четверг, 26 июля 2018 г.

Seeing Eyes Eyes are our window on the world, but for…

Seeing Eyes

Eyes are our window on the world, but for researchers hoping to discover the secrets behind how they work, they’re a window made of one-way glass. Much of our understanding of how the eye and brain interact comes from dissections of removed eyes, which can only tell you so much. A new approach uses a tiny injectable mesh of electronics (pictured in place in a mouse eye) to directly monitor activity in a healthy eye. The mesh settles, conforming to contours at the back of the eye (retina), and interfaces with individual cells without impairing vision or movement. Tiny sensors then record activity for up to two weeks, allowing researchers to track detailed patterns of cell activity. The technique has already revealed new information about how our eyes behave at different times of day, and researchers hope it could open a window on everything from glaucoma to vision-restoring prosthetics.

Written by Anthony Lewis

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First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole

Artist’s impression of S2 passing supermassive black hole at centre of Milky Way

PR Image eso1825b

Artist’s impression of S2 passing supermassive black hole at centre of Milky Way – annotated

PR Image eso1825c

Orbit diagram of S2 around black hole at centre of the Milky Way

PR Image eso1825d

Orbits of stars around black hole at the heart of the Milky Way

PR Image eso1825e

The daily motion of the S2 star as seen with GRAVITY

PR Image eso1825f

GRAVITY tracks star passing supermassive black hole

PR Image eso1825g 

NACO observation of the stars at the centre of the Milky Way


ESOcast 173: First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole

ESOcast 173: First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole

Artist's impression of star passing close to supermassive black hole

Artist’s impression of star passing close to supermassive black hole

Zooming in on the heart of the Milky Way

Zooming in on the heart of the Milky Way

The star S2 makes a close approach to the black hole at the centre of the Milky Way

The star S2 makes a close approach to the black hole at the centre of the Milky Way

Stars orbiting the black hole at the heart of the Milky Way

Stars orbiting the black hole at the heart of the Milky Way

Simulation of the orbits of stars around the black hole at the centre of the Milky Way

Simulation of the orbits of stars around the black hole at the centre of the Milky Way

Animation of the orbit of the star S2 around the galactic centre black hole

Animation of the orbit of the star S2 around the galactic centre black hole

Fulldome view of stars orbiting the black hole at the heart of the Milky Way

Fulldome view of stars orbiting the black hole at the heart of the Milky Way

Orbiting a black hole near the event horizon (fulldome)

Orbiting a black hole near the event horizon (fulldome)

Close-up of a black hole near the event horizon (fulldome)

Close-up of a black hole near the event horizon (fulldome)

Orbiting a black hole near the event horizon 2 (fulldome)

Orbiting a black hole near the event horizon 2 (fulldome)

Orbiting a black hole near the event horizon 3 (fulldome)

Orbiting a black hole near the event horizon 3 (fulldome)

Orbiting a black hole near the event horizon 4 (fulldome)

Orbiting a black hole near the event horizon 4 (fulldome)

Flight from the Earth to the Milky Way Black Hole

Flight from the Earth to the Milky Way Black Hole

Testing general relativity at the Galactic Centre — compilation

Testing general relativity at the Galactic Centre — compilation

Observations made with ESO’s Very Large Telescope have for the first time revealed the effects predicted by Einstein’s general relativity on the motion of a star passing through the extreme gravitational field near the supermassive black hole in the centre of the Milky Way. This long-sought result represents the climax of a 26-year-long observation campaign using ESO’s telescopes in Chile.

Obscured by thick clouds of absorbing dust, the closest supermassive black hole to the Earth lies 26 000 light-years away at the centre of the Milky Way. This gravitational monster, which has a mass four million times that of the Sun, is surrounded by a small group of stars orbiting around it at high speed. This extreme environment — the strongest gravitational field in our galaxy — makes it the perfect place to explore gravitational physics, and particularly to test Einstein’s general theory of relativity.

New infrared observations from the exquisitely sensitive GRAVITY [1], SINFONI and NACO instruments on ESO’s Very Large Telescope (VLT) have now allowed astronomers to follow one of these stars, called S2, as it passed very close to the black hole during May 2018. At the closest point this star was at a distance of less than 20 billion kilometres from the black hole and moving at a speed in excess of 25 million kilometres per hour — almost three percent of the speed of light [2].

The team compared the position and velocity measurements from GRAVITY and SINFONI respectively, along with previous observations of S2 using other instruments, with the predictions of Newtonian gravity, general relativity and other theories of gravity. The new results are inconsistent with Newtonian predictions and in excellent agreement with the predictions of general relativity.

These extremely precise measurements were made by an international team led by Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, in conjunction with collaborators around the world, at the Paris Observatory–PSL, the Université Grenoble Alpes, CNRS, the Max Planck Institute for Astronomy, the University of Cologne, the Portuguese CENTRA – Centro de Astrofisica e Gravitação and ESO. The observations are the culmination of a 26-year series of ever-more-precise observations of the centre of the Milky Way using ESO instruments [3].

“This is the second time that we have observed the close passage of S2 around the black hole in our galactic centre. But this time, because of much improved instrumentation, we were able to observe the star with unprecedented resolution,” explains Genzel. “We have been preparing intensely for this event over several years, as we wanted to make the most of this unique opportunity to observe general relativistic effects.

The new measurements clearly reveal an effect called gravitational redshift. Light from the star is stretched to longer wavelengths by the very strong gravitational field of the black hole. And the change in the wavelength of light from S2 agrees precisely with that predicted by Einstein’s theory of general relativity. This is the first time that this deviation from the predictions of the simpler Newtonian theory of gravity has been observed in the motion of a star around a supermassive black hole.

