The Daily Galaxy --Great Discoveries Channel: Sci, Space, Tech

Galaxy Evolution Fueled By Giant Cosmic Webs

2013-05-24T14:17:30-07:00

In the early universe, galaxies formed out of clumps of matter, connected by filaments in a giant cosmic web. Within the galaxies, nuggets of gas cooled and condensed, becoming dense enough to trigger the birth of stars. Our Milky Way spiral galaxy and its billions of stars took shape in this way. The previous, standard model of galaxy formation held that hot gas sank into the centers of burgeoning galaxies from all directions. Gas clouds were thought to collide into each other, sending out shock waves, which then heated up the gas. The process is similar to jets creating sonic booms, only in the case of galaxies, the in-falling gas travels faster than the speed of sound, piling up into waves. Eventually, the gas cools and sinks to the galactic center. This process was theorized to be slow, taking up to 8 billion years.

Recent research has contradicted this scenario in smaller galaxies, showing that the gas is not heated. An alternate "cold-mode" theory of galaxy formation was proposed instead, suggesting the cold gas might funnel along filaments into galaxy centers. Kyle Stewart, Stewart, who is now at the California Baptist University in Riverside, Calif., completed the majority of this work while at NASA's Jet Propulsion Laboratory in Pasadena, Calif. and his colleagues set out to test this theory and address the mysteries about how the cold gas gets into galaxies, as well as the rate at which it spirals in.

"Galaxy formation is really chaotic," said Kyle Stewart, lead author of the new study appearing in the May 20th issue of the Astrophysical Journal. "It took us several hundred computer processors, over months of time, to simulate and learn more about how this process works."Since it would take billions of years to watch a galaxy grow, the team simulated the process using supercomputers at JPL; NASA's Ames Research Center, Moffett Field, Calif.; and the University of California, Irvine.

They ran four different simulations of the formation of a galaxy like our Milky Way, starting from just 57 million years after the big bang until present day. The results show that cold gas -- fuel for stars -- spirals into the cores of galaxies along filaments, rapidly making its way to their "guts." Once there, the gas is converted into new stars, and the galaxies bulk up in mass.

The simulations began with the starting ingredients for galaxies -- hydrogen, helium and dark matter -- and then let the laws of physics take over to create their galactic masterpieces. Supercomputers are needed due to the enormous number of interactions.

"The simulations are like a gigantic game of chess," said Alyson Brooks, a co-author of the paper and expert in galaxy simulations at the University of Wisconsin, Madison. "For each point in time, we have to figure out how a given particle -- our chess piece -- should move based on the positions of all of the other particles. There are tens of millions of particles in the simulation, so figuring out how the gravitational forces affect each particle is time-consuming."

When the galaxy concoctions were ready, the researchers inspected the data, finding new clues about how cold gas sinks into the galaxy centers. The new results confirm that cold gas flows along filaments and show, for the first time, that the gas is spinning around faster than previously believed. The simulations also revealed that the gas is making its way down to the centers of galaxies more quickly than what occurs in the "hot-mode" of galaxy formation, in about 1 billion years.

"We have found that the filamentary structures that galaxies are built on are key to how they build up over time, by threading gas into them efficiently," said Leonidas Moustakas, a co-author at JPL.

The researchers looked at dark matter too -- an invisible substance making up about 85 percent of matter in the universe. Galaxies form out of lumps of regular matter, so-called baryonic matter that is composed of atoms, and dark matter. The simulations showed that dark matter is also spinning at a faster rate along the filaments, spiraling into the galaxy centers.

The results help answer a riddle in astronomy about galaxies with large extended disks of material spinning around them, far from their centers. Researchers didn't understand how the outer material could be spinning so fast. The cold-mode allows for this rapid spinning, fitting another jigsaw piece into the puzzle of how galaxies grow.

"The goal of simulating galaxies is to compare them to what telescopes observe and see if we really understand how to build a galaxy," said Stewart. "It helps us makes sense of the real universe."

The image at the top of the page is from NASA's Galaxy Evolution Explorer showing a young galaxy, NGC 300, located about seven million light-years away in the constellation Sculptor.

The Daily Galaxy via JPL

High Arctic Microbes --Clues to Life on Mars and Enceladus

2013-05-24T05:58:44-07:00

The temperature in the permafrost on Ellesmere Island in the Canadian high Arctic is nearly as cold as that of the surface of Mars. So the recent discovery by a McGill University led team of scientists of a bacterium that is able to thrive at –15ºC, the coldest temperature ever reported for bacterial growth, is exciting. The bacterium offers clues about some of the necessary preconditions for microbial life on both the Saturn moon Enceladus and Mars, where similar briny subzero conditions are thought to exist.

The team of researchers, led by Prof. Lyle Whyte and postdoctoral fellow Nadia Mykytczuk, both from the Dept. of Natural Resource Sciences at McGill University, discovered Planococcus halocryophilus OR1 after screening about 200 separate High Arctic microbes looking for the microorganism best adapted to the harsh conditions of the Arctic permafrost.

”We believe that this bacterium lives in very thin veins of very salty water found within the frozen permafrost on Ellesmere Island,” explains Whyte. “The salt in the permafrost brine veins keeps the water from freezing at the ambient permafrost temperature (~-16ºC), creating a habitable but very harsh environment. It’s not the easiest place to survive but this organism is capable of remaining active (i.e. breathing) to at least -25ºC in permafrost.”

In order to understand what it takes to be able to do so, Mykytczuk, Whyte and their colleagues studied the genomic sequence and other molecular traits of P. halocryophilus OR1. The researchers found that the bacterium adapts to the extremely cold, salty conditions in which it is found thanks to significant modifications in its cell structure and function and increased amounts of cold-adapted proteins. These include changes to the membranes that envelop the bacterium and protect it from the hostile environment in which it lives.

The genome sequence also revealed that this permafrost microbe is unusual in other ways. It appears to maintain high levels of compounds inside the bacterial cell that act as a sort of molecular antifreeze, keeping the microbe from freezing solid, while at the same time protecting the cell from the very salty exterior environment.

The researchers believe however, that such microbes may potentially play a harmful role in extremely cold environments such as the High Arctic by increasing carbon dioxide emissions from the melting permafrost, one of the results of global warming.

Whyte is delighted with the discovery and says with a laugh, “I’m kind of proud of this bug. It comes from the Canadian High Arctic and is our cold temperature champion, but what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system.”

The small, icy moon Enceladus shown below is a major source of ionized material filling the huge magnetic bubble around Saturn. About 200 lb (about 90kg) of water vapour per second – about as much as an active comet – spray out from long cracks in the south polar region known as ‘tiger stripes’. The ejected matter forms the Enceladus plume – a complex structure of icy grains and neutral gas that is mainly water vapour. The plume gets converted into charged particles interacting with the plasma that fills Saturn’s magnetosphere.

Enceladus is emerging as the most habitable spot beyond Earth in the Solar System for life as we know it. "It has liquid water, organic carbon, nitrogen [in the form of ammonia], and an energy source," says Chris McKay, an astrobiologist at NASA's Ames Research Center in Moffett Field, California. Besides Earth, he says, "there is no other environment in the Solar System where we can make all those claims."

In addition, geyser-like jets spew ice crystals and gases into space, allowing a spacecraft to sample the subsurface by flying overhead. The current Cassini mission has done that several times already, but it's only equipped to find the building blocks of life, not more complex molecules.

This research was funded by: Natural Sciences and Engineering Research Council of Canada CREATE Canadian Astrobiology Training Program, Canadian Space Agency, the Polar Continental Shelf Program, Canada Research Chairs Program, and the Canada Foundation for Innovation.

The Daily Galaxy via https://www.mcgill.ca/newsroom

"Rugged Terrain of South Africia Shaped Human Evolution"

2013-05-24T04:00:00-07:00

A new study by archaeologists at the University of York says our upright gait may have its origins in the rugged landscape of East and South Africa which was shaped during the Pliocene epoch by volcanoes and shifting tectonic plates. The York research challenges traditional hypotheses which suggest our early forebears were forced out of the trees and onto two feet when climate change reduced tree cover.

Humans are unique among living primates in that walking bipedally — on two feet — is humans' chief mode of locomotion. This upright posture freed their hands up for using tools, one of the key factors behind humans' domination of the planet.Among the earliest known relatives of humanity definitely known to walk upright was Australopithecus afarensis, the species including the famed 3.2-million-year-old "Lucy" (image below). Australopithecines are the leading candidates for direct ancestors of the human lineage, living about 2.9 million to 3.8 million years ago in East Africa.

Hominins, our early forebears, would have been attracted to the terrain of rocky outcrops and gorges because it offered shelter and opportunities to trap prey. But it also required more upright scrambling and climbing gaits, prompting the emergence of bipedalism.
The study, 'Complex Topography and Human Evolution: the Missing Link', was developed in conjunction with researchers from the Institut de Physique du Globe in Paris.

"Our research shows that bipedalism may have developed as a response to the terrain, rather than a response to climatically-driven vegetation changes," said Dr Isabelle Winder, from the Department of Archaeology at York and one of the paper's authors. "The broken, disrupted terrain offered benefits for hominins in terms of security and food, but it also proved a motivation to improve their locomotor skills by climbing, balancing, scrambling and moving swiftly over broken ground - types of movement encouraging a more upright gait."

The research suggests that the hands and arms of upright hominins were then left free to develop increased manual dexterity and tool use, supporting a further key stage in the evolutionary story. The development of running adaptations to the skeleton and foot may have resulted from later excursions onto the surrounding flat plains in search of prey and new home ranges.

"The varied terrain may also have contributed to improved cognitive skills such as navigation and communication abilities, accounting for the continued evolution of our brains and social functions such as co-operation and team work," said Winder. "Our hypothesis offers a new, viable alternative to traditional vegetation or climate change hypotheses. It explains all the key processes in hominin evolution and offers a more convincing scenario than traditional hypotheses."

The Daily Galaxy via University of York

The Ring Nebula --Hubble Reveals Its True Shape!

2013-05-23T15:53:48-07:00

The iconic Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star shown below reveals a new twist.

"The nebula is not like a bagel (NRAO radio image above), but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.

"With Hubble's detail, we see a completely different shape than what's been thought about historically for this classic nebula," O'Dell said. "The new Hubble observations show the nebula in much clearer detail, and we see things are not as simple as we previously thought."

The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers.

Previous observations by several telescopes had detected the gaseous material in the ring's central region. But the new view by Hubble's sharp-eyed Wide Field Camera 3 shows the nebula's structure in more detail. O'Dell's team suggests the ring wraps around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.

The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object.

O'Dell's team was surprised at the detailed Hubble views of the dark, irregular knots of dense gas embedded along the inner rim of the ring, which look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed the team to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.

All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.

The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. O'Dell's team measured the nebula's expansion by comparing the new Hubble observations with Hubble studies made in 1998.

The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium.

Studying the Ring Nebula's fate will provide insight into the sun's demise in another 6 billion years. The sun is less massive than the Ring Nebula's progenitor star, so it will not have an opulent ending.

"When the sun becomes a white dwarf, it will heat more slowly after it ejects its outer gaseous layers," O'Dell said. "The material will be farther away once it becomes hot enough to illuminate the gas. This larger distance means the sun's nebula will be fainter because it is more extended."

In the analysis, the research team also obtained images from the Large Binocular Telescope at the Mount Graham International Observatory in Arizona and spectroscopic data from the San Pedro Martir Observatory in Baja California, Mexico.

The Daily Galaxy via NASA

Chinese Astronomers Search for Alien Life

2013-05-23T07:21:11-07:00

Chinese astronomers, actively searching for Earth-like planets using survey instruments in Antarctica, believe efforts to seek an extra-solar planet that that harbors life will soon be rewarded. "It's highly possible that human beings might find such a planet in the coming few years," said Lifan Wang, an astronomer at Texas A&M University in College Station, and director of the Chinese Centre for Antarctic Astronomy in Nanjing. "Such planets likely exist in the Milky Way, with a possible distance of thousands of light years from us. We know too little about life. Maybe there are new forms of life that do not need exactly the same environment as we have on Earth. Some can survive in very harsh environments," Wang added.

