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Wednesday, July 23, 2014

Voyager Spacecraft Might Not Have Reached Interstellar Space

In 2012, the Voyager mission team announced that the Voyager 1 spacecraft had passed into interstellar space, traveling further from Earth than any other manmade object.

But, in the nearly two years since that historic announcement, and despite subsequent observations backing it up, uncertainty about whether Voyager 1 really crossed the threshold continues. There are some scientists who say that the spacecraft is still within the heliosphere – the region of space dominated by the Sun and its wind of energetic particles – and has not yet reached the space between the stars.

Now, two Voyager team scientists have developed a test that they say could prove once and for all if Voyager 1 has crossed the boundary. The new test is outlined in a study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The scientists predict that, in the next two years, Voyager 1 will cross the current sheet – the sprawling surface within the heliosphere where the polarity of the sun’s magnetic field changes from plus to minus. The spacecraft will detect a reversal in the magnetic field, proving that it is still within the heliosphere. But, if the magnetic field reversal doesn’t happen in the next year or two as expected, that is confirmation that Voyager 1 has already passed into interstellar space.

The heliosphere, in which the Sun and planets reside, is a large bubble inflated from the inside by the high-speed solar wind blowing out from the Sun. Pressure from the solar wind, along with pressure from the surrounding interstellar medium, determines the size and shape of the heliosphere. The supersonic flow of solar wind abruptly slows at the termination shock, the innermost boundary of the solar system. The edge of the solar system is the heliopause. The bow shock pushes ahead through the interstellar medium as the heliosphere plows through the galaxy.

Credit: Southwest Research Institute

“The proof is in the pudding,” said George Gloeckler, a professor in atmospheric, oceanic and space sciences at the University of Michigan in Ann Arbor and lead author of the new study.

Gloeckler has worked on the Voyager mission since 1972 and has been a vocal opponent of the view that Voyager 1 has entered interstellar space. He said that, although the spacecraft has observed many of the signs indicating it may have reached interstellar space, like cosmic rays, Voyager 1 did not see a change in magnetic field that many were expecting.

“This controversy will continue until it is resolved by measurements,” Gloeckler said.

If the new prediction is right, “this will be the highlight of my life,” he said. “There is nothing more gratifying than when you have a vision or an idea and you make a prediction and it comes true.”

The Voyager 1 and 2 spacecraft were launched in 1977 to study Jupiter and Saturn. The mission has since been extended to explore the outermost limits of the Sun’s influence and beyond. Voyager 2, which also flew by Uranus and Neptune, is on its way to interstellar space.

Gloeckler and co-author, Len Fisk, also a professor in atmospheric, oceanic and space sciences at the University of Michigan, are basing their new test on a model they developed and published earlier this year in The Astrophysical Journal. The model assumes that the solar wind is slowing down and, as a result, that the solar wind can be compressed. Based on this assumption, the study says Voyager 1 is moving faster than the outward flow of the solar wind and will encounter current sheets where the polarity of the magnetic field will reverse, proving that the spacecraft has not yet left the heliosphere. The scientists predict this reversal will most likely happen during 2015, based on observations made by Voyager 1.

“If that happens, I think if anyone still believes Voyager 1 is in the interstellar medium, they will really have something to explain,” Gloeckler said. “It is a signature that can’t be missed.”

Ed Stone of the California Institute of Technology in Pasadena and NASA’s Voyager Project Scientist said in a statement that “It is the nature of the scientific process that alternative theories are developed in order to account for new observations. This paper differs from other models of the solar wind and the heliosphere and is among the new models that the Voyager team will be studying as more data are acquired by Voyager.”

Alan Cummings, a senior research scientist at California Institute of Technology in Pasadena and a co-investigator on the Voyager mission, believes Voyager 1 has most likely crossed into interstellar space, but he said there is a possibility that Gloeckler and Fisk are right and the spacecraft is still in the heliosphere. He said that if Voyager 1 experiences a current sheet crossing like the one being proposed in the new study, it could also mean that the heliosphere is expanding and crossed the spacecraft again.

“If the magnetic field had cooperated, I don’t think we’d be having this discussion,” Cummings said. “This is a puzzle. It is very reasonable to explore alternate explanations. We don’t understand everything that happened out there.”

Stephen Fuselier, director of the space science department at the Southwest Research Institute in San Antonio, Texas, who is not involved with the research and is not on the Voyager 1 team, said the scientists have come up with a good test to prove once and for all if Voyager 1 has crossed into interstellar space. However, he does not agree with the assumption that the paper is making about the how fast the solar wind is moving. But, he said there is no way to measure this flow velocity, and if Gloeckler and Fisk’s assumptions are correct, the model makes sense and Voyager 1 could still be inside the heliosphere.

This artist’s concept shows the Voyager 1 spacecraft entering the space between stars. The Voyager mission team announced in 2012 that the Voyager 1 spacecraft had passed into interstellar space, but some scientists say it is still within the heliosphere – the region of space domininated by the Sun and its wind of energetic particles. In a new study, two Voyager team scientists are proposing a test that they say could prove once and for all of Voyager 1 has crossed the boundary.

Credit: NASA/JPL-Caltech

“I applaud them for coming out with a bold prediction,” said Fuselier, who works on the Interstellar Boundary Explorer mission that is examining the boundary between the solar wind and the interstellar medium. “If they are right, they are heroes. If they are wrong, though, it is important for the community to understand why … If they are wrong, then that must mean that one or more of their assumptions is incorrect, and we as a community have to understand which it is.”

Fuselier, who believes Voyager 1 has entered interstellar space, said he will reserve judgment on whether Gloecker and Fisk are correct until 2016. He said there is a sizeable fraction of the space community that is skeptical that Voyager 1 has entered interstellar space, but the new proposed test could help end that debate. Another good test will come when Voyager 2 crosses into interstellar space in the coming years, Fuselier and Cummings said.

“If you go back 10 years and talk to the Voyager people, they would have told you 10 years ago that what they would see upon exiting the heliosphere is very, very different from what they are seeing now,” Fuselier said. “We are just loaded down with surprises and this might be one of them.”


Contacts and sources:
Peter Weiss
American Geophysical Union 

Citation: A test for whether or not Voyager 1 has crossed the heliopause”  Authors:G. Gloeckler and L.A. Fisk: Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan, USA.

Model Of Titan's Astmosphere

A researcher from MIPT, Prof. Vladimir Krasnopolsky, who heads the Laboratory of High Resolution Infrared Spectroscopy of Planetary Atmospheres, has published the results of the comparison of his model of Titan’s atmosphere with the latest data.

The article in the journal Icarus compares the chemical composition of Titan’s atmosphere with parameters predicted by a mathematical model. The atmosphere of Saturn’s largest moon was described by a model that took into account the presence of 83 neutral molecules and33 ions and420 different chemical reactions between them. Despite the fact that Titan is located much further from the Sun than the Earth and that radiation flux coming from the Sun to the moon is 100 times less, the intensity of UV rays is enough to spur photochemical reactions in the upper layers of Titan’s atmosphere.

The data regarding the composition of Titan’s atmosphere, which is 1.6 times denser near the surface than the Earth’s air, was obtained from several sources, the main of which was the Cassini orbiter. It was equipped with a number of gauges, including ultraviolet and infrared spectrometers and equipment for studying the ions that were drawn into space. Within ten years in Saturn’s orbit, a plasma complex and a mass spectrometer designed specifically for this research project gathered enough data to compare it with mathematical models.

Titan’s atmosphere 
Image from the Cassini orbiter

In addition to Cassini, part of the data was obtained using the IRAM ground submillimeter telescope and the Hershel infrared space observatory. Data onthe distribution of aerosol particles in Titan’s atmosphere was received from a unique space capsule, Huygens, which landed on Titan for the first time in the history of mankind and sent the first photos of its surface.

Comparing this data with the previously developed model, Krasnopolsky showed that the theoretical description of Titan’s atmosphere matches the reality quite accurately. There are discrepancies, however, but they are caused by inevitable measurement errors – so far the concentrations of many substances are approximate. The most important thing is not the absolute matching of specific parameters but the correctness of the general model of chemical processes.

“The coherence of the model with reality means that we can correctly tell where different substances go from Titan’s ionosphere and where they come from,” Krasnopolsky said.

Krasnopolsky is considered a leading global expert on the atmosphere of celestial bodies of the solar system. He has participated in the creation of spectrometers for a variety of spacecraft, including the legendary Voyagers and the first Soviet interplanetary probes.


Contacts and sources: 
Prof. Vladimir Krasnopolsky
 MIPT 

SETI Targeting Alien Polluters With New Approach

Humanity is on the threshold of being able to detect signs of alien life on other worlds. By studying exoplanet atmospheres, we can look for gases like oxygen and methane that only coexist if replenished by life. But those gases come from simple life forms like microbes. What about advanced civilizations? Would they leave any detectable signs?

