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Friday, February 12, 2016

Unknown Species of Humans Found, Made Tools 2.18 Millions Years Ago

Two new hominin fossils have been found in a previously uninvestigated chamber in the Sterkfontein Caves, just North West of Johannesburg in South Africa. Specimens from the Homo genus and can be associated with early stone tools dated to 2.18 million years ago.

The two new specimens, a finger bone and a molar, are part of a set of four specimens, which seem to be from early hominins that can be associated with early stone tool-bearing sediments that entered the cave more than two million years ago.

New homonin molar was found in Sterkfontein Caves.
Credit: Jason Heaton

"The specimens are exciting not only because they are associated with early stone tools, but also because they possess a mixture of intriguing features that raise many more questions than they give answers," says lead researcher Dr Dominic Stratford, a lecturer at the Wits School of Geography, Archaeology and Environmental studies, and research coordinator at the Sterkfontein Caves.

The first fossil specimen, which is a very large proximal finger bone, is significantly larger and more robust than any other hand bone of any hominin yet found in South African plio-pleistocene sites.

A new homonin finger bone fossil was found in Sterkfontein Caves.
Credit: Jason Heaton

"It is almost complete and shows a really interesting mix of modern and archaic features. For example, the specimen is markedly curved - more curved than Homo naledi and is similarly curved to the much older species Australopithecus afarensis," says Stratford.

The level of curvature is often linked to arborealism, but it lacks the strong muscle attachments that are expected to be present.

"The finger is similar in shape to the partial specimen from Olduvai Gorge that has been called Homo habilis, but is much larger. Overall, this specimen is unique in the South African plio-pleistocene fossil hominin record and deserves more studies," says Stratford.

The other fossil is a relatively small, nearly complete adult 1st molar tooth that also has striking similarities to species Homo habilis.

"In size and shape it also bears a resemblance to two of the 10 1st molars of the H. naledispecimens, although further and more detailed comparisons are needed to verify this."

The shape of the tooth and particularly the shape and relative sizes of the cones on the surface of the tooth suggest this specimen belonged to an early member of the Homo genus and can be associated with early stone tools dated recently to 2.18 million years ago.

"The two other hominin fossils found are still being studied and further excavations are planned to hopefully find more pieces and expand our understanding of who these intriguing bones belonged to and how they lived and died on the Sterkfontein hill more than two million years ago," says Stratford.

The Sterkfontein Caves have been one of the most prolific palaeoanthropological sites in the world, since the discovery of the first ever adult Australopithecus by Robert Broom, 80 years ago this year. Since this incredible discovery, some of palaeoanthropology's most famous finds have come from the Sterkfontein Caves, including Ms. Ples and Little Foot.

Researchers explore the Milner Hall in the Sterkfontein Caves for new fossils.
Credit: Dominic Stratford

Sterkfontein remains the richest Australopithecus-bearing locality in the world and continues to yield remarkable specimens. The underground network of caves at the site extends over 5kms and the caves are filled with fossiliferous sediments that have been deposited underground over a period of more than 3.67 million years.

However, very few of these deep deposits have been systematically excavated and so remain largely unknown. The Milner Hall, where the four new hominin fossils were found, is one such chamber where several large deposits have been identified but never excavated.

The excavations that yielded these new hominin fossils were being conducted as part of a new phase of exploratory excavations away from the known hominin-bearing areas. Excavations in the Jacovec Cavern, Name Chamber and Milner Hall have been started under Dr Stratford's direction. Each has yielded exciting new fossils that shed further light on the story of our evolution and life on the Sterkfontein hill more than two million years ago.

During the second phase of excavation in the Milner Hall, which were started early in 2015 with student Kelita Shadrach, four hominin fossils were excavated from the upper layers of a long sequence of deposits that document the long history of fossil deposition in the cave, starting over 3.67 million years ago.



Contacts and sources:
Dr Dominic Stratford

Clues About Human Migration to Imperial Rome Uncovered in 2,000-Year-Old Cemetery


Isotope analysis of 2000-year-old skeletons buried in Imperial Rome reveal some were migrants from the Alps or North Africa, according to a study published February 10, 2016 in the open-access journal PLOS ONE by Kristina Killgrove from University of West Florida, USA, and Janet Montgomery from Durham University, UK.

Previous work has focused on the overall human migration patterns within the Roman Empire. To understand human migration on a more granular level, the authors of this study examined 105 skeletons buried at two Roman cemeteries during the 1st through 3rd centuries AD. They analyzed the oxygen, strontium, and carbon isotope ratios in the skeletons' teeth to determine their geographical origin and diet.

Skull of skeleton T15, a 35- to 50-year-old male who was buried in a cemetery in the modern neighborhood of Casal Bertone, Rome, Italy. Isotope ratios suggest he may have been born near the Alps.
Credit: Kristina Killgrove

They found up to eight individuals who were likely migrants from outside Rome, possibly from North Africa and the Alps. The individuals were mostly children and men, and the authors suggest their burial in a necropolis indicates that they may have been poor or even slaves.

They also found that their diet probably changed significantly when they moved to Rome, possibly adapting to the local cuisine, comprising mostly wheat and some legumes, meat and fish. The authors note that further isotope and DNA analysis is needed to provide more context for their findings. Nonetheless, they state that their study provides the first physical evidence of individual migrants to Rome during this period.



Contacts and sources:  
Beth Jones
PLoS ONE

Citation: Killgrove K, Montgomery J (2016) All Roads Lead to Rome: Exploring Human Migration to the Eternal City through Biochemistry of Skeletons from Two Imperial-Era Cemeteries (1st-3rd c AD). PLoS ONE 11(2): e0147585. doi:10.1371/journal.pone.0147585  http://dx.plos.org/10.1371/journal.pone.0147585

Thursday, February 11, 2016

Study Shows Rising Seas Slowed by Increasing Water on Land


New measurements from a NASA satellite have allowed researchers to identify and quantify, for the first time, how climate-driven increases of liquid water storage on land have affected the rate of sea level rise.

A new study by scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth’s continents to soak up and store an extra 3.2 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.


Credit: NASA

The water gains over land were spread globally, but taken together they equal the volume of Lake Huron, the world’s seventh largest lake. The study is published in the Feb. 12 issue of the journal Science.

Each year, a large amount of water evaporates from the oceans, falls over land as rain or snow, and returns to the oceans through runoff and river flows. This is known as the global hydrologic, or water, cycle. Scientists have long known small changes in the hydrologic cycle -- by persistent regional changes in soil moisture or lake levels, for instance -- could change the rate of sea level rise from what we would expect based on ice sheet and glacier melt rates. However, they did not know how large the land storage effect would be because there were no instruments that could accurately measure global changes in liquid water on land.

"We always assumed that people’s increased reliance on groundwater for irrigation and consumption was resulting in a net transfer of water from the land to the ocean,” said lead author J.T. Reager of JPL, who began work on the study as a graduate student at UC Irvine. "What we didn’t realize until now is that over the past decade, changes in the global water cycle more than offset the losses that occurred from groundwater pumping, causing the land to act like a sponge -- at least temporarily. These new data are vital for understanding decadal variations in sea level change. The information will be a critical complement to future long-term projections of sea level rise, which depend on melting ice and warming oceans.”

The 2002 launch of NASA’s Gravity Recovery and Climate Experiment (GRACE) twin satellites provided the first tool capable of quantifying land liquid water storage trends. By measuring the distance between the two GRACE satellites to within the width of a strand of human hair as they orbit Earth, researchers can detect changes in Earth’s gravitational pull that result from regional changes in the amount of water across Earth’s surface. With careful analysis of these data, JPL scientists were able to measure the change in liquid water storage on the continents, as well as the changes in ice sheets and glaciers.

