Friday 20 May 2016

Space mission first to observe key interaction between magnetic fields of Earth and sun

How magnetic reconnection takes place, a critical step in understanding space weather


Summary:: Physicists have now provided the first major results of NASA's Magnetospheric Multiscale (MMS) mission, including an unprecedented look at the interaction between the magnetic fields of Earth and the sun. The article describes the first direct and detailed observation of a phenomenon known as magnetic reconnection, which occurs when two opposing magnetic field lines break and reconnect with each other, releasing massive amounts of energy.

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This artist's rendition shows the four identical MMS spacecraft flying near the sun-facing boundary of Earth's magnetic field (blue wavy lines). The MMS mission has revealed the clearest picture yet of the process of magnetic reconnection between the magnetic fields of Earth and the sun -- a driving force behind space weather, solar flares and other energetic phenomena.

Credit: NASA

Most people do not give much thought to the Earth's magnetic field, yet it is every bit as essential to life as air, water and sunlight. The magnetic field provides an invisible, but crucial, barrier that protects Earth from the sun's magnetic field, which drives a stream of charged particles known as the solar wind outward from the sun's outer layers. The interaction between these two magnetic fields can cause explosive storms in the space near Earth, which can knock out satellites and cause problems here on Earth's surface, despite the protection offered by Earth's magnetic field.

A new study co-authored by University of Maryland physicists provides the first major results of NASA's Magnetospheric Multiscale (MMS) mission, including an unprecedented look at the interaction between the magnetic fields of Earth and the sun. The paper describes the first direct and detailed observation of a phenomenon known as magnetic reconnection, which occurs when two opposing magnetic field lines break and reconnect with each other, releasing massive amounts of energy.
The discovery is a major milestone in understanding magnetism and space weather. The research paper appears in the May 13, 2016, issue of the journal Science.
"Imagine two trains traveling toward each other on separate tracks, but the trains are switched to the same track at the last minute," said James Drake, a professor of physics at UMD and a co-author on the Science study. "Each track represents a magnetic field line from one of the two interacting magnetic fields, while the track switch represents a reconnection event. The resulting crash sends energy out from the reconnection point like a slingshot."
Evidence suggests that reconnection is a major driving force behind events such as solar flares, coronal mass ejections, magnetic storms, and the auroras observed at both the North and South poles of Earth. Although researchers have tried to study reconnection in the lab and in space for nearly half a century, the MMS mission is the first to directly observe how reconnection happens.
The MMS mission provided more precise observations than ever before. Flying in a pyramid formation at the edge of Earth's magnetic field with as little as 10 kilometers' distance between four identical spacecraft, MMS images electrons within the pyramid once every 30 milliseconds. In contrast, MMS' predecessor, the European Space Agency and NASA's Cluster II mission, takes measurements once every three seconds--enough time for MMS to make 100 measurements.
"Just looking at the data from MMS is extraordinary. The level of detail allows us to see things that were previously a blur," explained Drake, who served on the MMS science team and also advised the engineering team on the requirements for MMS instrumentation. "With a time interval of three seconds, seeing reconnection with Cluster II was impossible. But the quality of the MMS data is absolutely inspiring. It's not clear that there will ever be another mission quite like this one."
Simply observing reconnection in detail is an important milestone. But a major goal of the MMS mission is to determine how magnetic field lines briefly break, enabling reconnection and energy release to happen. Measuring the behavior of electrons in a reconnection event will enable a more accurate description of how reconnection works; in particular, whether it occurs in a neat and orderly process, or in a turbulent, stormlike swirl of energy and particles.
A clearer picture of the physics of reconnection will also bring us one step closer to understanding space weather--including whether solar flares and magnetic storms follow any sort of predictable pattern like weather here on Earth. Reconnection can also help scientists understand other, more energetic astrophysical phenomena such as magnetars, which are neutron stars with an unusually strong magnetic field.
"Understanding reconnection is relevant to a whole range of scientific questions in solar physics and astrophysics," said Marc Swisdak, an associate research scientist in UMD's Institute for Research in Electronics and Applied Physics. Swisdak is not a co-author on the Science paper, but he is actively collaborating with Drake and others on subsequent analyses of the MMS data.
"Reconnection in Earth's magnetic field is relatively low energy, but we can get a good sense of what is happening if we extrapolate to more energetic systems," Swisdak added. "The edge of Earth's magnetic field is an excellent test lab, as it's just about the only place where we can fly a spacecraft directly through a region where reconnection occurs."
To date, MMS has focused only on the sun-facing side of Earth's magnetic field. In the future, the mission is slated to fly to the opposite side to investigate the teardrop-shaped tail of the magnetic field that faces away from the sun.

Thursday 19 May 2016

Most Earth-like worlds have yet to be born

Summary:: Earth came early to the party in the evolving universe. According to a new theoretical study, when our solar system was born 4.6 billion years ago only eight percent of the potentially habitable planets that will ever form in the universe existed. And, the party won't be over when the sun burns out in another 6 billion years. The bulk of those planets - 92 percent - have yet to be born.

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An artist's impression of the innumerable Earth-like planets that have yet to be born over the next trillion years in the evolving universe.

Credit: NASA / ESA / G. Bacon (STScI)

Earth came early to the party in the evolving universe. According to a new theoretical study, when our solar system was born 4.6 billion years ago only eight percent of the potentially habitable planets that will ever form in the universe existed. And, the party won't be over when the sun burns out in another 6 billion years. The bulk of those planets -- 92 percent -- have yet to be born.

This conclusion is based on an assessment of data collected by NASA's Hubble Space Telescope and the prolific planet-hunting Kepler space observatory.
"Our main motivation was understanding the Earth's place in the context of the rest of the universe," said study author Peter Behroozi of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, "Compared to all the planets that will ever form in the universe, the Earth is actually quite early."
Looking far away and far back in time, Hubble has given astronomers a "family album" of galaxy observations that chronicle the universe's star formation history as galaxies grew. The data show that the universe was making stars at a fast rate 10 billion years ago, but the fraction of the universe's hydrogen and helium gas that was involved was very low. Today, star birth is happening at a much slower rate than long ago, but there is so much leftover gas available that the universe will keep cooking up stars and planets for a very long time to come.
"There is enough remaining material [after the big bang] to produce even more planets in the future, in the Milky Way and beyond," added co-investigator Molly Peeples of STScI.
Kepler's planet survey indicates that Earth-sized planets in a star's habitable zone, the perfect distance that could allow water to pool on the surface, are ubiquitous in our galaxy. Based on the survey, scientists predict that there should be 1 billion Earth-sized worlds in the Milky Way galaxy at present, a good portion of them presumed to be rocky. That estimate skyrockets when you include the other 100 billion galaxies in the observable universe.
This leaves plenty of opportunity for untold more Earth-sized planets in the habitable zone to arise in the future. The last star isn't expected to burn out until 100 trillion years from now. That's plenty of time for literally anything to happen on the planet landscape.
The researchers say that future Earths are more likely to appear inside giant galaxy clusters and also in dwarf galaxies, which have yet to use up all their gas for building stars and accompanying planetary systems. By contrast, our Milky Way galaxy has used up much more of the gas available for future star formation.
A big advantage to our civilization arising early in the evolution of the universe is our being able to use powerful telescopes like Hubble to trace our lineage from the big bang through the early evolution of galaxies. The observational evidence for the big bang and cosmic evolution, encoded in light and other electromagnetic radiation, will be all but erased away 1 trillion years from now due to the runaway expansion of space. Any far-future civilizations that might arise will be largely clueless as to how or if the universe began and evolved.

