that if it ever became possible to observe a microlensing flash from two well-separated vantage points, a parallax measurement (the apparent angular difference between the positions of the star as seen from the two separated sites) would determine the distance of the dark object. In fact, since 2014 Spitzer has been used successfully to measure the parallax for hundreds of microlensing events. In all these cases, Spitzer was used after ground-based observations had first identified a microlensing event underway.


CfA astronomers Jennifer Yee, Y. Jung, and In-Gu Shin were members of a collaboration that used Spitzer to record the first microlensing event in which only Spitzer (but not the ground-based sites) saw a double flash. Although this was in principle always possible, the effect had never before been observed, and proves that some double-peaked signals can be missed by ground-only observations. The result increases the importance of Spitzer observations beyond simply measuring parallax to include observing multiple-peak images and thus enabling a more precise characterization of the lens, which in the current instance is a binary system with a low-mass star and an orbiting companion.

Reference(s):


“OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only,” Tianshu Wang et al. ApJ 860, 25 (2018).











Archive link


https://xissufotoday.space/2018/07/gravitational-microlens-detection-from-spitzer/

2018 July 20 The Teapot and the Milky Way Image Credit &…


2018 July 20


The Teapot and the Milky Way
Image Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography)


Explanation: The recognizable stars of the Teapot asterism in the constellation Sagittarius posed with the Milky Way over Death Valley, planet Earth on this quiet, dark night. The surreal scene was appropriately captured from Teakettle Junction, marked by the wooden sign adorned with terrestrial teapots and kettles on the rugged road to Racetrack Playa. Shining against the luminous starlight of the central Milky Way is bright planet Saturn, just above the star at the celestial teapot’s peak. But the brightest celestial beacon, high above the southern horizon, is an orange tinted Mars at upper left in the frame.


∞ Source: apod.nasa.gov/apod/ap180720.html


https://xissufotoday.space/2018/07/2018-july-20-the-teapot-and-the-milky-way-image-credit/

Planck: final data from the mission lends support to the standard cosmological model

In 2013, ESA’s Planck mission unveiled a new image of the cosmos: an all-sky survey of the microwave radiation produced at the beginning of the Universe. This first light emitted by the Universe provides a wealth of information about its content, its rate of expansion, and the primordial fluctuations in density that were the precursors of the galaxies. The Planck consortium publishes the full and final version of these data and associated articles on the ESA website on 17 July 2018. The corresponding articles have been submitted to the journal Astronomy & Astrophysics. With its increased reliability and its data on the polarisation of relic radiation, the Planck mission corroborates the standard cosmological model with unrivalled precision for these parameters, even if some anomalies still remain. For this work the Planck consortium called upon some three hundred researchers, in particular from CNRS, CNES (the French national space agency), CEA (the French Alternative Energies and Atomic Energy Commission) and several universities in France.











Planck: final data from the mission lends support to the standard cosmological model
Planck’s view of the cosmic microwave background [Credit: ESA/Planck Collaboration]

Launched in 2009, ESA’s Planck satellite mapped the cosmic microwave background, microwave radiation emitted 380,000 years after the Big Bang, when the Universe was still a hot, almost completely homogeneous gas. Tiny variations in its temperature provide information about its content, its rate of expansion and the properties of the primordial fluctuations that gave rise to the galaxies. An initial analysis of the data set was published in 2015, in the form of eight all-sky maps that included the polarisation of the cosmic microwave background, which determines how the waves that make up light vibrate on tiny scales. This key information bears the imprint of the last interaction between light and matter in the primordial Universe. However, only a preliminary analysis had been carried out on it.



Operating between 2009 and 2013, ESA’s Planck mission scanned the sky at microwave wavelengths to observe


 the cosmic microwave background, or CMB, which is the most ancient light emitted in the history of our Universe. 


Data from Planck have revealed an ‘almost perfect Universe’: the standard model description of a cosmos containing 


ordinary matter, cold dark matter and dark energy, populated by structures that had been seeded during an early 


phase of inflationary expansion, is largely correct, but a few details to puzzle over remain. 


In other words: the best of both worlds [Credit: ESA/Planck Collaboration]


The polarisation of relic radiation produces a signal 50 to 100 times weaker than that of its temperature and 10 to 20 times weaker than that emitted by the polarized emission of Galactic dust. Thanks to its HFI (High Frequency Instrument), the Planck satellite nonetheless obtained an extremely precise map of primordial polarisation across the entire sky. This was a world first and provides us with a wealth of information.











Planck: final data from the mission lends support to the standard cosmological model
The Cosmic Microwave Background: temperature and polarisation
[Credit: ESA/Planck Collaboration]

Comprehensive, definitive and more reliable, the data published on 17 July 2018 confirms the preliminary findings, supporting a model which provides an excellent description of the content of the Universe in terms of ordinary matter, cold dark matter and dark energy (whose nature is unknown), with an inflation phase at its very beginning. This cosmological model can now be derived using temperature or polarisation data independently, with comparable accuracy. This considerably reinforces the standard model of cosmology, however surprising this may be. The results are described in a set of a dozen scientific papers, involving around three hundred researchers (see list of French laboratories involved below).











Planck: final data from the mission lends support to the standard cosmological model
The history of the Universe [Credit: European Space Agency]

However, some anomalies and limitations remain. In particular, the rate of expansion of the Universe differs by a few percent depending on whether the data from the Hubble Space Telescope or from the Planck mission are used. This question is still an open one, and a host of telescopes will be marshalled in an attempt to resolve the issue.