They might, if they spew industrial pollution into the atmosphere. New research by theorists at the Harvard-Smithsonian Center for Astrophysics (CfA) shows that we could spot the fingerprints of certain pollutants under ideal conditions. This would offer a new approach in the search for extraterrestrial intelligence (SETI).  
Credit: Harvard-Smithsonian Center for Astrophysics 

"We consider industrial pollution as a sign of intelligent life, but perhaps civilizations more advanced than us, with their own SETI programs, will consider pollution as a sign of unintelligent life since it's not smart to contaminate your own air," says Harvard student and lead author Henry Lin.

"People often refer to ETs as 'little green men,' but the ETs detectable by this method should not be labeled 'green' since they are environmentally unfriendly," adds Harvard co-author Avi Loeb.

The team, which also includes Smithsonian scientist Gonzalo Gonzalez Abad, finds that the upcoming James Webb Space Telescope (JWST) should be able to detect two kinds of chlorofluorocarbons (CFCs) -- ozone-destroying chemicals used in solvents and aerosols. They calculated that JWST could tease out the signal of CFCs if atmospheric levels were 10 times those on Earth. A particularly advanced civilization might intentionally pollute the atmosphere to high levels and globally warm a planet that is otherwise too cold for life.

There is one big caveat to this work. JWST can only detect pollutants on an Earth-like planet circling a white dwarf star, which is what remains when a star like our Sun dies. That scenario would maximize the atmospheric signal. Finding pollution on an Earth-like planet orbiting a Sun-like star would require an instrument beyond JWST -- a next-next-generation telescope.

The team notes that a white dwarf might be a better place to look for life than previously thought, since recent observations found planets in similar environments. Those planets could have survived the bloating of a dying star during its red giant phase, or have formed from the material shed during the star's death throes.

While searching for CFCs could ferret out an existing alien civilization, it also could detect the remnants of a civilization that annihilated itself. Some pollutants last for 50,000 years in Earth's atmosphere while others last only 10 years. Detecting molecules from the long-lived category but none in the short-lived category would show that the sources are gone.

"In that case, we could speculate that the aliens wised up and cleaned up their act. Or in a darker scenario, it would serve as a warning sign of the dangers of not being good stewards of our own planet," says Loeb.

This work has been accepted for publication in The Astrophysical Journal and is available online.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Contacts and sources:
David A. Aguilar
Harvard-Smithsonian Center for Astrophysics

Lives And Deaths Of Sibling Stars

This beautiful star cluster, NGC 3293, is found 8000 light-years from Earth in the constellation of Carina (The Keel). This cluster was first spotted by the French astronomer Nicolas-Louis de Lacaille in 1751, during his stay in what is now South Africa, using a tiny telescope with an aperture of just 12 millimetres. It is one of the brightest clusters in the southern sky and can be easily seen with the naked eye on a dark clear night.

In this image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile young stars huddle together against a backdrop of clouds of glowing gas and lanes of dust. The star cluster, known as NGC 3293, would have been just a cloud of gas and dust itself about ten million years ago, but as stars began to form it became the bright group we see here. Clusters like this are celestial laboratories that allow astronomers to learn more about how stars evolve.

Credit: ESO/G. Beccari

Star clusters like NGC 3293 contain stars that all formed at the same time, at the same distance from Earth and out of the same cloud of gas and dust, giving them the same chemical composition. As a result clusters like this are ideal objects for testing stellar evolution theory.

Most of the stars seen here are very young, and the cluster itself is less than 10 million years old. Just babies on cosmic scales if you consider that the Sun is 4.6 billion years old and still only middle-aged. An abundance of these bright, blue, youthful stars is common in open clusters like NGC 3293, and, for example, in the better known Kappa Crucis cluster, otherwise known as the Jewel Box or NGC 4755.

This zoom video starts from a broad view of the Milky Way and takes the viewer on a journey to the bright star cluster NGC 3293 in the constellation of Carina (The Keel). This spectacular object would have been just a cloud of gas and dust about ten million years ago, but as stars began to form it became the bright group we see here. Clusters like this are celestial laboratories that allow astronomers to learn more about how stars evolve.

Credit: ESO/G. Beccari/N. Risinger (skysurvey.org). Music: movetwo

These open clusters each formed from a giant cloud of molecular gas and their stars are held together by their mutual gravitational attraction. But these forces are not enough to hold a cluster together against close encounters with other clusters and clouds of gas as the cluster's own gas and dust dissipates. So, open clusters will only last a few hundred million years, unlike their big cousins, the globular clusters, which can survive for billions of years, and hold on to far more stars.

Despite some evidence suggesting that there is still some ongoing star formation in NGC 3293, it is thought that most, if not all, of the nearly fifty stars in this cluster were born in one single event. But even though these stars are all the same age, they do not all have the dazzling appearance of a star in its infancy; some of them look positively elderly, giving astronomers the chance to explore how and why stars evolve at different speeds.

This pan video gives a close-up view of a colourful image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. It shows a group of young stars huddled together against a backdrop of clouds of glowing gas and lanes of dust. This star cluster, known as NGC 3293, would have been just a cloud of gas and dust itself about ten million years ago, but as stars began to form it became the bright group we see here. Clusters like this are celestial laboratories that allow astronomers to learn more about how stars evolve.

Credit: ESO/G. Beccari. Music: movetwo

Take the bright orange star at the bottom right of the cluster. This huge star, a red giant, would have been born as one of the biggest and most luminous of its litter, but bright stars burn out fast. As the star used up the fuel at its core its internal dynamics changed and it began to swell and cool, becoming the red giant we now observe. Red giants are reaching the end of their life cycle, but this red giant's sister stars are still in what is known as the pre-main-sequence — the period before the long, stable, middle period in a star's life. We see these stars in the prime of their life as hot, bright and white against the red and dusty background.

This image was taken with the Wide Field Imager (WFI) installed on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in northern Chile.



Contacts and sources:

Transformer Pulsar Discovered

In late June 2013, an exceptional binary containing a rapidly spinning neutron star underwent a dramatic change in behavior never before observed. The pulsar's radio beacon vanished, while at the same time the system brightened fivefold in gamma rays, the most powerful form of light, according to measurements by NASA's Fermi Gamma-ray Space Telescope.

These artist's renderings show one model of pulsar J1023 before (top) and after (bottom) its radio beacon (green) vanished. Normally, the pulsar's wind staves off the companion's gas stream. When the stream surges, an accretion disk forms and gamma-ray particle jets (magenta) obscure the radio beam. 
Image Credit: NASA's Goddard Space Flight Center

"It's almost as if someone flipped a switch, morphing the system from a lower-energy state to a higher-energy one," said Benjamin Stappers, an astrophysicist at the University of Manchester, England, who led an international effort to understand this striking transformation. "The change appears to reflect an erratic interaction between the pulsar and its companion, one that allows us an opportunity to explore a rare transitional phase in the life of this binary."

Zoom into an artist's concept of AY Sextantis, a binary star system whose pulsar switched from radio emissions to high-energy gamma rays in 2013. This transition likely means the pulsar's spin-up process is nearing its end.



A binary consists of two stars orbiting around their common center of mass. This system, known as AY Sextantis, is located about 4,400 light-years away in the constellation Sextans. It pairs a 1.7-millisecond pulsar named PSR J1023+0038 -- J1023 for short -- with a star containing about one-fifth the mass of the sun. The stars complete an orbit in only 4.8 hours, which places them so close together that the pulsar will gradually evaporate its companion.

When a massive star collapses and explodes as a supernova, its crushed core may survive as a compact remnant called a neutron star or pulsar, an object squeezing more mass than the sun's into a sphere no larger than Washington, D.C. Young isolated neutron stars rotate tens of times each second and generate beams of radio, visible light, X-rays and gamma rays that astronomers observe as pulses whenever the beams sweep past Earth. Pulsars also generate powerful outflows, or "winds," of high-energy particles moving near the speed of light. The power for all this comes from the pulsar's rapidly spinning magnetic field, and over time, as the pulsars wind down, these emissions fade.

More than 30 years ago, astronomers discovered another type of pulsar revolving in 10 milliseconds or less, reaching rotational speeds up to 43,000 rpm. While young pulsars usually appear in isolation, more than half of millisecond pulsars occur in binary systems, which suggested an explanation for their rapid spin.

"Astronomers have long suspected millisecond pulsars were spun up through the transfer and accumulation of matter from their companion stars, so we often refer to them as recycled pulsars," explained Anne Archibald, a postdoctoral researcher at the Netherlands Institute for Radio Astronomy (ASTRON) in Dwingeloo who discovered J1023 in 2007.