New angles on visual cloaking of everyday objects

Summary:: Using the same mathematical framework as the Rochester Cloak, researchers have been able to use flat screen displays to extend the range of angles that can be hidden from view. Their method lays out how cloaks of arbitrary shapes, that work from multiple viewpoints, may be practically realized in the near future using commercially available digital devices.

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A multidirectional `perfect paraxial' cloak using four lenses. From a continuous range of viewing angles, the hand remains cloaked, and the grids seen through the device match the background on the wall (about 2 m away), in color, spacing, shifts, and magnification.

Credit: J. Adam Fenster / University of Rochester

Using the same mathematical framework as the Rochester Cloak, researchers at the University of Rochester have been able to use flat screen displays to extend the range of angles that can be hidden from view. Their method lays out how cloaks of arbitrary shapes, that work from multiple viewpoints, may be practically realized in the near future using commercially available digital devices.

The Rochester researchers have shown a proof-of-concept demonstration for such a setup, which is still much lower resolution than the nearly perfect imaging achieved by the Rochester Cloak lenses. But with increasingly higher resolution displays becoming available, the "digital integral cloak" they describe in their new Optica paper will continue to improve.
While the Rochester Cloak offered a simple way of cloaking, it was limited by the cloaking working only over small angles, and cloaking large objects would require large, expensive lenses.
By breaking up the information into distinct pieces, it becomes possible to use currently available digital cameras and digital displays. The Rochester researchers use a camera to scan a background and then encode the information in such a way that every pixel on a screen offers a unique view of a given point on the background for a given position of a viewer. By doing this for many views and using lenticular lenses -- a sheet of plastic with an array of thin, parallel semicylindrical lenses -- they can recreate multiple images of the background, each corresponding to a viewer at a different position. So if the viewer moves from side to side, every part of the background moves accordingly as if the screen was not there, "cloaking" anything in the space between the screen and the background.
In the current system, it takes PhD student Joseph Choi and his advisor Professor of Physics John Howell several minutes to scan, process and update the image on the screen, i.e. to update the background. But Choi explains they are hoping soon to be able to do this in real-time, even if at lower resolution.
Their mathematical framework and their proof-of-concept setup also demonstrates how any object of a fixed size can be cloaked, even when in motion -- so long as the shape of the object remains fixed and does not deform. To do this one side of the object would be covered in an array of sensors -- effectively cameras -- and the other side in pixels with tiny lenses over them. Choi's and Howell's approach could then be used to identify which sensors need to feed into which pixels so as to show the background as if an object wasn't there. A similar trick has been used in advertising, but for one viewing angle only. However, by using the Rochester group's setup, a car, for example, could be made invisible to viewers from multiple positions, not just to a person at a predetermined position.

Photonics advances allow us to be seen across the universe, with major implications for search for extraterrestrial intelligence

Summary:: Looking up at the night sky -- expansive and seemingly endless, stars and constellations blinking and glimmering like jewels just out of reach -- it's impossible not to wonder: Are we alone? For many of us, the notion of intelligent life on other planets is as captivating as ideas come. Maybe in some other star system, maybe a billion light years away, there's a civilization like ours asking the exact same question. Imagine if we sent up a visible signal that could eventually be seen across the entire universe. Imagine if another civilization did the same.

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Are we alone? Imagine if we sent up a visible signal that could eventually be seen across the entire universe. Imagine if another civilization did the same.

Credit: © Stefano Garau / Fotolia

Looking up at the night sky -- expansive and seemingly endless, stars and constellations blinking and glimmering like jewels just out of reach -- it's impossible not to wonder: Are we alone?

For many of us, the notion of intelligent life on other planets is as captivating as ideas come. Maybe in some other star system, maybe a billion light years away, there's a civilization like ours asking the exact same question.
Imagine if we sent up a visible signal that could eventually be seen across the entire universe. Imagine if another civilization did the same.
The technology now exists to enable exactly that scenario, according to UC Santa Barbara physics professor Philip Lubin, whose new work applies his research and advances in directed-energy systems to the search for extraterrestrial intelligence (SETI). His recent paper "The Search for Directed Intelligence" appears in the journal REACH -- Reviews in Human Space Exploration.
"If even one other civilization existed in our galaxy and had a similar or more advanced level of directed-energy technology, we could detect 'them' anywhere in our galaxy with a very modest detection approach," said Lubin, who leads the UCSB Experimental Cosmology Group. "If we scale it up as we're doing with direct energy systems, how far could we detect a civilization equivalent to ours? The answer becomes that the entire universe is now open to us.
"Similar to the use of directed energy for relativistic interstellar probes and planetary defense that we have been developing, take that same technology and ask yourself, 'What are consequences of that technology in terms of us being detectable by another 'us' in some other part of the universe?'" Lubin added. "Could we see each other? Can we behave as a lighthouse, or a beacon, and project our presence to some other civilization somewhere else in the universe? The profound consequences are, of course, 'Where are they?' Perhaps they are shy like us and do not want to be seen, or they don't transmit in a way we can detect, or perhaps 'they' do not exist."
The same directed energy technology is at the core of Lubin's recent efforts to develop miniscule, laser-powered interstellar spacecraft. That work, funded since 2015 by NASA (and just selected by the space agency for "Phase II" support) is the technology behind billionaire Yuri Milner's newsmaking, $100-million Breakthrough Starshot initiative announced April 12.
Lubin is a scientific advisor on Starshot, which is using his NASA research as a roadmap as it seeks to send tiny spacecraft to nearby star systems.
In describing directed energy, Lubin likened the process to using the force of water from a garden hose to push a ball forward. Using a laser light, spacecraft can be pushed and steered in much the same way. Applied to SETI, he said, the directed energy system could be deployed to send a targeted signal to other planetary systems.
"In our paper, we propose a search strategy that will observe nearly 100 billion planets, allowing us to test our hypothesis that other similarly or more advanced civilizations with this same broadcast capability exist," Lubin said.
"As a species we are evolving rapidly in photonics, the production and manipulation of light," he explained. "Our recent paper explores the hypothesis: We now have the ability to produce light extremely efficiently, and perhaps other species might also have that ability. And if so, then what would be the implications of that? This paper explores the 'if so, then what?'"
Traditionally and still, Lubin said, the "mainstay of the SETI community" has been to conduct searches via radio waves. Think Jodie Foster in "Contact," receiving an extraterrestrial signal by way of a massive and powerful radio telescope. With Lubin's UCSB-developed photonics approach, however, making "contact" could be much simpler: Take the right pictures and see if any distant systems are beaconing us.
"All discussions of SETI have to have a significant level of, maybe not humor, but at least hubris as to what makes reason and what doesn't," Lubin said. "Maybe we are alone in terms of our technological capability. Maybe all that's out there is bacteria or viruses. We have no idea because we've never found life outside of our Earth.
"But suppose there is a civilization like ours and suppose -- unlike us, who are skittish about broadcasting our presence -- they think it's important to be a beacon, an interstellar or extragalactic lighthouse of sorts," he added. "There is a photonics revolution going on on Earth that enables this specific kind of transmission of information via visible or near-infrared light of high intensity. And you don't need a large telescope to begin these searches. You could detect a presence like our current civilization anywhere in our galaxy, where there are 100 billion possible planets, with something in your backyard. Put in context, and we would love to have people really think about this: You can literally go out with your camera from Costco, take pictures of the sky, and if you knew what you were doing you could mount a SETI search in your backyard. The lighthouse is that bright."

