Wednesday, 29 April 2015

CERN: "Will This Summer's LHC Photon Collisions Reveal a New Theory of Space and Time?"


No significant signs of new physics with the present data from CERN's Large Hadron Collider, but it takes only 1 significant deviation in the data to change everything. First collisions of protons at the world's largest science experiment are expected to start the first or second week of June, according to a senior research scientist with CERN's Large Hadron Collider in Geneva.

"It will be about another six weeks to commission the machine, and many things can still happen on the way," said physicist Albert De Roeck, a staff member at CERN and a professor at the University of Antwerp, Belgium and UC Davis, California. De Roeck is a leading scientist on CMS, one of the Large Hadron Collider's key experiments.

The LHC in early April was restarted for its second three-year run after a two-year pause to upgrade the machine to operate at higher energies. At higher energy, physicists worldwide expect to see new discoveries about the laws that govern our natural universe.

De Roeck made the comments Monday while speaking during an international meeting of more than 250 physicists from 30 countries on the campus of Southern Methodist University, Dallas.

"There are no significant signs of new physics yet," De Roeck said of the data from the first run, adding however that especially SUSY diehards -- physicists who predict the existence of a unique new theory of space and time called SuperSymmetry -- maintain hopes of seeing evidence soon of that theory.

De Roeck in fact has high expectations for the possibility of new discoveries that could change the current accepted theory of physical reality, the Standard Model.

"It will take only one significant deviation in the data to change everything," De Roeck said. "The upgraded machine works. Now we have to get to the real operation for physics." But work remains to be done. One issue the accelerator physicists remain cautiously aware of, he said, is an "Unidentified Lying Object" in the beam pipe of the LHC's 17-mile underground tunnel, a vacuum tube where proton beams collide and scatter particles that scientists then analyze for keys to unlock the mysteries of the Big Bang and the cosmos.

Because the proton beam is sensitive to the geometry of the environment and can be easily blocked, the beam pipe must be free of even the tiniest amount of debris. Even something as large as a nitrogen particle could disrupt the beam. Because the beam pipe is a sealed vacuum it's impossible to know what the "object" is.

"The unidentified lying object turns out not to be a problem for the operation, it's just something to keep an eye on," De Roeck said. "It's in the vacuum tube and it's not a problem if it doesn't move and remains stable."

The world's largest particle accelerator, the Large Hadron Collider made headlines when its global collaboration of thousands of scientists in 2012 observed a new fundamental particle, the Higgs boson. After that, the collider was paused for the extensive upgrade. Much more powerful than before, as part of Run 2 physicists on the Large Hadron Collider's experiments are analyzing new proton collision data to unravel the structure of the Higgs.

The Large Hadron Collider straddles the border between France and Switzerland. Its first run began in 2009, led by CERN, the European Organization for Nuclear Research, in Geneva, through an international consortium of thousands of scientists.

Particle discoveries unlock mysteries of cosmos, pave way for new technology. The workshop in Dallas, the "2015 International Workshop on Deep-Inelastic Scattering," draws the world's leading scientists each year to an international city for nuts and bolts talks that drive the world's leading-edge physics experiments, such as the Large Hadron Collider.

Going into the second run, De Roeck said physicists will continue to look for anomalies, unexpected decay modes or couplings, multi-Higgs production, or larger decay rates than expected, among other things.

Particle discoveries by physicists resolve mysteries, such as questions surrounding Dark Matter and Dark Energy, and the earliest moments of the Big Bang. But particle discoveries also are ultimately applied to other fields to improve everyday life, such as medical technologies like MRIs and PET scans, which diagnose and treat cancer.

For example, proton therapy is the newest non-invasive, precision scalpel in the fight against cancer, with new centers opening all over the world.

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Tuesday, 28 April 2015

"Water May Have Been Abundant in First Billion Years After the Big Bang"


"We looked at the chemistry within young molecular clouds containing a thousand times less oxygen than our Sun. To our surprise, we found we can get as much water vapor as we see in our own galaxy," says astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA).

How soon after the Big Bang could water have existed? Not right away, because water molecules contain oxygen and oxygen had to be formed in the first stars. Then that oxygen had to disperse and unite with hydrogen in significant amounts. New theoretical work finds that despite these complications, water vapor could have been just as abundant in pockets of space a billion years after the Big Bang as it is today.

The early universe lacked elements heavier than hydrogen and helium. The first generation of stars are believed to have been massive and short-lived. Those stars generated elements like oxygen, which then spread outward via stellar winds and supernova explosions. This resulted in "islands" of gas enriched in heavy elements. Even these islands, however, were much poorer in oxygen than gas within the Milky Way today.