“These results will lead to a refinement of global sea level budgets, such as those presented in the Intergovernmental Panel on Climate Change (IPCC) reports, which acknowledge the importance of climate-driven changes in hydrology, but have been unable to include any reliable estimate of their contribution to sea level changes,” said JPL senior water scientist Jay Famiglietti, senior author of the paper and a professor at the University of California, Irvine.

Famiglietti also noted the study is the first to observe global patterns of changes in land water storage, with wet regions getting more wet and dry areas getting drier.

“These patterns are consistent with earlier observations of changing precipitation over both land and oceans, and with IPCC projections of changing precipitation under a warming climate,” he said. “But we’ll need a much longer data record to fully understand the underlying cause of the patterns and whether they will persist.”

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.



Contacts and sources:
NASA

The Sound of Two Black Holes Colliding; Gravitational Waves Detected 100 Years After Einstein's Prediction - Videos

For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.

Gravitational waves carry information about their dramatic origins and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed.
Credit: Caltech

The gravitational waves were detected on September 14, 2015 at 5:51 a.m. Eastern Daylight Time (09:51 UTC) by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA. The LIGO Observatories are funded by the National Science Foundation (NSF), and were conceived, built, and are operated by Caltech and MIT. The discovery, accepted for publication in the journal Physical Review Letters, was made by the LIGO Scientific Collaboration (which includes the GEO Collaboration and the Australian Consortium for Interferometric Gravitational Astronomy) and the Virgo Collaboration using data from the two LIGO detectors.

Based on the observed signals, LIGO scientists estimate that the black holes for this event were about 29 and 36 times the mass of the sun, and the event took place 1.3 billion years ago. About 3 times the mass of the sun was converted into gravitational waves in a fraction of a second—with a peak power output about 50 times that of the whole visible universe. By looking at the time of arrival of the signals—the detector in Livingston recorded the event 7 milliseconds before the detector in Hanford—scientists can say that the source was located in the Southern Hemisphere.

Ligo20160211_tn
Credit: Caltech

According to general relativity, a pair of black holes orbiting around each other lose energy through the emission of gravitational waves, causing them to gradually approach each other over billions of years, and then much more quickly in the final minutes. During the final fraction of a second, the two black holes collide into each other at nearly one-half the speed of light and form a single more massive black hole, converting a portion of the combined black holes’ mass to energy, according to Einstein’s formula E=mc2. This energy is emitted as a final strong burst of gravitational waves. It is these gravitational waves that LIGO has observed.

The existence of gravitational waves was first demonstrated in the 1970s and 80s by Joseph Taylor, Jr., and colleagues. Taylor and Russell Hulse discovered in 1974 a binary system composed of a pulsar in orbit around a neutron star. Taylor and Joel M. Weisberg in 1982 found that the orbit of the pulsar was slowly shrinking over time because of the release of energy in the form of gravitational waves. For discovering the pulsar and showing that it would make possible this particular gravitational wave measurement, Hulse and Taylor were awarded the Nobel Prize in Physics in 1993.

The new LIGO discovery is the first observation of gravitational waves themselves, made by measuring the tiny disturbances the waves make to space and time as they pass through the earth.

How our sun and Earth warp space and time, or spacetime, is represented here with a green grid. As Albert Einstein demonstrated in his theory of general relativity, the gravity of massive bodies warps the fabric of space and time—and those bodies move along paths determined by this geometry. His theory also predicted the existence of gravitational waves, which are ripples in space and time. These waves, which move at the speed of light, are created when massive bodies accelerate through space and time.
Ligo20160211e
Credit: Catech

“Our observation of gravitational waves accomplishes an ambitious goal set out over 5 decades ago to directly detect this elusive phenomenon and better understand the universe, and, fittingly, fulfills Einstein’s legacy on the 100th anniversary of his general theory of relativity,” says Caltech’s David H. Reitze, executive director of the LIGO Laboratory.

The discovery was made possible by the enhanced capabilities of Advanced LIGO, a major upgrade that increases the sensitivity of the instruments compared to the first generation LIGO detectors, enabling a large increase in the volume of the universe probed—and the discovery of gravitational waves during its first observation run. The US National Science Foundation leads in financial support for Advanced LIGO. Funding organizations in Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council, STFC) and Australia (Australian Research Council) also have made significant commitments to the project. 

Several of the key technologies that made Advanced LIGO so much more sensitive have been developed and tested by the German UK GEO collaboration. Significant computer resources have been contributed by the AEI Hannover Atlas Cluster, the LIGO Laboratory, Syracuse University, and the University of Wisconsin- Milwaukee. Several universities designed, built, and tested key components for Advanced LIGO: The Australian National University, the University of Adelaide, the University of Florida, Stanford University, Columbia University of the City of New York, and Louisiana State University.

Gravitational waves sent out from a pair of colliding black holes have been converted to sound waves, as heard in this animation. On September 14, 2015, LIGO observed gravitational waves from the merger of two black holes, each about 30 times the mass of our sun. The incredibly powerful event, which released 50 times more energy than all the stars in the observable universe, lasted only fractions of a second. 

The Sound of Two Black Holes Colliding

In the first two runs of the animation, the sound-wave frequencies exactly match the frequencies of the gravitational waves. The second two runs of the animation play the sounds again at higher frequencies that better fit the human hearing range. The animation ends by playing the original frequencies again twice.

As the black holes spiral closer and closer in together, the frequency of the gravitational waves increases. Scientists call these sounds "chirps," because some events that generate gravitation waves would sound like a bird's chirp.
“In 1992, when LIGO’s initial funding was approved, it represented the biggest investment the NSF had ever made,” says France Córdova, NSF director. “It was a big risk. But the National Science Foundation is the agency that takes these kinds of risks. We support fundamental science and engineering at a point in the road to discovery where that path is anything but clear. We fund trailblazers. It’s why the U.S. continues to be a global leader in advancing knowledge.”


Black Hole Waves Simulation: This simulation depicts the birth, 1.3 billion years ago, of the gravitational waves discovered by LIGO on September 14, 2015. The waves are generated by two black holes that spiral around each other, then collide and merge. In the bright green regions, the waves stretch space; in the dark green regions, they squeeze space. As the black holes approach each other, the waves get stronger and the separation between them gets shorter, giving rise to what scientists refer to as a "chirp."   This video is based on a computer simulation by the multi-university SXS (Simulating eXtreme Spacetimes) project. 
The two black holes collide and merge into a new black hole, bringing the waves to a crescendo. The newborn black hole vibrates briefly, then becomes quiet and stops generating waves. The waves all depart from the black hole’s vicinity, traveling out into the universe, carrying news of the black holes’ collision.
LIGO research is carried out by the LIGO Scientific Collaboration (LSC), a group of more than 1000 scientists from universities around the United States and in 14 other countries. More than 90 universities and research institutes in the LSC develop detector technology and analyze data; approximately 250 students are strong contributing members of the collaboration. The LSC detector network includes the LIGO interferometers and the GEO600 detector. The GEO team includes scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI), Leibniz Universität Hannover, along with partners at the University of Glasgow, Cardiff University, the University of Birmingham, other universities in the United Kingdom, and the University of the Balearic Islands in Spain.

“This detection is the beginning of a new era: The field of gravitational wave astronomy is now a reality,” says Gabriela González, LSC spokesperson and professor of physics and astronomy at Louisiana State University.

LIGO was originally proposed as a means of detecting these gravitational waves in the 1980s by Rainer Weiss, professor of physics, emeritus, from MIT; Kip Thorne, Caltech’s Richard P. Feynman Professor of Theoretical Physics, emeritus; and Ronald Drever, professor of physics, emeritus, also from Caltech.

“The description of this observation is beautifully described in the Einstein theory of general relativity formulated 100 years ago and comprises the first test of the theory in strong gravitation. It would have been wonderful to watch Einstein’s face had we been able to tell him,” says Weiss.