Chinese astronomers installed the first of three Antarctic Survey Telescopes (AST3-1) at Dome Argus, located at the highest elevation on the Antarctic continent, at the beginning of 2012. One of its primary missions is to search for extra-solar planets suitable for life.

Dome A may be the best place on Earth to gaze at the Universe, says Wang. At 4,093 meters above sea level, Dome A has an extremely thin and stable atmosphere, and the pressure is only half that at sea level. The extreme cold — temperatures can drop to –80 °C — makes the air very dry and reduces background radiation when observing in the infrared. There is almost no air pollution and the long winter nights allow for four months of uninterrupted observation.

"Antarctica has the best conditions on Earth for astronomical observation, as it has very flat ground, a transparent atmosphere and little turbulence. The ground-based telescopes here will bring us precious information from the universe," he said. "We will send people there to retrieve observation data. I hope we can find some likely candidates. It's hard to say precisely how many, but I hope there are no less than 10," Wang said. "So far, humans have yet to find an exact twin of the Earth."

"We search through a wide range of main sequence stars, mainly sun-like stars, and then look for planets within a suitable distance around them. Stars that are smaller and darker than the sun, such as dwarfs, are also in our survey scope," he said."If the stars are particularly large, they are inclined to evolve faster. Some will explode soon, and their planets will go missing after the explosion."

The second AST3 will be installed in Antarctica between late 2013 and early 2014, while the third one will be installed between late 2014 and early 2015. "These telescopes are expected to help us find at least 100 sun-like stars. We will work with Australian scientists to further study the movement of the stars to calculate their size," Wang said.

Chinese scientists are also planning to set up an Antarctic observatory to further boost their research and broaden the search for habitable planets. If approved and included in the 12th Five-Year Plan, the observatory should go into operation by 2020.

The Daily Galaxy via Nature and http://news.xinhuanet.com/english/china/2012-08/27/c_131810648.htm

Image of the Day: Haunting Bok Globules in a Spectacular Stellar Nursery

2013-05-23T06:33:10-07:00

This new view of a spectacular stellar nursery reveals thick clumps of dust silhouetted against the pink glowing gas cloud known to astronomers as IC 2944. The image celebrates an important anniversary for the Very Large Telescope— the world's most advanced optical instrument operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. Among the observations carried out using the VLT are the first direct image of an exoplanet, the tracking of individual stars moving around the supermassive black hole at the center of the Milky Way, and observations of the afterglow of the furthest known gamma-ray burst.

It is fifteen years since the first light on the first of its four Unit Telescopes, on 25 May 1998. Since then the four original giant telescopes have been joined by the four small Auxiliary Telescopes that form part of the VLT Interferometer (VLTI). The VLT is one of the most powerful and productive ground-based astronomical facilities in existence. In 2012 more than 600 refereed scientific papers based on data from the VLT and VLTI were published.

Interstellar clouds of dust and gas are the nurseries where new stars are born and grow. The new picture shows one of them, IC 2944, which appears as the softly glowing pink background. The nebula is associated with the bright star cluster IC 2948 and both of these names are also sometimes associated with the whole region. Many of the bright cluster stars appear in this picture.

This image is the sharpest view of the object ever taken from the ground. The cloud lies about 6500 light-years away in the southern constellation of Centaurus (The Centaur). This part of the sky is home to many other similar nebulae that are scrutinised by astronomers to study the mechanisms of star formation.

Emission nebulae like IC 2944 are composed mostly of hydrogen gas that glows in a distinctive shade of red, due to the intense radiation from the many brilliant newborn stars. Clearly revealed against this bright backdrop are mysterious dark clots of opaque dust, cold clouds known as Bok globules. They are named after the Dutch-American astronomer Bart Bok, who first drew attention to them in the 1940s as possible sites of star formation. This particular set is nicknamed the Thackeray Globules, discovered from South Africa by the English astronomer A. David Thackeray in 1950.

Larger Bok globules in quieter locations often collapse to form new stars but the ones in this picture are under fierce bombardment from the ultraviolet radiation from nearby hot young stars. They are both being eroded away and also fragmenting, rather like lumps of butter dropped into a hot frying pan. It is likely that Thackeray’s Globules will be destroyed before they can collapse and form stars.

Bok globules are not easy to study. As they are opaque to visible light it is difficult for astronomers to observe their inner workings, and so other tools are needed to unveil their secrets — observations in the infrared or in the submillimetre parts of the spectrum, for example, where the dust clouds, only a few degrees over absolute zero, appear bright. Such studies of the Thackeray globules have confirmed that there is no current star formation within them.

This region of sky has also been imaged in the past by the NASA/ESA Hubble Space Telescope (opo0201a). This new view from the FORS instrument on ESO’s Very Large Telescope at the Paranal Observatory in northern Chile covers a wider patch of sky than Hubble and shows a broader landscape of star formation.

The Daily Galaxy via ESO

Milky Way's Hidden World of Extreme Objects Magnetars

2013-05-23T05:00:00-07:00

Magnetars -- the dense remains of dead stars that erupt sporadically with bursts of high-energy radiation -- are some of the most extreme objects known in the Universe. A major campaign using NASA's Chandra X-ray Observatory and several other satellites shows magnetars may be more diverse -- and common -- than previously thought.

Most neutron stars are spinning rapidly -- a few times a second -- but a small fraction have a relatively low spin rate of once every few seconds, while generating occasional large blasts of X-rays. Because the only plausible source for the energy emitted in these outbursts is the magnetic energy stored in the star, these objects are called "magnetars."

Most magnetars have extremely high magnetic fields on their surface that are ten to a thousand times stronger than for the average neutron star. New observations show that the magnetar known as SGR 0418+5729 (SGR 0418 for short) doesn't fit that pattern. It has a surface magnetic field similar to that of mainstream neutron stars.

"We have found that SGR 0418 has a much lower surface magnetic field than any other magnetar," said Nanda Rea of the Institute of Space Science in Barcelona, Spain. "This has important consequences for how we think neutron stars evolve in time, and for our understanding of supernova explosions."

The neutron star, SGR 0418 was discovered on June 5, 2009 when the Fermi Gamma-ray Space Telescope detected bursts of gamma-rays from this object. Follow-up observations four days later with the Rossi X-Ray Timing Explorer (RXTE) showed that, in addition to sporadic X-ray bursts, the neutron star exhibits persistent X-ray emission with regular pulsations that indicate that the star has a rotational period of 9.1 seconds. RXTE was able to monitor this activity for about 100 days.

As neutron stars rotate, the radiation of low frequency electromagnetic waves or winds of high-energy particles carry energy away from the star, causing the rotation rate of the star to gradually decrease. Careful monitoring of SGR 0418 was possible because Chandra and XMM-Newton were able to measure its pulsation period even though it faded by a factor of 10 after the initial detection. What sets SGR 0418 apart from other magnetars is that careful monitoring over a span of 490 days has revealed no detectable decrease in its rotation rate.

The lack of rotational slowing implies that the radiation of low frequency waves must be weak, and hence the surface magnetic field must be much weaker than normal. But this raises another question: where does the energy come from to power bursts and the persistent X-ray emission from the source?

The generally accepted answer for magnetars is that the energy to power the X- and gamma-ray emission comes from an internal magnetic field that has been twisted and amplified in the turbulent interior of the neutron star, as depicted in the illustration above. Theoretical studies indicate that if the internal field becomes about ten or more times stronger than the surface field, the decay or untwisting of the field can lead to the production of steady and bursting X-ray emission through the heating of the neutron star crust or the acceleration of particles.

A crucial question is how large an imbalance can be maintained between the surface and interior fields. SGR 0418 represents an important test case. The observations already imply an imbalance of between 50 and 100. If further observations by Chandra push the surface magnetic field limit lower, then theorists may have to dig deeper for an explanation of this enigmatic object.

The researchers monitored SGR 0418 for over three years using Chandra, ESA's XMM-Newton as well as NASA's Swift and RXTE satellites. They were able to make an accurate estimate of the strength of the external magnetic field by measuring how its rotation speed changes during an X-ray outburst. These outbursts are likely caused by fractures in the crust of the neutron star precipitated by the buildup of stress in a relatively strong, wound-up magnetic field lurking just beneath the surface.

"This low surface magnetic field makes this object an anomaly among anomalies," said co-author GianLuca Israel of the National Institute of Astrophysics in Rome. "A magnetar is different from typical neutron stars, but SGR 0418 is different from other magnetars as well."

By modeling the evolution of the cooling of the neutron star and its crust, as well as the gradual decay of its magnetic field, the researchers estimated that SGR 0418 is about 550,000 years old. This makes SGR 0418 older than most other magnetars, and this extended lifetime has probably allowed the surface magnetic field strength to decline over time. Because the crust weakened and the interior magnetic field is relatively strong, outbursts could still occur.

The case of SGR 0418 may mean that there are many more elderly magnetars with strong magnetic fields hidden under the surface, implying that their birth rate is five to ten times higher than previously thought.

"We think that about once a year in every galaxy a quiet neutron star should turn on with magnetar-like outbursts, according to our model for SGR 0418," said Josè Pons of the University of Alacant in Spain. "We hope to find many more of these objects."
Another implication of the model is that the surface magnetic field of SGR 0418 should have once been very strong at its birth a half million years ago. This, plus a possibly large population of similar objects, could mean that the massive progenitor stars already had strong magnetic fields, or these fields were created by rapidly rotating neutron stars in the core collapse that was part of the supernova event.

If large numbers of neutron stars are born with strong magnetic fields then a significant fraction of gamma-ray bursts might be caused by the formation of magnetars rather than black holes. Also, the contribution of magnetar births to gravitational wave signals -- ripples in space-time -- would be larger than previously thought.

The possibility of a relatively low surface magnetic field for SGR 0418 was first announced in 2010 by a team with some of the same members. However, the scientists at that time could only determine an upper limit for the magnetic field and not an actual estimate because not enough data had been collected.

SGR 0418 is located in the Milky Way galaxy at a distance of about 6,500 light years from Earth. These new results on SGR 0418 appear online and will be published in the June 10, 2013 issue of The Astrophysical Journal. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

For Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra
For an additional interactive image, podcast, and video on the finding, visit: http://chandra.si.edu

The Daily Galaxy via NASA.

When a massive star runs out of fuel, its core collapses to form a neutron star, an ultradense object about 10 to 15 miles wide. The gravitational energy released in this process blows the outer layers away in a supernova explosion and leaves the neutron star behind.
Most neutron stars are spinning rapidly -- a few times a second -- but a small fraction have a relatively low spin rate of once every few seconds, while generating occasional large blasts of X-rays. Because the only plausible source for the energy emitted in these outbursts is the magnetic energy stored in the star, these objects are called "magnetars."

For Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra
For an additional interactive image, podcast, and video on the finding, visit: http://chandra.si.edu

The Daily Galaxy via NASA.

Massive "Missing-Link" Galaxy Discovered --10 Times Size of Milky Way

2013-05-22T10:24:39-07:00

Two young galaxies that collided 11 billion years ago are rapidly forming a massive galaxy about 10 times the size of the Milky Way, according to UC Irvine-led research published Wednesday in the journal Nature. Capturing the creation of this type of large, short-lived star body is extremely rare – the equivalent of discovering a missing link between winged dinosaurs and early birds, said the scientists, who relied on the once-powerful Herschel space telescope and observatories around the world. The new mega-galaxy, dubbed HXMM01, is the brightest, most luminous and most gas-rich submillimeter-bright galaxy merger known.