The team used SINFONI to measure the velocity of S2 towards and away from Earth and the GRAVITY instrument in the VLT Interferometer (VLTI) to make extraordinarily precise measurements of the changing position of S2 in order to define the shape of its orbit. GRAVITY creates such sharp images that it can reveal the motion of the star from night to night as it passes close to the black hole — 26 000 light-years from Earth.

Our first observations of S2 with GRAVITY, about two years ago, already showed that we would have the ideal black hole laboratory,” adds Frank Eisenhauer (MPE), Principal Investigator of GRAVITY and the SINFONI spectrograph. “During the close passage, we could even detect the faint glow around the black hole on most of the images, which allowed us to precisely follow the star on its orbit, ultimately leading to the detection of the gravitational redshift in the spectrum of S2.

More than one hundred years after he published his paper setting out the equations of general relativity, Einstein has been proved right once more — in a much more extreme laboratory than he could have possibly imagined!

Françoise Delplancke, head of the System Engineering Department at ESO, explains the significance of the observations: “Here in the Solar System we can only test the laws of physics now and under certain circumstances. So it’s very important in astronomy to also check that those laws are still valid where the gravitational fields are very much stronger.

Continuing observations are expected to reveal another relativistic effect very soon — a small rotation of the star’s orbit, known as Schwarzschild precession — as S2 moves away from the black hole.

Xavier Barcons, ESO’s Director General, concludes: “ESO has worked with Reinhard Genzel and his team and collaborators in the ESO Member States for over a quarter of a century. It was a huge challenge to develop the uniquely powerful instruments needed to make these very delicate measurements and to deploy them at the VLT in Paranal. The discovery announced today is the very exciting result of a remarkable partnership.”


[1] GRAVITY was developed by a collaboration consisting of the Max Planck Institute for Extraterrestrial Physics (Germany), LESIA of Paris Observatory–PSL / CNRS / Sorbonne Université / Univ. Paris Diderot and IPAG of Université Grenoble Alpes / CNRS (France), the Max Planck Institute for Astronomy (Germany), the University of Cologne (Germany), the CENTRA–Centro de Astrofisica e Gravitação (Portugal) and ESO.

[2] S2 orbits the black hole every 16 years in a highly eccentric orbit that brings it within twenty billion kilometres — 120 times the distance from Earth to the Sun, or about four times the distance from the Sun to Neptune — at its closest approach to the black hole. This distance corresponds to about 1500 times the Schwarzschild radius of the black hole itself.

[3] Observations of the centre of the Milky Way must be made at longer wavelengths (in this case infrared) as the clouds of dust between the Earth and the central region strongly absorb visible light.

More Information

This research was presented in a paper entitled “Detection of the Gravitational Redshift in the Orbit of the Star S2 near the Galactic Centre Massive Black Hole“, by the GRAVITY Collaboration, to appear in the journal Astronomy & Astrophysics on 26 July 2018.

The GRAVITY Collaboration team is composed of: R. Abuter (ESO, Garching, Germany), A. Amorim (Universidade de Lisboa, Lisbon, Portugal), N. Anugu (Universidade do Porto, Porto, Portugal), M. Bauböck (Max Planck Institute for Extraterrestrial Physics, Garching, Germany [MPE]), M. Benisty (Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France [IPAG]), J.P. Berger (IPAG; ESO, Garching, Germany), N. Blind (Observatoire de Genève, Université de Genève, Versoix, Switzerland), H. Bonnet (ESO, Garching, Germany), W. Brandner (Max Planck Institute for Astronomy, Heidelberg, Germany [MPIA]), A. Buron (MPE), C. Collin (LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Meudon, France [LESIA]), F. Chapron (LESIA), Y. Clénet (LESIA), V. Coudé du Foresto (LESIA), P. T. de Zeeuw (Sterrewacht Leiden, Leiden University, Leiden, The Netherlands; MPE), C. Deen (MPE), F. Delplancke-Ströbele (ESO, Garching, Germany), R. Dembet (ESO, Garching, Germany; LESIA), J. Dexter (MPE), G. Duvert (IPAG), A. Eckart (University of Cologne, Cologne, Germany; Max Planck Institute for Radio Astronomy, Bonn, Germany), F. Eisenhauer (MPE), G. Finger (ESO, Garching, Germany), N.M. Förster Schreiber (MPE), P. Fédou (LESIA), P. Garcia (Universidade do Porto, Porto, Portugal), R. Garcia Lopez (MPIA), F. Gao (MPE), E. Gendron (LESIA), R. Genzel (MPE; University of California, Berkeley, California, USA), S. Gillessen (MPE), P. Gordo (Universidade de Lisboa, Lisboa, Portugal), M. Habibi (MPE), X. Haubois (ESO, Santiago, Chile), M. Haug (ESO, Garching, Germany), F. Haußmann (MPE), Th. Henning (MPIA), S. Hippler (MPIA), M. Horrobin (University of Cologne, Cologne, Germany), Z. Hubert (LESIA; MPIA), N. Hubin (ESO, Garching, Germany), A. Jimenez Rosales (MPE), L. Jochum (ESO, Garching, Germany), L. Jocou (IPAG), A. Kaufer (ESO, Santiago, Chile), S. Kellner (Max Planck Institute for Radio Astronomy, Bonn, Germany), S. Kendrew (MPIA, ESA), P. Kervella (LESIA; MPIA), Y. Kok (MPE), M. Kulas (MPIA), S. Lacour (LESIA), V. Lapeyrère (LESIA), B. Lazareff (IPAG), J.-B. Le Bouquin (IPAG), P. Léna (LESIA), M. Lippa (MPE), R. Lenzen (MPIA), A. Mérand (ESO, Garching, Germany), E. Müller (ESO, Garching, Germany; MPIA), U. Neumann (MPIA), T. Ott (MPE), L. Palanca (ESO, Santiago, Chile), T. Paumard (LESIA), L. Pasquini (ESO, Garching, Germany), K. Perraut (IPAG), G. Perrin (LESIA), O. Pfuhl (MPE), P.M. Plewa (MPE), S. Rabien (MPE), J. Ramos (MPIA), C. Rau (MPE), G. Rodríguez-Coira (LESIA), R.-R. Rohloff (MPIA), G. Rousset (LESIA), J. Sanchez-Bermudez (ESO, Santiago, Chile; MPIA), S. Scheithauer (MPIA), M. Schöller (ESO, Garching, Germany), N. Schuler (ESO, Santiago, Chile), J. Spyromilio (ESO, Garching, Germany), O. Straub (LESIA), C. Straubmeier (University of Cologne, Cologne, Germany), E. Sturm (MPE), L.J. Tacconi (MPE), K.R.W. Tristram (ESO, Santiago, Chile), F. Vincent (LESIA), S. von Fellenberg (MPE), I. Wank (University of Cologne, Cologne, Germany), I. Waisberg (MPE), F. Widmann (MPE), E. Wieprecht (MPE), M. Wiest (University of Cologne, Cologne, Germany), E. Wiezorrek (MPE), J. Woillez (ESO, Garching, Germany), S. Yazici (MPE; University of Cologne, Cologne, Germany), D. Ziegler (LESIA) and G. Zins (ESO, Santiago, Chile).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 15 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a strategic partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Reinhard Genzel
Director, Max Planck Institute for Extraterrestrial Physics
Garching bei München, Germany
Tel: +49 89 30000 3280