Source: CNRS [July 18, 2018]



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https://xissufotoday.space/2018/07/planck-final-data-from-the-mission-lends-support-to-the-standard-cosmological-model/

X-ray data may be first evidence of a star devouring a planet

For nearly a century, astronomers have puzzled over the curious variability of young stars residing in the Taurus-Auriga constellation some 450 light years from Earth. One star in particular has drawn astronomers’ attention. Every few decades, the star’s light has faded briefly before brightening again.











X-ray data may be first evidence of a star devouring a planet
This artist’s illustration depicts the destruction of a young planet, which scientists may
have witnessed for the first time [Credit: NASA/CXC/M.Weiss]

In recent years, astronomers have observed the star dimming more frequently, and for longer periods, raising the question: What is repeatedly obscuring the star? The answer, astronomers believe, could shed light on some of the chaotic processes that take place early in a star’s development.


Now physicists from MIT and elsewhere have observed the star, named RW Aur A, using NASA’s Chandra X-Ray Observatory. They’ve found evidence for what may have caused its most recent dimming event: a collision of two infant planetary bodies, which produced in its aftermath a dense cloud of gas and dust. As this planetary debris fell into the star, it generated a thick veil, temporarily obscuring the star’s light.


“Computer simulations have long predicted that planets can fall into a young star, but we have never before observed that,” says Hans Moritz Guenther, a research scientist in MIT’s Kavli Institute for Astrophysics and Space Research, who led the study. “If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets.”


The star’s previous dimming events may have been caused by similar smash-ups, of either two planetary bodies or large remnants of past collisions that met head-on and broke apart again.


“It’s speculation, but if you have one collision of two pieces, it’s likely that afterward they may be on some rogue orbits, which increases the probability that they will hit something else again,” Guenther says.


A star cover-up


Scientists who study the early development of stars often look to the Taurus-Auriga Dark Clouds, a gathering of molecular clouds in the constellations of Taurus and Auriga, which host stellar nurseries containing thousands of infant stars. Young stars form from the gravitational collapse of gas and dust within these clouds. Very young stars, unlike our comparatively mature sun, are still surrounded by a rotating disk of debris, including gas, dust, and clumps of material ranging in size from small dust grains to pebbles, and possibly to fledgling planets.


“If you look at our solar system, we have planets and not a massive disk around the sun,” Guenther says. “These disks last for maybe 5 million to 10 million years, and in Taurus, there are many stars that have already lost their disk, but a few still have them. If you want to know what happens in the end stages of this disk dispersal, Taurus is one of the places to look.”


Guenther and his colleagues focus on stars that are young enough to still host disks. He was particularly interested in RW Aur A, which is at the older end of the age range for young stars, as it is estimated to be several million years old. RW Aur A is part of a binary system, meaning that it circles another young star, RW Aur B. Both these stars are about the same mass as the sun.


Since 1937, astronomers have recorded noticeable dips in the brightness of RW Aur A every few decades. Each dimming event appeared to last for about a month. In 2011, the star dimmed again, this time for about half a year. The star eventually brightened, only to fade again in mid-2014. In November 2016, the star returned to its full luminosity.


Astronomers have proposed that this dimming is caused by a passing stream of gas at the outer edge of the star’s disk. Still others have theorized that the dimming is due to processes occurring closer to the star’s center.


“We wanted to study the material that covers the star up, which is presumably related to the disk in some way,” Guenther says. “It’s a rare opportunity.”


An iron-clad signature


In January 2017, RW Aur A dimmed again, and the team used NASA’s Chandra X-Ray Observatory to record X-ray emission from the star.


“The X-rays come from the star, and the spectrum of the X-rays changes as the rays move through the gas in the disk,” Guenther says. “We’re looking for certain signatures in the X-rays that the gas leaves in the X-ray spectrum.”


In total, Chandra recorded 50 kiloseconds, or almost 14 hours of X-ray data from the star. After analyzing these data, the researchers came away with several surprising revelations: the star’s disk hosts a large amount of material; the star is much hotter than expected; and the disk contains much more iron than expected — not as much iron as is found in the Earth, but more than, say, a typical moon in our solar system. (Our own moon, however, has far more iron than the scientists estimated in the star’s disk.)


This last point was the most intriguing for the team. Typically, an X-ray spectrum of a star can show various elements, such as oxygen, iron, silicon, and magnesium, and the amount of each element present depends on the temperature within a star’s disk.


“Here, we see a lot more iron, at least a factor of 10 times more than before, which is very unusual, because typically stars that are active and hot have less iron than others, whereas this one has more,” Guenther says. “Where does all this iron come from?”


The researchers speculate that this excess iron may have come from one of two possible sources. The first is a phenomenon known as a dust pressure trap, in which small grains or particles such as iron can become trapped in “dead zones” of a disk. If the disk’s structure changes suddenly, such as when the star’s partner star passes close by, the resulting tidal forces can release the trapped particles, creating an excess of iron that can fall into the star.


The second theory is for Guenther the more compelling one. In this scenario, excess iron is created when two planetesimals, or infant planetary bodies, collide, releasing a thick cloud of particles. If one or both planets are made partly of iron, their smash-up could release a large amount of iron into the star’s disk and temporarily obscure its light as the material falls into the star.