The team examined the chemical reactions that could lead to the formation of water within the oxygen-poor environment of early molecular clouds. They found that at temperatures around 80 degrees Fahrenheit (300 Kelvin), abundant water could form in the gas phase despite the relative lack of raw materials.

"These temperatures are likely because the universe then was warmer than today and the gas was unable to cool effectively," explains lead author and PhD student Shmuel Bialy of Tel Aviv University.

"The glow of the cosmic microwave background was hotter, and gas densities were higher," adds Amiel Sternberg, a co-author from Tel Aviv University.

Although ultraviolet light from stars would break apart water molecules, after hundreds of millions of years an equilibrium could be reached between water formation and destruction. The team found that equilibrium to be similar to levels of water vapor seen in the local universe.

"You can build up significant quantities of water in the gas phase even without much enrichment in heavy elements," adds Bialy.

This current work calculates how much water could exist in the gas phase within molecular clouds that will form later generations of stars and planets. It doesn't address how much water would exist in ice form (which dominates within our galaxy) or what fraction of all the water might actually be incorporated into newly forming planetary systems.

The beautiful California Nebula in Perseus shown at the top of the page is just a small part of a giant molecular cloud that's as big as the largest such cloud in Orion.

This joint project was carried out as part of the Raymond and Beverly Sackler Tel Aviv University - Harvard Astronomy Program.

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A Cosmic Fossil is Reborn in a Remote Cluster of Over 350 Galaxies


There are three types of radio sources found in galaxy clusters like Abell 1033, a cluster of over 350 galaxies located about 1.7 billion light-years away. Collisions between galaxies in clusters are common events, and each merger heats and shocks the nearby gas. The rapidly moving, ionized gas then radiates intensely at radio wavelengths. The first, called radio relics, are found in the outskirts of galaxies and have radiation signatures characteristic of shocked material over large scales. The second type, called radio haloes, are centrally located in the cluster and are probably the result of large turbulent motions set up during collisions.

A radio phoenix is the third type of cluster radio source, and is much less well studied. After the initial effects of a collision have died down and the gas has cooled, the radio emission subsides. But a subsequent merger nearby can produce a strong shock wave, and if that passes through the fossil material it can compress and re-energize it to emit in the radio again.

The image above is false-color X-ray image of the galaxy cluster Abell 1033. The white contours help identify the X-ray flux levels, and the red contours trace the radio emission. The elongated red structure in the lower center is a radio phoenix: fossil gas that has been reheated by shocks from a nearby galaxy merger (obscured in this view).           

CfA astronomers Georgiana Ogrean and Reinout van Weeren, with five colleagues, used data from the Chandra X-ray Observatory, the Westerbork Synthesis Radio Telescope, the Very Large Array ad the optical Sloan Digital Sky Survey to study the Abell 1033 cluster and its family of galaxies. They discovered two subclusters in the source that seem to have recently collided; they were spotted from their X-ray emission.

Close to this region, and to a galactic nucleus, the team spotted a radio source with the emission and charged particle characteristics of a radio phoenix. The scientists conclude that shocks from the recent merger have propagated into old gas, reinvigorating this fossil remnant to new life.

"Abell 1033: Birth of a Radio Phoenix," F. de Gasperin, G. A. Ogrean, R. J. van Weeren, W. A. Dawson, M. Bruggen, A. Bonafede1 and A. Simionescu, MNRAS 448, 2197, 2015.

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Strange Object Found -- "The Long-Sought 'Missing Link' That Creates a Neutron Star or Black Hole"


The object, called Supernova 2012ap (SN 2012ap) is what astronomers term a core-collapse supernova. This type of blast occurs when the nuclear fusion reactions at the core of a very massive star no longer can provide the energy needed to hold up the core against the weight of the outer parts of the star. The core then collapses catastrophically into a superdense neutron star or a black hole. The rest of the star's material is blasted into space in a supernova explosion.

Astronomers using the National Science Foundation's Very Large Array (VLA) have found a long-sought "missing link" between supernova explosions that generate gamma-ray bursts (GRBs) and those that don't. The scientists found that a stellar explosion seen in 2012 has many characteristics expected of one that generates a powerful burst of gamma rays, yet no such burst occurred.

"This is a striking result that provides a key insight about the mechanism underlying these explosions," said Sayan Chakraborti, of the Harvard-Smithsonian Center for Astrophysics (CfA). "This object fills in a gap between GRBs and other supernovae of this type, showing us that a wide range of activity is possible in such blasts," he added.