Frank Eisenhauer
GRAVITY Principal Investigator, Max Planck Institute for Extraterrestrial Physics
Garching bei München, Germany
Tel: +49 (89) 30 000 3563

Stefan Gillessen
Max-Planck Institute for Extraterrestrial Physics
Garching bei München, Germany
Tel: +49 89 30000 3839

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591

Hannelore Hämmerle
Public Information Officer, Max Planck Institute for Extraterrestrial Physics
Garching bei München, Germany
Tel: +49 (89) 30 000 3980

Source: ESO/News

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This is Not the Hydrothermal Deposit You’re Looking For   A…

This is Not the Hydrothermal Deposit You’re Looking For

   A hotspot for exploration on Mars centers on areas that were once, or are currently, next to a significant source of heat such as volcanoes. Martian volcanoes have not been active for the last couple million years, but beneath the shifting sands and dust of the Red Planet we find old lava flows frozen in time.

These ancient lava flows may have provided a source of heat, along with liquid water or subsurface ice, to generate an environment conducive for the development of ancient life. Geological evidence for hot water interacting with rock is what we mean by hydrothermal: sites with these conditions are very difficult to identify from orbit.

One closeup view shows sand dunes scouring what appears to be a highly-cratered, old lava flow in the Tempe Terra region, located in the Northern Hemisphere. The flat, dark areas are basaltic in composition, a rock commonly found around active volcanoes, and the lighter-toned material is covered in rusted Martian dust. The recently-launched InSight lander will reveal whether Mars is geologically active internally. (289 km above the surface, less than 1 km across)

NASA/JPL/University of Arizona


A century-old model for life’s origin gets significant substantiation

In 1924, Russian biochemist Alexander Oparin claimed that life on Earth developed through gradual chemical changes of organic molecules, in the “primordial soup” which likely existed on Earth four billion years ago. In his view, the complex combination of lifeless molecules, joining forces within small oily droplets, could assume life faculties – self-replication, selection and evolution. These ideas were received with considerable doubt, still pertaining today.

A century-old model for life's origin gets significant substantiation
A ‘walk’ in composition space for a lipid world molecular assembly, shown in simplified 3 dimensions.
A point on the line signifies a specific composition along the time axis, whereby the three coordinates
 are amounts of the three different molecule types. A composome (pink background) is a time interval
when the composition stays almost unchanged, signifying compositional replication
[Credit: Weizmann Institute of Science]

Thirty years later, when DNA structure was deciphered, it was realized that this molecule is capable of self-replication, seemingly solving the enigma of life’s origin without resort to Oparin’s droplets. But critics argued that life requires not only replicators, but also enzyme catalysts to control­ metabolism. Another 30 years passed before the discovery that RNA, key component in information transfer from DNA to proteins, can also be an enzyme. This is how the concept of “RNA World” was born, whereby life began when the primordial soup gave birth to a ribozyme, which can both replicate and control metabolism.

Despite this doubts lingered, because a replicating ribosome is a highly complex molecule, with negligible probability of spontaneous appearance in the soup. This led to an alternative concept – mutually catalytic networks, affording the copying of entire molecular ensembles. This idea echoes Oparin’s evolving complex combination of simple molecules, each with high likelihood of appearance in the soup. What remained was to generate a detailed chemical model that will help support such a narrative.

Prof. Doron Lancet and colleagues at the Weizmann Institute of Science, Dept. of Molecular Genetics came up with such a model. First, it was necessary to identify the appropriate type of molecules, that can accrete together and effectively form networks of mutual interactions, in line with Oparin’s droplets. Lancet proposed lipids, oily compounds that spontaneously form the aggregated membranes enclosing all living cells. Lipid bubbles (vesicles) can grow and split much like living cells. This is how Lancet generated the concept “Lipid World” two decades ago.