During the initial mass-transfer stage, the system would qualify as a low-mass X-ray binary, with a slower-spinning neutron star emitting X-ray pulses as hot gas raced toward its surface. A billion years later, when the flow of matter comes to a halt, the system would be classified as a spun-up millisecond pulsar with radio emissions powered by a rapidly rotating magnetic field.

To better understand J1023's spin and orbital evolution, the system was regularly monitored in radio using the Lovell Telescope in the United Kingdom and the Westerbork Synthesis Radio Telescope in the Netherlands. These observations revealed that the pulsar's radio signal had turned off and prompted the search for an associated change in its gamma-ray properties.

A few months before this, astronomers found a much more distant system that flipped between radio and X-ray states in a matter of weeks. Located in M28, a globular star cluster about 19,000 light-years away, a pulsar known as PSR J1824-2452I underwent an X-ray outburst in March and April 2013. As the X-ray emission dimmed in early May, the pulsar's radio beam emerged.

While J1023 reached much higher energies and is considerably closer, both binaries are otherwise quite similar. What's happening, astronomers say, are the last sputtering throes of the spin-up process for these pulsars.

In J1023, the stars are close enough that a stream of gas flows from the sun-like star toward the pulsar. The pulsar's rapid rotation and intense magnetic field are responsible for both the radio beam and its powerful pulsar wind. When the radio beam is detectable, the pulsar wind holds back the companion's gas stream, preventing it from approaching too closely. But now and then the stream surges, pushing its way closer to the pulsar and establishing an accretion disk.

Gas in the disk becomes compressed and heated, reaching temperatures hot enough to emit X-rays. Next, material along the inner edge of the disk quickly loses orbital energy and descends toward the pulsar. When it falls to an altitude of about 50 miles (80 km), processes involved in creating the radio beam are either shut down or, more likely, obscured.

The inner edge of the disk probably fluctuates considerably at this altitude. Some of it may become accelerated outward at nearly the speed of light, forming dual particle jets firing in opposite directions -- a phenomenon more typically associated with accreting black holes. Shock waves within and along the periphery of these jets are a likely source of the bright gamma-ray emission detected by Fermi.

The findings were published in the July 20 edition of The Astrophysical Journal. The team reports that J1023 is the first example of a transient, compact, low-mass gamma-ray binary ever seen. The researchers anticipate that the system will serve as a unique laboratory for understanding how millisecond pulsars form and for studying the details of how accretion takes place on neutron stars.

"So far, Fermi has increased the number of known gamma-ray pulsars by about 20 times and doubled the number of millisecond pulsars within in our galaxy," said Julie McEnery, the project scientist for the mission at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Fermi continues to be an amazing engine for pulsar discoveries."


Contacts and sources:
NASA

Scientists Successfully Generate Human Platelets Using Next-Generation Bioreactor

Scientists at Brigham and Women's Hospital (BWH) have developed a scalable, next-generation platelet bioreactor to generate fully functional human platelets in vitro. The work is a major biomedical advancement that will help address blood transfusion needs worldwide.

The study is published July 21, 2014 in Blood.

"The ability to generate an alternative source of functional human platelets with virtually no disease transmission represents a paradigm shift in how we collect platelets that may allow us meet the growing need for blood transfusions," said Jonathan Thon, PhD, Division of Hematology, BWH Department of Medicine, lead study author.

Scanning electron micrograph of blood cells. From left to right: humanerythrocyte, activated platelet, leukocyte.

Credit: Wikipedia

According to the researchers, more than 2.17 million platelet units from donors are transfused yearly in the United States to treat patients undergoing chemotherapy, organ transplantation and surgery, as well as for those needing blood transfusions following a major trauma. However, increasing demand; a limited five-day shelf-life; and risk of contamination, rejection and infection have made blood platelet shortages common.

"Bioreactor-derived platelets theoretically have several advantages over conventional, donor-derived platelets in terms of safety and resource utilization," said William Savage, MD, PhD, medical director, Kraft Family Blood Donor Center at Dana Farber Cancer Institute/Brigham and Women's Hospital, who did not contribute to the study. "A major factor that has limited our ability to compare bioreactor platelets to donor platelets is the inefficiency of growing platelets, a problem that slows progress of clinical research. This study addresses that gap, while contributing to our understanding of platelet biology at the same time."

3D Rendering of Platelets

Credit:  Wikipedia

Blood cells, such as platelets, are made in bone marrow. The bioreactor-a device that mimics a biological environment to carry out a reaction on an industrial scale-uses biologically inspired engineering to fully integrate the major components of bone marrow, modeling both its composition and blood flow characteristics. The microfluidic platelet bioreactor recapitulates features such as bone marrow stiffness, extracellular matrix composition, micro-channel size, and blood flow stability under high-resolution live-cell microscopy to make human platelets.

Application of shear forces of blood flow in the bioreactor triggered a dramatic increase in platelet initiation from 10 percent to 90 percent, leading to functional human platelets.

"By being able to develop a device that successfully models bone marrow represents a crucial bridge connecting our understanding of the physiological triggers of platelet formation to support drug development and scale platelet production," said senior study author Joseph Italiano, Jr., PhD, Division of Hematology, BWH Department of Medicine, and the Vascular Biology Program at Boston Children's Hospital.

In terms of next steps, the researchers would like to commence phase 0/I in human clinical trials in 2017.

"The regulatory bar is appropriately set high for blood products, and it is important to us that we show platelet quality, function and safety over these next three years since we'll likely be recipients of these platelets ourselves at some point," said Thon.

This research was supported by the National Institutes of Health (R01Hl68130), American Society of Hematology Scholar Award, Brigham Research Institute at Brigham and Women's Hospital, and Marie Curie Actions International Outgoing Fellowship (300121).

Jonathan Thon, PhD, and Joseph Italiano, Jr., PhD, are both founders of Platelet BioGenesis, a company that aims to produce donor-independent human platelets from human-induced pluripotent stem cells at scale.



Contacts and sources:
 Brigham and Women's Hospital (BWH)

Bats Use Polarized Light To Navigate

Scientists have discovered that greater mouse-eared bats use polarization patterns in the sky to navigate – the first mammal that's known to do this.

The bats use the way the Sun's light is scattered in the atmosphere at sunset to calibrate their internal magnetic compass, which helps them to fly in the right direction, a study published in Nature Communications has shown.

Greater mouse-eared bat.
Credit: Natural Environment Research Council

Despite this breakthrough, researchers have no idea how they manage to detect polarised light.

"We know that other animals use polarisation patterns in the sky, and we have at least some idea how they do it: bees have specially-adapted photoreceptors in their eyes, and birds, fish, amphibians and reptiles all have cone cell structures in their eyes which may help them to detect polarisation," says Dr Richard Holland of Queen's University Belfast, co-author of the study.

"But we don't know which structure these bats might be using."

Polarisation patterns depend on where the sun is in the sky. They're clearest in a strip across the sky 90° from the position of the sun at sunset or sunrise.

But animals can still see the patterns long after sunset. This means they can orient themselves even when they can't see the sun, including when it's cloudy. Scientists have even shown that dung beetles use the polarisation pattern of moonlight for orientation.

A hugely diverse range of creatures -- including bees, anchovies, birds, reptiles and amphibians -- use the patterns as a compass to work out which way is north, south, east and west.

"Every night through the spring, summer and autumn, bats leave their roosts in caves, trees and buildings to search for insect prey. They might range hundreds of kilometres in a night, but return to their roosts before sunrise to avoid predators. But, until now, how they achieved such feats of navigation wasn't clear," says Stefan Greif of Queen's University Belfast, lead author of the study.

Even so, previous studies suggested that bats might detect polarisation patterns when they emerge from their caves at dusk.

"Most people are familiar with bats using echolocation to get around. But that only works up to about 50 metres, so we knew they had to be using another of their senses for longer range navigation," says Greif.

In a bid to shed light on the matter, Holland, Greif and colleagues from Tel Aviv University showed 70 adult, female mouse-eared bats one of two different types of polarisation patterns at sunset.

They then took them to one of two release sites in Bulgaria about 20 to 25 kilometres from their home roost. They released the bats at 01:00 AM -- when no polarisation is visible -- and followed the direction they set off in using small radio transmitters attached to their backs.

They found the bats that had been shown a shifted pattern of polarised light headed off in a direction shifted at right angles from the controls released at the same time.

Bats probably use a suite of senses, including the position of the Sun or the stars, Earth's magnetic field, smells, sight, and of course, echolocation to navigate.

Many bat species are declining across Europe, despite being protected. Ironically, wind turbines are seriously harming their populations.

"We know that bats must be 'seeing' the turbines, but it seems that the air pressure patterns around working turbines give the bats what's akin to the bends," says Holland.

"It's most common in migratory species, with around 300,000 bats affected every year in Europe alone. You just find bats dead at the bottom of these turbines. One option is to reduce turbine activity during times of peak migration."