Hubble takes Mars portrait near close approach

Summary:: On May 12, 2016, astronomers using NASA's Hubble Space Telescope captured this striking image of Mars, when the planet was 50 million miles from Earth. The photo reveals details as small as 20 miles to 30 miles across. This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and Mars will be 47 million miles from Earth.

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Mars.

Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute)

Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across.

The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view.
A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact.
The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands.
South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeus (to the east) and Sinus Meridiani (to the west). These darker regions are covered by dark bedrock and fine-grained sand deposits ground down from ancient lava flows and other volcanic features. These sand grains are coarser and less reflective than the fine dust that gives the brighter regions of Mars their ruddy appearance. Early Mars watchers first mapped these regions.
An extended blanket of clouds can be seen over the southern polar cap. The icy northern polar cap has receded to a comparatively small size because it is now late summer in the northern hemisphere. Hubble photographed a wispy, afternoon, lateral cloud extending for at least 1,000 miles at mid-northern latitudes. Early morning clouds and haze extend along the western limb.
This hemisphere of Mars contains landing sites for several NASA Mars surface robotic missions, including Viking 1 (1976), Mars Pathfinder (1997), and the still-operating Opportunity Mars rover. The landing sites of the Spirit and Curiosity Mars rovers are on the other side of the planet.
This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and when Mars will be at a distance of 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.
The biennial close approaches between Mars and Earth are not all the same. Mars' orbit around the sun is markedly elliptical; the close approaches to Earth can range from 35 million miles to 63 million miles.
They occur because about every two years Earth's orbit catches up to Mars' orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on "opposing" sides of Earth. This phenomenon is a result of the difference in orbital periods between Earth's orbit and Mars' orbit. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.

The Unique fragment from Earth's formation returns after billions of years in cold storage

Unique fragment from Earth's formation returns after billions of years in cold storage

Tailless Manx comet from Oort Cloud brings clues about the origin of the solar system

Summary:: Astronomers have found a unique object that appears to be made of inner solar system material from the time of Earth's formation, billions of years ago. Observations show that C/2014 S3 (PANSTARRS) is the first object to be discovered on a long-period cometary orbit that has the characteristics of a pristine inner solar system asteroid. It may help understanding how the solar system formed.

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Artist's impression of the unique object C/2014 S3 (PANSTARRS). Observations with ESO's Very Large Telescope, and the Canada France Hawai`i Telescope, show that this is the first object to be discovered that is on a long-period cometary orbit, but that has the characteristics of a pristine inner Solar System asteroid. It may provide important clues about how the Solar System formed. Because the object has spent most of its life away from the inner Solar System it suffered very few collisions, and its surface displays few or no craters. As it formed in the same region as the Earth did, it is mostly rocky, and therefore has only very limited cometary activity.

Credit: ESO/M. Kornmesser

In a paper to be published today in the journal Science Advances, lead author Karen Meech of the University of Hawai`i's Institute for Astronomy and her colleagues conclude that C/2014 S3 (PANSTARRS) formed in the inner Solar System at the same time as the Earth itself, but was ejected at a very early stage.

Their observations indicate that it is an ancient rocky body, rather than a contemporary asteroid that strayed out. As such, it is one of the potential building blocks of the rocky planets, such as the Earth, that was expelled from the inner Solar System and preserved in the deep freeze of the Oort Cloud for billions of years.*
Karen Meech explains the unexpected observation: "We already knew of many asteroids, but they have all been baked by billions of years near the Sun. This one is the first uncooked asteroid we could observe: it has been preserved in the best freezer there is."
C/2014 S3 (PANSTARRS) was originally identified by the Pan-STARRS1 telescope as a weakly active comet a little over twice as far from the Sun as the Earth. Its current long orbital period (around 860 years) suggests that its source is in the Oort Cloud, and it was nudged comparatively recently into an orbit that brings it closer to the Sun.
The team immediately noticed that C/2014 S3 (PANSTARRS) was unusual, as it does not have the characteristic tail that most long-period comets have when they approach so close to the Sun. As a result, it has been dubbed a Manx comet, after the [tailless cat]. Within weeks of its discovery, the team obtained spectra of the very faint object with ESO's Very Large Telescope in Chile.
Careful study of the light reflected by C/2014 S3 (PANSTARRS) indicates that it is typical of asteroids known as S-type, which are usually found in the inner asteroid main belt. It does not look like a typical comet, which are believed to form in the outer Solar System and are icy, rather than rocky. It appears that the material has undergone very little processing, indicating that it has been deep frozen for a very long time. The very weak comet-like activity associated with C/2014 S3 (PANSTARRS), which is consistent with the sublimation of water ice, is about a million times lower than active long-period comets at a similar distance from the Sun.
The authors conclude that this object is probably made of fresh inner Solar System material that has been stored in the Oort Cloud and is now making its way back into the inner Solar System.
A number of theoretical models are able to reproduce much of the structure we see in the Solar System. An important difference between these models is what they predict about the objects that make up the Oort Cloud. Different models predict significantly different ratios of icy to rocky objects. This first discovery of a rocky object from the Oort Cloud is therefore an important test of the different predictions of the models. The authors estimate that observations of 50-100 of these Manx comets are needed to distinguish between the current models, opening up another rich vein in the study of the origins of the Solar System.
Co-author Olivier Hainaut (ESO, Garching, Germany), concludes: "We've found the first rocky comet, and we are looking for others. Depending how many we find, we will know whether the giant planets danced across the Solar System when they were young, or if they grew up quietly without moving much."
* The Oort cloud is a huge region surrounding the Sun like a giant, thick soap bubble. It is estimated that it contains trillions of tiny icy bodies. Occasionally, one of these bodies gets nudged and falls into the inner Solar System, where the heat of the sun turns it into a comet. These icy bodies are thought to have been ejected from the region of the giant planets as these were forming, in the early days of the Solar System.
This research was presented in a paper entitled "Inner Solar System Material Discovered in the Oort Cloud," by Karen Meech et al., in the journal Science Advances.
The team is composed of Karen J. Meech (Institute for Astronomy, University of Hawai`i, USA), Bin Yang (ESO, Santiago, Chile), Jan Kleyna (Institute for Astronomy, University of Hawai`i, USA), Olivier R. Hainaut (ESO, Garching, Germany), Svetlana Berdyugina (Institute for Astronomy, University of Hawai'i, USA; Kiepenheuer Institut für Sonnenphysik, Freiburg, Germany), Jacqueline V. Keane (Institute for Astronomy, University of Hawai`i, USA), Marco Micheli (ESA, Frascati, Italy), Alessandro Morbidelli (Laboratoire Lagrange/Observatoire de la Côte d'Azur/CNRS/Université Nice Sophia Antipolis, France) and Richard J. Wainscoat (Institute for Astronomy, University of Hawai`i, USA).
ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become "the world's biggest eye on the sky."

Thursday 12 May 2016

Scientists store digital images in DNA, and retrieves them perfectly.

Summary:: Researchers have developed one of the first complete systems to store digital data in DNA -- allowing companies to store data that today would fill a big box store supercenter in a space the size of a sugar cube.

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All the movies, images, emails and other digital data from more than 600 basic smartphones (10,000 gigabytes) can be stored in the faint pink smear of DNA at the end of this test tube.

Credit: Tara Brown Photography/ University of Washington

Technology companies routinely build sprawling data centers to store all the baby pictures, financial transactions, funny cat videos and email messages its users hoard.