To analyze the invoked molecular networks, they have used tools of systems biology and computational chemistry, that allow instilling rigor into the somewhat ephemeral concept of mutually catalytic networks.

They first address in detail the nagging question of how lipid assemblies can store and transmit information from one growth-split generation to another. They come up with a hitherto rarely explored notion that what gets propagated is compositional information, and show by detailed computer simulations how this happens. Furthermore, they indicate a profound similarity of such composition copying to the way by which growing and proliferating living cells preserve their epigenetic information, that which is independent of DNA replication.

In an article just appeared in the Journal of the Royal Society Interface Lancet and colleagues report an extensive literature survey, showing that lipids can exert enzyme-like catalysis, similar to ribozymes. This s a property crucial for forming the mutual interaction networks. Subsequently, the authors show, using the tools of systems biology and computational chemistry, that the oily droplets can accumulate and store compositional information, and when undergoing fission, transmit the information to progeny.

Based on the computer model they developed, the scientists demonstrated that specific lipid compositions, called “composomes”, can undergo compositional mutations, be subject to natural selection in response to environmental changes, and even undergo Darwinian selection. Prof. Lancet comments that such an information system, which is based on compositions and not on the sequence of chemical “letters” as in DNA, is reminiscent of the realm of epigenetics, where traits are inherited independent of the DNA sequence. This lends credence to the scientists’ assumption that life could emerge before the advent of DNA and RNA. In their article they in fact delineate a chemical path that lead to the appearance of genetic material in the framework of the oily droplets.

Lancet’s “Lipid World” concept is contingent upon the question of whether there were sufficient oil-like “water hating” molecules in the primordial soup. Here too, the scientists describe a comprehensive literature search, according to which there is a high probability for such molecules to be present on early Earth. This conclusion was reinforced by a very recent study showing that Enceladus, one of Saturn’s moons, has a sub-glacial ocean (primordial ocean) replete with “water hating” compounds, some of which could form Lipid World-type droplets. Prof. Lancet contends that these findings, along with innovative model-based computations, show that the probability of life’s emergence is relatively high, including the exciting possibility that Enceladus presently harbors some early lipid-based life forms.

Source: Weizmann Institute of Science [July 25, 2018]




Unisexual salamander evolution: A long, strange trip

The reproductive history of the unisexual, ladies-only salamander species is full of evolutionary surprises.

Unisexual salamander evolution: A long, strange trip
New research from The Ohio State University has uncovered surprising details about the reproductive
 history of an all-female salamander species [Credit: Zac Herr, ZTH Photography]

In a new study, a team of researchers at The Ohio State University traced the animals’ genetic history back 3.4 million years and found some head-scratching details – primarily that they seem to have gone for millions of years without any DNA contributions from male salamanders and still have managed to persist. The research appears in the journal Evolution.

First, a bit about the unisexual Ambystoma salamander: They’re female, and they reproduce mainly through cloning and the occasional theft of another salamander species’ sperm, which the males of sexual species deposit on leaves and twigs and the like. When this happens, it stimulates egg production and the borrowed species’ genetic information is sometimes incorporated into the genome of the unisexual salamanders, a process called kleptogenesis.

Scientists who study these amphibians and their relatives, which are also called mole salamanders, have theorized that the theft of sperm is part of what has kept the unisexuals around so long. If all they ever did was clone themselves, biologists reason, they’d be vulnerable to all kinds of problems that unfold when you don’t mix up the DNA pool and would disappear from the earth fairly quickly.

Going into the study, the Ohio State team figured this sperm-borrowing happened with regularity throughout history, said study co-author H. Lisle Gibbs, a professor of evolution, ecology and organismal biology.

But findings revealed that the salamanders rarely dip into the other-species pool for genetic variation.

Unisexual salamander evolution: A long, strange trip
Researcher Rob Denton holds a unisexual Ambystoma salamander
[Credit: Kevin Fitzsimons, The Ohio State University]

“This research shows that millions of years went by where they weren’t taking DNA from other species, and then there were short bursts where they did it more frequently,” said Rob Denton, who led the project as an Ohio State graduate student and is currently a postdoctoral researcher at the University of Connecticut.

“Surprisingly, it doesn’t look like they’re suffering any ill genetic effects. It’s a mysterious scenario that an animal can avoid sexual reproduction for millions of years and not suffer the consequences of that.”

Using newly available technologies and a novel and complex approach to sequence and evaluate about 100 DNA samples from the salamanders, the Ohio State researchers developed a genetic blueprint for what unfolded in the last 3.4 million years.

“When interbreeding happens, or there are adaptations to new changing environmental conditions, that all gets captured in the patterns of their genetic variation,” Denton said.

Under normal circumstances in nature, one would expect these salamanders to be long-gone, Gibbs said.

“Most asexual lineages blink out after 100,000 years. We think these have been around for 5 million years,” he said.

A puzzling detail that emerged in the study is that the sampling of DNA from other species appears to have increased in frequency in recent times, he said.

“The reasons for this are sort of tantalizing, and make you wonder: Did this happen because of some sort of environmental change or specific interactions with other species? We don’t know those answers but now we have some provocative questions,” Denton said.

He also noted that the evolutionary history of the unisexual salamander is far different from the history of other unisexual species, such as Amazon mollies.

“The mollies live fast and die hard, in less than a year, but these salamanders live slow and for long periods of time, into their 20s and 30s. And they reproduce every few years,” Denton said.

“These salamanders are just sort of plodding through evolutionary time doing strange and surprising things.”