The most common type of such a supernova blasts the star's material outward in a nearly-spherical bubble that expands rapidly, but at speeds far less than that of light. These explosions produce no burst of gamma rays.

In a small percentage of cases, the infalling material is drawn into a short-lived swirling disk surrounding the new neutron star or black hole. This accretion disk generates jets of material that move outward from the disk's poles at speeds approaching that of light. This combination of a swirling disk and its jets is called an "engine," and this type of explosion produces gamma-ray bursts.

The new research shows, however, that not all "engine-driven" supernova explosions produce gamma-ray bursts.

"This supernova had jets moving at nearly the speed of light, and those jets were quickly slowed down, just like the jets we see in gamma-ray bursts," said Alicia Soderberg, also of CfA.


An earlier supernova seen in 2009 also had fast jets, but its jets expanded freely, without experiencing the slowdown characteristic of those that generate gamma-ray bursts. The free expansion of the 2009 object, the scientists said, is more like what is seen in supernova explosions with no engine, and probably indicates that its jet contained a large percentage of heavy particles, as opposed to the lighter particles in gamma-ray-burst jets. The heavy particles more easily make their way through the material surrounding the star.

"What we see is that there is a wide diversity in the engines in this type of supernova explosion," Chakraborti said. "Those with strong engines and lighter particles produce gamma-ray bursts, and those with weaker engines and heavier particles don't," he added.

"This object shows that the nature of the engine plays a central role in determining the characteristics of this type of supernova explosion," Soderberg said.

Chakraborti and Soderberg worked with an international team of scientists from five continents. In addition to the VLA, they also used data from the Giant Meterwave Radio Telescope (GMRT) in India and the InterPlanetary Network (IPN) of spacecraft equipped with GRB detectors. The team, led by Chakraborti, is reporting their work in a paper accepted to the Astrophysical Journal. Other articles, led by co-authors Raffaella Margutti and Dan Milisavljevic, also report on the X-ray and optical follow-up on SN 2012ap using a suite of space and ground-based facilities.

In 2007 NASA’s Spitzer space telescope found the infrared signature of silica (sand) in the core-collapse supernova remnant Cassiopeia A shown at the top of the page The light from this exploding star first reached Earth in the 1600s. The cyan dot just off center is all that remains of the star that exploded. NASA/JPL-Caltech/ O. Krause (Steward Observatory)

Researchers from Washington University in St. Louis report finding tiny grains of silica, which they believe came from a core-collapse supernova, in primitive meteorites.

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Monday, 27 April 2015

NASA --"Is It On the Verge of Discovering 'Warp Bubbles' Enabling Dreams of Interstellar Travel?

“Routine travel among the stars is impossible without new discoveries regarding the fabric of space and time, or capability to manipulate it for our needs,” says Neil deGrasse Tyson, the "Cosmos famous" astrophysicist at the American Museum of Natural History, said “By my read, the idea of a functioning warp drive remains far-fetched, but the real take-away is that people are thinking about it — reminding us all that the urge to explore continues to run deep in our species."

There have been hints in recent news that NASA may be on the path to discovering warp bubbles that could make the local universe accessible for human exploration. NASA scientists may be close announcing they may have broken the speed of light. According to state-of-the art theory, a warp drive could cut the travel time between stars from tens of thousands of years to weeks or months.

The catalyst for the trending warp-drive excitement is the Electromagnetic Drive or EM Drive, a thruster that was engineered to steer rockets which eliminates the use of a propellant originally intended for moon missions, Mars missions and low-Earth orbit (LEO) operations.

The experiment that led to the possibility of faster than light interstellar travel took place in the vacuum of space. According to posts on, a website devoted to the engineering side of space news, when lasers were fired through the EmDrive’s resonance chamber, some of the beams appeared to travel faster than the speed of light. If that’s true, it would mean that the EmDrive is producing a warp field or bubble. 

But "How?" If the laser beams are moving faster than the speed of light, then it would indicate that they are creating some sort of warp field, or bubble in the space-time foam, which in turn produces the thrust that could, in theory, power a spaceship bound for the center of the Milky Way or one of its dwarf galaxy satellites.

The bubble would contract space-time in front of the ship, flow over the ship, then expand back to normality behind it. It’s inaccurate to describe the spaceship as moving faster than the speed of light, but rather space-time is moving around the ship faster than the speed of light.