But a new technique developed by University of Washington and Microsoft researchers could shrink the space needed to store digital data that today would fill a Walmart supercenter down to the size of a sugar cube.
The team of computer scientists and electrical engineers has detailed one of the first complete systems to encode, store and retrieve digital data using DNA molecules, which can store information millions of times more compactly than current archival technologies.
In one experiment outlined in a paper presented in April at the ACM International Conference on Architectural Support for Programming Languages and Operating Systems, the team successfully encoded digital data from four image files into the nucleotide sequences of synthetic DNA snippets.
More significantly, they were also able to reverse that process -- retrieving the correct sequences from a larger pool of DNA and reconstructing the images without losing a single byte of information.
The team has also encoded and retrieved data that authenticates archival video files from the UW's Voices from the Rwanda Tribunal project that contain interviews with judges, lawyers and other personnel from the Rwandan war crime tribunal.
"Life has produced this fantastic molecule called DNA that efficiently stores all kinds of information about your genes and how a living system works -- it's very, very compact and very durable," said co-author Luis Ceze, UW associate professor of computer science and engineering.
"We're essentially repurposing it to store digital data -- pictures, videos, documents -- in a manageable way for hundreds or thousands of years."
The digital universe -- all the data contained in our computer files, historic archives, movies, photo collections and the exploding volume of digital information collected by businesses and devices worldwide -- is expected to hit 44 trillion gigabytes by 2020.
That's a tenfold increase compared to 2013, and will represent enough data to fill more than six stacks of computer tablets stretching to the moon. While not all of that information needs to be saved, the world is producing data faster than the capacity to store it.
DNA molecules can store information many millions of times more densely than existing technologies for digital storage -- flash drives, hard drives, magnetic and optical media. Those systems also degrade after a few years or decades, while DNA can reliably preserve information for centuries. DNA is best suited for archival applications, rather than instances where files need to be accessed immediately.
The team from the Molecular Information Systems Lab housed in the UW Electrical Engineering Building, in close collaboration with Microsoft Research, is developing a DNA-based storage system that it expects could address the world's needs for archival storage.
First, the researchers developed a novel approach to convert the long strings of ones and zeroes in digital data into the four basic building blocks of DNA sequences -- adenine, guanine, cytosine and thymine.
"How you go from ones and zeroes to As, Gs, Cs and Ts really matters because if you use a smart approach, you can make it very dense and you don't get a lot of errors," said co-author Georg Seelig, a UW associate professor of electrical engineering and of computer science and engineering. "If you do it wrong, you get a lot of mistakes."
The digital data is chopped into pieces and stored by synthesizing a massive number of tiny DNA molecules, which can be dehydrated or otherwise preserved for long-term storage.
The UW and Microsoft researchers are one of two teams nationwide that have also demonstrated the ability to perform "random access" -- to identify and retrieve the correct sequences from this large pool of random DNA molecules, which is a task similar to reassembling one chapter of a story from a library of torn books.
To access the stored data later, the researchers also encode the equivalent of zip codes and street addresses into the DNA sequences. Using Polymerase Chain Reaction (PCR) techniques -- commonly used in molecular biology -- helps them more easily identify the zip codes they are looking for. Using DNA sequencing techniques, the researchers can then "read" the data and convert them back to a video, image or document file by using the street addresses to reorder the data.
Currently, the largest barrier to viable DNA storage is the cost and efficiency with which DNA can be synthesized (or manufactured) and sequenced (or read) on a large scale. But researchers say there's no technical barrier to achieving those gains if the right incentives are in place.
Advances in DNA storage rely on techniques pioneered by the biotechnology industry, but also incorporate new expertise. The team's encoding approach, for instance, borrows from error correction schemes commonly used in computer memory -- which hadn't been applied to DNA.
"This is an example where we're borrowing something from nature -- DNA -- to store information. But we're using something we know from computers -- how to correct memory errors -- and applying that back to nature," said Ceze.
"This multidisciplinary approach is what makes this project exciting. We are drawing from a diverse set of disciplines to push the boundaries of what can be done with DNA. And, as a result, creating a storage system with unprecedented density and durability," said Karin Strauss, a researcher at Microsoft and UW affiliate associate professor of computer science and engineering.
The research was funded by Microsoft Research, the National Science Foundation, and the David Notkin Endowed Graduate Fellowship.
Co-authors include UW computer science and engineering doctoral student James Bornholt, UW bioengineering doctoral student Randolph Lopez and Douglas Carmean, a partner architect at Microsoft Research and a UW affiliate professor of computer science and engineering.

Brazilian Zika virus strain causes birth defects in experimental models

First direct experimental proof of causal effect, researchers say

Summary:: Researchers have described the first 'direct experimental proof' that the Brazilian strain of Zika virus can actually cause severe birth defects.

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Cross section of a human cerebral organoid shows different structures reminiscent of human embryonic cortical development, such as the proliferative zone in the center, with migrating cells to the surface forming the cortical plate. Cortical progenitor cells are in red, neurons in green and cell nuclei in blue.

Credit: UC San Diego Health

Researchers at University of California San Diego School of Medicine, with colleagues in Brazil and Senegal, have described the first "direct experimental proof" that the Brazilian strain of Zika virus can actually cause severe birth defects. The findings are published in the May 11 online issue of Nature.

The team, headed by Alysson R. Muotri, PhD, associate professor in the UC San Diego School of Medicine departments of Pediatrics and Cellular and Molecular Medicine, and co-corresponding senior author Patricia C.B. Beltrao-Braga, PhD, at the University of Sao Paulo, conducted studies in mouse models, human stem cells and in cerebral organoids -- miniature brains grown in vitro.
"Rising infection rates of Zika virus in places like Brazil, with a corresponding increase in cases of microcephaly, have powerfully suggested an association, but until now hard evidence has been lacking," said Muotri. "Our findings provide direct experimental proof that the Brazilian Zika virus strain causes severe birth defects -- and that the full adverse effect upon health, even beyond microcephaly, is not yet fully understood."
Muotri said the model developed to determine Zika cause-and-effect provides a new tool to assess the effectiveness of potential therapies to counteract the virus during human neurodevelopment.
"Our platform can now be used to understand what is unique about the Brazilian Zika virus and to test drugs to prevent the neurological problems associated with the infection," he said. "Moreover, we now have a robust animal model that will be useful during validation of potential vaccines against the virus."
The Zika virus is not new. It was first described in 1947 in rhesus monkeys in Uganda, but researchers say the twin lineages of Zika -- African and Asian -- did not cause meaningful infections in humans until 2007, when the Asian strain, carried by Aedes aegypti mosquitoes, caused an epidemic on the Pacific island of Yap. Further outbreaks occurred in New Caledonia and French Polynesia from 2013 to 2015.
In 2013, the Asian lineage of Zika reached Brazil and subsequently other countries in South and Central America. In Brazil, the virus has aroused international attention and concern, with infections of pregnant women alarmingly linked to congenital malformations, including microcephaly (an undersized head and brain) in newborns and other severe neurological diseases, such as Guillain-Barre syndrome.
In the Nature paper, authors used mouse models to track Brazilian virus infections to birth defects. "This is the first animal model to document Zika-induced birth defects. It shows that the virus can cross the placenta membrane and infect the fetus," said Muotri. Like humans, newborn mouse pups infected via their mothers with the Brazilian Zika virus strain displayed smaller-than-normal heads and stunted body growth. Tissue and genetic analyses revealed other abnormalities, including eye problems and ongoing cell death.
"The data in mice also suggest that microcephaly is only the tip of the iceberg. The animals have extensive intra-uterine growth arrest, which essentially means poor fetal development in the womb. Media covering the Zika story have focused upon affected babies with small heads because such images are profoundly dramatic, but the true health impact is likely to be more widespread and devastating."
Interestingly, Muotri noted that not all mouse models tested showed a causal effect when infected by the Zika virus. In at least one strain of mice, the Brazilian Zika virus could not cross the placenta of the mother to infect her unborn pups. Muotri said the finding suggests that in mice -- and humans -- some individuals may be more susceptible to infection than others, possibly due to genetic differences or varying robustness of the immune system response.
The researchers also conducted studies using human pluripotent stem cells to generate cortical progenitor cells that ordinarily would differentiate into neurons forming the brain's cerebral cortex or folded outer layer. Infection of these cortical progenitor cells by the Brazilian viral strain resulted in increased progenitor cell death. The effects of the African virus is not as pronounced, indicating that the mutations of the Brazilian strains made the virus more aggressive in human cells.
Finally, researchers exposed human brain organoids -- three-dimensional buds of cells created from pluripotent stem cells that structurally represent specific organs writ small -- to the Zika virus. They noted that infection resulted in reduced areas of growth in the organoids and disrupted cortical layers. Again, the Brazilian virus had a more dramatic impact on cortical malformations in these human organoids.
Muotri said they tested the Brazilian Zika virus in organoids derived from chimpanzees to assess its adaptability compared to the African strain. "The Brazilian virus has a slow replication rate in the chimp organoid compared to the African virus," Muotri said, "which suggests that the Brazilian strain has, somehow, adapted to humans. We are investigating how genetic differences might cause that difference."