The researchers noted that the study looked only at salamander DNA samples from Ohio and Michigan, so it’s unclear if the same patterns would be seen throughout Eastern North America and Canada, where the unisexual Ambystoma is also common.

Gibbs said it’s possible that this research could inform other areas of study, including plant science, because many plants are – like the unisexual salamanders – polyploid organisms. That means that they have more than two sets of chromosomes.

“If we can find patterns in common with these plants and animals, it would help us understand how these organisms evolve and how the molecular machinery of species with more than two sets of chromosomes works,” Gibbs said.

Source: The Ohio State University [July 25, 2018]




Yellowstone super-volcano has a different history than previously thought

Scientists have long thought that Yellowstone Caldera, part of the Rocky Mountains and located mostly in Wyoming, is powered by heat from the Earth’s core, similar to most volcanoes such as the recently active Kilauea volcano in Hawaii. However, new research published in Nature Geoscience by Ying Zhou, an associate professor with the Virginia Tech College of Science’s Department of Geosciences, shows a different past.

Yellowstone super-volcano has a different history than previously thought
Yellowstone National Park’s Grand Prismatic hot spring is among the park’s myriad hydrothermal features created
by the fact Yellowstone is a supervolcano – the largest type of volcano on Earth [Credit: University of Utah]

“In this research, there was no evidence of heat coming directly up from the Earth’s core to power the surface volcano at Yellowstone,” Zhou said. “Instead, the underground images we captured suggest that Yellowstone volcanoes were produced by a gigantic ancient oceanic plate that dove under the Western United States about 30 million years ago. This ancient oceanic plate broke into pieces, resulting in perturbations of unusual rocks in the mantle which led to volcanic eruptions in the past 16 million years.”

The eruptions were very explosive, Zhou added. A theoretical seismologist, Zhou created X-ray-like images of the Earth’s deep interior from USArray – part of the Earthscope project funded by the National Science Foundation – and discovered an anomalous underground structure at a depth of about 250 to 400 miles right beneath the line of volcanoes.

“This evidence was in direct contradiction to the plume model,” Zhou said.

In her study, Zhou found the new images of the Earth’s deep interior showed that the oceanic Farallon plate, which used to be where the Pacific Ocean is now, wedged itself beneath the present-day Western United States. The ancient oceanic plate was broken into pieces just like the seafloor in the Pacific today. A section of the subducted oceanic plate started tearing off and sinking down to the deep earth.

The sinking section of oceanic plate slowly pushed hot materials upward to form the volcanoes that now make up Yellowstone. Further, the series of volcanoes that make up Yellowstone have been slowly moving, achingly so, ever since. “The process started at the Oregon-Idaho border about 16 million years ago and propagated northwestward, forming a line of volcanoes that are progressively younger as they stretched northwest to present-day Wyoming,” Zhou added.

Yellowstone super-volcano has a different history than previously thought
This is the location of the Yellowstone’s hotspot track. The triangles indicate general locations of the Yellowstone
 and Snake River Plain age-progressive volcanoes with ages shown in millions of years, plotted
on a topography map of the Western United States [Credit: Virginia Tech]

The previously-held plume model was used to explain the unique Yellowstone hotspot track – the line of volcanoes in Oregon, Idaho, and Wyoming that dots part of the Midwest. “If the North American plate was moving slowly over a position-fixed plume at Yellowstone, it will displace older volcanoes towards the Oregon-Idaho border and form a line of volcanoes, but such a deep plume has not been found.” Zhou said. So, what caused the track? Zhou intends to find out.

“It has always been a problem there, and scientists have tried to come up with different ways to explain the cause of Yellowstone volcanoes, but it has been unsuccessful,” she said, adding that hotspot tracks are more popular in oceans, such as the Hawaii islands. The frequent Geyser eruptions at Yellowstone are of course not volcanic eruptions with magna, but due to super-heated water. The last Yellowstone super eruption was about 630,000 years ago, according to experts. Zhou has no predictions on when or if Yellowstone could erupt again.

The use of the X-ray-like images for this study is unique in itself. Just as humans can see objects in a room when a light is on, Zhou said seismometers can see structures deep within the earth when an earthquake occurs. The vibrations spread out and create waves when they hit rocks. The waves are detected by seismometers and used in what is known as diffraction tomography.

“This is the first time the new imaging theory has been applied to this type of seismic data, which allowed us to see anomalous structures in the Earth’s mantle that would otherwise not be resolvable using traditional methods,” Zhou said.

Zhou will continue her study of Yellowstone. “The next step will be to increase the resolution of the X-ray-like images of the underground rock,” she added.

“More detailed images of the unusual rocks in the deep earth will allow us to use computer simulation to recreate the fragmentation of the gigantic oceanic plate and test different scenarios of how rock melting and magma feeding system work for the Yellowstone volcanoes.”

Source: Virginia Tech [July 25, 2018]




Great Barrier Reef reveals rapid changes of ancient glaciers

Graphs of global sea levels around the time of the poorly understood Last Glacial Maximum (27,000 to 20,000 years ago) previously showed stable ice sheets for about 10,000 years before the ice slowly started to melt. New analysis of the first Great Barrier Reef samples covering the time 22,000 years ago to 19,000 years ago finally adds detail to that period, providing valuable insights for models of climate and ice sheet dynamics.