The discovery solves a riddle in understanding how giant elliptical galaxies developed quickly in the early universe and why they stopped producing stars soon after. Other astronomers have theorized that giant black holes in the heart of the galaxies blew strong winds that expelled the gas. But cosmologist Asantha Cooray, the UC Irvine team's leader, said that they and colleagues across the globe found definitive proof that cosmic mergers and the resulting highly efficient consumption of gas for stars are causing the quick burnout.

HXMM01 is fading away as fast as it forms, a victim of its own cataclysmic birth. As the two parent galaxies smashed together, they gobbled up huge amounts of hydrogen, emptying that corner of the universe of the star-making gas.

"These galaxies entered a feeding frenzy that would quickly exhaust the food supply in the following hundreds of million years and lead to the new galaxy's slow starvation for the rest of its life," said lead author Hai Fu, a UC Irvine postdoctoral scholar.

"Finding this type of galaxy is as important as the discovery of the archaeopteryx was in understanding dinosaurs' evolution into birds, because they were both caught at a critical transitional phase," Fu said.

The new galaxy was initially spotted by UC Irvine postdoctoral scholar Julie Wardlow, also with Cooray's group. She noticed "an amazing, bright blob" in images of the so-called cold cosmos – areas where gas and dust come together to form stars – recorded by the European Space Agency's Herschel telescope with important contributions from NASA's Jet Propulsion Laboratory in Pasadena. "Herschel captured carpets of galaxies, and this one really stood out."

Follow-up views at a variety of wavelengths were obtained at more than a dozen ground-based observatories, particularly the W. M. Keck Observatory in Hawaii.

The image at the top of the page shows a close-up of the colliding galaxies in red and green. The red data show dust-enshrouded regions of star formation. The green data show gas in the merging galaxies. The blue spots are visible-light observations of galaxies located much closer to us.

Image Credit: JPL-Caltech/UC Irvine/Keck Observatory/STScI/NRAO/SAO/ESA/NASA.

New Physics "Most-Wanted" List -- The Hunt for Dark Matter Particles

2013-05-22T07:57:33-07:00

Now that it looks like the hunt for the Higgs boson is over, particles of dark matter are at the top of the physics "Most Wanted" list. Dozens of experiments have been searching for them, but often come up with contradictory results. Theorists from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint SLAC-Stanford institute, believe they've come up with an algorithm – a mathematical description of how the individual dark-matter particles behave – that could help narrow the search for these elusive particles, which are thought to make up more than 25 percent of the matter and energy in the universe.

It starts with assumptions, said Yao-Yuan Mao, lead author of a paper published in The Astrophysical Journal that outlines their new search tool. Assumptions are a good starting point when you don’t know where to look. A popular assumption about dark matter is that it's made up of WIMPs, Weakly Interacting Massive Particles. The "M" in WIMP accounts for gravity's ability to herd these particles around; the "P" and "I" hint at why they're so hard to detect otherwise.

Most dark matter detectors are based on the assumption that, every once in a while, a WIMP must smack into the nucleus of an atom of visible matter, making the nucleus vibrate and releasing a signal. Such disruptions can be detected. But what that disruption looks like and how often it happens depends on yet more assumptions. How heavy is the dark matter particle? How fast is it moving?

Another common assumption that touches on these issues, said Mao, is that collections of WIMPs behave as an ideal gas, a collection of particles that hang out together and occasionally bounce off each other. Sometimes a lucky bounce gives a particle more energy, sending it zooming off at a greater speed. How often particles pick up more energy and more speed depends on how much you turn up the heat or put on the pressure.

But, as far as scientists can tell, turning up the heat and putting on the pressure doesn't affect WIMPs. Only gravity does.

"The Ideal Gas Law doesn't describe a system of particles, like dark matter particles, that don't seem to transfer energy to each other," said Mao. This incorrect description can distort the carefully built picture upon which a search for WIMPs is based. In particular, it means predictions of their velocities can be off by a significant amount, but velocities affect what a detector will see.

Mao and his colleagues have used simulations to provide new insight into how fast WIMPs are expected to move. WIMPs that move fast enough to reach escape velocity and leave the dark matter halo that surrounds the Milky Way take themselves completely out of the hunt. That reduction in the number of WIMPs affects how often one hits the nucleus of an atom in a detector. The remaining WIMPs must be moving more slowly than escape velocity, which affects how hard they can hit. If they hit a detector whose atoms are too massive, the WIMPs bounce off without a sign, like pebbles scattering off a boulder. So the trick is to build a detector out of materials that are a good match for the particle’s expected mass and speed.

As theorist Louis Strigari, another author on the paper, said, "The heavier the WIMP, the more collisions you can detect." But there's a growing suspicion that WIMPs might be as much as 10 times lighter than previously thought. "If WIMPs do have this low mass," said Strigari, "the model used to describe their behavior would have significant effects on an experiment's result."

In fact, Mao, Strigari and Risa Wechsler, a professor at SLAC and Stanford, are now busy interpreting the results of experiments based on their new description, and they believe it explains some of the conflicting results obtained by such experiments as XENON100 (which uses the fairly heavy element xenon as the material for dark matter to smack into) and the Cryogenic Dark Matter Search II, or CDMS II (which took its readings with detectors made from the much lighter element silicon).

KIPAC member Blas Cabrera is a Stanford physics professor and, as a leader of CDMS II, a dark matter hunter from the experimental side. He said the theorists have made an important contribution. "It really emphasizes that, for light-mass WIMPs, different types of detectors would have different responses,” he said.

"I'm actually hoping we can talk the experimental community into using their model," Cabrera added. "It's important to get everyone to agree to use the same parameters so we're comparing apples to apples instead of apples to oranges."

The computer-generated image at the top of the page shows the simulated distribution of dark matter in a galaxy cluster formed in the universe with dark energy. The clumps are locations where galaxies form.

The Daily Galaxy via SLAC

Image credit: courtesy of Andrey Kravtsov

The Thirty Meter Telescope --"Next Generation in the Search for Extraterrestrial Life"

2013-05-22T07:27:03-07:00

The Thirty Meter Telescope (TMT) - soon to be the world's widest eye on space - has got the go-ahead for construction on the summit of Mauna Kea, Hawaii. Most of Mauna Kea is below sea level. When measured from its oceanic base, its height is 33,500 ft (10,200 m)—more than twice Mount Everest's base-to-peak height. The sacred mountain is about one million years old --long past the most active shield stage of life hundreds of thousands of years ago--providing a stable platform for what will will be the world’s most advanced and capable ground-based optical, near-infrared, and mid-infrared observatory.

The TMT will integrate the latest innovations in precisions control, segmented mirror design, and adaptive optics. The giant eye will enable groundbreaking advances in a wide range of scientific areas, from the most distantreaches of the Universe to our own Solar System. TMT will allow astronomers to explore virtually every aspect of this picture, from inflation to exoplanets.

The resolution and sensitivity provided by its large aperture and adaptive optics systems, combined with a flexible and powerful suite of instruments, will enable astronomers to address many of the most fundamental questions ofthe coming decades.

One of the primary missions of the TMT will be the detection and analysis of life-bearing exo planets. The exoplanets that have so far been detected are gas giants like Jupiter and Neptune. They were found because their large mass noticeably perturbs the motion of the host star. Surprisingly, many are found very close to their host star. As the higher temperatures there would prevent such planets from forming, itseems that they must have migrated inward, after forming at greater distances. Most astronomers believe that smaller terrestrial planets exist, but these cannot be detected with present telescopes. The TMT will help answer such questions as are such planets common and can they survive the disruption that would result from migration of the massive planets? Do they have atmospheres like Earth?

If terrestrial planets exist, are conditions conducive to the development of life? Each star has a habitable zone, where a planet would have a surface temperature similar to that of Earth. If, as expected, exoplanetary systems have populations of small icy bodies like comets, it is possible that water and organic molecules could have been delivered to such planets by impacts. If life then develops, it might be detected by signatures of biological activity in planetary atmospheres.

Adaptive optics (AO) systems allow the largestoptical-infrared telescopes on Earth to achieve higher resolution than telescopes in space, which necessarily have smaller apertures. By compensating atmospheric turbulence, AO allows telescopes to reach the diffraction limit, in which the angular resolution achieved is proportional to the diameter of the telscope aperture.

The TMT will dwarf 13 other telescopes located on the extinct volcano --the biggest currently is the twin 10-metre Keck telescopes. The summit is a perfect location as it offers clear skies for 300 days of the year. The TMT will have to cede the world size record, when the European Southern Observatory's 39-metre European Extremely Large Telescope on the mountain Cerro Armazones goes live in Chile early next decade.

The Daily Galaxy via TMT

Hurricane Season Looming for Saturn's Titan

2013-05-22T06:30:00-07:00

Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan's northern hemisphere, waves could ripple across the moon's hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA's Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.

"If you think being a weather forecaster on Earth is difficult, it can be even more challenging at Titan," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We know there are weather processes similar to Earth's at work on this strange world, but differences arise due to the presence of unfamiliar liquids like methane. We can't wait for Cassini to tell us whether our forecasts are right as it continues its tour through Titan spring into the start of northern summer."

Titan's north polar region, which is bejeweled with sprawling hydrocarbon seas and lakes, was dark when Cassini first arrived at the Saturn system in 2004. But sunlight has been creeping up Titan's northern hemisphere since August 2009, when the sun's light crossed the equatorial plane at equinox. Titan's seasons take about seven Earth years to change. By 2017, the end of Cassini's mission, Titan will be approaching northern solstice, the height of summer.

Given the wind-sculpted dunes Cassini has seen on Titan, scientists were baffled about why they hadn't yet seen wind-driven waves on the lakes and seas. A team led by Alex Hayes, a member of Cassini's radar team who is based at Cornell University, Ithaca, N.Y., set out to look for how much wind would be required to generate waves. Their new model, just published in the journal Icarus, improves upon previous ones by simultaneously accounting for Titan's gravity; the viscosity and surface tension of the hydrocarbon liquid in the lakes; and the air-to-liquid density ratio.

“We now know that the wind speeds predicted during the times Cassini has observed Titan have been below the threshold necessary to generate waves," Hayes said. "What is exciting, however, is that the wind speeds predicted during northern spring and summer approach those necessary to generate wind waves in liquid ethane and/or methane. It may soon be possible to catch a wave in one of the solar system’s most exotic locations.”

The new model found that winds of 1 to 2 mph (2 to 3 kilometers per hour) are needed to generate waves on Titan lakes, a speed that has not yet been reached during Titan's currently calm period. But as Titan's northern hemisphere approaches spring and summer, other models predict the winds may increase to 2 mph (3 kilometers per hour) or faster. Depending on the composition of the lakes, winds of that speed could be enough to produce waves 0.5 foot (0.15 meter) high.

The other model about hurricanes, recently published in Icarus, predicts that the warming of the northern hemisphere could also bring hurricanes, also known as tropical cyclones. Tropical cyclones on Earth gain their energy from the build-up of heat from seawater evaporation and miniature versions have been seen over big lakes such as Lake Huron. The new modeling work, led by Tetsuya Tokano of the University of Cologne, Germany, shows that the same processes could be at work on Titan as well, except that it is methane rather than water that evaporates from the seas. The most likely season for these hurricanes would be Titan's northern summer solstice, when the sea surface gets warmer and the flow of the air near the surface becomes more turbulent. The humid air would swirl in a counterclockwise direction over the surface of one of the northern seas and increase the surface wind over the seas to possibly 45 mph (about 70 kilometers per hour).

"For these hurricanes to develop at Titan, there needs to be the right mix of hydrocarbons in these seas, and we still don't know their exact composition," Tokano said. "If we see hurricanes, that would be one good indicator that there is enough methane in these lakes to support this kind of activity. So far, scientists haven't yet been able to detect methane directly."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. The mission is managed by JPL for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena, Calif.

The image at the top of the from NASA's Cassini spacecraft chronicles the change of seasons as it captures clouds concentrated near the equator of Saturn's largest moon, Titan.