The missing brown dwarfs.

The missing brown dwarfs

Summary:: When re-analyzing cataloged and updated observational data of brown dwarfs in the solar neighborhood, astronomers have found that a significant number of nearby brown dwarfs should still be out there, awaiting their discovery. The study challenges the previously established picture of brown dwarfs in the solar neighborhood.

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Possible manifestations of brown dwarfs (artist's impression). As brown dwarfs are nearly invisible in the optical light and only emit radiation in the IR regime, they exhibit different colors in that range.

Credit: AIP/J. Fohlmeister

When re-analysing catalogued and updated observational data of brown dwarfs in the solar neighbourhood, astronomers from Potsdam have found that a significant number of nearby brown dwarfs should still be out there, awaiting their discovery. The corresponding study by Gabriel Bihain and Ralf-Dieter Scholz from the Leibniz Institute for Astrophysics Potsdam (AIP) challenges the previously established picture of brown dwarfs in the solar neighbourhood.

Brown dwarfs are objects that are too large to be called planets, yet too small to be stars. Having a mass of only less than seven per cent of the mass of the Sun, they are unable to create sufficient pressure and heat in their interiors to ignite hydrogen-to-helium fusion, a fundamental physical mechanism by which stars generate radiation. In this sense brown dwarf are "failed stars." It is therefore important to know how many brown dwarfs really exist in different regions of the sky in order to achieve a better understanding of star formation and of the motion of stars in the Milky Way.
Gabriel Bihain and Ralf-Dieter Scholz have taken a careful look at the distribution of nearby known brown dwarfs from a point of view that was not looked at before. To their surprise they discovered a significant asymmetry in the spatial configuration, strongly deviating from the known distribution of stars.
"I projected the nearby brown dwarfs onto the galactic plane and suddenly realized: half of the sky is practically empty! We absolutely didn't expect this, as we have been looking at an environment that should be homogeneous.," Gabriel Bihain explained. Seen from Earth, the empty region overlaps with a large part of the northern sky.
The scientists concluded that there should be many more brown dwarfs in the solar neighbourhood that are yet to be discovered and that will fill the observed gap. If they are right, this would mean that star formation fails significantly more often than previously thought, producing one brown dwarf for every four stars. In any case, it appears, the established picture of the solar neighbourhood and of its brown dwarf population will have to be rethought.
"It is quite possible that not only brown dwarfs are still hiding in the observational data, but also other objects with even smaller, planetary-like masses. So it is definitely worth it to take another deep look at both existing and future data.," Ralf-Dieter Scholz concluded.

Supernova iron found on the moon

Confirmation of supernova explosion in the neighborhood of our solar system

Summary:: Approximately two million years ago a star exploded in a supernova close to our solar system: Its traces can still be found today in the form of an iron isotope found on the ocean floor. Now scientists have found increased concentrations of this supernova-iron in lunar samples as well. They believe both discoveries to originate from the same stellar explosion.

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Since the moon generally provides a better cosmic record than Earth, the scientists were also able to specify for the first time an upper limit for the flow of 60Fe that must have reached the moon.

Credit: © SkyLine / Fotolia

A dying star ends its life in a cataclysmic explosion, shooting the majority of the star's material, primarily new chemical elements created during the explosion, out into space.

One or more such supernovae appear to have occurred close to our solar system approximately two million years ago. Evidence of the fact has been found on Earth in the form of increased concentrations of the iron isotope 60Fe detected in Pacific ocean deep-sea crusts and in ocean-floor sediment samples.
This evidence is highly compelling: The radioactive 60Fe isotope is created almost exclusively in supernova explosions. And with a half-life of 2.62 million years, relatively short compared to the age of our solar system, any radioactive 60Fe originating from the time of the solar system's birth should have long ago decayed into stable elements and thus should no longer be found on Earth.
Lunar samples from the Apollo missions
This supernova hypothesis was first put forth in 1999 by researchers at the Technical University of Munich (TUM) who had found initial evidence in a deep-sea crust. Now their claim has received further substantiation: Physicists at the TUM and their colleagues from the USA have succeeded in demonstrating an unusually high concentration of 60Fe in lunar ground samples as well.
The samples were gathered between 1969 and 1972 during Apollo lunar missions 12, 15 and 16, which brought the lunar material back to earth.
It's also conceivable that 60Fe can occur on the moon as the result of bombardment with cosmic particles, since these particles do not break up when colliding with air molecules, as is the case with Earth's atmosphere. Instead they directly impact the lunar surface and can thus result in transmutation of elements. "But this can only account for a very small portion of the 60Fe found," explains Dr. Gunther Korschinek, physicist at TUM and scientist of the Cluster of Excellence Structure and Origin of the Universe.
Deposits of newly produced stellar matter
"We therefore assume that the 60Fe found in both terrestrial and lunar samples has the same source: These deposits are newly created stellar matter, produced in one or more supernovae," says Dr. Korschinek.
Since the moon generally provides a better cosmic record than Earth, the scientists were also able to specify for the first time an upper limit for the flow of 60Fe that must have reached the moon. Among other things this also makes it possible for the researchers to infer the distance to the supernova event: "The measured 60Fe-flow corresponds to a supernova at a distance of about 300 light years," says Korschinek. "This value is in good agreement with a recently theoretical estimation published in nature."
The lunar samples were investigated using the high-sensitivity accelerator mass spectrometer of the Maier-Leibnitz Laboratory near Munich.

This 5-fingered robot hand learns to get a grip on its own

This 5-fingered robot hand learns to get a grip on its own.

Summary:: Computer science experts and engineering researchers have built a robot hand that can not only perform dexterous manipulation -- one of the most difficult problems in robotics to solve -- but also learn from its own experience.