“There are many processes that happen in young stars, but these two scenarios could possibly make something that looks like what we observed,” Guenther says.


He hopes to make more observations of the star in the future, to see whether the amount of iron surrounding the star has changed — a measure that could help researchers determine the size of the iron’s source. For instance, if the same amount of iron appears in, say, a year, that may signal that the iron comes from a relatively massive source, such as a large planetary collision, versus if there is very little iron left in the disk.


“Much effort currently goes into learning about exoplanets and how they form, so it is obviously very important to see how young planets could be destroyed in interactions with their host stars and other young planets, and what factors determine if they survive,” Guenther says.


The study is published in the Astronomical Journal.


Author: Jennifer Chu | Source: Massachusetts Institute of Technology [July 18, 2018]




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https://xissufotoday.space/2018/07/x-ray-data-may-be-first-evidence-of-a-star-devouring-a-planet/

In the ocean’s twilight zone, tiny organisms may have giant effect on Earth’s...

Deep in the ocean’s twilight zone, swarms of ravenous single-celled organisms may be altering Earth’s carbon cycle in ways scientists never expected, according to a new study from Florida State University researchers.











In the ocean's twilight zone, tiny organisms may have giant effect on Earth's carbon cycle
Stukel and his team found that hordes of microorganisms called phaeodarians, depicted above,
could be playing an outsized role in the global carbon cycle [Credit: Mike Stukel]

In the area 100 to 1,000 meters below the ocean’s surface — dubbed the twilight zone because of its largely impenetrable darkness — scientists found that tiny organisms called phaeodarians are consuming sinking, carbon-rich particles before they settle on the seabed, where they would otherwise be stored and sequestered from the atmosphere for millennia.


This discovery, researchers suggest, could indicate the need for a re-evaluation of how carbon circulates throughout the ocean, and a new appraisal of the role these microorganisms might play in Earth’s shifting climate.


Lead researcher and FSU Assistant Professor of Oceanography Mike Stukel, who conducted the study with the California Current Ecosystem Long-Term Ecological Research program, investigates the biological pump — the process by which carbon is transported from the surface to the deep ocean.


“Carbon dioxide is constantly diffusing into the ocean from the atmosphere and back into the atmosphere from the ocean,” Stukel said. “In the surface ocean, when phytoplankton do photosynthesis, they’re taking up carbon dioxide. But phytoplankton only have lifespans of days to a week, so those phytoplankton are likely to die in the surface ocean — usually by getting eaten by small organisms like krill.”


When krill and other zooplankton breathe, they release carbon dioxide back into the surface ocean, and eventually back into the atmosphere. Typically, carbon dioxide in the surface ocean and atmosphere remain balanced at a near equilibrium.


The only way the ocean experiences a net uptake of carbon dioxide from the atmosphere is if the organic carbon at the surface is transported to the deep ocean, usually in the form of sinking particles.


Particles can sink from the surface ocean for any number of reasons. Dead organisms, fecal matter or amalgamated packages of organic particles are all common vehicles for carbon transport. Diatoms, a type of abundant phytoplankton that perform roughly a quarter of the world’s photosynthesis, produce glass-like silica shells that make them substantially denser than the water, causing them to quickly sink.


If these sinking particles were to reach the deep ocean unobstructed, their carbon would be withheld from the atmosphere for hundreds of years. But, as Stukel and his team found, that’s not always the case.


Using an advanced camera system that allowed researchers to identify organisms as small as 500 microns (half the thickness of a dime), the team discovered a profusion of microorganisms — far more than they expected — in the crucial ocean twilight zone. Their major question: What were the roles of these organisms, and phaeodarians specifically, in consuming sinking particles?


“By quantifying how many were there and then quantifying the proportion of particles they would be intercepting, we were able to calculate that they could be consuming as much as about 20 percent of the particles sinking out of the surface layer,” Stukel said. “And this was just for one particular family of phaeodarians, called aulosphaeridae.”


When sinking particles are consumed, those particles are necessarily prevented from reaching the deep ocean. The notion that one group of microorganisms could be consuming 20 percent of the carbon-rich particles sinking from the surface waters of this limited study area, Stukel said, suggests that microorganisms around the world could be playing a far more outsized role in the carbon cycle than scientists previously believed.


While at some points aulosphaeridae would be so abundant as to consume up to 30 percent of sinking particles, other times the organisms were barely present at all. Better understanding this variability in abundance of aulosphaeridae and similar organisms can help researchers like Stukel more accurately predict how the biological pump might evolve in the future.


“Our ability to understand how these things will change is important in understanding how the global carbon cycle is going to shift,” Stukel said. “We need to learn what’s going on in the rest of the world, and we need to know what causes these huge changes from when these organisms are a really dominant player to when they’re a marginal player.”


The findings were published in the journal Limnology and Oceanography.


Author: Zachary Boehm | Source: Florida State University [July 18, 2018]



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Atlantic circulation is not collapsing – but as it shifts gears, warming will...

A huge circulation pattern in the Atlantic Ocean took a starring role in the 2004 movie “The Day After Tomorrow.” In that fictional tale the global oceanic current suddenly stops and New York City freezes over.