Bats provide a vital service that tends to be overlooked -- they're natural pest controllers. It's estimated that they save us millions of pounds in pesticides by eating insects.

"Anything we can do to understand how they get about, how they move and navigate will be step forward in helping to protect them," adds Holland.

The study was funded by a Natural Environment Research Council grant to Richard Holland and by the Max Planck Society.


Contacts and sources: 


Citation: Stefan Greif, Ivailo Borissov, Yossi Yovel & Richard A. Holland, A functional role of the sky's polarization pattern for orientation in the greater mouse-eared bat, Myotis myotis, Nature Communications, published 22nd July 2014, doi

Map: Unhappiest Cities In The U.S. Revealed In New Study

A map of the U.S. which shows each metropolitan and rural area’s adjusted life satisfaction.

New research identifies the unhappiest cities in the U.S., but finds that some young people are still willing to relocate to them for a good job opportunity or lower housing prices.



The analysis, co-authored by Joshua Gottlieb of the University of British Columbia’s Vancouver School of Economics, suggests people may be deciding to trade happiness for other gains.

The working paper “Unhappy Cities,” released last week by the U.S. National Bureau of Economic Research, relies on a large survey that asks respondents about their satisfaction with life. This measure, which is often interpreted as a measure of happiness, indicates that individuals may willingly endure less happiness in exchange for higher incomes or lower housing costs.

Prof. Joshua Gottlieb



“Our research indicates that people care about more than happiness alone, so other factors may encourage them to stay in a city despite their unhappiness,” says Gottlieb. “This means that researchers and policy-makers should not consider an increase in reported happiness as an overriding objective.”

Gottlieb and his co-authors investigated which regions of the U.S. tend to report lower life satisfaction, and found that residents of declining cities appear less happy than those who live in other parts of the U.S. Long-term residents of these cities appear equally as unhappy as newer residents, suggesting that the city’s unhappiness persists over time. Historical data indicate that cities currently in decline were also unhappy in their more prosperous past.

Read the full study here. High resolution images available upon request. Gottlieb’s co-authors for “Unhappy Cities” are Harvard University’s Edward Glaeser and Oren Ziv.

BACKGROUND

Top 10 happiest metropolitan areas with a population greater than 1 million (as of 2010):

1. Richmond-Petersburg, VA
2. Norfolk-Virginia Beach-Newport News, VA
3. Washington, DC
4. Raleigh-Durham, NC
5. Atlanta, GA
6. Houston, TX
7. Jacksonville, FL
8. Nashville, TN
9. West Palm Beach-Boca Raton, FL
10. Middlesex-Somerset-Hunterdon, NJ

Top 10 unhappiest metropolitan areas with a population greater than 1 million (as of 2010):

1. New York, NY
2. Pittsburgh, PA
3. Louisville, KY
4. Milwaukee, WI
5. Detroit, MI
6. Indianapolis, IN
7. St. Louis, MO
8. Las Vegas, NV
9. Buffalo, NY
10. Philadelphia, PA

U.S. metropolitan areas with the highest reported happiness:

1. Charlottesville, VA
2. Rochester, MN
3. Lafayette, LA
4. Naples, FL
5. Baton Rouge, LA
6. Flagstaff, AZ
7. Shreveport, LA
8. Houma, LA
9. Corpus Christi, TX
10. Provo, UT

The least happy American regions are:

1. Scranton, PA
2. St. Joseph, MO
3. Erie, PA
4. South Bend, IN
5. Jersey City, NJ
6. Johnstown, PA
7. Non-metropolitan West Virginia
8. Springfield, MA
9. New York, NY
10. Evansville-Henderson, IN-KY



Contacts and sources:
University of British Columbia

Tuesday, July 22, 2014

Amplifying The Force Of The Vacuum, Empty Space Bubbling Soup Of Virtual Particles

Vacuum fluctuations may be among the most counter-intuitive phenomena of quantum physics. Theorists from the Weizmann Institute (Rehovot, Israel) and the Vienna University of Technology propose a way to amplify their force.

Vacuum is not as empty as one might think. In fact, empty space is a bubbling soup of various virtual particles popping in and out of existence – a phenomenon called “vacuum fluctuations”. Usually, such extremely short-lived particles remain completely unnoticed, but in certain cases vacuum forces can have a measurable effect.

Two atoms exchanging a virtual photon. Empty space around them is not as empty as one might think.
Credit:  TU Vienna

A team of researchers from the Weizmann Institute of Science (Rehovot, Israel) and the Vienna University of Technology has now proposed a method of amplifying these forces by several orders of magnitude using a transmission line, channelling virtual photons.

“Borrowing” Energy, but just for a Little While

If you park your car somewhere and later it is gone, that is most probably not due to vacuum fluctuations. Objects do not disappear or reappear, that would violate the law of energy conservation. In the world of quantum physics, however, things are a bit more complicated. “Due to the uncertainty principle, virtual particles can come into existence for a brief period of time”, says Igor Mazets from the Vienna University of Technology. “The higher their energy, the faster they will disappear again.”

But such virtual particles can have a measurable collective effect. At very short distances, vacuum fluctuations can lead to an attractive force between atoms or molecules – the Van der Waals forces. Even the ability of a gecko to climb flat surfaces can in part be attributed to vacuum fluctuations and virtual particles. The famous Casimir effect is another example of the power of the vacuum: The physicist Hendrik Casimir calculated in 1948 that two parallel mirrors in empty space will attract each other due to the way they influence the vacuum around them.

Atoms and Photons

Two atoms close to each other will also change the local vacuum around them. If one of them emits a virtual photon, which is almost instantly absorbed by the other, then on any timescale larger than the brief moment of the photon’s existence, nothing much has happened – the total energy is conserved. But the fact that virtual particles can be exchanged modifies the vacuum around the atoms, and this leads to a force.

“Usually, such forces are very hard to measure”, says Igor Mazets. “This is partly due to the fact, that such a photon may be emitted into any direction, and the chances of the second atom absorbing it are very small.”

But what if the virtual particle has a little help to find its way? Ephraim Shahmoon, Gershon Kurizki (Weizmann Institute of Science) and Igor Mazets calculated what happens to vacuum forces between atoms when they are placed in the vicinity of an electrical transmission line such as a coaxial cable or a coplanar waveguide (a device used in cavity quantum electrodynamics experiments as an open transmission line), cooled to very low temperatures. “In that case, the fluctuations are effectively confined to one dimension”, says Igor Mazets. The virtual particles will be forced to go into the direction of the other atom.

In that case, the fluctuation-mediated attraction between the atoms becomes orders of magnitude stronger than in free space. Usually, the force decreases rapidly with increasing distance between the atoms. Due to the transmission line, it falls off with one over the distance cubed, instead of one over the seventh power of the distance, as in the usual case.

The researchers believe that their proposed enhancement of the power of vacuum fluctuations can have profound implications for understanding Casimir- and Van der Waals forces and it may even be used for applications in quantum information processing and other emerging quantum technologies.



Contacts and sources:
Vienna University of Technology, TU Vienna

Mammoth and Mastodon Behavior Was More Stay At Home Than Roam

Their scruffy beards weren't ironic, but there are reasons mammoths and mastodons could have been the hipsters of the Ice Age.

According to research from the University of Cincinnati, the famously fuzzy relatives of elephants liked living in Greater Cincinnati long before it was trendy – at the end of the last ice age. A study led by Brooke Crowley, an assistant professor of geology and anthropology, shows the ancient proboscideans enjoyed the area so much they likely were year-round residents and not nomadic migrants as previously thought. 

Research led by UC's Brooke Crowley, posing with this mammoth mandible, has uncovered some interesting ideas about mammoth and mastodon behavior.
Credit: Dottie Stover, UC Creative Services

They even had their own preferred hangouts. Crowley's findings indicate each species kept to separate areas based on availability of favored foods here at the southern edge of the Last Glacial Maximum's major ice sheet.

"I suspect that this was a pretty nice place to live, relatively speaking," Crowley says. "Our data suggest that animals probably had what they needed to survive here year-round."

COULD THE PAST SAVE THE FUTURE?

Crowley's research with co-author and recent UC graduate Eric Baumann, "Stable Isotopes Reveal Ecological Differences Among Now-Extinct Proboscideans from the Cincinnati Region, USA," was recently published in Boreas, an international academic research journal.

UC's Brooke Crowley uses isotopic analysis in her research. Here she works with samples of bones from extinct lemurs.
Credit: Dottie Stover, UC Creative Services

Learning more about the different behaviors of these prehistoric creatures could benefit their modern-day cousins, African and Asian elephants. Both types are on the World Wildlife Fund's endangered species list. Studying how variable different types of elephants might have been in the past, Crowley says, might help ongoing efforts to protect these largest of land mammals from continued threats such as poaching and habitat destruction.