The Daily Galaxy http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov

Image credit: NASA/JPL/SSI

"The Google Brain" --Are Humans Entering a New Epoch of Evolution?

2013-05-21T08:05:37-07:00

In June of 2012, The New York Times reported that inside Google's high-tech R&D "X" laboratory the search giant has been creating a simulation of the human brain. And rather than teaching it programs, Google's staff have been exposing it to information from the Net so that it learns organically, a little like the way we humans do. It's built by hooking together 16,000 processor cores with over one billion interconnections, in a model of the around 86 billion neurons in a typical adult human brain.

In the past decade, we’ve examined our Solar System’s orbit through the Milky Way to ask whether there may be clues to periodic mass extinctions on our planet. We've launched missions seeking out habitable "Alien Earths" and the existence of dark energy and have migrated from wondering if there's life on Mars to searching out and studying myriads of exo planets in the Milky Way and infinite galaxies beyond.

Our incredible advances have also underscored own, very human limitations — our eyes, notes astronomer James Kaler see wavelengths between 0.00004 and 0.00008 of a centimeter. Kaler calls our visual spectrum “…but one octave on an imaginary electromagnetic piano with a keyboard hundreds of kilometers long.”

In The Star Thrower evolutionary biologist, Loren Eiseley, writes that "We are rag dolls made out of many ages and skins, changelings, who have slept in wood nests or hissed in the uncouth guise of waddling amphibians. We have played such roles for infinitely longer ages than we have been men."

Physicist Stephen Hawking believes that we have entered a new phase of evolution. "At first, evolution proceeded by natural selection, from random mutations. This Darwinian phase, lasted about three and a half billion years, and produced us, beings who developed language, to exchange information."

But what distinguishes us from our cave man ancestors is the knowledge that we have accumulated over the last ten thousand years, and particularly, Hawking points out, over the last three hundred.

"I think it is legitimate to take a broader view, and include externally transmitted information, as well as DNA, in the evolution of the human race," Hawking said.

In the last ten thousand years the human species has been in what Hawking calls, "an external transmission phase," where the internal record of information, handed down to succeeding generations in DNA, has not changed significantly. "But the external record, in books, and other long lasting forms of storage," Hawking says, "has grown enormously. Some people would use the term, evolution, only for the internally transmitted genetic material, and would object to it being applied to information handed down externally. But I think that is too narrow a view. We are more than just our genes."

The time scale for evolution, in the external transmission period, has collapsed to about 50 years, or less.

Meanwhile, Hawking observes, our human brains "with which we process this information have evolved only on the Darwinian time scale, of hundreds of thousands of years. This is beginning to cause problems. In the 18th century, there was said to be a man who had read every book written. But nowadays, if you read one book a day, it would take you about 15,000 years to read through the books in a national Library. By which time, many more books would have been written."

But we are now entering a new phase, of what Hawking calls "self designed evolution," in which we will be able to change and improve our DNA. "At first," he continues "these changes will be confined to the repair of genetic defects, like cystic fibrosis, and muscular dystrophy. These are controlled by single genes, and so are fairly easy to identify, and correct. Other qualities, such as intelligence, are probably controlled by a large number of genes. It will be much more difficult to find them, and work out the relations between them. Nevertheless, I am sure that during the next century, people will discover how to modify both intelligence, and instincts like aggression."

If the human race manages to redesign itself, to reduce or eliminate the risk of self-destruction, we will probably reach out to the stars and colonize other planets. But this will be done, Hawking believes, with intelligent machines based on mechanical and electronic components, rather than macromolecules, which could eventually replace DNA based life, just as DNA may have replaced an earlier form of life.

The Daily Galaxy via http://www.centauri-dreams.org/

Image credit: http://www.humanconnectomeproject.org/gallery/

Astronomers Probe 1st Large-scale Structures Produced by Dark Matter

2013-05-21T06:57:09-07:00

“The first massive stars to form in the universe produced copious ultraviolet light that ionized gas from neutral hydrogen. CIBER observes in the near infrared, as the expansion of the universe stretched the original short ultraviolet wavelengths to long near-infrared wavelengths today," said Jamie Bock, CIBER principal investigator from the California Institute of Technology. CIBER investigates two telltale signatures of first star formation -- the total brightness of the sky after subtracting all foregrounds, and a distinctive pattern of spatial variations.

CIBER is a cooperative instrument designed and built by the California Institute of Technology, University of California Irvine, the Japan Aerospace Exploration Agency (JAXA), and the Korean Astronomy and Space Science Institute (KASI). The same team is also developing an improved follow-on experiment, with more capable optics and detector arrays, that will be completed next year.

“The objectives of the experiment are of fundamental importance for astrophysics, to probe the process of first galaxy formation, but the measurement is also extremely difficult technically,” he noted. The image below shows early dark matter filaments.

This will be the fourth flight for CIBER on a NASA sounding rocket. The previous launches were in 2009, 2010, and 2012 from the White Sands Missile Range, New Mexico. After each flight the experiment or payload was recovered for post-calibrations and re-flight.

For this flight CIBER will fly on a larger and more powerful rocket than before. This will loft CIBER to a higher altitude than those previously obtained, thus providing longer observation time for the instruments. The experiment, which will safely splash down in the Atlantic Ocean more than 400 miles off the Virginia coast, will not be recovered.

CIBER previously flew on two-stage Black Brant IX sounding rockets. Bock said, “The collection of data from the three flights allows us to compare data and rigorously test sources of potential systematic error from both the instrument and astrophysical foregrounds. We have been through the end-to-end process in analyzing our data, so we understand the benefits of going with a non-recovered Black Brant XII. We also know the performance of the instrument very well from these flights and that makes us confident going forward with this more capable but final flight.”

The 70-foot tall four-stage Black Brant XII rocket will carry CIBER to an altitude of about 350 miles. According to Bock, “This flight is pioneering a new direction in the astrophysics program in that we are flying our instrument on a non-recovered Black Brant XII. The XII gives us a significantly higher trajectory, providing about 560 seconds of flight time above 250 km (155 miles) altitude, compared with 250 seconds on standard Black Brant IX flights out of White Sands.”

“Our experience in the near-infrared waveband is that we see appreciable emission from the atmosphere up to 250 km. The higher trajectory allows us to do some new things that are not possible on a Black Brant IX. For example, we expect to have enough independent images of the sky to directly determine the in-flight gain of the infrared cameras, which will allow us to measure background fluctuations in single exposures. This gives us a much more direct way to compare with satellite data than the statistical combinations we have had to use to date. The higher trajectory of course comes with a price in that the payload is not recovered,” he said.

Backup launch days for this project are June 5 – 10.

The image at the top of the page shows galaxy BX442, was observed using the Hubble Space Telescope as it existed 3 billion years after the Big Bang. Think about that: It means the light from that part of the universe took 10.7 billion years to get here. "As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric," says Alice Shapley, a UCLA associate professor of physics and astronomy. "The vast majority of old galaxies look like train wrecks."

The Daily Galaxy via http://www.nasa.gov/mission_pages/sounding-rockets/

Image credit: Courtesy of Jamie Bock/Cal Tech

"Quantum Weirdness" --New Insights

2013-05-21T04:20:00-07:00

Entanglement, by general consensus of physicists, is the weirdest part of quantum science. To say that two particles, A and B, are entangled means that they are actually two parts of an inseparable quantum thing. An important consequence of this inherent kinship is that measuring a property of A (say, the particle's polarization) is necessarily to know the corresponding property of B, even if you're not there with a detector to observe B and even if (as explained below) the existence of that property had no prior fixed value until the moment particle A was detected.

To create such entanglement it is generally necessary to generate particles two at a time and to generate them so that they are born with this connected property. The most basic step in measuring such a system is to measure and detect both particles and to do so efficiently. So it had better be the case that if one detector registers a particle, the other detector should collect and register the other particle.

Because we know that if we see one particle, the other must exist, we say that the detection of one particle "heralds" the existence of the other, just as medieval heralds, with their banners and bugles, signified the arrival of a king. Although in this case, because with these particles born in twos, one photon is no more regal than the other, so we can equally well say that one photon heralds the other and vice versa. But as in the case of a king, in real life even though the herald announces the king he may be waylaid and never appear.

An experiment conducted at the Joint Quantum Institute establishes a new record for heralding efficiency for a pair of entangled photons (particles of light). The JQI work is published in the May 15 issue of the journal Optics Letters (see below). What happens is this: about 84% of the time the researchers observe photon A they also observe photon B just where it should be, and vice versa.

The JQI detection scheme will be useful for a number of reasons: it should help experiments to tighten remaining loopholes over the fundamental sway of quantum reality; it shows that sources of single heralded photons can achieve a certain level of reliability; and that might be a critical ingredient in producing a source of random numbers in a way that guarantees that any nefarious attempts to "load the dice" are impossible.

The JQI experiment demonstrates a photon source which could allow one to get to the heart of counter-intuitive nature of quantum reality by looking at indeterminacy. In common experience a coin facing up has a definite value: it is a head or a tail. Even if you don't look at the coin you trust that it must be a head or tail. In quantum experience the situation is more unsettling: material properties of things do not exist until they are measured. Until you "look" (measure the particular property) at the coin, as it were, it has no fixed face up.

What this indeterminacy means is that until it is observed an object has no definite value for that property. So the property in question, whether it is position, velocity, charge, polarization, or some other attribute, cannot even be said to exist. Instead the object is said to be in a superposition of states and its physical attributes can potentially take on a variety of values.

When describing the existence of this particle, we can do no more than specify a set of probabilities that the object's properties have certain values. At the moment measurement occurs the object undergoes a "collapse of probability." The probability estimates in play just before measurement become superfluous. The property being measured -- the polarization of a photon, say -- has assumed a definite value, horizontal or vertical in this case.

Describing reality in terms of indeterminacy and probability bothered Albert Einstein. Surely, he said, a particle's property exists before it is measured and a theory more complete than quantum mechanics would include the existence of those properties before they were measured. Those properties before measurement must be contained in some variables hidden from the standard quantum mechanical representation. The search for those "hidden variables" pertaining to the existence of things occupied a lot of Einstein's time in the latter part of his life, and has been a topic of concern with physicists ever since.

In the 1960s John Bell proposed a number of experiments designed to test the validity of things like entanglement and indeterminacy. So far all such tests have supported the validity of quantum indeterminacy and have discouraged the idea of any hidden variables. But for some skeptics, loopholes remain, and they argue that the reality of entanglement has not yet been adequately demonstrated. One reason for this is the difficulty in measuring properties of two or more (supposedly entangled) objects with sufficient efficiency. The relatively poor measurement efficiency, resulting in the failure to detect one or the other of the pair of entangled photons, allowed skeptics to assert that the measured sample of pairs did not constitute a good enough representation of the overall set of objects to be able to say something definitive about entanglement.

The experiment effort in Alan Migdall's JQI lab specifically targets the efficiency of the heralding process. To start, the researchers send a beam of ultraviolet photons into a special crystal where, at a rate of about one per billion, a UV photon is turned into a pair of entangled photons. This process is called spontaneous parametric down-conversion (PDC). The laws of physics dictate that the momentum and energy of the incoming photon (from the pump beam) should be split between the daughter photons (one is called the "signal" and the other the "idler"). In this picture omega is the frequency of the respective photon and is proportional to its energy.

The daughters might, for instance, be a green photon plus a near-infrared photon, or two red photons, or any other combination of colors so long as the sum of the energies of the photons adds up the energy of the pump photon.

Each of the two photons makes its way through a lens and into a fiber so narrow that only a single mode can propagate. That is, if we think of the light not as a particle (photon) but as a bundle of electric and magnetic fields, the lateral profile of the ray will have a simple Gaussian shape. This kind of fiber, aligned to exacting standards, ensures that photons of a very specific energy and direction will be channeled into a photodetector where its presence and time of arrival can be determined.
Photon or Vacuum?