“With this discovery, we humans are embarking on a marvelous new quest: the quest to explore the warped side of the universe—objects and phenomena that are made from warped spacetime. Colliding black holes and gravitational waves are our first beautiful examples,” says Thorne.

Virgo research is carried out by the Virgo Collaboration, consisting of more than 250 physicists and engineers belonging to 19 different European research groups: 6 from Centre National de la Recherche Scientifique (CNRS) in France; 8 from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; 2 in The Netherlands with Nikhef; the Wigner RCP in Hungary; the POLGRAW group in Poland; and the European Gravitational Observatory (EGO), the laboratory hosting the Virgo detector near Pisa in Italy.

Fulvio Ricci, Virgo Spokesperson, notes that, “This is a significant milestone for physics, but more importantly merely the start of many new and exciting astrophysical discoveries to come with LIGO and Virgo.”

Bruce Allen, managing director of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute), adds, “Einstein thought gravitational waves were too weak to detect, and didn’t believe in black holes. But I don’t think he’d have minded being wrong!”

“The Advanced LIGO detectors are a tour de force of science and technology, made possible by a truly exceptional international team of technicians, engineers, and scientists,” says David Shoemaker of MIT, the project leader for Advanced LIGO. “We are very proud that we finished this NSF-funded project on time and on budget.”

At each observatory, the two-and-a-half-mile (4-km) long L-shaped LIGO interferometer uses laser light split into two beams that travel back and forth down the arms (four-foot diameter tubes kept under a near-perfect vacuum). The beams are used to monitor the distance between mirrors precisely positioned at the ends of the arms. According to Einstein’s theory, the distance between the mirrors will change by an infinitesimal amount when a gravitational wave passes by the detector. A change in the lengths of the arms smaller than one-ten-thousandth the diameter of a proton (10-19 meter) can be detected.

Two Black Holes Merge into One: A computer simulation shows the collision of two black holes, a tremendously powerful event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO. LIGO detected gravitational waves, or ripples in space and time generated as the black holes spiraled in toward each other, collided, and merged. This simulation shows how the merger would appear to our eyes if we could somehow travel in a spaceship for a closer look. It was created by solving equations from Albert Einstein's general theory of relativity using the LIGO data.

The two merging black holes are each roughly 30 times the mass of the sun, with one slightly larger than the other. Time has been slowed down by a factor of about 100. The event took place 1.3 billion years ago.

“To make this fantastic milestone possible took a global collaboration of scientists—laser and suspension technology developed for our GEO600 detector was used to help make Advanced LIGO the most sophisticated gravitational wave detector ever created,” says Sheila Rowan, professor of physics and astronomy at the University of Glasgow.

Independent and widely separated observatories are necessary to determine the direction of the event causing the gravitational waves, and also to verify that the signals come from space and are not from some other local phenomenon.

Journey of a Gravity Wave: LIGO scientist David Reitze takes us on a 1.3 billion year journey that begins with the violent merger of two black holes in the distant universe. The event produced gravitational waves, tiny ripples in the fabric of space and time, which LIGO detected on September 14, 2015, as they passed Earth.

Toward this end, the LIGO Laboratory is working closely with scientists in India at the Inter-University Centre for Astronomy and Astrophysics, the Raja Ramanna Centre for Advanced Technology, and the Institute for Plasma to establish a third Advanced LIGO detector on the Indian subcontinent. Awaiting approval by the government of India, it could be operational early in the next decade. The additional detector will greatly improve the ability of the global detector network to localize gravitational-wave sources.

“Hopefully this first observation will accelerate the construction of a global network of detectors to enable accurate source location in the era of multi-messenger astronomy,” says David McClelland, professor of physics and director of the Centre for Gravitational Physics at the Australian National University.



Contacts and sources:
Kathy Svitil
Caltech

Einstein's Gravitational Waves Found, Black-Hole Models Led The Way

The National Science Foundation (NSF) has announced the detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of ground-based observatories in Hanford, Washington, and Livingston, Louisiana.

Albert Einstein predicted the existence of gravitational waves in his general theory of relativity a century ago, and scientists have been attempting to detect them for 50 years. Einstein pictured these waves as ripples in the fabric of space-time produced by massive, accelerating bodies, such as black holes orbiting each other. Scientists are interested in observing and characterizing these waves to learn more about the sources producing them and about gravity itself.

An artist's impression of gravitational waves generated by binary neutron stars. 
Credits: R. Hurt/Caltech-JPL

Gravitational waves were predicted by Einstein's theory of general relativity in 1916, and now, almost exactly 100 years later, the faint ripples across space-time have been found. The advanced Laser Interferometric Gravitational-wave Observatory (aLIGO) has achieved the first direct measurement.

"We already have indirect evidence of gravitational wave emission from binary pulsars like the Hulse-Taylor system. But this LIGO measurement provides the first direct detection and confirms what our modeling and simulation results have been suggesting - Einstein was right," said Christopher Fryer, Los Alamos National Laboratory Fellow and longtime researcher in this field.

A simulation of two merging black holes, creating gravitational waves.

Photo courtesy of LIGO.

"Working with experts in radiation transport and atomic physics in the Advanced Simulation and Computing program at Los Alamos, members of the theoretical astrophysics center are modeling this emission to compare theoretical models with direct observations," said Charlie McMillan, Los Alamos National Laboratory director. "This type of crosscutting capability is a hallmark of the national laboratory system and Los Alamos is gratified to have participated in a discovery of this magnitude."

This movie shows a simulation of the merger of two black holes and the resulting emission of gravitational radiation. The colored fields represent a component of the curvature of space-time. The outer sheets (red) correspond directly to outgoing gravitational radiation, which was recently detected by the NSF’s LIGO observatories.

Credits: NASA/C. Henze

A primary source of gravitational waves is a series of astronomical events called compact object mergers, involving the merger of binary systems consisting of neutron stars and/or black holes. "The actual observation was of a black-hole/black-hole merger. This proves aLIGO can detect these compact mergers. The detection process for neutron-star/neutron-star mergers is the same and our models predict both will occur. Observations of neutron-star/neutron star mergers will help us understand a great deal of physics and astronomy and the prospects for gravitational wave science are extremely exciting," said Fryer.

The electromagnetic follow-up, at Los Alamos and elsewhere, focuses on what we can learn from neutron-star/neutron-star mergers. It is this type of phenomenon that computer scientists, physicists and astronomy experts have been exploring, using computers to model the merger's many components to understand the basic physics more clearly.

LIGO itself comprises a set of two widely separated interferometers--one in Hanford, Washington and the other in Livingston, Louisiana--that are operated in unison to detect the gravitational waves produced in the end-state of these merging systems. The facility's multi-kilometer-scale gravitational wave detectors use laser interferometry to measure the ripples in space-time caused by passing waves.

"Beyond the detection of gravitational waves, aLIGO provides a new window into studying astrophysical transients. Astronomers across the globe have been studying how LIGO observations, coupled with telescopes from radio to gamma-rays, can be used to probe the extreme physics in these cosmic explosions," Fryer said.

"Even though the modeling and observations of these gravitational wave sources is difficult, requiring detailed, multi-physics models, the potential to study new realms of physics and understand new astrophysical transients is tremendous. Los Alamos is well-poised to solve these problems," Fryer said.

At Los Alamos National Laboratory's theoretical astrophysics center a broad effort has been underway, studying many aspects of these mergers from their progenitors (work led by former Oppenheimer Fellow Krzysztoff Belczynski) to their implications in helping scientists understand astrophysical transients and as probes of the physics of matter under extreme conditions.

"Our program studying merger progenitors argued that the most-likely system would be a binary black hole system," stated Fryer, "and it is gratifying to see that this first detection is exactly such a system. As aLIGO detects more of these mergers we will be able to probe aspects of stellar evolution."