"There are regionally different stories going on," Crowley says. "There's not one overarching theme that we can say about a mammoth or a mastodon. And that's becoming more obvious in studies people are doing in different places. A mammoth in Florida did not behave the same as one in New York, Wyoming, California, Mexico or Ohio."

THE WISDOM IN TEETH

For their research, Crowley and Baumann looked to the wisdom in teeth – specifically museum specimens of molars from four mastodons and eight mammoths from Southwestern Ohio and Northwestern Kentucky. Much can be revealed by carefully drilling a tooth's surface and analyzing the stable carbon, oxygen and strontium isotopic signatures in the powdered enamel. 

UC graduate Eric Baumann worked with Brooke Crowley researching mammoth and mastodon behavior.
  Photo provided by Brooke Crowley

Each element tells a different story. Carbon provides insight into an animal's diet, oxygen relates to overall climatic conditions of an animal's environment and strontium indicates how much an animal may have traveled at the time its tooth was forming.

"Strontium reflects the bedrock geology of a location," Crowley says. "So if a local animal grows its tooth and mineralizes it locally and dies locally, the strontium isotope ratio in its tooth will reflect the place where it lived and died. If an animal grows its tooth in one place and then moves elsewhere, the strontium in its tooth is going to reflect where it came from, not where it died."

Their analysis allowed them to determine several things:

Mammoths ate more grasses and sedges than mastodons, which favored leaves from trees or shrubs.
Strontium from all of the animals (except one mastodon) matched local water samples, meaning they likely were less mobile and migratory than previously thought.
Differences in strontium and carbon between mammoths and mastodons suggest they didn't inhabit the same localities.
Mammoths preferred to be closer to the retreating ice sheet where grasses were more abundant, whereas mastodons fed farther from the ice sheet in more forested habitat.

“As a geologist, questioning the past is one of the most interesting and exciting things to do,” says Baumann, an environmental geologist with a contractor for the U.S. Environmental Protection Agency. “Based on our data, mammoths and mastodons seemed to have different diets and lived in different areas during their lives. This is important because it allows us to understand how species in the past lived and interacted. And the past is the key to the present.”

Crowley of the McMicken College of Arts and Sciences plans further research into how strontium isotopes can be used to explore megafauna, including other projects dealing with mammoths and mastodons.


Contacts and sources:
Tom Robinette
University of Cincinnati

Middle East Respiratory Syndrome Coronavirus Detected In The Air Of A Saudi Arabian Camel Barn

Saudi Arabian researchers have detected genetic fragments of Middle East Respiratory Syndrome coronavirus (MERS-CoV) in the air of a barn holding a camel infected with the virus. The work, published this week in mBio®, the online open-access journal of the American Society for Microbiology, indicates that further studies are needed to see if the disease can be transmitted through the air.


Credit: Wikipedia

MERS, a serious viral respiratory illness caused by the coronavirus, has been identified in 699 people as of June 11, according to the World Health Organization; 209 people have died from the condition. An additional 113 cases occurring between 2012 and 2014 were reported by the Saudi Arabian Ministry of Health on June 3.

For the study, researchers on three consecutive days last November collected three air samples from a camel barn owned by a 43-year-old male MERS patient who lived south of the town of Jeddah, who later died from the condition. Four of the man's nine camels had shown signs of nasal discharge the week before the patient became ill; he had applied a topical medicine in the nose of one of the ill camels seven days before experiencing symptoms.

Credit: Wikipedia

Using a laboratory technique called reverse transcription polymerase chain reaction (RT-PCR) to detect gene expression, they found that the first air sample, collected on November 7, contained genetic fragments of MERS-CoV. This was the same day that one of the patient's camels tested positive for the disease. The other samples did not test positive for MERS-CoV, suggesting short or intermittent shedding of the virus into the air surrounding the camels, said lead study author Esam Azhar, PhD, head of the Special Infectious Agents Unit at King Fahd Medical Research Center and associate professor of medical virology at King Abdulaziz University in Jeddah.

Additional experiments confirmed the presence of MERS-CoV-specific genetic sequences in the first air sample and found that these fragments were exactly identical to fragments detected in the camel and its sick owner.

"The clear message here is that detection of airborne MERS-CoV molecules, which were 100% identical with the viral genomic sequence detected from a camel actively shedding the virus in the same barn on the same day, warrants further investigations and measures to prevent possible airborne transmission of this deadly virus," Azhar said.

"This study also underscores the importance of obtaining a detailed clinical history with particular emphasis on any animal exposure for any MERS-CoV case, especially because recent reports suggest higher risk of MERS-CoV infections among people working with camels," he added.

Meanwhile, he said, mounting evidence for camel-to-human transmission of MERS-CoV warrants taking precautionary measures: People who care for camels or who work for slaughterhouses should wear face masks, gloves and protective clothing, and wash their hands frequently. It is also important to avoid contact with animals that are sick or have tested positive for MERS-CoV. Those who visit camel barns, farms or markets should wash hands before and after contact with animals. In addition, pasteurization of camel milk and proper cooking of camel meat are strongly recommended.

The study was supported by King Abdulaziz University.



Contacts and sources:
Jim Sliwa
American Society for Microbiology

Transiting Exoplanet With Longest Known Year

Astronomers have discovered a transiting exoplanet with the longest known year. Kepler-421b circles its star once every 704 days. In comparison, Mars orbits our Sun once every 780 days. Most of the 1,800-plus exoplanets discovered to date are much closer to their stars and have much shorter orbital periods.

"Finding Kepler-421b was a stroke of luck," says lead author David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA). "The farther a planet is from its star, the less likely it is to transit the star from Earth's point of view. It has to line up just right."

Credit:  Harvard-Smithsonian Center for Astrophysics

Kepler-421b orbits an orange, type K star that is cooler and dimmer than our Sun. It circles the star at a distance of about 110 million miles. As a result, this Uranus-sized planet is chilled to a temperature of -135° Fahrenheit.

As the name implies, Kepler-421b was discovered using data from NASA's Kepler spacecraft. Kepler was uniquely suited to make this discovery. The spacecraft stared at the same patch of sky for 4 years, watching for stars that dim as planets cross in front of them. No other existing or planned mission shows such long-term, dedicated focus. Despite its patience, Kepler only detected two transits of Kepler-421b due to that world's extremely long orbital period.

The planet's orbit places it beyond the "snow line" - the dividing line between rocky and gas planets. Outside of the snow line, water condenses into ice grains that stick together to build gas giant planets.

"The snow line is a crucial distance in planet formation theory. We think all gas giants must have formed beyond this distance," explains Kipping.

Since gas giant planets can be found extremely close to their stars, in orbits lasting days or even hours, theorists believe that many exoplanets migrate inward early in their history.

Kepler-421b shows that such migration isn't necessary. It could have formed right where we see it now.

"This is the first example of a potentially non-migrating gas giant in a transiting system that we've found," adds Kipping.

The host star, Kepler-421, is located about 1,000 light-years from Earth in the direction of the constellation Lyra.

This research has been accepted for publication in The Astrophysical Journal and is available online. Additional information can be found at https://www.cfa.harvard.edu/~dkipping/kepler421.html

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Sunday, July 20, 2014

3D Printed Bodies To Teach Doctors

The creators of a unique kit containing anatomical body parts produced by 3D printing say it will revolutionize medical education and training, especially in countries where cadaver use is problematical.

The ‘3D Printed Anatomy Series’, developed by experts from Monash University, is thought to be the first commercially available resource of its kind. The kit contains no human tissue, yet it provides all the major parts of the body required to teach anatomy of the limbs, chest, abdomen, head and neck.

Professor Paul McMenamin, Director of the University’s Centre for Human Anatomy Education, said the simple and cost-effective anatomical kit would dramatically improve trainee doctors’ and other health professionals’ knowledge and could even contribute to the development of new surgical treatments.

Michelle Quayle is pictured with part of the ‘3D Printed Anatomy Series’ thought to be the first commercially available resource of its kind
Credit: Monash University

“For centuries cadavers bequested to medical schools have been used to teach students about human anatomy, a practice that continues today. However many medical schools report either a shortage of cadavers, or find their handling and storage too expensive as a result of strict regulations governing where cadavers can be dissected,” he said.

“Without the ability to look inside the body and see the muscles, tendons, ligaments, and blood vessels, it’s incredibly hard for students to understand human anatomy. We believe our version, which looks just like the real thing, will make a huge difference.”

The kit, which is set to go on sale later this year, could have particular impact in developing countries where cadavers aren’t readily available, or are prohibited for cultural or religious reasons.

“Even when cadavers are available, they’re often in short supply, are expensive and they can smell a bit unpleasant because of the embalming process. As a result some people don’t feel that comfortable working with them,” Professor McMenamin said.