Atlantic circulation is not collapsing - but as it shifts gears, warming will reaccelerate
In the Atlantic Ocean’s part of the global ocean circulation, warmer water travels north at the surface,
then sinks in the far northern part of the North Atlantic and travels back
deep below the surface [Credit: NOAA]

While many aspects of the movie are unrealistic, oceanographers are concerned about the long-term stability of the Atlantic Ocean circulation, and previous studies show that it has slowed dramatically in the past decade. New research from the University of Washington and the Ocean University of China finds the slowdown is not caused by global warming but is part of regular, decades-long cycle that will affect temperatures in coming decades.


“Climate scientists have expected the Atlantic overturning circulation to decline long-term under global warming, but we only have direct measurements of its strength since April 2004. And the decline measured since then is 10 times larger than expected,” said corresponding author Ka-Kit Tung, a UW professor of applied mathematics with an adjunct appointment in atmospheric sciences.


“Many have focused on the fact that it’s declining very rapidly, and that if the trend continues it will go past a tipping point, bringing a catastrophe such as an ice age. It turns out that none of that is going to happen in the near future. The fast response may instead be part of a natural cycle and there are signs that the decline is already ending.”


The results have implications for surface warming. The current’s speed determines how much surface heat gets transferred to the deeper ocean, and a quicker circulation would send more heat to the deep Atlantic. If the current slows down, then it will store less heat, and Earth will be likely to see air temperatures rise more quickly than the rate since 2000.


“The global climate models can project what’s going to happen long-term if carbon dioxide increases by a certain amount, but they currently lack the capability to predict surface warming in the next few decades, which requires a knowledge of how much the excess heat trapped by greenhouse gases is being absorbed by the oceans,” Tung said.











Atlantic circulation is not collapsing - but as it shifts gears, warming will reaccelerate
The top panel shows global average surface temperature changes since 1950, with two periods of slower
 change and a period of rapid warming from 1975 to 2000. The lower panels show the strength of the Atlantic
overturning circulation. The blue (and, on the right, purple) curve is the salinity north of 45N, an indirect
 measure, or proxy, for the AMOC strength. The green curve is an established proxy of AMOC
[Credit: Ka-Kit Tung/University of Washington]

The Atlantic Meridional Overturning Circulation, or AMOC, is a conveyor belt that brings surface water northward in the Atlantic; from there, the heavier salty water sinks and returns at depth from the Labrador and Nordic seas, near the North Pole, all the way south to the Southern Ocean. Most people are interested in what happens at the surface — the Gulf Stream and associated Atlantic currents carry warmer water north, bringing mild temperatures to Western Europe.


But the new paper argues that the most important step, from a climate perspective, is what happens next. In the North Atlantic, the saltier water from the tropics sinks almost a mile (1,500 meters). As it does, it carries heat down with it away from the surface.


Changes in the strength of the AMOC affect how much heat leaves our atmosphere. The new study uses a combination of data from Argo floats, ship-based temperature measurements, tidal records, satellite images of sea-surface height that can show bulges of warm water, and recent high-tech tracking of the AMOC itself to suggest that its strength fluctuates as part of a roughly 60- to 70-year, self-reinforcing cycle.


When the current is faster, more of the warm, salty tropical water travels to the North Atlantic. Over years this causes more glaciers to melt, and eventually the freshwater makes the surface water lighter and less likely to sink, slowing the current.


When the AMOC is in a slow phase, the North Atlantic becomes cooler, ice melt slows, and eventually the freshwater melt source dries up and the heavier saltier water can plunge down again, which speeds up the whole circulation.











Atlantic circulation is not collapsing - but as it shifts gears, warming will reaccelerate
These lines show different ways of gauging the strength of the Atlantic overturning circulation. Direct monitoring
 only began in 2004, so other oceanic measures are needed to extend the dataset back to 1950
[Credit: Ka-Kit Tung/University of Washington]

The new study argues that this current is not collapsing, but is just transitioning from its fast phase to its slower phase – and that this has implications for heating at the surface.


From 1975 to 1998, the AMOC was in a slow phase. As greenhouse gases were accumulating in the atmosphere, Earth experienced distinct warming at the surface. From about 2000 until now, the AMOC has been in its faster phase, and the increased heat plunging in the North Atlantic has been removing excess heat from the Earth’s surface and storing it deep in the ocean.


“We have about one cycle of observations at depth, so we do not know if it’s periodic, but based on the surface phenomena we think it’s very likely that it’s periodic,” Tung said.


The new paper supports the authors’ previous research showing that since 2000, during which observations show a slowdown in surface warming, heat has accumulated deep in the Atlantic Ocean. The new study shows this is the same period when Atlantic overturning circulation was in its fast phase.


Recent measurements of density in the Labrador Sea suggest the cycle is beginning to shift, Tung said. That means that in coming years the AMOC will no longer be sending more of the excess heat trapped by greenhouse gases deep into the North Atlantic.


“The good news is the indicators show that this slowdown of the Atlantic overturning circulation is ending, and so we shouldn’t be alarmed that this current will collapse any time soon,” Tung said. “The bad news is that surface temperatures are likely to start rising more quickly in the coming decades.”


The paper was published in the journal Nature.


Author: Hannah Hickey | Source: University of Washington [July 18, 2018]



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Great Barrier Reef not bouncing back as before, but there is hope

The Great Barrier Reef is losing its ability to recover from disturbances, but effective local management could revive its capacity to bounce back.