Scientists at Washington’s National Science Foundation and Moscow State University have confirmed the discovery of Albert Einstein’s gravitational waves. The breakthrough, possibly the biggest in physics in a century, could be the key to new understanding of the universe.

Credit: RT

Working with a team of experts from many areas of physics and astronomy, including dense nuclear matter, binary stellar evolution, gamma ray bursts and multi-physics computational modeling, Fryer has focused on determining what we can learn from these gravitational wave detections. The team uses a combination of Newtonian merger calculations, neutron star equation of state studies, and population synthesis simulation to model the outcome of the merger of the two neutron stars.

The researchers determined the statistical likelihood that the remnant from the merger

1) collapses directly to a black hole,

2) collapses to a black hole after a delay, or

3) remains a neutron star.

Whether the core is a black hole or neutron star depends on whether it is more massive than the maximum neutron star mass at its spin rate.

The LIGO detections represent a much-awaited first step toward opening a whole new branch of astrophysics. Nearly everything we know about the universe comes from detecting and analyzing light in all its forms across the electromagnetic spectrum – radio, infrared, visible, ultraviolet, X-rays and gamma rays. The study of gravitational waves opens a new window on the universe, one that scientists expect will provide key information that will complement what we can learn through electromagnetic radiation.

Just as in other areas of astronomy, astronomers need both ground-based and space-based observatories to take full advantage of this new window. LIGO is sensitive to gravitational waves within the range of 10 to 1,000 cycles per second (10 to 1,000 Hz). A space-based system would be able to detect waves at much lower frequencies, from 0.0001 to 0.1 Hz, and detect different types of sources. NASA is working closely with the European Space Agency (ESA) to develop a concept for a space-based gravitational wave observatory.



Contacts and sources:
Nancy Ambrosiano, Los Alamos National Laboratory

NASA


Related papers on this subject are as follows:

Chris L. Fryer et al 2015 ApJ 812 24. doi:10.1088/0004-637X/812/1/24

http://adsabs.harvard.edu/abs/2015ApJ...806..263D

http://adsabs.harvard.edu/abs/2013ApJ...779...72D

Tuesday, February 9, 2016

Life Found In Mantle Rock at the Atlantis Massif near Lost City

An international expedition, led by ETH Professor Gretchen Bernasconi-Green, has discovered traces of life in a core sample. The geologist explains what this means.

Gretchen Bernasconi-Green.
 Photograph: ETH Zurich

An international team of scientists returned last December from anIODP (International Ocean Discovery Program) expedition to the Atlantis Massif in the Atlantic Ocean. During the expedition, they were able to obtain a series of mantle rocks in core samples taken from the seabed near the famous Lost City hydrothermal field. When they analysed the rock samples, the researchers discovered signs of life. The expedition’s co-leader, ETH Professor Gretchen Bernasconi-Green, spoke to ETH News about whether and why the find can be considered a scientific sensation.


Ms Bernasconi-Green, an expedition you led to the Atlantis Massif on the Mid-Atlantic Ridge has discovered traces of life in mantle rock. That sounds like a scientific sensation – is it?
First, I should say that we did not find the signs of life in the earth’s mantle itself, but rather in rock that originates from the earth’s mantle. This rock is found on the seabed at the Atlantis Massif near Lost City. Here the tectonic plates are drifting apart and large active faults have formed that carry mantle material towards the surface, just like a conveyor belt. We were able to obtain samples of the mantle rock through boreholes, and a microbiologist on the research ship managed to isolate cells from a few of these samples.

What kinds of cells?
For now, all we know for sure is that they are microbial cells. Whether these are bacteria or archaea, it’s too soon to say. What we do know is that they differ considerably from cells found in ocean sediment. The next step is for the cells to be examined more closely in the laboratory. What’s unusual, and quite exciting for us, is that these cells are present in mantle rock and most likely do not originate from the seawater.

Strongly deformed serpentine lies directly beneath Lost City. The fish measures 1 meter.
 
Credit: Univ. of Washington, IFE, URI-IAO and NOAA

Do you think it’s really possible for life to occur in rock?
Yes, I think it is quite possible. Mantle rock contains a mineral called olivine, which turns into serpentine when it comes into contact with water at low temperatures. This produces hydrogen and methane. Both these gases provide a source of energy for micro-organisms that have to manage without sunlight. 

Perhaps the cells we found are capable of using these gases, which are present inside the rock, to carry out their metabolic processes. But life in the rock is tough and the microbes are exposed to some very hostile conditions. The fluids that seep out of the vents at Lost City are extremely alkaline – they have a pH value of 11. Thus, both the vents and their environment are difficult to colonise, even for very resistant micro-organisms.

This beehive-like vent dismisses a steamingly hot and highly alcaline fluid.
Credit: Univ. of Washington, IFE, URI-IAO and NOAA

What is the significance of finding cells in rock like this?
The conversion of olivine to serpentine may occur on other planets too – on Mars, for example, where the presence of methane and hydrogen has already been established. Some scientists believe that would be sufficient in itself to allow the emergence of basic life forms.

What other goals did you set for the expedition?
Mainly, we wanted to find out how mantle rock ended up on the sea floor and how it reacts with seawater; the primary focus was on the serpentinisation process. We also wanted to find out more about the carbonisation process that led to the formation of the vents at Lost City. The chimneys are made of calcium, or rather calcium carbonate, which precipitates from the alkaline fluids. This is a natural form of carbon dioxide fixation. We wanted to better understand how much carbon is stored as carbonate in these rocks and the potential of this sequestration, especially in terms of an artificial CO2 sequestration on the sea floor or on land, aided by the serpentinisation reaction that led to the formation of alkaline hydrothermal vents.

Have you come to any conclusions about this potential yet?
We have not finished analysing the core samples yet, but I see the potential as being quite limited. It may be feasible, but the effort required to fix significant quantities of CO2 in places like the mid-ocean ridges would be very great – too great for it to be successful.

What other findings resulted from the expedition?
This expedition was the first time that we used a new kind of drill, a seabed rock drill, to extract core samples. These drills sit right on the seabed and can drill 50 to 70 metres into the rock. The advantage over the conventional method is that the drill is not as disturbed by heavy seas. The drill heads are finer, too, which is less damaging to the rock. As the boreholes are often left open for long periods, thus letting in seawater, we used a new technique to seal up four of the boreholes. This is another example of innovation in sea drilling. 

In a year’s time, the area in and around the boreholes will have recovered from the disturbance of drilling and we will be able to remove the plug and take measurements and water samples. We also equipped the drills with a number of different sensors, which, for the first time, were able to measure the water temperature, oxygen reduction potential, methane concentration and the pH of the water before, during and after the drilling process.

So what happens next?
The core samples were taken to the Center for Marine Environmental Sciences (MARUM) in Bremen, and over the last two weeks have been examined by the team of 30 participating scientists. Incidentally, women are in the majority on that team – another first on an IODP mission! They will each take small samples and continue their analysis. The microbiologists will also conduct detailed genetic investigations and make incubation experiments. In about two years, we will reconvene to discuss the results.

Will you take part in the analysis?
Yes, I’ll bring samples back to ETH Zurich and, together with my colleagues, analyse them for carbonates, organic carbons and mineral reactions related to serpentinisation.

The project, incidentally, is financed by the Swiss National Science Foundation, which also ensures Swiss membership in IODP.



Contacts and sources: 
By: Peter Rüegg
ETH Zurich


A Deep Look Into A Single Molecule

The quantum state of a molecular ion has been measured live and in a non-destructive fashion for the first time.  

The interaction of thermal energy from the environment with motional degrees of freedom is well known and often referred to as Brownian motion (also thermal motion). But in the case of polar molecules, the internal degrees of freedom - in particular the rotational quantum state - are also influenced by the thermal radiation. So far, the detection of the rotational state was only possible by destroying the molecule. 