“Our 3D printed series can be produced quickly and easily, and unlike cadavers they won’t deteriorate – so they are a cost-effective option too.”

After scanning real anatomical specimens with either a CT or a surface laser scanner, the body parts are 3D printed either in a plaster-like powder or in plastic, resulting in high resolution, accurate color reproductions. 

Printed skull
Credit: Monash University

“Radiographic imaging, such as CT, is a really sophisticated means of capturing information in very thin layers, almost like the pages of a book. By taking this data and making a 3D rendered model we can then color that model and convert that to a file format that the 3D printer uses to recreate, layer by layer, a three-dimensional body part to scale,” Professor McMenamin said.

The research team is currently negotiating with potential commercial partners.

Further details have been published online in the journal Anatomical Sciences Education.


Contacts and sources:
Monash University

Saturday, July 19, 2014

Crash Of MH17 Sparks UN Security Council Emergency Meeting

The apparent deliberate downing of a Malaysian passenger plane over eastern Ukraine highlights the need for an urgent resumption of a ceasefire and a serious effort to end the ongoing crisis, the United Nations political chief told an emergency meeting of the Security Council yesterday.

The UN Security Council holds a moment of silence in honor of the victims of crashed flight MH17.
UN Photo/Loey Felipe

Malaysia Airlines flight MH17, carrying 298 people, was en route from Amsterdam to Kuala Lumpur when it crashed on Thursday in eastern Ukraine, near the Russian border.

Under-Secretary-General for Political Affairs Jeffrey Feltman said that while the UN has at this point no independent verification of the circumstances regarding the tragic crash, Secretary-General Ban Ki-moon is alarmed at what seem to be “credible, numerous reports” that suggest that a sophisticated surface-to-air missile was used.

“The Secretary-General strongly condemns this apparently deliberate downing of a civilian aircraft,” said Mr. Feltman. “This horrifying incident serves as the starkest reminder of how dire the situation in eastern Ukraine has become – and how it affects countries and families well beyond Ukraine’s borders.”

A separate statement issued by Mr. Ban’s spokesperson said that “this horrifying incident must at the very least prompt a serious and sustained effort to end the fighting in Ukraine.” It also stressed the need for accountability for the tragedy.

Both the Secretary-General and the Security Council have called for an international investigation into the incident. The Council, in a press statement, also stressed the need for all parties to grant immediate access by investigators to the crash site.

Mr. Feltman said the UN is fully ready to cooperate, and it has been in touch with the UN International Civil Aviation Organization (ICAO), which has offered to Ukrainian officials its investigative capacity in order to put together an international team.

Among the casualties of the crash was a staff member of the World Health Organization (WHO), Glenn Thomas, who was on his way to an international AIDS conference in Australia. The Joint UN Programme on HIV/AIDS (UNAIDS) said in a statement that a number of other passengers on the flight were also on their way to participate in the conference.


Credit: UN Photo/Loey Felipe 

“The UNAIDS family is in deep shock. Our hearts go out to the families of all the victims of this tragic crash,” said Executive Director Michel Sidibé. “The deaths of so many committed people working against HIV will be a great loss for the AIDS response.”

On the Ukraine crisis, Mr. Feltman reported that following the 30 June announcement by President Petro Poroshenko of the end of the 10-day ceasefire and subsequent resumption of the security and law enforcement operation in the east, the fighting between Government forces and armed groups has intensified dangerously, resulting in numerous deaths.

According to the Ukrainian authorities, a number of towns, including notably the cities of Sloviansk and Kramatorsk, as well as various smaller villages in the Donetsk and Lugansk regions, have been returned to their control.

However, Mr. Feltman said, relentless fighting has continued particularly in and around the cities of Lugansk and Donetsk, where the armed groups appear to have consolidated their presence. Earlier this week, a fierce battle was also fought over the international airport in Lugansk that now appears under the Ukrainian Government’s control.

The situation on and around the border between Ukraine and Russia is of “particular concern,” he said, noting that, while it is impossible for the UN to independently verify these accounts, a number of fatal incidents as well as intense fighting have been reported in recent days.

“As the Secretary-General has reiterated on countless occasions, armed groups need to immediately disarm and stop engaging in unlawful and violent acts,” the official stated.

“At the same time, we continue to strongly urge the Ukrainian authorities to act with maximum restraint and to make every effort possible to ensure the protection of civilians caught in the fighting.”

While estimations of the total number of civilian casualties vary, the UN human rights office reports there have been approximately 500 casualties so far and 1,400 people injured. Also, the UN refugee agency estimates that the crisis has displaced some tens of thousands of people.

“Grievances can and must never justify endangering the lives of those one claims and aims to represent and protect,” Mr. Feltman stated. “As the fighting continues, we are, however, disconcerted by the apparent lack of tangible progress toward a political solution.

“A first, critical step would be the immediate resumption of a ceasefire,” he stated.

“Establishing a path to peace in Ukraine, as in areas of conflict elsewhere in the world, requires a concerted effort by national actors from across the political spectrum, backed by strong and unified support of the international community,” said Mr. Feltman, who is expected to return to Kiev and Moscow in the coming days in the spirit of the Secretary-General’s good offices.


Contacts and sources:
United Nations

Comet Churyumov-Gerasimenko – Neither Ball Nor Potato

Comets have irregular and rather potato-like shapes – this is a well-known fact. But the comet 67P/Churyumov-Gerasimenko, on which the Philae lander is scheduled to descend in November 2014, has an unexpected shape. The pictures acquired by the OSIRIS camera on board the European Space Agency (ESA) Rosetta spacecraft – just 14,000 kilometres from its target – show that the comet is a contact binary, consisting of two parts in close contact.

Credit: DLR

"This shape is most surprising," says comet researcher Ekkehard Kührt from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). For 30 years, the project leader has been studying these celestial bodies for scientific experiments on the probe and lander. 

"But it is not unlikely. Comets were formed by the collision of small building blocks far away from the Sun during the emergence of the Solar System." The effect of the comet's unusual shape on the landing cannot be estimated yet.

Fused together 4.5 billion years ago

Rosetta and the Philae lander are currently less than 10,000 kilometres away from their destination. So far, Churyumov-Gerasimenko has been an enigma for scientists: only recordings from a distance, such as those from the Hubble Space Telescope or the first images of OSIRIS as well as the navigation camera provide clues of what the orbiter and lander will encounter. 
Credit: DLR 

Previous observations estimated the comet to be about three by five kilometres in size. The fact that two clearly distinguishable parts make up Churyumov-Gerasimenko is a surprise. "The two blocks likely formed 4.5 billion years ago, collided at low speed, stuck to each other and have since been moving together," says Kührt.

 "Scientifically, it is now of course very interesting to find out whether the two components differ in their composition." If the two parts are from different regions, their structure might also differ.

Waiting for details

In the coming months, as the spacecraft get closer to their target, the scientists will learn more about the comet. "For the landing, it is especially important to have a detailed view of the comet and understand how the two parts are connected," says Koen Geurts, an engineer at the Lander Control Centre at DLR in Cologne. 

This information will be incorporated into the planning of the trajectory of Rosetta spacecraft – and its course and height in turn has an impact on the landing of Philae, as it is the first time that a lander touches down on a comet and performs in situ measurements. "So far, it looks as though there are large flat regions on the comet." 

The location where the two parts are connected will likely not be considered as the landing site. In addition to being a suitable, reasonably flat terrain, the landing site should also have a day-night cycle so that the Philae lander can cool down out of the sunlight and so that scientific research can be carried out under different conditions. 

Regular communication with the Rosetta spacecraft is necessary for the lander team to send the recorded data to Earth and empty the data storage. "These aspects are currently still hard to assess."

Rosetta is a European Space Agency mission with contributions from its Member States and NASA. Rosetta's Philae lander has been contributed by a consortium led by DLR, MPS, the French space agency, CNES (Centre National d’Études Spatiales), and the Italian space agency, ASI (Agenzia Spaziale Italiana).

The European Space Agency (ESA) Rosetta spacecraft and its lander Philae were around two million kilometers from their target comet in May, 67P/Churyumov-Gerasimenko when images acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) camera system could already show the comet awakening on its way towards the Sun, enveloped in a cloud of small dust particles.
Credit; DLR

Using these observations, the OSIRIS science team, which includes planetary researchers from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), have been able to determine the comet’s rotation period with additional precision – 12.4 hours. In August, Rosetta will arrive at the comet, and will deploy the Philae lander onto the comet’s surface in November – the first ever landing on a comet.