Great Barrier Reef reveals rapid changes of ancient glaciers
An international research team including University of Tokyo geochemist Professor Yusuke Yokoyama collected core
samples of ancient coral reefs for research projects that reveal ancient sea levels and may improve future
climate prediction models. No living coral is harmed while collecting samples of ancient reefs
[Credit: Hironobu Kan]

The research team, led by Professor Yusuke Yokoyama of the University of Tokyo, now divides the Last Glacial Maximum into two distinct periods:

– period A – 30,000 to 21,500 years ago, the sea level was relatively stable
– period B – 21,000 to 17,000 years ago, the sea level was unstable with large, rapid fluctuations

The rapid drop in sea level observed 21,000 years ago is particularly striking because it contradicts current understanding of this period.

“This challenges the paradigm that glacier size can only change slowly, because rapid sea level changes mean water must melt or freeze rapidly,” said Yokoyama, lead author of the research paper published in the journal Nature.

These rapid shifts in the size of ancient glaciers are significant in the context of modern climate change and its associated impacts.

“Current models of glacier dynamics may be too conservative. The possibility of rapid increases or decreases in sea level should be considered,” said Yokoyama.

Future climate prediction models are tested by their ability to accurately calculate historic climate parameters that are verified by sample data. All accurate, detailed data about ancient climates are additional points to check the accuracy of climate models.

“Research teams like ours collect data about how the Earth used to be, and then other research groups use those data to continuously improve their models of the future climate,” said Yokoyama.

“It’s really important to understand the size and location of ice sheets because large bodies of ice act like a freezer for the local environment – glaciers change ocean temperature and salinity, which affect ocean conditions. Understanding ancient sea levels can reveal geological structures, such as land bridges, that could have been important for migration routes or species separation,” said Yokoyama.

Great Barrier Reef reveals rapid changes of ancient glaciers
Coral reefs grow in shallow waters where they remain covered by the sea but still receive sunlight. The remains
of ancient reefs were examined to determine sea levels from long ago by a research team led by
University of Tokyo Professor Yusuke Yokoyama [Credit: Hironobu Kan]

Collecting from the reef

In 2010, Yokoyama was the co-chief scientist of the international Integrated Ocean Drilling Program Expedition 325: Great Barrier Reef Environmental Changes. Associate Professor Jody Webster from the University of Sydney, School of Geosciences was also co-chief scientist on the expedition. The research team spent two months on the 93.6-meter-long (102-yard-long) research vessel Greatship Maya collecting fossil coral reef samples. The reef cores analyzed in this study came from two sites: Hydrographers Passage offshore of Mackay and Noggin Pass offshore of Cairns, both on the East Coast of the Australian state of Queensland.

Collecting fossil corals from the Last Glacial Maximum is technically and logistically challenging.

“We sampled coral from 90 meters to 130 meters (98 to 142 yards) below the current sea level. It’s difficult to collect data anywhere between 50 and 200 meters (55 and 219 yards) underwater; divers usually can’t go below 30 meters (33 yards) and ship captains prefer to not go shallower than 200 meters,” said Yokoyama.

The Great Barrier Reef was selected as the coral core sample site because it can reveal a uniquely clear picture of past glacier ice sheet behavior. The reef’s tropical position near the equator means it was and remains far from the immediate influence of glacier ice sheets, so sea level changes local to the Great Barrier Reef reflect global changes.

Additionally, the Australian tectonic plate has minimal seismic activity, so earthquakes did not change the position of the reef. The gentle sloping structure of the ancient Great Barrier Reef also meant researchers could physically collect the samples they need.

“Sites close to the former ice sheets cannot provide accurate sea level histories because over time they are overwritten by large deformations of the Earth,” said Yokoyama.

Studying reef samples

Researchers studied the structure of coral and algae layers within coral core samples to determine water depth. Advanced radiocarbon and uranium-thorium dating results provided by the team at the University of Tokyo identified when water was at particular levels. Researchers combine time and depth data to determine when global average sea levels would have reached certain depths.

Great Barrier Reef reveals rapid changes of ancient glaciers
The Greatship Maya is about to start sample collection using a research drill (center) over the remains of ancient
portions of the Great Barrier Reef, now submerged in deep water. In the distance, waves break over the modern
Great Barrier Reef in shallow waters. University of Tokyo Professor Yusuke Yokoyama was co-chief
scientist on the expedition to collect fossil coral core samples in 2010
[Credit: Yusuke Yokoyama]

“Two death events of reefs are very clear in the coral cores we examined,” said Yokoyama.

When the ice sheets grew, the global sea level fell so the coral dried out and died, but coral in deeper waters survived. If the water becomes too deep, sunlight and nutrients become unavailable and the reef can drown.

These two death events are consistent with a drop in sea level and a subsequent rise. The ages of the two death events suggest that both happened over only 4,000 years, which researchers remark is particularly abrupt.

Webster led the team of reef scientists from Spain, Japan, and the U.S. responsible for interpreting ecological data used to track reef habitat depth, and therefore relative sea level, over time. That information was then combined with radiometric data and used by Yokoyama and his team to model fluctuations in the vertical position of the seafloor caused by changes in water or ice volume. The combined results clarified ice sheet dynamics during the poorly understood Last Glacial Maximum period.

“Fossil coral reefs were very sensitive to environmental changes, so by examining the biological assemblages in the cores we were able to reconstruct how ancient water depths changed through time,” said Webster.

Source: University of Tokyo [July 25, 2018]




Creating ‘synthetic’ fossils in the lab sheds light on fossilization...

A newly published experimental protocol, involving University of Bristol scientists, could change the way fossilisation is studied.

Creating 'synthetic' fossils in the lab sheds light on fossilization processes
Experimental samples compared to fossils down to the microscopic structure of melanosomes
[Credit: Nicholas Edwards and Wang Yuan]

In addition to directly studying fossils themselves, experimental treatments of fresh organismal remains can be utilised to study fossilisation.