However, a German research group has now demonstrated the first implementation of a non-destructive state detection technique for molecular ions. Piet Schmidt and his colleagues from the QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB) observed changes in the rotational state of a trapped and indirectly cooled molecular ion in real time and in situ. This technique enables novel spectroscopy methods with applications ranging from chemistry to tests of fundamental physics. The results are published in the current issue of "Nature".

Basic concept of the experiment: MgH+ (orange) and Mg+ (green) are trapped together in a linear ion trap. The two-ion compound is cooled to the motional ground state via the atomic ion. An oscillating dipole force changes the motional state according to the rotational state of the molecular ion. This motional excitation can be detected on the atomic ion. (
Credit: PTB

Nowadays atoms can be manipulated with lasers and their spectral features can be investigated with high precision e.g. in optical clocks. In these experiments state detection plays a crucial role: the fluorescence of an atom under illumination with laser light reveals its internal quantum state. 

Many atoms and most molecules, however, do not fluoresce at all. Therefore, one of the standard procedures for state detection in molecules exploited the fact that molecules can be broken apart with laser light of a certain frequency, depending on their quantum state. This lets one measure the quantum state of the molecule by destroying it. Of course this detection procedure can only be applied once per molecule.

Project leader Piet Schmidt has a long experience of systems in which state detection is difficult to achieve. He was involved in the development of 'quantum logic spectroscopy' in the research group of Nobel laureate David J. Wineland and extended it with his own research team to 'photon recoil spectroscopy'. 

Typical detection signal, where a quantum jump into the (J=1)-rotational state (from red to blue area) and a subsequent jump out of this state (blue to red) can be seen 
Credit: PTB

All of these novel spectroscopy techniques are based on a common principle: beside the ion under investigation, one traps a second ion of a different species that is controllable and whose fluorescence can be used for state detection. Because of their electrical repulsion, both particles behave as if they were connected by a strong spring, such that their motion is synchronized. 

This is how the measurement of one particle can reveal properties of the other particle. Schmidt and his colleagues use a molecular MgH+-ion (which is the subject of the investigation) and an atomic Mg+-ion (on which the measurements will be performed). They hold both particles with electric fields in an ion trap. Then, lasers are used to cool the particles' motion to the ground state, where the synchronous motion almost comes to rest.

The new trick demonstrated in this experiment relies on an additional laser, whose action is similar to an optical tweezer. It can be used to exert forces on the molecule. "The laser shakes the molecule only if the molecule is in one particular rotational state" explains Fabian Wolf, physicist in Schmidt's research group "We can detect the effect¬ -which is an excitation of the common motion of the molecule and the atom- on the atomic ion by using additional lasers. If the atom lights up, the molecule was in the state we probed. If it stays dark, the molecule was in some other state."

Piet Schmidt highlights two main results of the team's findings: "Because of the non-destructive nature of our technique, we could observe the molecule jumping from one rotational state to the other. It is the first time such quantum jumps have been observed directly in an isolated molecule. Moreover, we could improve on the uncertainty of a transition frequency to an electronically excited state". He also points towards future goals: "The next step is the systematic preparation of the molecule in that quantum state instead of waiting for the thermal radiation to randomly prepare it."

The researchers feel confident that their development will be important for the scientific communities that need precise methods for spectroscopy, e.g. quantum chemistry, where the inner structure of molecules is investigated, or astronomy, where spectra of cold molecules can teach us new things about the origin and the properties of the universe. Furthermore, precision molecular spectroscopy is important for the search for a variation of the fundamental constants and so far hidden properties of fundamental particles, such as the electric dipole moment of the electron.

These tests of fundamental physics were Schmidt's original motivation for working on the novel detection technique."To make these applications practical, we have to push molecular spectroscopy to a level similar to that of today's optical clocks based on atoms", says Piet Schmidt, when he gets asked for his long term goal, "For this purpose we have to improve our measurement resolution by orders of magnitude, which for sure will take several years".





Contacts and sources:
Prof. Dr. Piet O. Schmidt
QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB)


Citation: F. Wolf, Y. Wan, J.C. Heip, F. Gebert, C. Shi, P.O. Schmidt: Non-destructive state detection for quantum logic spectroscopy of molecular ions. Nature (2016), DOI: 10.1038/nature16513





Great Attractor Pulling Milky Way and Hundreds of Hidden Galaxies Towards Itself

Hundreds of hidden nearby galaxies have been studied for the first time, shedding light on a mysterious gravitational anomaly dubbed the Great Attractor.

Despite being just 250 million light years from Earth—very close in astronomical terms—the new galaxies had been hidden from view until now by our own galaxy, the Milky Way.

Using CSIRO’s Parkes radio telescope equipped with an innovative receiver, an international team of scientists were able to see through the stars and dust of the Milky Way, into a previously unexplored region of space.

An annotated animation showing the location of the galaxies discovered in the 'Zone of Avoidance'. Until now this region of space has remained hidden from view because of the gas and dust of the Milky Way which blocks light at optical wavelengths from reaching telescopes on Earth. By using CSIRO's Parkes radio telescope to detect radio waves that can travel through our galaxy's gas and dust, hundreds of new galaxies have been found in the region of space known to astronomers as the 'Zone of Avoidance'. This animation has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colors.
Credit: ICRAR. Music by Holly Broadbent.

The discovery may help to explain the Great Attractor region, which appears to be drawing the Milky Way and hundreds of thousands of other galaxies towards it with a gravitational force equivalent to a million billion Suns.

Lead author Professor Lister Staveley-Smith, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said the team found 883 galaxies, a third of which had never been seen before.

“The Milky Way is very beautiful of course and it’s very interesting to study our own galaxy but it completely blocks out the view of the more distant galaxies behind it,” he said.

An annotated artist's impression showing radio waves travelling from the new galaxies, then passing through the Milky Way and arriving at the Parkes radio telescope on Earth (not to scale). 
Credit: ICRAR

Professor Staveley-Smith said scientists have been trying to get to the bottom of the mysterious Great Attractor since major deviations from universal expansion were first discovered in the 1970s and 1980s.

“We don’t actually understand what’s causing this gravitational acceleration on the Milky Way or where it’s coming from,” he said.

“We know that in this region there are a few very large collections of galaxies we call clusters or superclusters, and our whole Milky Way is moving towards them at more than two million kilometres per hour.”

The research identified several new structures that could help to explain the movement of the Milky Way, including three galaxy concentrations (named NW1, NW2 and NW3) and two new clusters (named CW1 and CW2).

University of Cape Town astronomer Professor Renée Kraan-Korteweg said astronomers have been trying to map the galaxy distribution hidden behind the Milky Way for decades.

“We’ve used a range of techniques but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars,” she said.

“An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn't know about until now.”

A visualisation showing the coordinates of the new 'hidden galaxies'. At the centre is Earth. Blue represents galaxies found in other surveys and other colours show the locations of the new galaxies. 
Credit: ICRAR

Dr. Bärbel Koribalski from CSIRO Astronomy and Space Science said innovative technologies on the Parkes Radio telescope had made it possible to survey large areas of the sky very quickly.

“With the 21-cm multibeam receiver on Parkes we’re able to map the sky 13 times faster than we could before and make new discoveries at a much greater rate,” she said.

The study involved researchers from Australia, South Africa, the US and the Netherlands, and was published today in the Astronomical Journal.

An artist’s impression of the galaxies found in the ‘Zone of Avoidance’ behind the Milky Way. This scene has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colors.
 Credit: ICRAR

An animation showing the location of the galaxies discovered in the 'Zone of Avoidance'. Until now this region of space has remained hidden from view because of the gas and dust of the Milky Way which blocks light at optical wavelengths from reaching telescopes on Earth. By using CSIRO's Parkes radio telescope to detect radio waves that can travel through our galaxy's gas and dust, hundreds of new galaxies have been found in the region of space known to astronomers as the 'Zone of Avoidance'. This animation has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colours. 
Credit: ICRAR. Music by Holly Broadbent.