"In effect the observation of photon A brings photon B into existence," says Alan Migdall, "at least if these are true entangled photons." This entanglement between the existence of a photon and no photon (or vacuum) is not what is usually considered to be entanglement but it is nonetheless.

The aim of this JQI experiment is not itself to test the Bell criteria for entanglement (as it turns out the polarizations of photons A and B are known be forehand), but rather to optimize the process of heralding -- the ability to say that if A is here then B is there. For some theories a heralding efficiency must at least 82% if entanglement loopholes are to be closed.

The JQI physicists have now exceeded this yardstick. They typically observe about 50,000 signal photons (photon A) per second in their detector. And when this happens about 84% of the time a photon is seen in detector B. And simultaneously, when the roles of the two detectors are reversed a comparable percentage is registered. This is the highest symmetric heralding efficiency for a single-mode fiber yet seen in any experiment.

Migdall says that because of the random nature of observing a photon with an appropriately prepared polarization state, the measurement of a heralded photon can be turned into a number that is truly random and guaranteed to be free of tampering. Such random numbers can, in turn, be used in various schemes to encrypt messages that can never be cracked.

The Joint Quantum Institute is operated jointly by the National Institute of Standards and Technology in Gaithersburg, MD and the University of Maryland in College Park.

The Daily Galaxy Courtesy of the Joint Quantum Institute. http://www.nist.gov/index.html

Image Credits: NIST and (top of page) courtesy of http://reactioncrate.wordpress.com/

Complex Biochemistry Possible at Origins of Life on Earth

2013-05-20T03:00:00-07:00

A new study shows that RNA is capable of catalyzing electron transfer under conditions similar to those of the early Earth. Because electron transfer, the moving of an electron from one chemical species to another, is involved in many biological processes – including photosynthesis, respiration and the reduction of RNA to DNA – the study’s findings suggest that complex biochemical transformations may have been possible when life began. The study was sponsored by the NASA Astrobiology Institute, which established the Center for Ribosomal Origins and Evolution (Ribo Evo) at Georgia Tech.

Free oxygen gas was almost nonexistent in the Earth’s atmosphere more than 3 billion years ago. When free oxygen began entering the environment as a product of photosynthesis, it turned the earth’s iron to rust, forming massive banded iron formations that are still mined today. The free oxygen produced by advanced organisms caused iron to be toxic, even though it was – and still is – a requirement for life. Loren Williams, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology believes the environmental transition caused a slow shift from the use of iron to magnesium for RNA binding, folding and catalysis.

There is considerable evidence that the evolution of life passed through an early stage when RNA played a more central role, before DNA and coded proteins appeared. During that time, more than 3 billion years ago, the environment lacked oxygen but had an abundance of soluble iron.

“Our study shows that when RNA teams up with iron in an oxygen-free environment, RNA displays the powerful ability to catalyze single electron transfer, a process involved in the most sophisticated biochemistry, yet previously uncharacterized for RNA,” said Loren Williams, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology.

The results of the study were published online on May 19, 2013, in the journal Nature Chemistry. The study was sponsored by the NASA Astrobiology Institute, which established the Center for Ribosomal Origins and Evolution (Ribo Evo) at Georgia Tech.

Williams and Georgia Tech School of Chemistry and Biochemistry postdoctoral fellow Chiaolong Hsiao used a standard peroxidase assay to detect electron transfer in solutions of RNA and either the iron ion, Fe2+, or magnesium ion, Mg2+. For 10 different types of RNA, the researchers observed catalysis of single electron transfer in the presence of iron and absence of oxygen. They found that two of the most abundant and ancient types of RNA, the 23S ribosomal RNA and transfer RNA, catalyzed electron transfer more efficiently than other types of RNA. However, none of the RNA and magnesium solutions catalyzed single electron transfer in the oxygen-free environment.

“Our findings suggest that the catalytic competence of RNA may have been greater in early Earth conditions than in present conditions, and our experiments may have revived a latent function of RNA,” added Williams, who is also director of the Ribo Evo Center.

This new study expands on research published in May 2012 in the journal PLoS ONE. In the previous work, Williams led a team that used experiments and numerical calculations to show that iron, in the absence of oxygen, could substitute for magnesium in RNA binding, folding and catalysis. The researchers found that RNA’s shape and folding structure remained the same and its functional activity increased when magnesium was replaced by iron in an oxygen-free environment.

In future studies, the researchers plan to investigate whether other unique functions may have been conferred on RNA through interaction with a variety of metals available on the early Earth.

This work was supported by NASA (Award No. NNA09DA78A). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of NASA.

CITATION: Chiaolong Hsiao, et al., “RNA with iron(II) as a cofactor catalyses electron transfer,” (Nature Chemistry, 2013). http://dx.doi.org/10.1038/nchem.1649

The Daily Galaxy via Georgia Tech

Giant Elliptical Galaxy Harbors Largest Known Black Hole in Universe

2013-05-20T01:00:00-07:00

The black hole at the center of the super giant elliptical galaxy M87 in cluster Virgo fifty million light-years away is the most massive black hole for which a precise mass has been measured -6.6 billion solar masses. Orbiting the galaxy is an abnormally large population of about 12,000 globular clusters, compared to 150-200 globular clusters orbiting the Milky Way. The team theorized that the M87 black hole grew to its massive size by merging with several other black holes. M87 is the largest, most massive galaxy in the nearby universe, and is thought to have been formed by the merging of 100 or so smaller galaxies. The M87 black hole’s large size and relative proximity, astronomers think that it could be the first black hole that they could actually “see.”

In 2011, using the Frederick C. Gillett Gemini Telescope on Mauna Kea, Hawaii, a team of astronomers calculated the black hole’s mass, which is vastly larger than the black hole in the center of the Milky Way, which is about 4 million solar masses. The black hole’s event horizon, 20 billion km across “could swallow our solar system whole.”

In order to calculate the black hole’s mass, the astronomers measured how fast surrounding stars orbit the black hole. They found that, on average, the stars orbit at speeds of nearly 500 km/s (for comparison, the sun orbits the black hole at the center of the Milky Way at about 220 km/s). From these observations, the astronomers could come up with what they say is the most accurate estimate for the mass of a supermassive black hole.

Future calculations may attempt to calculate the size of another black hole with a roughly estimated mass of 18 billion solar masses, which is located in a galaxy about 3.5 billion light-years away.

In the image at the top of the page, a central jet is surrounded by nearby bright arcs and dark cavities in the multimillion degree Celsius atmosphere of M87. Much further out, at a distance of about fifty thousand light years from the galaxy's center, faint rings can be seen and two spectacular plumes extend beyond the rings. These features, shown in X-rays, together with VLA radio observations, are dramatic evidence that repetitive outbursts from the central supermassive black hole have been affecting the entire galaxy for a hundred million years or more.

The Daily Galaxy via Chandra X-Ray Observatory

Saving Kepler! --The Mission That Changed Our View of the Probability of Life in the Universe

2013-05-20T00:31:00-07:00

The NASA mission that has changed our view of the probability of life in the Universe is in jeopardy. The Kepler has shown that planets are common throughout the Milky Way and the billions of galaxies in the cosmos. NASA officials announced Wednesday, May 15, that the Kepler space telescope – the agency's primary instrument for detecting planets beyond our solar system – had suffered a critical failure and could soon be shut down permanently.Stanford professor and former NASA official explains how NASA might revive the Kepler space telescopeS, Scott Hubbard, a consulting professor of aeronautics and astronautics, helped guide the Kepler mission when he served as director of NASA Ames Research Center. He explains how NASA might bring the planet-hunting spacecraft back online.

The Kepler spacecraft's photo-detector array registers more than 100,000 stars at a time, Hubbard said, and in order to detect exoplanets (planets orbiting stars outside our solar system), the telescope must remain extremely steady so that the stars do not wander across the optics. A series of four gyroscope-like reaction wheels whir within the telescope to hold its gaze. At least three must be functioning to keep Kepler stable. One failed about a year ago and was shut off, and NASA scientists announced Wednesday, May 15, that a second wheel was no longer operating and that Kepler had paused operations.

In a conversation with Stanford News Service, Hubbard explained the possible ways that NASA could bring the spacecraft back online, and what planet hunters will do next if that's not possible.

It will be very sad if it can't go on any longer, but the taxpayers did get their money's worth. Kepler has, so far, detected more than 2,700 candidate exoplanets orbiting distant stars, including many Earth-size planets that are within their star's habitable zone, where water could exist in liquid form.

Kepler has done what the program managers said it would do, and that is to give us an inventory of extrasolar planets. It completed its primary observation phase, and had entered its extended science phase. We're already in the gravy train period – there's still a year and a half's worth of data in the pipeline that scientists will analyze to identify other candidate planets, and there will continue to be Kepler science discoveries for quite some time.

There are two possible ways to salvage the spacecraft. One is that they could try turning back on the reaction wheel that they shut off a year ago. It was putting metal on metal, and the friction was interfering with its operation, so you could see if the lubricant that is in there, having sat quietly, has redistributed itself, and maybe it will work.

The other scheme, and this has never been tried, involves using thrusters and the solar pressure exerted on the solar panels to try and act as a third reaction wheel and provide additional pointing stability. Hubbard's impression is that it would require sending a lot more operational commands to the spacecraft.

It's important to make clear, though, that in the original queue of missions aimed at finding life elsewhere, a mission like Kepler was a survey mission to establish the statistical frequency of whether these planets are rare or common. It lived the length of its prime mission, and was extremely successful during that time at achieving this goal. It has paved the way for additional missions, such as TESS – Transiting Exoplanet Survey Satellite – and TPF – Terrestrial Planet Finder – which will continue the search for Earth-like exoplanets in the near future.

The Daily Galaxy via Stanford University

Image credit: nexsci.caltech.edu

Image of the Day: Star Being Ripped Apart by a Supermassive Black Hole

2013-05-19T00:45:00-07:00

Results from NASA's Chandra X-ray Observatory and the Magellan telescopes suggest that a dense stellar remnant was ripped apart by a black hole a thousand times as massive as the Sun in NGC 1399, an elliptical galaxy about 65 million light years from Earth. In the image above, X-rays from Chandra Space Observatory are shown in blue and are overlaid on an optical image from the Hubble Space Telescope. The Chandra observations show that this object is a so-called ultraluminous X-ray source (ULX). ULXs emit more X-rays than stars, but less than quasars. Their exact nature has remained a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and a thousands times that of the Sun.

If confirmed, this discovery would be a cosmic double play: it would be strong evidence for an intermediate mass black hole, which has been a hotly debated topic, and would mark the first time such a black hole has been caught tearing a star apart.

The intensity of the X-ray emission places the source in the "ultraluminous X-ray source" or ULX category, meaning that it is more luminous than any known stellar X-ray source, but less luminous than the bright X-ray sources (active galactic nuclei) associated with supermassive black holes in the nuclei of galaxies. The nature of ULXs is a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and several thousand times that of the Sun, a range intermediate between stellar-mass black holes and supermassive black holes located in the nuclei of galaxies.

This ULX is in a globular cluster, a very old and crowded conglomeration of stars. Astronomers have suspected that globular clusters could contain intermediate-mass black holes, but conclusive evidence for this has been elusive.

"Astronomers have made cases for stars being torn apart by supermassive black holes in the centers of galaxies before, but this is the first good evidence for such an event in a globular cluster," said Jimmy Irwin of the University of Alabama.

Irwin and his colleagues obtained optical spectra of the object using the Magellan I and II telescopes in Las Campanas, Chile. These data reveal emission from gas rich in oxygen and nitrogen but no hydrogen, a rare set of signals from globular clusters. The physical conditions deduced from the spectra suggest that the gas is orbiting a black hole of at least 1,000 solar masses.

The abundant amount of oxygen and absence of hydrogen indicate that the destroyed star was a white dwarf, the end phase of a solar-type star that has burned its hydrogen leaving a high concentration of oxygen. The nitrogen seen in the optical spectrum remains an enigma.