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This five-fingered robot hand developed by University of Washington computer science and engineering researchers can learn how to perform dexterous manipulation -- like spinning a tube full of coffee beans -- on its own, rather than having humans program its actions.

Credit: University of Washington

Robots today can perform space missions, solve a Rubik's cube, sort hospital medication and even make pancakes. But most can't manage the simple act of grasping a pencil and spinning it around to get a solid grip.

Intricate tasks that require dexterous in-hand manipulation -- rolling, pivoting, bending, sensing friction and other things humans do effortlessly with our hands -- have proved notoriously difficult for robots.
Now, a University of Washington team of computer science and engineering researchers has built a robot hand that can not only perform dexterous manipulation but also learn from its own experience without needing humans to direct it. Their latest results are detailed in a paper to be presented May 17 at the IEEE International Conference on Robotics and Automation.
"Hand manipulation is one of the hardest problems that roboticists have to solve," said lead author Vikash Kumar, a UW doctoral student in computer science and engineering. "A lot of robots today have pretty capable arms but the hand is as simple as a suction cup or maybe a claw or a gripper."
By contrast, the UW research team spent years custom building one of the most highly capable five-fingered robot hands in the world. Then they developed an accurate simulation model that enables a computer to analyze movements in real time. In their latest demonstration, they apply the model to the hardware and real-world tasks like rotating an elongated object.
With each attempt, the robot hand gets progressively more adept at spinning the tube, thanks to machine learning algorithms that help it model both the basic physics involved and plan which actions it should take to achieve the desired result.
This autonomous learning approach developed by the UW Movement Control Laboratory contrasts with robotics demonstrations that require people to program each individual movement of the robot's hand in order to complete a single task.
"Usually people look at a motion and try to determine what exactly needs to happen --the pinky needs to move that way, so we'll put some rules in and try it and if something doesn't work, oh the middle finger moved too much and the pen tilted, so we'll try another rule," said senior author and lab director Emo Todorov, UW associate professor of computer science and engineering and of applied mathematics.
"It's almost like making an animated film -- it looks real but there was an army of animators tweaking it," Todorov said. "What we are using is a universal approach that enables the robot to learn from its own movements and requires no tweaking from us."
Building a dexterous, five-fingered robot hand poses challenges, both in design and control. The first involved building a mechanical hand with enough speed, strength responsiveness and flexibility to mimic basic behaviors of a human hand.
The UW's dexterous robot hand -- which the team built at a cost of roughly $300,000 -- uses a Shadow Hand skeleton actuated with a custom pneumatic system and can move faster than a human hand. It is too expensive for routine commercial or industrial use, but it allows the researchers to push core technologies and test innovative control strategies.
"There are a lot of chaotic things going on and collisions happening when you touch an object with different fingers, which is difficult for control algorithms to deal with," said co-author Sergey Levine, UW assistant professor of computer science and engineering who worked on the project as a postdoctoral fellow at University of California, Berkeley. "The approach we took was quite different from a traditional controls approach."
The team first developed algorithms that allowed a computer to model highly complex five-fingered behaviors and plan movements to achieve different outcomes -- like typing on a keyboard or dropping and catching a stick -- in simulation.
Most recently, the research team has transferred the models to work on the actual five-fingered hand hardware, which never proves to be exactly the same as a simulated scenario. As the robot hand performs different tasks, the system collects data from various sensors and motion capture cameras and employs machine learning algorithms to continually refine and develop more realistic models.
"It's like sitting through a lesson, going home and doing your homework to understand things better and then coming back to school a little more intelligent the next day," said Kumar.
So far, the team has demonstrated local learning with the hardware system -- which means the hand can continue to improve at a discrete task that involves manipulating the same object in roughly the same way. Next steps include beginning to demonstrate global learning -- which means the hand could figure out how to manipulate an unfamiliar object or a new scenario it hasn't encountered before.

Introducing the disposable laser

Ultra-low-cost, easy to fabricate 'lasing capsules' made with an inkjet printer.

Summary:: Since lasers were invented more than 50 years ago, they have transformed a diverse swath of technology -- from CD players to surgical instruments. Now researchers have invented a way to print lasers that's so cheap, easy and efficient they believe the core of the laser could be disposed of after each use.

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Inkjet printed "lasing capsules" serve as the core of an organic laser. Figure (a) shows a schematic of the laser setup, while figure (b) shows actual lasing capsules, which would cost only a few cents to produce. OC stands for "Output Coupler" and FP stands for Febry-Perot etalon.

Credit: Sanaur, et al/JAP

Since lasers were invented more than 50 years ago, they have transformed a diverse swath of technology -- from CD players to surgical instruments.

Now researchers from France and Hungary have invented a way to print lasers that's so cheap, easy and efficient they believe the core of the laser could be disposed of after each use. The team reports its findings in the Journal of Applied Physics, from AIP Publishing.
"The low-cost and easiness of laser chip fabrication are the most significant aspects of our results," said Sébastien Sanaur, an associate professor in the Center of Microelectronics in Provence at the Ecole Nationale Supérieure des Mines de Saint-Étienne in France.
Sanaur and his colleagues made organic lasers, which amplify light with carbon-containing materials. Organic lasers are not as common as inorganic lasers, like those found in laser pointers, DVD players, and optical mice, but they offer benefits such as high-yield photonic conversion, easy fabrication, low-cost and a wide range of wavelengths.
One obstacle that has held back organic lasers is the fact that they degrade relatively quickly -- but that hurdle might be less daunting if the lasers are so cheap they could be tossed when they fail.
Sanaur's research team produced their ultra-low-cost organic laser using a familiar technology: an inkjet printer.
Inkjet printing is a relatively inexpensive manufacturing process that works by squirting small jets of fluid onto an underlying material. The inkjet printer at your office is only one form of the technology -- scientists have also adapted it to print electronic circuits, pharmaceutical drugs and even biological cells.
"By piezoelectric inkjet printing, you print 'where you want, when you want,' without wasting raw materials," Sanaur said. The technique doesn't require masks, can be done at room temperature and can print onto flexible materials.
The researchers tested a variety of possible inks, before settling on a commercial ink variety called EMD6415, which they mixed with dyes. The ink was printed in small square shapes onto a quartz slide.
The dyed ink acted as the core of the laser, called a gain medium. A gain medium amplifies light and produces the characteristically narrow, single-color laser beam.
A laser also requires mirrors to reflect light back and forth through the gain medium and an energy source, called a pump, to keep the light amplification going.
The disposable part of the new laser is the printed gain medium, which the researchers call the "lasing capsule." They estimate it could be produced for only a few cents. Like the replaceable blades in a razor, the lasing capsule could be easily swapped out when it deteriorates.
The research team used two different types of dyes to produce laser emission ranging from yellow to deep red. Other dyes could cover the blue and green part of the spectrum, they predict.
With further development, the inexpensive inkjet-printed laser could send data over short plastic fibers and serve as a tool for analysing chemical or biological samples.

Second strongest shock wave found in merging galaxy clusters

Summary:: Astronomers have discovered the second-strongest merger shock in clusters of galaxies ever observed.

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The RGB (Red Green Blue image) of the cluster. Red color shows optical radiation, Green shows Radio and Blue color shows X-rays emission.

Credit: Chandra X-Ray Observatory

The discovery by a physics doctoral student at The University of Alabama in Huntsville (UAH) of the second-strongest merger shock in clusters of galaxies ever observed has generated excitement that is opening doors to further scientific exploration.