One commonly employed experimental approach is known as ‘artificial maturation’, where high heat and pressure accelerate the chemical degradation reactions that normally occur over millions of years when a fossil is buried deep underground and exposed to geothermal heat and pressure from overlying sediment.

Maturation has been a staple of organic geochemists who wish to study the formation of fossil fuels and is in some ways similar to the more intense experimental conditions that produce synthetic diamonds.

More recently, maturation has been used to study the formation of exceptional fossils that preserve soft tissues as dark, organic films in addition to mineralised tissues like bone, including fossil dinosaurs from China with organically preserved feathers.

However, much maturation equipment is often limited by the use of small, sealed chambers which trap not only the highly stable organic molecules of interest to palaeontologists and organic geochemists, but also the breakdown products of less stable molecules that are less likely to be retained in fossils. Therefore, direct comparisons between the experiments and the fossils become complicated.

For example, when Evan Saitta, who recently submitted his PhD at the University of Bristol’s School of Earth Sciences and is now a postdoctoral researcher at the Field Museum of Natural History in Chicago, ran these more traditional maturation experiments on feathers during his MSc (also at Bristol), the result was a foul-smelling fluid.

Jakob Vinther, senior lecturer at Bristol’s School of Earth Sciences and School of Biological Sciences as well as Saitta’s PhD and MSc advisor, added: “What we are coming to realise is that fossils aren’t simply a result of how fast they rot, but rather the molecular composition of different tissues. However, it is inherently difficult to take the conceptual leap from understanding chemical stability to understanding how tissues and organs may, or may not, survive.”

Saitta said: “By the end of my MSc, I became a bit ambitious. If maturation was known to be a useful simulation of fossilisation processes, I thought to myself, then running these experiments on specimens compacted in sediment might just produce ‘synthetic’ fossils. Fossils form in sedimentary rocks, which can be porous and would allow for volatile degradation products to escape.”

Saitta then teamed up with Tom Kaye of the Foundation for Scientific Advancement who provided the engineering experience required to see the idea to fruition.

Kaye said: “My lab deals with high pressure devices all the time. We had the capability of compressing matrix around the specimens which was the game changer simulating burial. Our next step is to expand the system to take large specimens.”

As the researchers describe in their new paper, published in the journal Palaeontology, the results did not disappoint.

Saitta explained: “The sediment acts as a filter allowing unstable molecules to escape from the sample, revealing browned, flattened bones surrounded by dark, organic films where soft tissues once were.

“These results closely resemble exceptional fossils, not just visually, but also microscopically as revealed using a scanning electron microscope.”

Microscopic, pigment-bearing structures called melanosomes reside within the organic films in feathers and lizards treated with the new method while unstable protein and fatty tissues degrade and are lost, just as in exceptional fossils which have been used by scientists such as Vinther to reconstruct the original colours of dinosaurs.

Preliminary tests on leaves and beetles are also encouragingly comparable to their fossil equivalents, and tree resin can even be hardened in a manner resembling fossil copal or amber.

The researchers say the new method of sediment filtration represents an improvement upon earlier maturation experiments and will allow for the testing of many hypotheses regarding organic preservation in fossils and sediments.

Future additions to the protocol will incorporate other aspects of fossilisation beyond simulation of the heat and pressure of deep burial.

Source: University of Bristol [July 25, 2018]




Archaeological plant remains point to southwest Amazonia as crop domestication centre

The remains of domesticated crop plants at an archaeological site in southwest Amazonia supports the idea that this was an important region in the early history of crop cultivation, according to a study published in the open-access journal PLOS ONE by Jennifer Watling from the Museum of Archaeology and Ethnology at the University of São Paulo, Brazil and colleagues.

Archaeological plant remains point to southwest Amazonia as crop domestication centre
The authors believe that the Teotonio waterfall is what attracted people to this location for over 9000 years, as it was an
extremely rich fishing location and an obligatory stopping point for people travelling by boat on this stretch of the
Madeira river. It was the location of a fishing village (the village of Teotonio) until 2011, when residents were
forced to move inland ahead of dam construction. The dam submersed the village and the waterfall
[Credit: Eduardo Neves, 2011]

Genetic analysis of plant species has long pointed to the lowlands of southwest Amazonia as a key region in the early history of plant domestication in the Americas, but systematic archaeological evidence to support this has been rare. The new evidence comes from recently-exposed layers of the Teotonio archaeological site, which has been described by researchers as a “microcosm of human occupation of the Upper Madeira [River]” because it preserves a nearly continuous record of human cultures going back approximately 9,000 years.

Archaeological plant remains point to southwest Amazonia as crop domestication centre
Images of excavated pre-ceramic units at Teotonio highlighting their stratigraphy, the location of radiocarbon dates,
and the origin of archaeobotanical samples: a) Photograph and drawing of east-facing profiles of Units 1 and 2
(Arqueotrop, MAE, 2016), b) Photograph of east-facing profile of Unit 5 (Arqueotrop, MAE, 2011), with
the relevant stratigraphic information projected upon it. Phytolith samples were taken from
 the north-facing profile [Credit: Watling et al. PLOS (2018)]

In this study, Watling and colleagues analyzed the remains of seeds, phytoliths, and other plant materials in the most ancient soils of the site as well as on artefacts used for processing food. They found some of the earliest evidence of cultivated manioc, a crop which geneticists say was domesticated here over 8,000 years ago, as well as squash, beans, and perhaps calathea, and important tree crops such as palms and Brazil nut. They also saw evidence of disturbed forest and a soil type called “Anthropogenic Dark Earths” which both result from human alteration of local environments.