Theoretical work suggests that the tidal disruption-induced X-ray emission could stay bright for more than a century, but it should fade with time. So far, the team has observed there has been a 35 percent in X-ray emission from 2000 to 2009.

The Daily Galaxy via JPL/NASA

NASAs 'Curiosity' Search for Life Targets Water-Altered Rock

2013-05-18T06:00:04-07:00

NASA's senior Mars rover, Opportunity, is driving to a new study area after a dramatic finish to 20 months on "Cape York" with examination of a rock intensely altered by water. The pale rock in the upper center of the image above, about the size of a human forearm, includes a target called "Esperance," which was inspected by NASA's Mars Exploration Rover Opportunity. Data from the rover's alpha particle X-ray spectrometer (APXS) indicate that Esperance's composition is higher in aluminum and silica, and lower in calcium and iron, than other rocks Opportunity has examined in more than nine years on Mars. Preliminary interpretation points to clay mineral content due to intensive alteration by water. The fractured rock provides evidence about a wet ancient environment possibly favorable for life.

The mission's principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., said, "Esperance was so important, we committed several weeks to getting this one measurement of it, even though we knew the clock was ticking."

"What's so special about Esperance is that there was enough water not only for reactions that produced clay minerals, but also enough to flush out ions set loose by those reactions, so that Opportunity can clearly see the alteration," said Scott McLennan of the State University of New York, Stony Brook, a long-term planner for Opportunity's science team.

This rock's composition is unlike any other Opportunity has investigated during nine years on Mars -- higher in aluminum and silica, lower in calcium and iron.

The next destination, Solander Point, and the area Opportunity is leaving, Cape York, both are segments of the rim of Endeavour Crater, which spans 14 miles (22 kilometers) across. The planned driving route to Solander Point is about 1.4 miles (2.2 kilometers). Cape York has been Opportunity's home since the rover arrived at the western edge of Endeavour in mid-2011 after a two-year trek from a smaller crater.

"Based on our current solar-array dust models, we intend to reach an area of 15 degrees northerly tilt before Opportunity's sixth Martian winter," said JPL's Scott Lever, mission manager. "Solander Point gives us that tilt and may allow us to move around quite a bit for winter science observations."

Northerly tilt increases output from the rover's solar panels during southern-hemisphere winter. Daily sunshine for Opportunity will reach winter minimum in February 2014. The rover needs to be on a favorable slope well before then.

The first drive away from Esperance covered 81.7 feet (24.9 meters) on May 14. Three days earlier, Opportunity finished exposing a patch of the rock's interior with the rock abrasion tool. The team used a camera and spectrometer on the robotic arm to examine Esperance.

The team identified Esperance while exploring a portion of Cape York where the Compact Reconnaissance Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter had detected a clay mineral. Clays typically form in wet environments that are not harshly acidic. For years, Opportunity had been finding evidence for ancient wet environments that were very acidic. The CRISM findings prompted the rover team to investigate the area where clay had been detected from orbit. There, they found an outcrop called "Whitewater Lake," containing a small amount of clay from alteration by exposure to water.

"There appears to have been extensive, but weak, alteration of Whitewater Lake, but intense alteration of Esperance along fractures that provided conduits for fluid flow," Squyres said. "Water that moved through fractures during this rock's history would have provided more favorable conditions for biology than any other wet environment recorded in rocks Opportunity has seen."

NASA's Mars Exploration Rover Project launched Opportunity to Mars on July 7, 2003, about a month after its twin rover, Spirit. Both were sent for three-month prime missions to study the history of wet environments on ancient Mars and continued working in extended missions. Spirit ceased operations in 2010.

The Daily Galaxy via NASA/JPL

Image Credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.

The Higgs Boson and a 'New Physics' --"Could Make the Speed of Light Possible"

2013-05-18T02:00:00-07:00

Scientists hailed CERN's confirmation of the Higgs Boson in July of 2012, speculating that it could one day make light speed travel possible by "un-massing" objects or allow huge items to be launched into space by "switching off" the Higgs. CERN scientist Albert de Roeck likened it to the discovery of electricity, when he said humanity could never have imagined its future applications.

CERN physicists hope that the "new physics" will provide a more straightforward explanation for the characteristics of the Higgs boson than that derived from the current Standard Model. This new physics is sorely needed to find solutions to a series of yet unresolved problems, as presently only the visible universe is explained, which constitutes just four percent of total matter.

"The Standard Model has no explanation for the so-called dark matter, so it does not describe the entire universe – there is a lot that remains to be understood," says Dr. Volker Büscher of Johannes Gutenberg University Mainz (JGU).

The discovery of the long-sought Higgs boson, an elusive particle thought to help explain why matter has mass, was hailed as a huge moment for science by physicists. In July of 2012, CERN, the European Organization for Nuclear Research in Geneva, announced the discovery of a new particle that could be the long sought-after Higgs boson. The particle has a mass of about 126 gigaelectron volts (GeV), roughly that of 126 protons.

The new evidence came from an enormously large volume of data that has been more than doubled since December 2011. According to CERN, the LHC collected more data in the months between April and June 2012 than in the whole of 2011. In addition, the efficiency has been improved to such an extent that it is now much easier to filter out Higgs-like events from the several hundred million particle collisions that occur every second.

The existence of the Higgs boson was predicted in 1964 and it is named after the British physicist Peter Higgs. It is the last piece of the puzzle that has been missing from the Standard Model of physics and its function is to give other elementary particles their mass. According to the theory, the so-called Higgs field extends throughout the entire universe. The mass of individual elementary particles is determined by the extent to which they interact with the Higgs bosons.

"The discovery of the Higgs boson represents a milestone in the exploration of the fundamental interactions of elementary particles," said Professor Dr. Matthias Neubert, Professor for Theoretical Elementary Particle Physics and spokesman for the Cluster of Excellence PRISMA at JGU.

On the one hand, the Higgs particle is the last component missing from the Standard Model of particle physics. On the other hand, physicists are struggling to understand the detected mass of the Higgs boson. Using theory as it currently stands, the mass of the Higgs boson can only be explained as the result of a random fine-tuning of the physical constants of the universe at a level of accuracy of one in one quadrillion.

The Higgs helps explains how the world could be the way that it is in the first millionth of a second in the Big Bang.

Physicist Ray Volkas said "almost everybody" was hoping that, rather than fitting the so-called Standard Model of physics -- a theory explaining how particles fit together in the Universe -- the Higgs boson would prove to be "something a bit different".

"If that was the case that would point to all sorts of new physics, physics that might have something to do with dark matter," he said, referring to the hypothetical invisible matter thought to make up much of the universe.

It could be that the Higgs particle acts as a bridge between ordinary matter, which makes up atoms, and dark matter, which we know is a very important component of the universe.

"That would have really fantastic implications for understanding all of the matter in the universe, not just ordinary atoms," he added. De Roeck said scrutinising the new particle and determining whether it supported something other than the Standard Model would be the next step for CERN scientists.

Definitive proof that it fit the Standard Model could take until 2015 when the LHC had more power and could harvest more data.

Instead, De Roeck was hoping it would be a "gateway or a portal to new physics, to new theories which are actually running nature" such as supersymmetry, which hypothesises that there are five different Higgs particles governing mass.

For the image at the top of the page, two teams of astronomers used data from NASA's Chandra X-ray Observatory and other telescopes to map the distribution of dark matter in a galaxy cluster known as Abell 383, which is located about 2.3 billion light years from Earth. Not only were the researchers able to find where the dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight. Several lines of evidence indicate that there is about six times as much dark matter as "normal", or baryonic, matter in the Universe. Understanding the nature of this mysterious matter is one of the outstanding problems in astrophysics.

Galaxy clusters are the largest gravitationally-bound structures in the universe, and play an important role in research on dark matter and cosmology, the study of the structure and evolution of the universe. The use of clusters as dark matter and cosmological probes hinges on scientists' ability to use objects such as Abell 383 to accurately determine the three-dimensional structures and masses of clusters.

The Daily Galaxy via Johannes Gutenberg University Mainz (JGU), CERN, and 2012 AFP

Missing Lithium in Milky Way Dwarf Galaxy Challenges Big Bang Theory

2013-05-17T08:20:56-07:00

Stars in the Milky Way have about four times less lithium on the surface than expected by Big Bang predictions. Some scientists suggest that stellar activity might destroy lithium, or the element might sink from the surface through lighter hydrogen, but the remarkably consistent ratio from star to star is a challenge to those explanations. Observations of gas in the Small Magellanic Cloud (above), a dwarf galaxy of the Miloky Way, revealed the amount of lithium that predictions say would have been produced at the Big Bang, but leave no room for subsequent production of the element.

One explanation could be a novel kind of physics operating at the Big Bang that left less lithium than the Standard Model predicts. J. Christopher Howk, Nicolas Lehner and Grant Mathews of the Center for Astrophysics at the University of Notre Dame published a paper last fall in the journal Nature titled "Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud."

The astrophysicists explored a discrepancy between the amount of lithium predicted by the standard models of elemental production during the Big Bang and the amount of lithium observed in the gas of the Small Magellanic Cloud, a galaxy near to our own.

"The paper involves measuring the amount of lithium in the interstellar gas of a nearby galaxy, but it may have implications for fundamental physics, in that it could imply the presence of dark matter particles in the early universe that decay or annihilate one another," Howk says. "This may be a probe of physics in the early universe that gives us a handle on new physics we don't have another way to get a handle on right now."

Using observations from European Southern Observatory's Very Large Telescope (VLT) in Chile, the team measured the amount of lithium in the interstellar gas of the Small Magellanic Cloud, which has far fewer star-produced heavy elements than the Milky Way.

In addition to the production of elements by fusion in the core of stars, scientists believe conditions immediately after the Big Bang led to the formation of some elements, including a small amount of lithium. The team will conduct three nights of observations on the VLT in November. They will look for the lithium isotope 7Li in the Large Magellanic Cloud and 6Li in both the Large Magellanic Cloud and the Small Magellanic Cloud. The standard model predicts that no 6Li was created at the Big Bang.

The Daily Galaxy via Nature

Image of the Day: Mars --Impact Central!

2013-05-17T03:00:00-07:00

Taking before and after pictures of Martian terrain, researchers of the UA-led HiRISE imaging experiment have identified almost 250 fresh impact craters on the Red Planet, providing a more accurate yardstick of surface processes on Mars. Scientists using images from NASA's Mars Reconnaissance Orbiter, or MRO, have estimated that the planet is bombarded by more than 200 small asteroids or bits of comets per year forming craters at least 12.8 feet (3.9 meters) across.

Researchers have identified 248 new impact sites on parts of the Martian surface in the past decade, using images from the spacecraft to determine when the craters appeared. The 200-per-year planetwide estimate is a calculation based on the number found in a systematic survey of a portion of the planet.

The University of Arizona's High Resolution Imaging Science Experiment, or HiRISE camera, took pictures of the fresh craters at sites where before and after images had been taken. This combination provided a new way to make direct measurements of the impact rate on Mars and will lead to better age estimates of recent features on Mars, some of which may have been the result of climate change.

"It's exciting to find these new craters right after they form," said Ingrid Daubar of the UA, lead author of the paper published online this month by the journal Icarus. "It reminds you Mars is an active planet, and we can study processes that are happening today."

These asteroids or comet fragments typically are no more than 3 to 6 feet (1 to 2 meters) in diameter. Space rocks too small to reach the ground on Earth cause craters on Mars because the Red Planet has a much thinner atmosphere.

HiRISE targeted places where dark spots had appeared during the time between images taken by the spacecraft's Context Camera, or CTX, or cameras on other orbiters. The new estimate of cratering rate is based on a portion of the 248 new craters detected. If comes from a systematic check of a dusty fraction of the planet with CTX since late 2006.