Sarthak Dasadia, who is advised by assistant physics professor Dr. Ming Sun, discovered the very strong shock in the merging galaxy cluster Abell 655 using observations from the Chandra X-ray Observatory.
The shock to the north of this cluster is second in strength only to the Bullet Cluster shock.
The shock is traveling with an astonishing speed of 2,700 kilometers per second, about three times the local speed of sound in the cluster. By comparison, NASA's Juno spacecraft in 2013 became the fastest human-made object when it was slingshot around Earth toward Jupiter at a relatively pedestrian 40 kilometers a second.
"Studying mergers of galaxy clusters has proven to be crucial to our understanding of how such large scale objects form and evolve," says Dasadia. Shocks provide unique opportunities to study high-energy phenomena in the intra-cluster medium -- the hot plasma between galaxies.
"This could open a door, where people can do a number of different studies based on what I have found," Dasadia says. Already, scientists are targeting shocks in galaxy clusters to study dark matter, the magnetic field in the intracluster space, particle acceleration and energy transfer in the intracluster medium.
In only 10 days, Dasadia's research was accepted for publication by The Astrophysical Journal Letters. Dasadia recently received one year of research support from the Alabama EPSCoR Graduate Research Scholars Program (ALEPSCoR). He also gave an oral presentation on his research in August at the International Astronomical Union (IAU) General Assembly in Honolulu, Hawaii.
The universe is populated with galaxy clusters that are relaxed and unrelaxed, Dasadia says. The relaxed ones are mellow -- they've been around a lot longer, have seen lots of past mergers and really aren't dynamically active. It's the unrelaxed clusters like Abell 665 that are good candidates to study merger features such as shocks and turbulence.
"These galaxy clusters are not boundary objects," he says. "They do not have a very well-defined boundary around them."
When the undefined boundaries of massive clusters of galaxies 3 million light-years across are drawn together in a slow-motion collision, their cold cores and surrounding hot gases are disrupted into shock waves and gas fronts of various temperatures.
"When two cold cores collide, they may create a shock of heated gas," Dasadia says. "Such mergers are actually among the most energetic events in the universe, other than the Big Bang itself."
If talking about fronts and shock waves and temperature differentials sounds lot like the weather on Earth, Dasadia says that's because there is not much difference as far as the physics involved.
"Technically, we observe the same features in space that we do on Earth," he says. "This area has been studied extensively before at small scales, but few had done the work to discover what I found here at such big scales."
He was able to measure the velocity of the collision and the dynamics of what is happening in it -- or rather, what was happening in it. It took 3.2 billion years for the light in the observations to reach Earth, so the events all happened that far back in time. Dynamic observations included the energy in the collision, the gas movement, and measurements of the discrepancy between the visible and dark matter involved.
"It amazes me how long it takes for this information to even reach the Earth," Dasadia says. "Then I am also amazed by our technology, by how much we have advanced in developing the telescopes and equipment it takes to be able to observe and study these interactions."

Cosmic dust reveals Earth's ancient atmosphere

Summary:: Using the oldest fossil micrometeorites -- space dust -- ever found, new research has made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago.

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This is one of 60 micrometeorites extracted from 2.7 billion year old limestone, from the Pilbara region in Western Australia. These micrometeorites consist of iron oxide minerals that formed when dust particles of meteoritic iron metal were oxidised as they entered Earth's atmosphere, indicating that the ancient upper atmosphere was surprisingly oxygen-rich.

Credit: Andrew Tomkins

Using the oldest fossil micrometeorites -- space dust -- ever found, Monash University-led research has made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago.

The findings of a new study published today in the journal Nature -- led by Dr Andrew Tomkins and a team from the School of Earth, Atmosphere and Environment at Monash, along with scientists from the Australian Synchrotron and Imperial College, London -- challenge the accepted view that Earth's ancient atmosphere was oxygen-poor. The findings indicate instead that the ancient Earth's upper atmosphere contained about the same amount of oxygen as today, and that a methane haze layer separated this oxygen-rich upper layer from the oxygen-starved lower atmosphere.
Dr Tomkins explained how the team extracted micrometeorites from samples of ancient limestone collected in the Pilbara region in Western Australia and examined them at the Monash Centre for Electron Microscopy (MCEM) and the Australian Synchrotron.
"Using cutting-edge microscopes we found that most of the micrometeorites had once been particles of metallic iron -- common in meteorites -- that had been turned into iron oxide minerals in the upper atmosphere, indicating higher concentrations of oxygen than expected," Dr Tomkins said.
"This was an exciting result because it is the first time anyone has found a way to sample the chemistry of the ancient Earth's upper atmosphere," Dr Tomkins said.
Imperial College researcher Dr Matthew Genge -- an expert in modern cosmic dust -- performed calculations that showed oxygen concentrations in the upper atmosphere would need to be close to modern day levels to explain the observations.
"This was a surprise because it has been firmly established that the Earth's lower atmosphere was very poor in oxygen 2.7 billion years ago; how the upper atmosphere could contain so much oxygen before the appearance of photosynthetic organisms was a real puzzle," Dr Genge said.
Dr Tomkins explained that the new results suggest the Earth at this time may have had a layered atmosphere with little vertical mixing, and higher levels of oxygen in the upper atmosphere produced by the breakdown of CO 2 by ultraviolet light.
"A possible explanation for this layered atmosphere might have involved a methane haze layer at middle levels of the atmosphere. The methane in such a layer would absorb UV light, releasing heat and creating a warm zone in the atmosphere that would inhibit vertical mixing," Dr Tomkins said.
"It is incredible to think that by studying fossilised particles of space dust the width of a human hair, we can gain new insights into the chemical makeup of Earth's upper atmosphere, billions of years ago." Dr Tomkins said.
Dr Tomkins outlined next steps in the research.
"The next stage of our research will be to extract micrometeorites from a series of rocks covering over a billion years of Earth's history in order to learn more about changes in atmospheric chemistry and structure across geological time. We will focus particularly on the great oxidation event, which happened 2.4 billion years ago when there was a sudden jump in oxygen concentration in the lower atmosphere."

Wednesday 11 May 2016

Chemists use DNA to build the world's tiniest thermometer

Summary:: Researchers have created a programmable DNA thermometer that is 20,000x smaller than a human hair. One of the main advantages of using DNA to engineer molecular thermometers is that DNA chemistry is relatively simple and programmable. So, the research team has created various DNA structures that can fold and unfold at specifically defined temperatures.

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3D render of DNA structure. One of the main advantages of using DNA to engineer molecular thermometers is that DNA chemistry is relatively simple and programmable.

Researchers at University of Montreal have created a programmable DNA thermometer that is 20,000x smaller than a human hair. This scientific advance reported this week in the journal Nano Letters may significantly aid our understanding of natural and human designed nanotechnologies by enabling to measure temperature at the nanoscale.