The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.

Professor Lister Staveley-Smith is ICRAR’s Director of Science at UWA and the Deputy Director of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO).

Dr Bärbel S. Koribalski is a CSIRO Science Leader, leading the HI group at CSIRO Astronomy and Space Science. Dr Koribalski and Prof Staveley-Smith are the principal investigators of WALLABY, the ASKAP HI All-Sky Survey.

The ‘Great Attractor’ is a diffuse concentration of mass 250 million light-years away, that’s pulling our galaxy, the Milky Way, and hundreds of thousands of other galaxies towards it.

CSIRO’s Parkes telescope, or “the Dish”, is a 64-metre radio telescope located in New South Wales, Australia. The telescope has been in operation since 1961 and continues to be at the forefront of astronomical discovery.




Contacts and sources:
Prof. Lister Staveley-Smith, University of Western Australia, ICRAR, CAASTRO
Prof. Renée C. Kraan-Korteweg, University of Cape Town
Dr Bärbel Koribalski, CSIRO Astronomy and Space Science
Pete Wheeler, Media Contact, ICRAR


Citation:
‘The Parkes HI Zone of Avoidance Survey’, published in the Astronomical Journal February 9th, 2016. Available at this link.

Earth-Like Planets Have Earth-Like Interiors


Every school kid learns the basic structure of the Earth: a thin outer crust, a thick mantle, and a Mars-sized core. But is this structure universal? Will rocky exoplanets orbiting other stars have the same three layers? New research suggests that the answer is yes - they will have interiors very similar to Earth.

"We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like," says lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA).

To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth's interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.

This artist's illustration compares the interior structures of Earth (left) with the exoplanet Kepler-93b (right), which is one and a half times the size of Earth and 4 times as massive. New research finds that rocky worlds share similar structures, with a core containing about a third of the planet's mass, surrounded by a mantle and topped by a thin crust.

Credit: M. Weiss/CfA

They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet's mass. In comparison, about a third of the Earth's mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.

"We've only understood the Earth's structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can't visit them," adds Zeng.

The new code also can be applied to smaller, icier worlds like the moons and dwarf planets in the outer solar system. For example, by plugging in the mass and size of Pluto, the team finds that Pluto is about one-third ice (mostly water ice but also ammonia and methane ices).

The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures. The team expects to explore these questions in future research.



Contacts and sources:
Christine Pulliam
Harvard-Smithsonian Center for Astrophysics (CfA)

Mysterious Menominee Crack Is Unusual Geological Pop-Up Feature

Seismologists studying a massive crack in the ground that appeared north of Menominee, Michigan in 2010 now think they know what the unusual feature might be. But as they explain in their study published this week in the journal Seismological Research Letters, there are still some mysteries to clear up about the strange geological occurrence in the rural Michigan woods.

A photo taken in 2010 of the Menominee Crack, a 'pop-up' geological feature.
Credit: Wayne Pennington/ Michigan Technological University

A team of scientists led by Wayne Pennington of Michigan Technological University says that the crack, which lies along the crest of a two-meter-high ridge that appeared at the same time, is probably a "pop-up" feature. Pop-ups occur in places where shallowly-buried rock layers spring upward after having been weighed down by rock or ice. Pop-ups--sometimes called "A-tents" for their shape--may develop in places where the earth rebounds upward after an overlying glacier shrinks away, or when rock overburden is removed in a quarry.

However, the last glaciers retreated from Menominee 11,000 years ago--and there isn't any quarrying in the area.

"One of our reasons for publishing this was that in our search of the literature we could find no other mention of modern pop-ups that didn't occur at something like the base of a quarry, where people had removed massive amounts of rock earlier," Pennington explained. "As far as we can tell, this is a one-of-a-kind event."

Residents near Menominee heard a loud noise and shaking in the early morning of October 4, 2010, and soon discovered the crack when they went into the nearby woods to clean up the debris left from removing a big double-trunked white pine tree a few days earlier. The crack split the ground for 110 meters, and was as deep as 1.7 meters in some places. Tree trunks tilted at precarious angles on either side of the fracture.

Pennington went to visit the site on his way back home from a scientific conference, he recalled. He paced off some measurements in his dress shoes and collected some GPS data with his phone. "I was completely blown away by it, because it wasn't what I was expecting when I saw it," he recalled. "It wasn't like anything I had seen before."

Although the crack was the most dramatic feature, Pennington was intrigued by the new ridge underneath it. "I kept trying to think of ways that there could have been an uplift from a thrusting earthquake or something, but anything like that requires such a huge amount of displacement in order to produce that amount of crustal shortening, that nothing made sense."

He shared the photos and data with his colleagues, until Stanford University geophysicist Norm Sleep pointed out that the feature formed from a shallow-buried layer of limestone, and looked like a pop-up. "This made perfect sense to us," Pennington said, "except for what caused it. And that then became the puzzle."

The researchers needed to get a better look at the rock underneath the ridge to confirm that it was a pop-up, so they turned to a technique called seismic refraction. The technique measures the speed of seismic waves as they travel within layers of the earth, as determined at different distances from the seismic source. In this case, the seismologists used a sledgehammer to strike a large metal ball lying on the ground, and captured the resulting seismic waves.

In broken rock, the waves travel faster as they move parallel to cracks in the rock, and slower when they move perpendicular to the cracks and have to travel across the fractures. The scientists found a pattern of refraction speeds that seemed to be consistent with the intense bending and then fracturing of the brittle limestone of a pop-up feature.

But what caused the pop-up to...pop-up? Without the usual suspects in play, Pennington and his colleagues had to do a little detective work. The limestone in the area may have been stressed almost to the point of cracking when the last glaciers retreated, they say. The recent removal of the double-trunked pine, which may have weighed as much as 2000 kilograms--over two tons--could have been the final straw, allowing the rock to bend upward when that weight was removed.

"There's a 60% chance that this explanation we provide is the right one," Pennington noted. "But since we haven't seen this kind of thing elsewhere, and the tree is such a small effect, we wonder if there might be something else."

The seismologists studied aerial photos of the region to see how soil has been removed in the past 50 years from road work and a re-design of the area's drainage system. These changes might have channeled more rainwater below the surface, potentially weakening the rock as it froze and thawed, the scientists suggest.

Pennington said "no one should be losing sleep" over the strange feature, which technically counted as the first natural earthquake in Michigan's Upper Peninsula--measuring less than magnitude 1.

"It may be a one-of-a kind phenomenon," he said. "But if it happens again, we'll be all over it, trying to figure it out."



Contacts and sources:
Becky Ham
Seismological Society of America

Mindboggling Fossil Fish Found


An international team of scientists have discovered two new plankton-eating fossil fish species of the genus called Rhinconichthys (Rink-O-nik-thees) from the oceans of the Cretaceous Period, about 92 million years ago, when dinosaurs roamed the planet.

One of the authors of the study, Kenshu Shimada, a paleobiologist at DePaul University, said Rhinconichthys are exceptionally rare, known previously by only one species from England. But a new skull from North America, discovered in Colorado along with the re-examination of another skull from Japan have tripled the number of species in the genus with a greatly expanded geographical range. According to Shimada, who played a key role in the study, these species have been named R. purgatoirensis and R. uyenoi, respectively.

An international team of scientists have discovered two new plankton-eating fossil fish species, of the genus called Rhinconichthys, which lived 92 million years ago in the oceans of the Cretaceous Period.

Credit:  Robert Nicholls  


"I was in a team that named Rhinconichthys in 2010, which was based on a single species from England, but we had no idea back then that the genus was so diverse and so globally distributed," said Shimada.

The new study, "Highly specialized suspension-feeding bony fish Rhinconichthys (Actinopterygii: Pachycormiformes) from the mid-Cretaceous of the United States, England and Japan," will appear in the forthcoming issue of the international scientific journalCretaceous Research.