The sequence of images acquired by the OSIRIS camera system between 24 March and 4 May, during the flight towards Churyumov-Gerasimenko, reveal the expansion of the comet’s dusty veil, or coma. Although 67P is still more than 600 million kilometres from the Sun, its surface has already started to warm up, and, as a result, volatiles have begun to evaporate from its surface, carrying tiny dust particles with them. The images acquired in early May show that the comet’s gas and dust cloud has reached approximately 1300 kilometres into space. 

The comet nucleus has a diameter of about four kilometres. “It’s beginning to look like a real comet,” says Holger Sierks from the Max Planck Institute for Solar System Research (Max-Planck-Institut für Sonnensystemforschung; MPS), the OSIRIS Principal Investigator.

This image, acquired by the OSIRIS camera system on 30 April 2014, shows Comet 67P/Churyumov-Gerasimenko. The target of the Rosetta comet mission has a dust cloud formed around it, which stretches up to 1300 kilometres into space.

Credit: DLR

Unveiling the unknown

The OSIRIS team also revealed a new fact. Until now, comet researchers believed the rotation period of Churyumov-Gerasimenko to be 12.7 hours. Through observation and analysis of the changes in brightness of the comet, the research team was able to determine that the comet only takes 12.4 hours to rotate around its axis. 

“Knowing the exact rotation period of the comet is of vital importance, both for the optimal planning of the mission and scientific data gathering and for the interpretation of the acquired data,” said Stefano Mottola, who studies comets at the DLR Institute of Planetary Research and is a member of the OSIRIS team.

Any information obtained during the approach to the comet also helps to plan the manoeuvres required for the Rosetta spacecraft to enter orbit around the comet and the landing by Philae. One thing is certain – with the awakening of the comet, Rosetta and Philae will be able to study its coma and tail. The first manoeuvre to prepare the probe for its rendezvous with Churyumov-Gerasimenko in August has already been carried out. 

In May, the engineers and scientists were also able to breathe again – all the instruments on the spacecraft and lander have survived two and a half years of hibernation during their journey through space – they have all passed their ‘Health Check’. Eleven instruments are being carried on board the Rosetta orbiter and ten scientific experiments on the lander. For the first time ever, measurements will be conducted directly on the surface of a comet.


Contacts and sources:
 German Aerospace Center

Nature’s Strongest Super-Glue Comes Unstuck


Over a 150 years since it was first described by Darwin, scientists are finally uncovering the secrets behind the super strength of barnacle glue.

Still far better than anything we have been able to develop synthetically, barnacle glue – or cement - sticks to any surface, under any conditions.

But exactly how this superglue of superglues works has remained a mystery – until now.

An international team of scientists led by Newcastle University, UK, and funded by the US Office of Naval Research, have shown for the first time that barnacle larvae release an oily droplet to clear the water from surfaces before sticking down using a phosphoprotein adhesive.

Nauplius larva of Elminius modestus
Credit: Wikipedia

Publishing their findings this week in the prestigious academic journal Nature Communications, author Dr Nick Aldred says the findings could pave the way for the development of novel synthetic bioadhesives for use in medical implants and micro-electronics. The research will also be important in the production of new anti-fouling coatings for ships.

“It’s over 150 years since Darwin first described the cement glands of barnacle larvae and little work has been done since then,” says Dr Aldred, a research associate in the School of Marine Science and Technology at Newcastle University, one of the world’s leading institutions in this field of research.

“We’ve known for a while there are two components to the bioadhesive but until now, it was thought they behaved a bit like some of the synthetic glues - mixing before hardening. But that still left the question, how does the glue contact the surface in the first place if it is already covered with water? This is one of the key hurdles to developing glues for underwater applications.

“Advances in imaging techniques, such as 2-photon microscopy, have allowed us to observe the adhesion process and characterise the two components. We now know that these two substances play very different roles – one clearing water from the surface and the other cementing the barnacle down.

“The ocean is a complex mixture of dissolved ions, the pH varies significantly across geographical areas and, obviously, it’s wet. Yet despite these hostile conditions, barnacle glue is able to withstand the test of time.

“It’s an incredibly clever natural solution to this problem of how to deal with a water barrier on a surface it will change the way we think about developing bio-inspired adhesives that are safe and already optimised to work in conditions similar to those in the human body, as well as marine paints that stop barnacles from sticking.”

Barnacles have two larval stages – the nauplius and the cyprid. The nauplius, is common to most crustacea and it swims freely once it hatches out of the egg, feeding in the plankton.

The final larval stage, however, is the cyprid, which is unique to barnacles. It investigates surfaces, selecting one that provides suitable conditions for growth. Once it has decided to attach permanently, the cyprid releases its glue and cements itself to the surface where it will live out the rest of its days.

“The key here is the technology. With these new tools we are able to study processes in living tissues, as they happen. We can get compositional and molecular information by other methods, but they don't explain the mechanism. There's no substitute for seeing things with your own eyes. ” explains Dr Aldred.

“In the past, the strong lasers used for optically sectioning biological samples have typically killed the samples, but now technology allows us to study life processes exactly as they would happen in nature.”

The research will also be of interest to the shipping industry.

Biofouling – the accumulation of marine life on ship’s hulls – increases drag on ships and costs the global industry an estimated $7.5 billion a year in wasted fuel.

Barnacles on a ship's hull. 

Credit: Physical Chemistry Chemical Physics

Other implications include the movement of invasive species around the world and increased emission of greenhouse gases.


Contacts and sources:
School of Marine Science and Technology
Newcastle University


Citation: “Synergistic roles for lipids and proteins in the permanent adhesive of barnacle larvae.” N V Gohad, N Aldred, C M Hartshorn, Y Jong Lee, M T Cicerone, B Orihuela, A S Clare, D Rittschof and A S Mount. Nature Communications July 2014

New Global Geologic Map Of Mars

A new global geologic map of Mars –the most thorough representation of the "Red Planet's" surface – has been published by the U.S. Geological Survey. This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration.

This new global geologic map of Mars depicts the most thorough representation of the “Red Planet’s” surface. This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration
Credit: USGS

The new map brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years. The result is an updated understanding of the geologic history of the surface of Mars – the solar system’s most Earth-like planet and the only other one in our Sun’s “habitable zone.” The new geologic map of Mars is available for download online.

This new global geologic map of Mars depicts the most thorough representation of the "Red Planet's" surface. This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration.

Credit: U.S. Geological Survey (USGS)

For hundreds of years, geologic maps have helped drive scientific thought. This new global geologic map of Mars, as well as the recent global geologic maps of Jupiter’s moons Ganymede and Io, also illustrates the overall importance of geologic mapping as an essential tool for the exploration of the solar system.

View of the northern part of the western hemisphere of Mars. Left half shows a color elevation, shaded relief view highlighting the immense shields of the Tharsis rise. Right half shows a true-color view of the vast Valles Marineris and Kasei Valles canyon systems, which connect to the dark basin of Chryse Planitia at upper right.
Image data from NASA

"Spacecraft exploration of Mars over the past couple decades has greatly improved our understanding of what geologic materials, events and processes shaped its surface," said USGS scientist and lead author, Dr. Kenneth Tanaka. “The new geologic map brings this research together into a holistic context that helps to illuminate key relationships in space and time, providing information to generate and test new hypotheses.”

The USGS-led mapping effort reveals that the Martian surface is generally older than previously thought. Three times as much surface area dates to the first major geologic time period - the Early Noachian Epoch - than was previously mapped. This timeframe is the earliest part of the Noachian Period, which ranges from about 4.1 to about 3.7 billion years ago, and was characterized by high rates of meteorite impacts, widespread erosion of the Martian surface and the likely presence of abundant surface water.

The map also confirms previous work that suggests Mars had been geologically active until the present day. There is evidence that major changes in Mars’ global climate supported the temporary presence of surface water and near-surface groundwater and ice. These changes were likely responsible for many of the major shifts in the environments where Martian rocks were formed and subsequently eroded. This new map will serve as a key reference for the origin, age and historic change of geological materials anywhere on Mars.

"Findings from the map will enable researchers to evaluate potential landing sites for future Mars missions that may contribute to further understanding of the planet’s history," said USGS Acting Director Suzette Kimball. "The new Mars global geologic map will provide geologic context for regional and local scientific investigations for many years to come."

The Martian surface has been the subject of scientific observation since the 1600s, first by Earth-based telescopes, and later by fly-by missions and orbiting spacecraft. The Mariner 9 and Viking Orbiter missions produced the first planet-wide views of Mars’ surface, enabling publication of the first global geologic maps (in 1978 and 1986-87, respectively) of a planetary surface other than the Earth and the Moon. A new generation of sophisticated scientific instruments flown on the Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter spacecraft has provided diverse, high quality data sets that enable more sophisticated remapping of the global-scale geology of Mars.