Over 60 years ago, researchers discovered that the DNA molecules that encode our genetic information can unfold when heated. "In recent years, biochemists also discovered that biomolecules such as proteins or RNA (a molecule similar to DNA) are employed as nanothermometers in living organisms and report temperature variation by folding or unfolding," says senior author Prof. Alexis Vallée-Bélisle. "Inspired by those natural nanothermometers, which are typically 20,000x smaller than a human hair, we have created various DNA structures that can fold and unfold at specifically defined temperatures."
One of the main advantages of using DNA to engineer molecular thermometers is that DNA chemistry is relatively simple and programmable. "DNA is made from four different monomer molecules called nucleotides: nucleotide A binds weakly to nucleotide T, whereas nucleotide C binds strongly to nucleotide G," explains David Gareau, first author of the study. "Using these simple design rules we are able to create DNA structures that fold and unfold at a specifically desired temperature." "By adding optical reporters to these DNA structures, we can therefore create 5 nm-wide thermometers that produce an easily detectable signal as a function of temperature," adds Arnaud Desrosiers, co-author of this study.
These nanoscale thermometers open many exciting avenues in the emerging field of nanotechnology, and may even help us to better understand molecular biology. "There are still many unanswered questions in biology," adds Prof. Vallée-Bélisle, "For example, we know that the temperature inside the human body is maintained at 37° C, but we have no idea whether there is a large temperature variation at the nanoscale inside each individual cell." One question currently under investigation by the research team is to determine whether nanomachines and nanomotors developed by nature over millions years of evolution also overheat when functioning at high rate. "In the near future, we also envision that these DNA-based nanothermometers may be implement in electronic-based devices in order to monitor local temperature variation at the nanoscale," concludes Prof. Vallée-Bélisle.

Engineers create a better way to boil water, with industrial, electronics applications

Summary:: Engineers have found a new way to induce and control boiling bubble formation, that may allow everything from industrial-sized boilers to advanced electronics to work better and last longer.

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Researchers at Oregon State University use new technology to control the formation and release of bubbles. Here that technology is illustrated with the letters "OSU" printed on a substrate.

Credit: Image courtesy of Oregon State University

Engineers at Oregon State University have found a new way to induce and control boiling bubble formation, that may allow everything from industrial-sized boilers to advanced electronics to work better and last longer.

Advances in this technology have been published in Scientific Reports and a patent application filed.
The concept could be useful in two ways, researchers say -- either to boil water and create steam more readily, like in a boiler or a clothing iron; or with a product such as an electronics device to release heat more readily while working at a cooler temperature.
"One of the key limitations for electronic devices is the heat they generate, and something that helps dissipate that heat will help them operate at faster speeds and prevent failure," said Chih-hung Chang, a professor of electrical engineering in the OSU College of Engineering. "The more bubbles you can generate, the more cooling you can achieve.
"On the other hand, if you want to create steam at a lower surface temperature, this approach should be very useful in boilers and improve their efficiency. We've already shown that it can be done on large surfaces and should be able to scale up in size to commercial use."
The new approach is based on the use of piezoelectric inkjet printing to create hydrophobic polymer "dots" on a substrate, and then deposit a hydrophilic zinc oxide nanostructure on top of that. The zinc oxide nanostructure only grows in the area without dots. By controlling both the hydrophobic and hydrophilic structure of the material, bubble formation can be precisely controlled and manipulated for the desired goal.
This technology allows researchers to control both boiling and condensation processes, as well as spatial bubble nucleation sites, bubble onset and departure frequency, heat transfer coefficient and critical heat flux for the first time.
In electronics, engineers say this technology may have applications with some types of solar energy, advanced lasers, radars, and power electronics -- anywhere it's necessary to dissipate high heat levels.
In industry, a significant possibility is more efficient operation of the steam boilers used to produce electricity in large electric generating facilities.
This work was supported by the OSU Venture Development Fund and the Scalable Nanomanufacturing Program of the National Science Foundation.

Star with different internal driving force than the sun

Summary:: A star like the sun has an internal driving in the form of a magnetic field that can be seen on the surface as sunspots. Now astrophysicists have observed a distant star in the constellation Andromeda with a different positioning of sunspots and this indicates a magnetic field that is driven by completely different internal dynamic.

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Star with different internal driving force than the sun

Date:: May 4, 2016
Source:: University of Copenhagen - Niels Bohr Institute
Summary:: A star like the sun has an internal driving in the form of a magnetic field that can be seen on the surface as sunspots. Now astrophysicists have observed a distant star in the constellation Andromeda with a different positioning of sunspots and this indicates a magnetic field that is driven by completely different internal dynamics.
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On our star, the Sun, the sunspots are seen in a belt around the equator. Sunspots are cool areas caused by the strong magnetic fields where the flow of heat is slowed.

Credit: NASA

A star like the Sun has an internal driving in the form of a magnetic field that can be seen on the surface as sunspots. Now astrophysicists from the Niels Bohr Institute have observed a distant star in the constellation Andromeda with a different positioning of sunspots and this indicates a magnetic field that is driven by completely different internal dynamics. The results are published in the scientific journal, Nature.

Stars are glowing balls of gas that through atomic processes release energy that is emitted as light and heat. In the interior of the star are charged particles that swirl and spin and thereby create a magnetic field that can burst out onto the surface of the star, where it appears as sunspots. Sunspots are cool areas caused by the strong magnetic fields where the flow of heat is slowed. On our star, the Sun, the sunspots are seen in a belt around the equator, but now scientists have observed a large, distant star where sunspots are located near the poles.
Sunspots at the poles
"What we can observe on the star is that it has a large sunspot at its north pole. We cannot see the south pole, but we can see sunspots at latitudes near the poles and these sunspots are not there at the same time, they are seen alternately on the northern and southern hemispheres. This asymmetry of sunspots indicates that the star's magnetic field is formed in a different way than the way it happens in the Sun," explains astrophysicist Heidi Korhonen, Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.
The star that has been observed is a massive star that is approximately 16 times the size of the Sun in diameter. It is located180 light years away in the constellation Andromeda. It is much too far away to be able to observe the details on the surface of a star that is only seen as a spot of light that is less than one pixel. Astronomers have previously seen sunspots on Zeta Andromeda using the Doppler method, which means that you observe that light wavelengths of the rotating star. Sunspots are cool areas and by studying the wavelengths you can construct a map of the surface temperature. So far this has been the best way to observe the surface structures of distant stars, but there may be misinterpretations, so there have been doubts about the accuracy concerning the existence of the polar sunspots.
But by using a method where you gather images from several different telescopes that you observe simultaneously, you can get far more details than you could achieve with even with the largest telescopes individually. But it was not easy. It is a method that has been used for decades in the radio waveband field and using the CHARA Array, consisting of six telescopes, it has now become possible to observe the visible and near-infrared light.
"With these new observations, we have many more details and extra high resolution. Our new measurements confirm that there are large sunspots at the poles. We see dark sunspots on the northern visible pole, while the observations reveal that the lower latitudes are areas with sunspots that do not last, but appear and disappear again with an asymmetrical distribution on the surface of the star and this was surprising," says Heidi Korhonen, who is an expert on sunspots.
Powerful magnetic field
But why is the location of the sunspots different than those we know from the Sun?
Heidi Korhonen explains that it is a very different star than the Sun. It is a binary star, that is, two stars orbiting each other. This causes the stars to rotate more quickly. The Zeta Andromeda star, which is the larger of the two stars, rotates at 40 km per second. The Sun rotates at 2 km per second.
"It is the rapid rotation that creates a different and very strong magnetic field. The strong magnetic field gives a more complicated dynamo effect that resembles what you see at the stage where a new star is being created. Here we are seeing the same effect in an old active star that is in its final stage," explains Heidi Korhonen.
On the Sun, the sunspots appear and disappear on a regular basis and the number increases periodically approximately every 11 years. The magnetic field that creates the sunspots can also trigger large, explosive discharges of plasma, causing solar storms to hit the Earth. These storms result in very strong northern lights and can also cause problems for orbiting satellites and the power grid on Earth.

On our star, the Sun, the sunspots are seen in a belt around the equator. Sunspots are cool areas caused by the strong magnetic fields where the flow of heat is slowed.

Credit: NASA