The research team includes scientists from government, museum, private sector and university careers. They include Bruce A. Schumacher from the United Sates Forest Service who discovered the new specimen. It also includes researchers, Jeff Liston from the National Museum of Scotland and Anthony Maltese from the Rocky Mountain Dinosaur Resource Center.

Rhinconichthys belongs to an extinct bony fish group called pachycormids, which contains the largest bony fish ever to have lived. The new study specifically focuses on highly elusive forms of this fish group that ate plankton.

Rhinconichthys was estimated to be more than 6.5 feet and fed on plankton. It had a pair of bones called hyomandibulae, which formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth.
               
Credit: Kenshu Shimada

Rhinconichthys was estimated to be more than 6.5 feet and fed on plankton. It had a highly unusual specialization for bony fish. According to Shimada, one pair of bones called hyomandibulae formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth, similar to the way many sharks open their mouth.

A planktivorous diet, also called suspension-feeding, is known among some specialized aquatic vertebrates today, including the Blue Whale, Manta Ray and Whale Shark. The name Rhinconichthys means a fish like the Whale Shark, Rhincodon. Suspension-feeding in the dinosaur era is a new emerging area of research.

"Based on our new study, we now have three different species of Rhinconichthys from three separate regions of the globe, each represented by a single skull," Shimada noted. "This tells just how little we still know about the biodiversity of organisms through the Earth's history. It's really mindboggling ."


Contacts and sources:  
Jon Cecero
DePaul University

Saturday, February 6, 2016

Man-Made Underwater Sound May Have Wider Ecosystem Effects Than Previously Thought

Underwater sound linked to human activity could alter the behavior of seabed creatures that play a vital role in marine ecosystems, according to new research from the University of Southampton.

The study, reported in the journal Scientific Reports published by Nature, found that exposure to sounds that resemble shipping traffic and offshore construction activities results in behavioral responses in certain invertebrate species that live in the marine sediment.

These species make a crucial contribution to the seabed ecosystem as their burrowing and bioirrigation activities (how much the organism moves water in and out of the sediment by its actions) are crucial in nutrient recycling and carbon storage.

Image shows a langoustine (Nephrops norvegicus)
Credit: University of Southampton

The study showed that some man-made sounds can cause certain species to reduce irrigation and sediment turnover. Such reductions can lead to the formation of compacted sediments that suffer reduced oxygen, potentially becoming anoxic (depleted of dissolved oxygen and a more severe condition of hypoxia), which may have an impact on seabed productivity, sediment biodiversity and also fisheries production.

Lead author Martin Solan, Professor in Marine Ecology, said: "Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with increasing levels of offshore human activity. Previous work has almost exclusively focussed on direct physiological or behavioural responses in marine mammals and fish, and has not previously addressed the indirect impacts of sound on ecosystem properties.

"Our study provides evidence that exposing coastal environments to anthropogenic sound fields is likely to have much wider ecosystem consequences than are presently understood."

The Southampton researchers exposed three species - the langoustine (Nephrops norvegicus), a slim, orange-pink lobster which grows up to 25 cm long, the Manila clam (Ruditapes philippinarum) and the brittlestar Amphiura filfiformis - to two different types of underwater sound fields: continuous broadband noise (CBN) that mimics shipping traffic and intermittent broadband noise (IBN) reflecting marine construction activity.

The sounds were reproduced in controlled test tanks and experiments were run on one species at a time. For CBN, a recording (one minute duration, continuously looped) of a ship made in the English Channel at a distance of around 100 metres was used'. For IBN, a recording (two minutes duration, continuously looped) of a wind farm in the North Sea at a distance of about 60 metres was used.

The results showed that the sounds could alter the way these species behaved when interacting with their environments.

With the langoustine, which disturbs the sediment to create burrows in which it lives, the researchers saw a reduction in the depth of sediment redistribution (how much of the surface sediment was overturned into the deeper layers) with exposure to IBN or CBN. Under CBN and IBN there was evidence that bioirrigation increased.

The Manila clam, a commercial fishery species in Europe that lives in the sediment and connects to the overlying water through a retractable siphon, reduced its surface activity under CBN, which affected the surface roughness of the sediment. Bioirrigation, which is strongly influenced by clam behaviour and the activity of the siphon, was markedly reduced by CBN and slightly reduced under IBN.

However, the sound fields had little impact on the brittlestar.

Co-author Dr Chris Hauton, Associate Professor in Invertebrate Ecophysiology and Immune Function, said: "I think these findings raise the prospect that anthropogenic sounds in the marine environment are impacting marine invertebrate species in ways that have not been previously anticipated. The potential effects of anthropogenic noise on ecosystem function, mediated through changes in organism behaviour merits further study as, in the long term, it may identify impacts to the productivity of seabed systems that have, to date, not really been constrained."

Tim Leighton, Professor of Ultrasonics and Underwater Acoustics and study co-author, added: "There has been much discussion over the last decade of the extent to which whales, dolphins and fish stocks, might be disturbed by the sounds from shipping, windfarms and their construction, seismic exploration etc. However, one set of ocean denizens has until now been ignored, and unlike these other classes, they cannot easily move away from loud man-made sound sources. These are the bottom feeders, such as crabs, shellfish and invertebrates similar to the ones in our study, which are crucial to healthy and commercially successful oceans because they form the bottom of the food chain."


Contacts and sources:

Land Degradation Affects 3.2 Billion People

Land degradation is on the rise to a dramatic extent, affecting around 3.2 billion people worldwide. Every dollar invested in saving land and soils today will save us five dollars in the future. Professor Klaus Töpfer, former Executive Director of UNEP; Professor Joachim von Braun, Director of the Center for Development Research, University of Bonn (ZEF); and Dr. Stefan Schmitz, German Federal Ministry for Economic Cooperation and Development (BMZ) will present the latest research insights on this issue.


Credit:  United Nations

The press conference will be held on Thursday, February 11, 2016, 10:00 AM – 11:00 AM in the Berlin-Brandenburgische Akademie der Wissenschaften, Jägerstraße 22/23, in 10117 Berlin.

Land and soil are the basis of life on Earth. Nevertheless, insufficient effort has been made so far to ensure sustainable land use and the protection of soils. This is the conclusion that a team of international scientists has drawn from studies conducted in 12 world regions and countries, including India, Argentina, Central Asia, Russia and a large number of African countries. 

The findings, partly based on remote-sensing satellite data, are alarming: Globally, 33 percent of grasslands, 25 percent of croplands and 23 percent of forests have experienced degradation over the past three decades. Around 30 percent of the global land area, home to around 3.2 billion people, is affected by significant soil degradation. The global costs amount to around 300 billion Euros per annum. The global assessment concludes: Every US Dollar invested today will save us five US Dollars in the future.

“Sustainable land management contributes to achieving several of the Sustainable Development Goals (SDGs), such as land degradation neutrality and an ambitious climate and biodiversity agenda. This fact was highlighted in the series of Global Soil Week events held in Berlin in recent years”, explains Professor Klaus Töpfer, former Executive Director the United Nations Environment Programme (UNEP).

“Soil is the most neglected natural resource”, states Professor Joachim von Braun, Director of the Center for Development Research (ZEF) and co-editor of the book “Economics of Land Degradation and Improvement – A Global Assessment for Sustainable Development”, which was published by Springer recently. “Yet, investments in land and soil are crucial for food supply, climate and human security”, von Braun adds.

According to von Braun: “The international scientists involved in these country case studies basically all reach the same conclusion; namely, that if we invest in rescuing global land and soil now, the cost will be much lower than if we wait longer. This applies both to industrialized and developing countries alike”.