The impacts disturb the dust, creating noticeable blast zones. In this part of the research, 44 fresh impact sites were identified.

The meteor over Chelyabinsk, Russia, in February was about 10 times bigger than the objects that dug the fresh Martian craters.

Estimates of the rate at which new craters appear serve as scientists' best yardstick for estimating the ages of exposed landscape surfaces on Mars and other worlds.

Daubar and co-authors calculated a rate for how frequently new craters at least 12.8 feet (3.9 meters) in diameter are excavated. The rate is equivalent to an average of one each year on each area of the Martian surface roughly the size of the U.S. state of Texas. Earlier estimates pegged the cratering rate at three to 10 times more craters per year. They were based on studies of craters on the moon and the ages of lunar rocks collected during NASA's Apollo missions in the late 1960s and early 1970s.

"Mars now has the best-known current rate of cratering in the solar system," said UA's HiRISE Principal Investigator Alfred McEwen, a co-author on the paper.

MRO has been examining Mars with six instruments since 2006. Daubar is an imaging targeting specialist who has been on the HiRISE uplink operation s team from the very beginning. She is also a graduate student in the UA's department of planetary science and plans on graduating with her doctorate in spring 2014.

"There are five of us who help plan the images that HiRISE will take over a two-week cycle," she explained. "We work with science team members across the world to understand their science goals, help select the image targets and compile the commands for the spacecraft and the camera."

"The longevity of this mission is providing wonderful opportunities for investigating changes on Mars," said MRO Deputy Project Scientist Leslie Tamppari of NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The 'Daily Galaxy' Followers Soar Above 265,000!

2013-05-17T00:10:00-07:00

Join the 269,000 Daily Galaxy fans around the world who follow us via their Twitter page. Our followers include many of the planet's leading astronomers and scientists, astronauts, space observatories, news organizations, universities and governmental space organizations such as NASA, JPL, ESO, SETI, Harvard-Smithsonian Center for Astrophysics (CfA) and Royal Astronomy Society members. Follow us daily at twitter.com/dailygalaxy

Image Credit: With thanks to Vikram K. Mulligan. Used with permission

"First Evidence for Extraterrestrial Sources of High-Energy Neutrinos" --Reports Antarctica Observatory

2013-05-16T05:24:43-07:00

Although cosmic rays were discovered 100 years ago, their origin remains one of the most enduring mysteries in physics. Until now. A massive telescope at the IceCube Neutrino Observatory in the Antarctic ice reports the detection of 28 extremely high-energy neutrinos that might have their origin in cosmic sources. Two of these reached energies greater than 1 petaelectronvolt (PeV), an energy level thousands of times higher than the highest energy neutrino yet produced in a manmade accelerator.

“We’re looking for the first time at high energy neutrinos that are not coming from the atmosphere,” says Francis Halzen, principal investigator of IceCube and the Hilldale and Gregory Breit Distinguished Professor of Physics at University of Wisconsin–Madison. “This is what we were looking for,” he adds.

Because they rarely interact with matter and are unimpeded by gravity, neutrinos can carry information about the workings of the highest-energy and most distant phenomena in the universe. Though billions of neutrinos pass through the Earth every second, the vast majority originate either in the sun or in the Earth’s atmosphere. Far rarer are high-energy neutrinos that may hail from the most powerful cosmic events — such as gamma ray bursts, black holes, or star formation — where they would be created in association with high-energy cosmic rays that can reach energies up to thousands of PeVs.

Postdoctoral fellow Nathan Whitehorn described 28 high-energy neutrino events captured by the detector between May 2010 and May 2012. These events, including two that exceeded the unprecedented energy level of 1 PeV, were one of the main goals for building a detector such as IceCube.

“Their properties are strongly inconsistent with what you would expect of atmospheric sources and are almost exactly what you would expect from an astrophysical source,” Whitehorn says. It is premature to speculate where these neutrinos originated, he adds, but the IceCube collaboration is continuing to refine and expand the analysis.

IceCube is comprised of more than 5,000 digital optical modules suspended in a cubic kilometer of ice at the South Pole. The National Science Foundation-supported observatory detects neutrinos through the tiny flashes of blue light produced when a neutrino interacts with a water molecule in the ice.

The first hints of high-energy neutrinos came with the unexpected discovery in April 2012 of two detector events above 1 PeV. An analysis of those events was reported last month in a paper submitted to the journal Physical Review Letters. An intensified search, led by Whitehorn and fellow WIPAC scientists Claudio Kopper and Naoko Kurahashi Neilson, turned up 26 additional events exceeding 30 teraelectronvolts (TeV; one-thousandth of a PeV), which will be described in a forthcoming publication.

The Daily Galaxy via http://www.news.wisc.edu/21790

Asteroid QE2 Will Sail Past Earth in Two Weeks

2013-05-16T03:00:00-07:00

On May 31, 2013, asteroid 1998 QE2, which is believed to be about 1.7 miles (2.7 kilometers) or nine Queen Elizabeth 2 ship-lengths in size, will sail serenely past Earth, getting no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the moon. And while QE2 is not of much interest to those astronomers and scientists on the lookout for hazardous asteroids, it is of interest to those who dabble in radar astronomy and have a 230-foot (70-meter) -- or larger -- radar telescope at their disposal.

"Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features," said radar astronomer Lance Benner, the principal investigator for the Goldstone radar observations from NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin. We will also use new radar measurements of the asteroid's distance and velocity to improve our calculation of its orbit and compute its motion farther into the future than we could otherwise."

The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC). This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.

The asteroid is not named after that 12-decked, transatlantic-crossing flagship for the Cunard Line. Instead, the name is assigned by the NASA-supported Minor Planet Center in Cambridge, Mass., which gives each newly discovered asteroid a provisional designation starting with the year of first detection, along with an alphanumeric code indicating the half-month it was discovered, and the sequence within that half-month.

Radar images from the Goldstone antenna could resolve features on the asteroid as small as 12 feet (3.75 meters) across, even from 4 million miles away.

"It is tremendously exciting to see detailed images of this asteroid for the first time," said Benner. "With radar we can transform an object from a point of light into a small world with its own unique set of characteristics. In a real sense, radar imaging of near-Earth asteroids is a fundamental form of exploring a whole class of solar system objects."

Asteroids, which are always exposed to the sun, can be shaped like almost anything under it. Those previously imaged by radar and spacecraft have looked like dog bones, bowling pins, spheroids, diamonds, muffins, and potatoes. To find out what 1998 QE2 looks like, stay tuned. Between May 30 and June 9, radar astronomers using NASA's 230-foot-wide (70 meter) Deep Space Network antenna at Goldstone, Calif., and the Arecibo Observatory in Puerto Rico, are planning an extensive campaign of observations. The two telescopes have complementary imaging capabilities that will enable astronomers to learn as much as possible about the asteroid during its brief visit near Earth.

NASA places a high priority on tracking asteroids and protecting our home planet from them. In fact, the U.S. has the most robust and productive survey and detection program for discovering near-Earth objects. To date, U.S. assets have discovered over 98 percent of the known NEOs.

In 2012, the NEO budget was increased from $6 million to $20 million. Literally dozens of people are involved with some aspect of near-Earth object (NEO) research across NASA and its centers. Moreover, there are many more people involved in researching and understanding the nature of asteroids and comets, including those that come close to the Earth, plus those who are trying to find and track them in the first place.

The Daily Galaxy via http://neo.jpl.nasa.gov/and http://www.jpl.nasa.gov/asteroidwatch

Image credit: With thanks to http://spaceref.com/asteroids/asteroid-1998-qe2-to-sail-past-earth-9-times-larger-than-cruise-ship.html

"Extreme Physics" Detected in Binary Neutron-Star System

2013-05-16T02:00:00-07:00

South Africa's new radio telescope reveals giant outbursts from binary star system. Using the seven-dish KAT-7 telescope and the 26 m radio telescope at the Hartebeesthoek Radio Astronomy Observatory (HartRAO) in South Africa, astronomers have observed a neutron star system known as Circinus X-1 as it fires energetic matter from its core into the surrounding system in extensive, compact `jets' that flare brightly, details of which are visible only in radio waves.

Circinus X-1 is an X-ray binary (or two-star system) where one of the companion stars is a high-density, compact neutron star (a neutron star is an extremely dense and compact remnant of an exploded star and only 20km in diameter.) The two stars orbit each other every 16.5 days in an elliptical orbit. When the two stars are at their closest the gravity of the dense neutron star pulls material from the companion star. A powerful jet of material then blasts out from the system.

"This project will test the extremes of physics, density, temperature, pressure, velocity, gravitational and magnetic fields, and are beyond anything achievable in any laboratory on Earth. It provides a unique glimpse of the laws of physics operating in extraordinary regimes," said Rob Fender, head of the Astronomy Research Group at the University of Southampton,

During the time astronomers observed Circinus X-1 (13 December 2011 to 16 January 2012) the system flared twice at levels among the highest observed in recent years. KAT-7 was able to catch both of these flares and follow them as they progressed. This is the first time that the system has been observed in such detail during the full flare cycle.

"One way of explaining what is happening is that the compact neutron star gobbles up parts of its companion star and then fires much of this matter back out again," explains Dr Richard Armstrong, an SKA SA Fellow at the University of Cape Town and lead author of the paper. "The dramatic radio flares happen when the matter Circinus X-1 has violently ejected slows down as it smashes into the surrounding medium."

"Circinus X-1 continues to reveal new aspects of its behaviour, and is arguably the best laboratory for relativistic jet astrophysics in the southern hemisphere," says Fender.

"These types of observations are crucial for understanding the processes of both accretion of matter onto extremely dense systems, such as neutron stars and black holes of both about the sun's mass, and also the so-called supermassive variety we now know to be at the centre of most galaxies," added Armstrong.

KAT-7 is the world's first radio telescope array consisting of composite antenna structures. It is the test array for MeerKAT, a much larger radio array, which is itself in turn a precursor for the dish-based component of the SKA.

The MNRAS study was carried out as part of the development for the ThunderKAT project on MeerKAT, which will find many more of these types of systems in the galaxy and search for new types of radio systems that change rapidly with time.

Reference: 'A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7 (Armstrong et al, 2013)' published in Monthly Notices of the Royal Astronomical Society.

The Daily Galaxy via Royal Astronomical Society and http://www.southampton.ac.uk/

Search for Habitable Planets in Jeopardy --"Kepler Mission in Potential Terminal Malfunction"

2013-05-15T18:22:32-07:00

The Kepler Space Mission, one of the most successful programs in NASA history that's surveying 1/400 of our Milky Way Galaxy for habitable planets, may be coming to a premature end. NASA officials announced via a press conference this afternoon that the Kepler spacecraft, which has found more than 2700 planetary candidates outside the solar system, has lost the ability to point in a specified direction due to the malfunctioning of one of its reaction wheels. The spacecraft has been put into safe mode while engineers attempt to figure out how to resolve the malfunction.

During the Kepler team's semi-weekly contact on Tuesday, May 14, 2013, they found the Kepler spacecraft once again in safe mode. As was the case earlier this month, this was a Thruster-Controlled Safe Mode. The root cause is not yet known, however the proximate cause appears to be an attitude error. The spacecraft was oriented with the solar panels facing the sun, slowly spinning about the sun-line. The communication link comes and goes as the spacecraft spins.

"We are not down and out," says Charles Sobeck, deputy project manager for Kepler at NASA's Ames Research Center in Moffett Field, California. "The spacecraft is safe and stable. We'll proceed with our investigation."

The Kepler team attempted to return to reaction wheel control as the spacecraft rotated into communication, and commanded a stop rotation. Initially, it appeared that all three wheels responded and that rotation had been successfully stopped, but reaction wheel 4 remained at full torque while the spin rate dropped to zero --a clear indication that there has been an internal failure within the reaction wheel, likely a structural failure of the wheel bearing. The spacecraft was then transitioned back to Thruster-Controlled Safe Mode.