Great Barrier Reef not bouncing back as before, but there is hope
Reefs experiencing flood and poor water quality [Credit: Peter Mumby]

Scientists at The University of Queensland, The Nature Conservancy, ARC Centre of Excellence for Coral Reefs Studies (Coral CoE) and the Australian Institute of Marine Science (AIMS) have found a decline in the ability of Great Barrier Reef Marine Park reefs to recover after bleaching events, outbreaks of crown of thorns starfish or cyclones over an 18-year period, from 1992 to 2010, even before the recent back-to-back bleaching in 2016 and 2017.


Dr Juan Ortiz, lead author from The Australian Institute of Marine Sciences and UQ’s School of Biological Sciences, said that during this time, average coral recovery rates showed a six-fold decline across the Great Barrier Reef.


“This is the first time a decline in recovery rate of this magnitude has been identified in coral reefs,” he said.


The decline is driven by a combination of the legacy effect of acute disturbances like coral bleaching and cyclones and the ongoing effect of chronic pressures like poor water quality and climate change.











Great Barrier Reef not bouncing back as before, but there is hope
Reefs experiencing moderate levels of sediment deposition [Credit: Peter Mumby]

Professor Peter Mumby of the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland, said that this was serious cause for concern, particularly given the accelerating impacts of climate change on reefs, but it is important to stress that not all reefs are failing.


“I believe there is scope for management to help remedy the situation,” he said.


“Our results indicate that coral recovery is sensitive to water quality, and is suppressed for several years following powerful cyclones.


“Some reefs could improve their recovery ability if the quality of the water entering the reef is actively improved.”











Great Barrier Reef not bouncing back as before, but there is hope
Healthy coral reef after recovery [Credit: Peter Mumby]

Study co-author Dr Nicholas Wolff, from The Nature Conservancy, said that some areas of the reef are faring better than others, but their overall finding was that action needs to be taken.


“While there was variability among regions, the decline in recovery rate was consistent in all coral types included in the study,” he said.


Dr Ortiz said that the frequency of acute disturbances was predicted to increase, making careful management key.


“The future of the Great Barrier Reef is threatened without further local management to reduce chronic disturbances and support recovery, and strong global action to limit the effect of climate change.”


The study is published in Science Advances.


Source: University of Queensland [July 18, 2018]



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Billion-year-old lake deposit yields clues to Earth’s ancient biosphere

A sample of ancient oxygen, teased out of a 1.4 billion-year-old evaporative lake deposit in Ontario, provides fresh evidence of what the Earth’s atmosphere and biosphere were like during the interval leading up to the emergence of animal life.











Billion-year-old lake deposit yields clues to Earth's ancient biosphere
Credit: McGill University

The findings, published in the journal Nature, represent the oldest measurement of atmospheric oxygen isotopes by nearly a billion years. The results support previous research suggesting that oxygen levels in the air during this time in Earth history were a tiny fraction of what they are today due to a much less productive biosphere.


“It has been suggested for many decades now that the composition of the atmosphere has significantly varied through time,” says Peter Crockford, who led the study as a PhD student at McGill University. “We provide unambiguous evidence that it was indeed much different 1.4 billion years ago.”


The study provides the oldest gauge yet of what earth scientists refer to as “primary production,” in which micro-organisms at the base of the food chain – algae, cyanobacteria, and the like – produce organic matter from carbon dioxide and pour oxygen into the air.


A smaller biosphere


“This study shows that primary production 1.4 billion years ago was much less than today,” says senior co-author Boswell Wing, who helped supervise Crockford’s work at McGill. “This means that the size of the global biosphere had to be smaller, and likely just didn’t yield enough food – organic carbon – to support a lot of complex macroscopic life,” says Wing, now an associate professor of geological sciences at University of Colorado at Boulder.


To come up with these findings, Crockford teamed up with colleagues from Yale University, University of California Riverside, and Lakehead University in Thunder Bay, Ontario, who had collected pristine samples of ancient salts, known as sulfates, found in a sedimentary rock formation north of Lake Superior. Crockford shuttled the samples to Louisiana State University, where he worked closely with co-authors Huiming Bao, Justin Hayles, and Yongbo Peng, whose lab is one of a handful in the world using a specialized mass-spectrometry technique capable of probing such materials for rare oxygen isotopes within sulfates.


The work also sheds new light on a stretch of Earth’s history known as the “boring billion” because it yielded little apparent biological or environmental change.


“Subdued primary productivity during the mid-Proterozoic era – roughly 2 billion to 800 million years ago – has long been implied, but no hard data had been generated to lend strong support to this idea,” notes Galen Halverson, a co-author of the study and associate professor of earth and planetary sciences at McGill. “That left open the possibility that there was another explanation for why the middle Proterozoic ocean was so uninteresting, in terms of the production and deposit of organic carbon.” Crockford’s data “provide the direct evidence that this boring carbon cycle was due to low primary productivity.”


Exoplanet clues


The findings could also help inform astronomers’ search for life outside our own solar system.


“For most of Earth history our planet was populated with microbes, and projecting into the future they will likely be the stewards of the planet long after we are gone,” says Crockford, now a postdoctoral researcher at Princeton University and Israel’s Weizmann Institute of Science. “Understanding the environments they shape not only informs us of our own past and how we got here, but also provides clues to what we might find if we discover an inhabited exoplanet.”


Source: McGill University [July 18, 2018]



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Life on Earth kept to darkness for much of history, study finds

Tiny creatures that lived in the dark – either underground or below the sea floor – were the dominant life forms on Earth for much of the planet’s history, a study suggests.