Archaeological plant remains point to southwest Amazonia as crop domestication centre
Photographs of starch grains encountered in lithic residues: a) Phaseolus sp. starch grain (artefact 1957–1 [US],
Unit 5, 60–70 cm); b) Modern Phaseolus vulgaris starch grain; c) cf. Arecaceae starch (artefact 1972–1 [WB],
Unit 5, 120–130 cm); d) Modern starch grain from Attalea maripa seed. This morphotype was also reported in
other Arecaceae species in the comparative reference collection; e) Arecaceae phytolith (artefact 1974–1 [WB],
Unit 5, 140–150 cm); f) Unidentified Type 1 starch grain showing darkened centre (hilum projections),
rotated to show quadrangular face (1974–1 [US], Unit 5, 140–150 cm); g) cf. Unidentified Type 1
with shattered appearance under polarized light (1956–2 [US], Unit 5, 40–50 cm)
[Credit: Watling et al. PLOS (2018)]

These findings suggest that the people of this region transitioned from early hunter-gatherer lifestyles to cultivating crops before 6,000 years ago, much earlier than previously thought. Along with plant domestication also came the familiar human habit of landscape modification, suggesting that human impact on Amazonian forests in this region goes back many thousands of years. Altogether, these results point to the Upper Madeira as a key locality to explore the earliest days of crop domestication in the New World.

Watling notes: “This discovery at the Teotonio waterfall in Southest Amazonia is some of the oldest evidence for plant cultivation in lowland South America, confirming genetic evidence”.

Source: Public Library of Science [July 25, 2018]




Ancient Footprints Sculpture at Brungerley Park, Clitheroe,…

Ancient Footprints Sculpture at Brungerley Park, Clitheroe, Lancashire, 26.7.18.

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New satellite launch extends Galileo’s global reach

ESA – Galileo Programme patch.

 26 July 2018

Four more Galileo satellites were launched today by an Ariane 5. Their arrival in orbit brings the Galileo constellation to 26 satellites, extending the global coverage of the constellation.

Galileo liftoff

Ariane 5 flight VA244, operated by Arianespace under contract to ESA, lifted off from Europe’s Spaceport in Kourou, French Guiana, at 11:25 GMT (13:25 CEST, 08:25 local time), carrying Galileo satellites 23–26. The first pair of 715 kg satellites was released almost 3 hours 36 minutes after liftoff, while the second pair separated 20 minutes later.

They were released into their target 22 922 km-altitude orbit by the dispenser atop the Ariane 5 upper stage. In the coming days, this quartet will be steered into their final working orbits by the French space agency CNES, under contract to the Galileo operator SpaceOpal for the European Global Navigation Satellite System Agency (GSA). There, they will begin around six months of tests by SpaceOpal to verify their operational readiness so they can join the working Galileo constellation.

Galileos atop Ariane 5

“Galileo is ESA’s largest ever satellite constellation, built up to its present size in rapid time, with 22 Full Operational Capability satellites added within just the last four years,” remarked Jan Wörner, ESA’s Director General.

“We must thank our industrial partners OHB (DE) and SSTL (GB) for the satellites, as well as Thales Alenia Space (FR/IT) and Airbus Defence and Space (GB/FR) for the ground segment and all their subcontractors throughout Europe for their continued support to the programme. Together with ESA, the entire industrial team has worked hard for the point at which we now are and this cooperation have proven to be very successful, as we can show in the excellent performance of Galileo.”

Galileo’s Ariane 5

Paul Verhoef, ESA’s Director of Navigation, added, “Galileo has been providing Initial Services on a worldwide basis since 15 December 2016, and today has more than 100 million users, and rapidly increasing. Today’s satellites will increase the global coverage of Galileo with a performance that is widely recognised as excellent.

“This is the end of the current phase of Galileo deployment, but our pace is not slacking. A further 12 Galileo ‘Batch 3’ satellites are in preparation as in-orbit spares and as replacements for the oldest Galileo satellites, first launched in 2011, in order to keep the system working seamlessly into the future.

Galileo quartet placed atop Ariane 5

“Then a new generation of Galileos are planned for the middle of the next decade, offering improved performance and added features, maintaining Galileo as a permanent feature of the global GNSS landscape.”

About Galileo:

Galileo is Europe’s civil global satellite navigation system. Once complete, the system will consist of 24 operational satellites plus orbital spares, and the ground infrastructure for the provision of positioning, navigation and timing services. But the system is already available to users with recent receivers which combine the Galileo and GPS navigation messages for a more precise positioning.

The Galileo programme is funded and owned by the EU. The European Commission has the overall responsibility for the programme, managing and overseeing the implementation of all programme activities.

Galileo satellites

Galileo’s deployment, the design and development of the new generation of systems and the technical development of infrastructure are entrusted to ESA. The definition, development and in-orbit validation phases were carried out by ESA, and co‑funded by ESA and the European Commission.

Galileo 23–26 – Liftoff replay

GSA is ensuring the uptake and security of Galileo. Galileo operations and provision of services were entrusted to the GSA in July 2017.

Related links:

What is Galileo?: http://www.esa.int/Our_Activities/Navigation/Galileo/What_is_Galileo

EC Galileo website: http://ec.europa.eu/growth/sectors/space/galileo/index_en.htm

European GNSS Agency: http://www.gsa.europa.eu/

Navigation: http://www.esa.int/Our_Activities/Navigation

Images, Video, Text, Credits: ESA/Pierre Carril, 2017/CNES/Arianespace/Optique Video du CSG/P Baudon/OHB System AG.

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