An Anomaly Review Board concurred that the data appear to unambiguously indicate a wheel 4 failure, and that the team’s priority is to complete preparations to enter Point Rest State. Point Rest State is a loosely-pointed, thruster-controlled state that minimizes fuels usage while providing a continuous X-band communication downlink. The software to execute that state was loaded to the spacecraft last week, and last night the team completed the upload of the parameters the software will use.

The spacecraft is stable and safe, if still burning fuel. The Kepler fuel budget is sufficient that NASA can take due caution while they finish planning. In its current mode, fuel will last for several months. A "Point Rest State" would extend that period to years.

The Kepler Mission team has requested and received additional NASA Deep Space Network communication coverage, and this morning the Anomaly Review Board approved the transition to Point Rest State later today. Because this is a new operating mode of the spacecraft, the team will closely monitor the spacecraft, but no other immediate actions are planned. They will take the next several days and weeks to assess options and develop new command products. These options are likely to include steps to attempt to recover wheel functionality and to investigate the utility of a hybrid mode, using both wheels and thrusters.

With the failure of a second reaction wheel, it's unlikely that the spacecraft will be able to return to the high pointing accuracy that enables its high-precision photometry. However, no decision has been made to end data collection.

Kepler had successfully completed its primary three-and-a-half year mission and entered an extended mission phase in November 2012.
Even if data collection were to end, the mission has substantial quantities of data on the ground yet to be fully analyzed, and the string of scientific discoveries is expected to continue for years to come.

NASA Creates 1st Global Map of Titan --Saturn's Potential Life-Bearing Moon

2013-05-15T11:41:40-07:00

Scientists have created the first global topographic map of Saturn’s moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The image above provided by NASA's Jet Propulsion Laboratory shows a flattened projection of the Huygens probe's view from 6 miles above Titan. Researchers have found that Titan's distinctive sand dunes are caused by winds blowing in reverse of the prevailing weather.

Titan is Saturn’s largest moon – at 1,600 miles (2,574 kilometers) across it’s bigger than planet Mercury – and is the second-largest moon in the solar system. Scientists care about Titan because it’s the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth’s, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan’s atmosphere, lakes and rivers and may offer clues about the origins of life.

“Titan has so much interesting activity – like flowing liquids and moving sand dunes – but to understand these processes it’s useful to know how the terrain slopes,” said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. “It’s especially helpful to those studying hydrology and modeling Titan’s climate and weather, who need to know whether there is high ground or low ground driving their models.”

Titan’s thick haze scatters light in ways that make it very hard for remote cameras to “see” landscape shapes and shadows, the usual approach to measuring topography on planetary bodies. Virtually all the data we have on Titan comes from NASA’s Saturn-orbiting Cassini spacecraft, which has flown past the moon nearly 100 times over the past decade. On many of those flybys, Cassini has used a radar imager, which can peer through the haze, and the radar data can be used to estimate the surface height.

"With this new topographic map, one of the most fascinating and dynamic worlds in our solar system now pops out in 3-D," said Steve Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "On Earth, rivers, volcanoes and even weather are closely related to heights of surfaces – we're now eager to see what we can learn from them on Titan."

There are challenges, however. “Cassini isn’t orbiting Titan,” Lorenz said. “We have only imaged about half of Titan’s surface, and multiple ‘looks’ or special observations are needed to estimate the surface heights. If you divided Titan into 1-degree by 1-degree [latitude and longitude] squares, only 11 percent of those squares have topography data in them.”

Lorenz’s team used a mathematical process called splining – effectively using smooth, curved surfaces to “join” the areas between grids of existing data. “You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess,” he said. “If you pick a point, and all the nearby points are high altitude, you’d need a special reason for thinking that point would be lower. We’re mathematically papering over the gaps in our coverage.”

The estimations fit with current knowledge of the moon – that its polar regions are “lower” than areas around the equator, for example – but connecting those points allows scientists to add new layers to their studies of Titan’s surface, especially those modeling how and where Titan’s rivers flow, and the seasonal distribution of its methane rainfall. “The movement of sands and the flow of liquids are influenced by slopes, and mountains can trigger cloud formation and therefore rainfall. This global product now gives modelers a convenient description of this key factor in Titan’s dynamic climate system,” Lorenz said.

The most recent data used to compile the map is from 2012; Lorenz says it could be worth revising when the Cassini mission ends in 2017, when more data will have accumulated, filling some of the gaps in present coverage. “We felt we couldn’t wait and should release an interim product,” he says. “The community has been hoping to get this for a while. I think it will stimulate a lot of interesting work.”

The map is published as part of a paper in the journal Icarus.

The Daily Galaxy via NASA/JPL

Orion Molecular Cloud --"A Source of the Complex Building Blocks of Life"

2013-05-15T07:45:18-07:00

The spectacular new image above shows just a part of a bigger complex called the Orion Molecular Cloud, in the constellation of Orion (The Hunter). A rich melting pot of bright nebulae, hot young stars and cold dust clouds, this region is hundreds of light-years across and located about 1350 light-years from us. The orange glow represents faint light coming from grains of cold interstellar dust, at wavelengths too long for human eyes to see. It was observed by the ESO-operated Atacama Pathfinder Experiment (APEX) in Chile.

Clouds of gas and interstellar dust are the raw materials from which stars are made. But these tiny dust grains block our view of what lies within and behind the clouds — at least at visible wavelengths — making it difficult to observe the processes of star formation.

At submillimetre wavelengths, rather than blocking light, the dust grains shine due to their temperatures of a few tens of degrees above absolute zero . The APEX telescope with its submillimetre-wavelength camera LABOCA, located at an altitude of 5000 metres above sea level on the Chajnantor Plateau in the Chilean Andes, is the ideal tool for this kind of observation.

Hotter objects give off most of their radiation at shorter wavelengths and cooler ones at longer wavelengths. As an example very hot stars (surface temperatures around 20 000 degrees Kelvin) look blue and cooler ones (surface temperatures of around 3000 degrees Kelvin) look red. And a cloud of dust with a temperature of only ten degrees Kelvin has its peak of emission at a much longer wavelength — around 0.3 millimetres — in the part of the spectrum where APEX is very sensitive.

The large bright cloud in the upper right of the image is the well-known Orion Nebula, also called Messier 42. It is readily visible to the naked eye as the slightly fuzzy middle “star” in the sword of Orion. The Orion Nebula is the brightest part of a huge stellar nursery where new stars are being born, and is the closest site of massive star formation to Earth.

The dust clouds form beautiful filaments, sheets, and bubbles as a result of processes including gravitational collapse and the effects of stellar winds. These winds are streams of gas ejected from the atmospheres of stars, which are powerful enough to shape the surrounding clouds into the convoluted forms seen here.

Astronomers have used these and other data from APEX along with images from ESA’s Herschel Space Observatory, to search the region of Orion for protostars — an early stage of star formation. They have so far been able to identify 15 objects that appeared much brighter at longer wavelengths than at shorter wavelengths. These newly discovered rare objects are probably among the youngest protostars ever found, bringing astronomers closer to witnessing the moment when a star begins to form.

Orion is typical of dust clouds throughout the Universe that have recently been discovered to incubate the comlpex organic building blocks of life. While these dense interstellar clouds seem dark and obscured in visible-light observations, APEX’s LABOCA camera can detect the heat glow of the dust and reveal the hiding places where new stars are being formed. But one of these dark clouds is not what it seems.

In space, dense clouds of cosmic gas and dust are the birthplaces of new stars. In visible light, this dust is dark and obscuring, hiding the stars behind it. So much so that, when astronomer William Herschel observed one such cloud in the constellation of Scorpius in 1774, he thought it was a region empty of stars and is said to have exclaimed, "Truly there is a hole in the sky here!"

In order to better understand star formation, astronomers need telescopes that can observe at longer wavelengths, such as the submillimetre range, in which the dark dust grains shine rather than absorb light. APEX, on the Chajnantor Plateau in the Chilean Andes, is the largest single-dish submillimetre-wavelength telescope operating in the southern hemisphere, and is ideal for astronomers studying the birth of stars in this way.

The Orion Molecular Cloud Complex is the closest region of massive star formation to Earth, and contains a treasury of bright nebulae, dark clouds and young stars. The new image shows just part of this vast complex in visible light, with the APEX observations overlaid in brilliant orange tones that seem to set the dark clouds on fire. Often, the glowing knots from APEX correspond to darker patches in visible light — the tell-tale sign of a dense cloud of dust that absorbs visible light, but glows at submillimetre wavelengths, and possibly a site of star formation.

Recent discoveries in vast interstellar dust clouds permeating the universe and in nebula have revealed hints of organic matter that could be created naturally by stars, according to researchers in a 2011 study at the University of Hong Kong. The discovery team observed stars at different evolutionary phases and found that they are able to produce complex organic compounds and eject them into space, filling the voids between stars.

The compounds are so complex that their chemical structures resemble the makeup of coal and petroleum, the study's lead author, Sun Kwok of the University of Hong Kong, said. Kwok and his colleague Yong Zhang, also of the University of Hong Kong, studied a set of well-known but mysterious infrared emissions found in stars, interstellar space and galaxies. These phenomena, which are collectively called Unidentified Infrared Emission (UIE) features, have been known for 30 years, but the exact source of the emissions has not been identified, and remains a broad assumption.

Such chemical complexity was thought to arise only from living organisms, but the results of the new study show that these organic compounds can be created in space even when no life forms are present. In fact, such complex organics could be produced naturally by stars, and at an extremely rapid pace.

The Daily Galaxy via ESO and University of Hong Kong

"More Complex than a Galaxy" --New Insights into the Human Brain

2013-05-15T04:00:00-07:00

"Consider the human brain," says the physicist Sir Roger Penrose. "If you look at the entire physical cosmos, our brains are a tiny, tiny part of it. But they're the most perfectly organized part. Compared to the complexity of a brain, a galaxy is just an inert lump."

In a new study, scientists argue that many of our high-level abilities are carried out by more extensive brain networks linking many different areas of the brain. They suggest it may be the structure of these extended networks more than the size of any isolated brain region that is critical for cognitive functioning. The frontal lobes in humans vs. other species are not — as previously thought — disproportionately enlarged relative to other areas of the brain, according to a study by Durham and Reading universities.

It concludes that the size of our frontal lobes — an area in the brain of mammals located at the front of each cerebral hemisphere — cannot solely account for humans’ superior cognitive abilities.

The study also suggest that supposedly more “primitive” areas, such as the cerebellum, were equally important in the expansion of the human brain. These areas may therefore play unexpectedly important roles in human cognition and its disorders, such as autism and dyslexia, say the researchers.

The Durham and Reading researchers, funded by The Leverhulme Trust, analyzed data sets from previous animal and human studies using phylogenetic (“evolutionary family tree”) methods, and found consistent results across all their data. They used a new method to look at the speed with which evolutionary change occurred, concluding that the frontal lobes did not evolve especially fast along the human lineage after it split from the chimpanzee lineage.

Human brains share a consistent genetic blueprint and possess enormous biochemical complexity. The same basic functional elements are used throughout the cortex and understanding how one area works in detail will uncover fundamentals that apply to the other areas as well, according to an earlier study completed by scientists at the Allen Institute for Brain Science.

Human brains share a consistent genetic blueprint, and possess enormous biochemical complexity, they said, based on the first deep and large-scale analysis of the vast data set publicly available in the Allen Human Brain Atlas. Among other findings, these data show that 84% of all genes are expressed somewhere in the human brain and in patterns that are substantially similar from one brain to the next.

Robert A. Barton and Chris Venditti, Human frontal lobes are not relatively large, Proceedings of the National Academy of Sciences, 2013, DOI: 10.1073/pnas.1215723110

The Daily Galaxy via The Leverhulme Trust, EPFL, and Allen Institute for Brain Science

Image Credit: www.ucl.ac.uk