Life on Earth kept to darkness for much of history, study finds
Life on Earth is thought to have begun around 3.8 billion years ago with single-celled organisms
[Credit: University of Aberdeen]

Microscopic organisms, including bacteria, were the most abundant forms of life on Earth from about 2 billion years ago until 400 million years ago, when plants began to spread across the land, researchers say.


During this era, these organisms weighed around 10 times as much as all other life on the planet combined, according to the study, which offers insight into the evolution of life on Earth.


Researchers from the Universities of Aberdeen and Edinburgh used data on the current make-up of life on the planet to work out how this has changed over billions of years.


They did this by estimating how changes to the chemical composition of the atmosphere and oceans through time – which are recorded in rocks found around the world – would have affected the ability of different life forms to thrive.


Life on Earth is thought to have begun around 3.8 billion years ago with single-celled organisms. Dinosaurs first appeared around 230 million years ago, and the earliest mammals are believed to have evolved millions of years later.


Plants dominate life on the planet today in terms of their combined weight of carbon, which is about 500 billion tonnes, researchers say. Underground bacteria are now the second most abundant life form, with a combined weight of about 100 billion tonnes of carbon.


Researchers hope their work will help develop new techniques to study microscopic fossils from ancient underground regions. The study, published in Journal of the Geological Society, was supported by the European Union’s Horizon 2020 Research and Innovation Programme.


Professor John Parnell, of the University of Aberdeen’s School of Geosciences, said: “Life underground was the norm on Earth. Until quite recently, the biggest habitat was below ground.”


Dr Sean McMahon, of the University of Edinburgh’s School of Physics and Astronomy, added: “Prehistoric life on Earth was like an iceberg – most of it was found below the surface. The total mass of life on the planet was far smaller before plants took over.”


Source: University of Aberdeen [July 18, 2018]



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Barley heads east: Living plant varieties reveal ancient migration routes across Eurasia

The emergence of agriculture is one of the most important transitions in the development of human societies, as it allowed the establishment of settled communities, specialization of labour and technological innovation.


Barley heads east: Living plant varieties reveal ancient migration routes across Eurasia










Barley heads east: Living plant varieties reveal ancient migration routes across Eurasia
Close-ups of two-rowed (Top) and six-rowed (Bottom) hulled barley
[Credit: Catherine Kneale]

One centre of agricultural origins is the Near East, where barley was domesticated around 10,500 years ago, along with wheat and a number of other crops. Archaeological evidence shows that barley cultivation spread to its ecological limits in Europe, North Africa, and Central, South and East Asia, over a period of approximately 6,000 years.


New results published in PLOS ONE show that different types of barley, suited to different end uses, ecological conditions and cropping regimes, spread via a variety of routes across Eurasia. In many cases, these routes of spread are backed up by archaeological and archaeobotanical evidence.


According to lead author Dr Diane Lister, researcher at the McDonald Institute for Archaeological Research, University of Cambridge, “These results are based on the genetic analysis of living crops – traditional farmers’ varieties known as ‘landraces’.”


“These landraces were mostly collected during the early 20th century and are maintained in what are known as ‘germplasm’ collections around the world, with many landraces having precise geographical coordinates recorded. Numerous studies have shown that, remarkably, landraces can preserve an ancient and local genetic signature of the initial spread of farming during prehistory, and this is beautifully illustrated in this current study.”


The results indicate that the different eastward routes of spread of each barley population were distinct from each other in a number of ways, reflecting human choice of particular attributes or the effect of environmental adaptation. These different routes include ones to the north and south of the Iranian Plateau; through the Inner Asian Mountain Corridor in Central Asia, possibly connecting up to the Chinese section of the Silk Road; a high altitude spread on the southern edge of the Tibetan Plateau; a high latitude spread through the northern steppe; two distinct spreads into Japan; and a maritime route from South Asia. Previous research has provided increasing numbers of direct radiocarbon dates enabling the different routes to be dated.











Barley heads east: Living plant varieties reveal ancient migration routes across Eurasia
Map showing proposed routes of spread of six different ancestral populations of barley landraces.
Direct radiocarbon dates from archaeological barley grain have enabled the timing
of these different routes to be elucidated [Credit: D. Lister]

Lister describes further, “One barley population is widespread, particularly around the coastlines. This population may have travelled eastwards via a maritime route from South Asia, via Southeast Asia. This particular population is made up of winter-sown varieties of barley, which are thought to be important in rice-growing areas of East Asia, where a crop of rice is commonly grown in the summer months, and barley adapted to winter-sowing regimes can be planted after the rice harvest. The development of multi-cropping practices during prehistory is thought to have greatly increased productivity and stability, enabling more complex societies to develop.”


“Another barley population predominates on the high Tibetan Plateau. This barley has a naked grain, making it a particularly attractive staple, as it doesn’t require the pearling process that hulled barley requires for human consumption. Along with the herding of yak, this naked type of barley is an essential for the Tibetan way of life, and their importance are clearly seen in the offerings of naked barley grains and yak butter in Tibetan Buddhist temples around the region. The staple carbohydrate eaten by the Tibetans is tsampa, made from roasted naked barley flour and mixed with salty Tibetan butter tea.”