The high levels of land degradation in croplands and grazing lands in developing countries, especially in sub-Saharan Africa, pose a serious problem too and may lead to migration. Often, there is a lack of advisory services and knowledge transfer for farmers, for example about integrated soil fertility management. Poor access to markets is another obstacle as well as weak security of land tenure.

The latter means that farmers are not motivated to practice sustainable land use methods. “In order to change this, the German government has been substantially involved in sustainable land use initiatives”, emphasizes Stefan Schmitz of the German Federal Ministry for Economic Cooperation and Development (BMZ), who is the coordinator of the BMZ special initiative ‘One World no Hunger’. “Combating land degradation is one of the most important elements in our fight against hunger”, he adds.


Contacts and sources:
Universität Bonn

Global Sea Levels Could Rise 3 Meters Due to Melting Antarctic Ice

Loss of ice in Antarctica caused by a warming ocean could raise global sea levels by three meters, research by Northumbria and Edinburgh universities suggests.

Scientists carrying out fieldwork in the region have assessed the landscape to determine how the West Antarctic ice sheet might respond to increasing global temperatures.

In the first study of its kind, researchers were able to gauge how levels of ice covering the land have changed over hundreds of thousands of years. They did so by studying peaks protruding through ice in the Ellsworth Mountains, on the Atlantic flank of Antarctica.

Credit: Northumbria University

The team assessed changes on slopes at various heights on the mountainside, which indicate levels previously reached by the ice sheet. They also mapped the distribution of boulders on the mountainside, which were deposited by melting glaciers. Chemical technology – known as exposure dating – showed how long rocks had been exposed to the atmosphere, and their age.

Their results indicate that during previous warm periods, a substantial amount of ice would have been lost from the West Antarctic ice sheet by ocean melting, but it would not have melted entirely. This suggests that ice would have been lost from areas below sea level, but not on upland areas. The research shows that parts of the West Antarctic ice sheet have existed continuously for at least 1.4 million years.

The study, published in Nature Communications, was carried out by researchers at Northumbria University and the University of Edinburgh, alongside the Scottish Universities Environmental Research Centre. It was supported by the Natural Environment Research Council and the British Antarctic Survey.

Credit: Northumbria University

Professor John Woodward, Northumbria’s Associate Dean (Research and Innovation) in Engineering and Environment, co-led the study.

He said: “It is possible that the ice sheet has passed the point of no return and, if so, the big question is how much will go and how much will sea levels rise.”

Dr Andrew Hein, of the University of Edinburgh’s School of GeoSciences, joint leader of the study, added: “Our findings narrow the margin of uncertainty around the likely impact of the West Antarctic Ice Sheet on sea level rise. This remains a troubling forecast since all signs suggest the ice from West Antarctica could disappear relatively quickly.”

Cold and paleo environments are one of Northumbria’s research specialisms in the Department of Geography. Research involves field based projects in cold regions across the globe, including Antarctica, a range of high Arctic European and Canadian sites, New Zealand, the Alps, Alaska and Chile.

The group applies novel techniques to field data collection, including ground-penetrating radar, new borehole radar technologies, seismics, NIR camera techniques, meteorological monitoring technologies, the use of unmanned aerial vehicles (UAV) and terrestrial laser scanning (TLS), to address fundamental questions in Earth Systems Science. Cutting-edge physical and numerical modelling, remote sensing and laboratory techniques for palaeo-environmental work are also applied.


Contacts and sources:
Northumbria University

Turbulent Times: When Stars Approach

HITS astrophysicists are using new methods to simulate the common-envelope phase of binary stars and discovering dynamic irregularities that may help to explain how supernovae evolve.

When we look at the night sky, we see stars as tiny points of light eking out a solitary existence at immense distances from Earth. But appearances are deceptive. More than half the stars we know of have a companion, a second nearby star that can have a major impact on their primary companions. 

The interplay within these so-called binary star systems is particularly intensive when the two stars involved are going through a phase in which they are surrounded by a common envelope consisting of hydrogen and helium. Compared to the overall time taken by stars to evolve, this phase is extremely short, so astronomers have great difficulty observing and hence understanding it. This is where theoretical models with highly compute-intensive simulations come in. Research into this phenomenon is relevant understanding a number of stellar events such as supernovae.

The simulation video visualizes the evolution of the density during a time span of 105 days. As the core of the red giant and the companion draw closer together, the gravity between them releases energy that passes into the common envelope. The turbulent instabilities that occur during this phase become clearly evident. (\
Video: Sebastian Ohlmann / HITS

Using new methods, astrophysicists Sebastian Ohlmann, Friedrich Roepke, Ruediger Pakmor, and Volker Springel of the Heidelberg Institute for Theoretical Studies (HITS) have now made a step forward in modeling this phenomenon. As they report in The Astrophysical Journal Letters, the scientists have successfully used simulations to discover dynamic irregularities that occur during the common-envelope phase and are crucial for the subsequent existence of binary star systems. These so-called instabilities change the flow of matter inside the envelope, thus influencing the stars' distance from one another and determining, for example, whether a supernova will ensue and, if so, what kind it will be.

This image shows a slice through the three-dimensional simulation volume after 105 days in the common envelope. In the orbital plane (figure 1), the companion star and the red giant core are circling around each other. 
Image: Sebastian Ohlmann / HITS

The article is the fruit of collaboration between two HITS research groups, the Physics of Stellar Objects (PSO) group and the Theoretical Astrophysics group (TAP). Prof. Volker Springel's Arepo code for hydrodynamic simulations was used and adapted for the modeling. It solves the equations on a moving mesh that follows the mass flow, and thus enhances the accuracy of the model.

Two stars, one envelope

More than half the stars we know of have evolved in binary star systems. The energy for their luminosity comes from the nuclear fusion of hydrogen at the core of the stars. As soon as the hydrogen fueling the nuclear fusion is exhausted in the heavier of the two stars, the star core shrinks. At the same time, a highly extended stellar envelope evolves, consisting of hydrogen and helium. The star becomes a red giant.

As the envelope of the red giant goes on expanding, the companion star draws the envelope to itself via gravity, and part of the envelope flows towards it. In the course of this process the two stars come closer to one another. Finally, the companion star may fall into the envelope of the red giant and both stars are then surrounded by a common envelope. 

As the core of the red giant and the companion draw closer together, the gravity between them releases energy that passes into the common envelope. As a result, the envelope is ejected and mixes with interstellar matter in the galaxy, leaving behind it a close binary star system consisting of the core of the giant and the companion star.

The path to stellar explosion

Sebastian Ohlmann of the PSO group explains why this common-envelope phase is important for our understanding of the way various star systems evolve: "Depending on what the system of the common envelope looks like initially, very different phenomena may ensue in the aftermath, such as thermonuclear supernovae." 

Figure 2 shows a plane perpendicular to the orbital plane.

Image: Sebastian Ohlmann / HITS

Ohlmann and colleagues are investigating the run-up to these stellar explosions, which are among the most luminous events in the universe and can light up a whole galaxy. But modeling the systems that can lead to such explosions is bedeviled by major uncertainty in the description of the common-envelope phase. 

One of the reasons for this is that the core of the giant is anything between a thousand and ten thousand times smaller than the envelope, so that spatial and temporal scale differences complicate the modeling process and make approximations necessary. The methodically innovative simulations performed by the Heidelberg scientists are a first step towards a better understanding of this phase.



Contacts and sources:
Dr. Peter Saueressig
HITS Heidelberg Institute for Theoretical Studies


Citation: Ohlmann, S. T., Roepke, F. K., Pakmor, R., & Springel, V. (2016): Hydrodynamic moving-mesh simulations of the common envelope phase in binary stellar systems, The Astrophysical Journal Letters, 816, L9, DOI: 10.3847/2041-8205/816/1/L9
http://arxiv.org/abs/1512.04529
Astrophysics Data System: http://adsabs.harvard.edu/abs/2016ApJ...816L...9O