The production of planetary cartographic products has been a focal point of research at the USGS Astrogeology Science Center since its inception in the early 1960s. USGS began producing planetary maps in support of the Apollo Moon landings, and continues to help establish a framework for integrating and comparing past and future studies of extraterrestrial surfaces. In many cases, these planetary geologic maps show that, despite the many differences between bodies in our solar system, there are many notable similarities that link the evolution and fate of our planetary system together.

The project was funded by NASA through its Planetary Geology and Geophysics Program.

The mission of the USGS Astrogeology Science Center is to serve the Nation, the international planetary science community, and the general public’s pursuit of new knowledge of our solar system. The Team’s vision is to be a national resource for the integration of planetary geosciences, cartography, and remote sensing. As explorers and surveyors, with a unique heritage of proven expertise and international leadership, USGS astrogeologists enable the ongoing successful investigation of the solar system for humankind. For more information, visit Astrogeology Science Center

See the complete map at http://pubs.usgs.gov/sim/3292/pdf/sim3292_map.pdf  with all annotations.


Contacts and sources:
Jennifer LaVista
U.S. Geological Survey

New Earthquake Map: 42 States at Risk; 16 States at High Risk

To help make the best decisions to protect communities from earthquakes, new USGS maps display how intense ground shaking could be across the nation.

The USGS recently updated their U.S. National Seismic Hazard Maps, which reflect the best and most current understanding of where future earthquakes will occur, how often they will occur, and how hard the ground will likely shake as a result.

42 States at Risk; 16 States at High Risk

2014 USGS National Seismic Hazard Map, displaying intensity of potential ground shaking from an earthquake in 50 years (which is the typical lifetime of a building).

Credit: USGS

While all states have some potential for earthquakes, 42 of the 50 states have a reasonable chance of experiencing damaging ground shaking from an earthquake in 50 years (the typical lifetime of a building). Scientists also conclude that 16 states have a relatively high likelihood of experiencing damaging ground shaking. These states have historically experienced earthquakes with a magnitude 6 or greater.

The hazard is especially high along the west coast, intermountain west, and in several active regions of the central and eastern U.S., such as near New Madrid, MO, and near Charleston, SC. The 16 states at highest risk are Alaska, Arkansas, California, Hawaii, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming.

While these overarching conclusions of the national-level hazard are similar to those of the previous maps released in 2008, details and estimates differ for many cities and states. Several areas have been identified as being capable of having the potential for larger and more powerful earthquakes than previously thought due to more data and updated earthquake models. The most prominent changes are discussed below.

Informed Decisions Based on the Maps

With an understanding of potential ground shaking levels, various risk analyses can be calculated by considering factors like population levels, building exposure, and building construction practices. This is used for establishing building codes, and in the analysis of seismic risk for key structures. This can also help in determining insurance rates, emergency preparedness plans, and private property decisions such as re-evaluating one’s home and making it more resilient.

These maps are part of USGS contributions to the National Earthquake Hazards Reduction Program (NEHRP), which is a congressionally-established partnership of four federal agencies with the purpose of reducing risks to life and property in the U.S. that result from earthquakes. The contributing agencies are the USGS, Federal Emergency Management Agency (FEMA), National Institute of Standards and Technology, and National Science Foundation (NSF). As an example of the collaboration, the hazards identified in the USGS maps underlie FEMA-sponsored seismic design provisions that are incorporated into building codes adopted by states and localities. The maps also reflect investments in research by academic and other scientists supported by grants from the USGS and the NSF.

“The standards for seismic safety in building codes are directly based upon USGS assessments of potential ground shaking from earthquakes, and have been for years,” said Jim Harris, a member and former chair of the Provisions Update Committee of the Building Seismic Safety Council.

“The committees preparing those standards welcome this updated USGS information as a basis for making decisions and continuing to ensure the most stable and secure construction.”

Key Updates

East Coast

The eastern U.S. has the potential for larger and more damaging earthquakes than considered in previous maps and assessments. As one example, scientists learned a lot following the magnitude 5.8 earthquake that struck Virginia in 2011. It was among the largest earthquakes to occur along the east coast in the last century, and helped determine that even larger events are possible. Estimates of earthquake hazards near Charleston, SC, have also gone up due to the assessment of earthquakes in the state.

In New York City, the maps indicate a slightly lower hazard for tall buildings than previously thought (but still a hazard nonetheless). Scientists estimated a lower likelihood for slow shaking from an earthquake near the city. Slow shaking is likely to cause more damage to tall structures in contrast, compared to fast shaking which is more likely to impact shorter structures.

Central U.S.

The New Madrid Seismic Zone has been identified to have a larger range of potential earthquake magnitudes and locations than previously identified. This is a result of a range of new research, part of which was recently compiled by the Nuclear Regulatory Commission.

West Coast

In California, earthquake hazard extends over a wider area than previously thought. Most notably, faults were recently discovered, raising earthquake hazard estimates for San Jose, Vallejo and San Diego. On the other hand, new insights on faults and rupture processes reduced earthquake hazard estimates for Irvine, Santa Barbara and Oakland. Hazard increased in some parts of the San Francisco Bay Area and Los Angeles region and decreased in other parts. These updates were from the new Uniform California Earthquake Rupture Forecast Model, which incorporates many more potential fault ruptures than did previous assessments. Recent earthquakes in Alaska, Mexico and New Zealand taught scientists more about complex ruptures and how faults can link together. This insight was applied to California for which approximately 250,000 potential complex ruptures were modeled.

New research on the Cascadia Subduction Zone resulted in increased estimates of earthquake magnitude up to magnitude 9.3. Deep-sea cores were collected that show evidence within the sea-floor sediments of large earthquake-generated mudflows. Earthquake shaking estimates were also increased following abundant data gathered from the magnitude 9.0 earthquake in Tohoku, Japan in 2011 and the magnitude 8.2 earthquake offshore of Chile in 2014, as those events ruptured along subduction zones similar to the Pacific Northwest zone.

Damage to the Washington National Cathedral in DC from the earthquake in Virginia on August 23, 2011.
 Photo Credit: William Leith, USGS

In Washington, scientists incorporated new knowledge of the Tacoma Fault into the maps and identified changes to the geometry of the Whidbey Island fault in the northern Puget Sound. Earthquake hazard also increased for Las Vegas because of new science. In Utah, scientists dug trenches to study prehistoric earthquakes along the Wasatch Fault. While the overall seismic hazard didn’t change significantly, detailed changes were made to the fault models in this region and robust data were acquired to hone the assessments. This is valuable since approximately 75% of Utah’s population, including the residents of Salt Lake City, lives near this fault.

The magnitude 7.9 earthquake in Wenchuan, China in 2008 provided many new records of shaking that are very similar to anticipated future earthquakes in the western U.S., as the fault structures are similar. Previously, scientists did not have nearly as many shaking records from earthquakes of this size.

Induced Earthquakes … Research Underway

Some states have experienced increased seismicity in the past few years that may be associated with human activities such as the disposal of wastewater in deep wells.

One specific focus for the future is including an additional layer to these earthquake hazard maps to account for recent potentially triggered earthquakes that occur near some wastewater disposal wells. Injection-induced earthquakes are challenging to incorporate into hazard models because they may not behave like natural earthquakes and their rates change based on man-made activities.

You Can’t Plan If …

“USGS earthquake science is vital because you can’t plan for earthquakes if you don’t know what you are planning for,” said Mark Petersen, Chief of the USGS National Seismic Hazard Mapping Project. “Our nation’s population and exposure to large earthquakes has grown tremendously in recent years. The cost of inaction in planning for future earthquakes and other natural disasters can be very high, as demonstrated by several recent damaging events across the globe. It is important to understand the threat you face from earthquakes at home and the hazards for the places you might visit. The USGS is dedicated to applying the best available science in developing reliable products useful for reducing the earthquake risk across the U.S.”

Start with USGS Science

The USGS is the only federal agency with responsibility for recording and reporting earthquake activity nationwide and providing a seismic hazard assessment. The USGS regularly updates the national seismic hazard models and maps, typically every 6 years, in sync with the building code updates. The 2014 update focuses on the conterminous U.S. Maps are also available for Alaska (last updated in 2007); Hawaii (1998); Puerto Rico (2003); Guam and Marianna Islands (2012); and American Samoa (2012).


Contacts and sources:
By Jessica Robertson and Mark Petersen
USGS

Documentation for the 2014 Update of the United States National Seismic Hazard Maps
By Mark D. Petersen, Morgan P. Moschetti, Peter M. Powers, Charles S. Mueller, Kathleen M. Haller, Arthur D. Frankel, Yuehua Zeng, Sanaz Rezaeian, Stephen C. Harmsen, Oliver S. Boyd, Ned Field, Rui Chen, Kenneth S. Rukstales, Nico Luco, Russell L. Wheeler, Robert A. Williams, and Anna H. Olsen Report PDF (113 MB)