Previous research carried out through the Food Globalization in Prehistory project at the University of Cambridge showed that barley cultivation appeared in the Chinese Tibetan Plateau 4,000 years ago, and is thought to have been of essential importance in colonizing the ‘roof of the world’. Some scholars have questioned whether this barley was a product of a local domestication of a wild ancestor separate from those in the Near East. This current study also looked at the genetic relationship between landrace barley, it’s wild progenitor, and weedy varieties. The results show that is unlikely that barley was domesticated in this region, and that ‘wild’ barleys on the plateau are probably weedy derivatives of cultivated barley.


What does this mean for today? Lister concludes, “Barley is an extremely hardy crop, able to grow in regions where other crops are unable to grow, and is an important staple in such environments. Understanding the spread of its cultivation during prehistory, and the various factors that affected its establishment in different regions of Eurasia, will contribute towards our understanding of climate change and its current and future effects on agriculture.”


Source: University of Cambridge [July 18, 2018]



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Research cites faulty science and ethics in DNA analyzes of ‘Ata’

University of Otago-led international collaborative research calls into question the ethics and skeletal and genomic analysis surrounding research into the much publicised alien-like “Atacama mummy”.











Research cites faulty science and ethics in DNA analyzes of 'Ata'
The Atacama mummy [Credit: Bhattacharya et al. Genome Research, 2018]

University of Otago bioarchaeologist Associate Professor Sian Halcrow led an international research team focusing on the very small mummified body, whose findings are published in the International Journal of Paleopathology. The team evaluated work carried out on the body by Stanford University researchers, which was published in Genome Research earlier this year.


The mummy in question was discovered more than a decade ago in an abandoned town in the Atacama Desert of Chile and nicknamed “Ata”. In analysing this tiny mummified body, the Stanford researchers concluded genetic abnormalities could explain perceived abnormal characteristics of the skeleton, which was only 15cm long.


However, Associate Professor Halcrow and her peers from Universities in the United States, Sweden and Chile, have highlighted a number of concerns about the ethics, skeletal and genomic analysis around the research.


As experts in human anatomy and skeletal development, the Otago-led research team found no evidence for any of the skeletal anomalies reported by the Stanford researchers. All the abnormal characteristics cited by the Stanford researchers are part of normal skeletal development of a foetus, the Otago-led research team say.


“Unfortunately, there was no scientific rationale to undertake genomic analyses of Ata because the skeleton is normal, the identified genetic mutations are possibly coincidental, and none of the genetic mutations are known to be strongly associated with skeletal pathology that would affect the skeleton at this young age,” Associate Professor Halcrow says.


The situation highlights the need for an interdisciplinary research approach for a case study such as “Ata”, she says.


“This case study allows us to showcase how drawing together multiple experts in osteology, medicine, archaeology, history and genetics is essential for accurate scientific interpretations and for considering the ethical implications of genomic analysis.


“A nuanced understanding of skeletal biological processes and cultural context is essential for accurate scientific interpretation and for acting as a check on the ethics and legality of such research.”


Co-author Bernardo Arriaza, a bioarchaeologist from the University of Tarapacá in Chile says it is crucial to consider the archaeological content in addition to an interdisciplinary approach. It is important to remember the situation is a pregnancy loss possibly from the very recent past.


“This mummy reflects a sad loss for a mother in the Atacama Desert,” Dr Arriaza says.


The Otago-led research team also highlighted concerns around archaeological legislation and the ethics of carrying out research with no ethical consents, nor archaeological permits cited by the Stanford researchers.


“We caution DNA researchers about getting involved in cases that lack clear context and legality, or where the remains have resided in private collections. In the case of Ata, costly and time-consuming scientific testing using whole genome techniques was unnecessary,” Associate Professor Halcrow says.


Associate Professor Halcrow is also disappointed that she and co-author, Kristina Killgrove, from the University of North Carolina at Chapel Hill’s Department of Anthropology, were unable to submit a response to the article and research in question to Genome Research.


“We were both told that Genome Research does not publish letters to the editor, only original research papers, despite senior authors Nola and Butte’s (the Stanford University researchers’) later response statement in which they seek to justify the ethics of their analyses,” Associate Professor Halcrow says.


“For the scientific process to advance it is essential to have open debate through peer-reviewed journals.”


Source: University of Otago [July 18, 2018]



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Archaeologists find ancient pottery workshop in Egypt

Archaeologists in Egypt have discovered an ancient pottery manufacturing workshop dating to more than 4,000 years ago in the southern province of Aswan, the Antiquities Ministry said Thursday.











Archaeologists find ancient pottery workshop in Egypt
The 4000-year old pottery workshop that was recently discovered close to the Nile River
 in Aswan province, southern Egypt [Credit: Ministry of Antiquities]

The workshop, the oldest pottery workshop in the Old Kingdom, belongs to the 4th Dynasty, spanning 2,613 to 2,494 BC, the ministry said in a statement. The Old Kingdom is also known as the age when pyramid-building flourished.











Archaeologists find ancient pottery workshop in Egypt
Hollow for kneading clay [Credit: Ministry of Antiquities]

Inside the workshop, archaeologists found an ancient pottery wheel made of a limestone turntable and a hollow base.











Archaeologists find ancient pottery workshop in Egypt
Potter’s Wheel [Credit: Ministry of Antiquities]

Mostafa al-Waziri, secretary general of the Supreme Council of Antiquities, says the discovery is “rare” and reveals more about the development of pottery manufacturing and the daily lives of ancient Egyptians during that time in history.


Source: The Associated Press [July 19, 2018]



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Neanderthals could make fire – just like our modern ancestors

Neanderthals were able to make fire on a large scale with the aid of pyrite and hand-axes. This means they could decide when and where they wanted fire and were not dependent on natural fire, as was thought earlier. Archaeologist Andrew Sorensen has discovered the first material evidence for this.











Neanderthals could make fire – just like our modern ancestors
Neanderthal reconstruction [Credit: Natural History Museum/Allan Henderson]

Dependent on natural fire


‘Late prehistoric modern humans could make fire whenever they needed it,’ says archaeologist Andrew Sorensen. They did so by striking a piece of pyrite – a mineral that contains iron – with flint tools called strike-a-lights. But there was no evidence their more ancient relatives the Neanderthals, a long extinct prehistoric human species, used this technique as well.


The general idea was therefore that Neanderthals did not make their own fire, but were dependent on natural fires caused by lightning strikes, for instance. Sorensen: ‘They would have collected flaming sticks to light their own fires, which they kept burning at all times and were even able to take with them as they moved around.’ No mean feat, nor are you always guaranteed fire.


Microscopic wear


This idea now appears to be incorrect, at least among some younger Neanderthal groups. Sorensen has discovered that our Stone Age cousins were able to make their own fires, and that this practice was widespread.











Neanderthals could make fire – just like our modern ancestors
Images of mineral use-wear traces on an archaeological biface from Meyrals (top) and biface BdV 2692
 from Bous-des-Vergnes (bottom), both situated in the Dordogne. The white lines demarcate the zones
where mineral use wear traces comparable to pyrite are present. The arrows indicates the
orientation of striations [Credit: Sorensen et al. Scientific Reports, 2018] 

Together with French archaeologist Emilie Claud and Leiden Archaeology Professor Marie Soressi, he discovered very specific microscopic wear on flint hand-axes (also called bifaces) from the Middle Palaeolithic, the era of the Neanderthals.


‘I recognised this type of wear from my earlier experimental work. These are the traces you get if you try to generate sparks by striking a piece of flint against a piece of pyrite.’ Only these hand-axes are much older than the fire making tools on which this wear has so far been found.


Making fire on a large scale


Sorensen and Claud studied dozens of hand-axes of about 50,000 years in age from various sites throughout France. They found the same distinctive wear on all of them. ‘This proves that it was not an incidental find, but that the Neanderthals could make fire on a large scale,’ says Sorensen.











Neanderthals could make fire – just like our modern ancestors
Images of experimental wear traces at low-magnification
[Credit: Sorensen et al. Scientific Reports, 2018]

And that is of huge significance. Sorensen explains: ‘Being able to make their own fire gives the Neanderthals much more flexibility in their lives. It’s a skill we suspected, but didn’t know for sure they possessed.


That they figured out bashing two rocks together could produce a brand new substance (fire) completely unlike the parent materials gives us new insight into the cognitive skills of Neanderthals. It shows Neandertals possessed similar technological capabilities to modern humans, even though they sometimes behaved differently.’











Neanderthals could make fire – just like our modern ancestors
Map of southwest France with locations of sites discussed in text. Inset map includes northern
France and Belgium [Credit: Sorensen et al. Scientific Reports, 2018]

Striking flint with pyrite


With a combination of microscopic research and experiments, Sorensen discovered that the traces of wear were specific to fire making. ‘You see percussion marks in the shape of a letter C. You also see parallel scratches, or striations, along the length of the hand-axe and mineral polish on the surface.’ He carried out various experiments to eliminate other causes of this distinctive wear. He used hand-axes to grind pigments, sharpen other tools, and for other pounding and rubbing activities using various types of stone. ‘A hand-axe was the Neanderthal Swiss Army Knife. They used them for everything. But only making fire with pyrite would have produced this exact suite of use-wear traces.’


The study is published in Scientific Reports.

Source: Leiden University [July 19, 2018]



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Archaeologists in Egypt open large black granite sarcophagus found in Alexandria

Archaeologists in Egypt have opened a large, sealed, black granite sarcophagus dating 2,300 years in the coastal city of Alexandria.











Archaeologists in Egypt open large black granite sarcophagus found in Alexandria
Only waterlogged skeletal remains were found in the sarcophagus
[Credit: Egyptian Ministry of Antiquities]

The discovery, announced earlier this month, triggered speculation in local and international media about its contents.











Archaeologists in Egypt open large black granite sarcophagus found in Alexandria
The sarcophagus, which is almost two metres high and three metres in length, was discovered last week
[Credit: Egyptian Ministry of Antiquities]

However, Al-Waziri told reporters that only skeletal remains and sewage water were found in the sarcophagus, quashing speculation that it belonged to some ancient ruler.











Archaeologists in Egypt open large black granite sarcophagus found in Alexandria
Archaeologists removing the sarcophagus lid
[Credit: Ministry of Antiquities]

He said the sarcophagus, weighting some 30 tons, likely belonged to a wealthy family that lived during the Ptolemaic era.


Source: The Associated Press [July 19, 2018]



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Newly discovered armored dinosaur from Utah reveals intriguing…


Newly discovered armored dinosaur from Utah reveals intriguing family history http://www.geologypage.com/2018/07/newly-discovered-armored-dinosaur-from-utah-reveals-intriguing-family-history.html


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