Harold G. White, a physicist and advanced propulsion engineer at NASA and other NASA engineers are trying to determine whether faster-than-light travel — warp drive — might someday be possible. The team has attempting to slightly warp the trajectory of a photon, changing the distance it travels in a certain area, and then observing the change with a device called an interferometer.

“Space has been expanding since the Big Bang 13.7 billion years ago,” said Dr. White, 43, who runs the research project told the New York Times. “And we know that when you look at some of the cosmology models, there were early periods of the universe where there was explosive inflation, where two points would’ve went receding away from each other at very rapid speeds. Nature can do it,” he added. “So the question is, can we do it?”

In 1994, a Mexican physicist, Miguel Alcubierre, theorized that faster-than-light speeds were possible in a way that did not contradict Einstein by harnessing the expansion and contraction of space itself. Under Dr. Alcubierre’s hypothesis, a ship still couldn’t exceed light speed in a local region of space. But a theoretical propulsion system he sketched out manipulated space-time by generating a so-called “warp bubble” that would expand space on one side of a spacecraft and contract it on another.

An Alcubierre Warp Drive stretches spacetime in a wave causing the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship can ride the wave to accelerate to high speeds and time travel. The Alcubierre drive, also known as the Alcubierre metric or Warp Drive, is a mathematical model of a spacetime exhibiting features reminiscent of the fictional "warp drive" from Star Trek, which can travel "faster than light/"

Alcubierre-warp-drive-manifold“In this way, the spaceship will be pushed away from the Earth and pulled towards a distant star by space-time itself,” Dr. Alcubierre wrote. Dr. White, the NYT reports, has likened it to stepping onto a moving walkway at an airport.

Alcubierre’s theory, however, depended on large amounts of a little understood or observed type of “exotic matter” that violates typical physical laws.

In general relativity, one often first specifies a plausible distribution of matter and energy, and then finds the geometry of the spacetime associated with it; but it is also possible to run the Einstein field equations in the other direction, first specifying a metric and then finding the energy-momentum tensor associated with it, and this is what Alcubierre did in building his metric. This practice means that the solution can violate various energy conditions and require exotic matter. The need for exotic matter leads to questions about whether it is actually possible to find a way to distribute the matter in an initial spacetime which lacks a "warp bubble" in such a way that the bubble will be created at a later time.

Yet another problem according to Serguei Krasnikov is that it would be impossible to generate the bubble without being able to force the exotic matter to move at locally FTL speeds, which would require the existence of tachyons. Some methods have been suggested which would avoid the problem of tachyonic motion, but would probably generate a naked singularity at the front of the bubble.

Dr. White believes that advances he and others have made render warp speed less implausible. Among other things, he has redesigned the theoretical warp-traveling spacecraft — and in particular a ring around it that is key to its propulsion system — in a way that he believes will greatly reduce the energy requirements. But ”We’re not bolting this to a spacecraft,” he said of the technology.

Richard Obousy, a physicist who is president of Icarus Interstellar, a nonprofit group composed of volunteers collaborating on starship design, said “it is not airy-fairy, pie in the sky. We tend to overestimate what we can do on short time scales, but I think we massively underestimate what we can do on longer time scales.”

Dr. White likened his experiments to the early stages of the WW 11 Manhattan Project, which were aimed at creating a very small nuclear reaction merely as proof that it could be done.

Still, one of the most dubious is Dr. Alcubierre himself. He listed a number of concerns, starting with the vast amounts of exotic matter that would be needed. “The warp drive on this ground alone is impossible,” he said. “At speeds larger than the speed of light, the front of the warp bubble cannot be reached by any signal from within the ship,” he said. “This does not just mean we can’t turn it off; it is much worse. It means we can’t even turn it on in the first place.”

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Coming This Fall: "Galaxy Radio" To Be Integrated into The Daily Galaxy


As usually happens, we learned a big lesson the hard way. After promoting Daily Galaxy Radio ($24 a year subscription price) for three days to our free advertising-supported home site, Twitter, and Facebook fans, we pulled the plug. It was no contest: free won over paid loudly and decisively. Beginning this fall, we will be integrating a weekend "Galaxy Radio" feature, which we hope you'll enjoy! With thanks, your Daily Galaxy team.

« Eleven Elliptical Galaxies Found Flying Free in Space Beyond Their Home Clusters | Main

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Eleven Elliptical Galaxies Found Flying Free in Space Beyond Their Home Clusters


Until 2006 scientists knew only 6 extremely compact elliptical galaxies like the Andromeda satellite Messier32 that host up-to several billion stars. They are so small, that they look like stripped cores of ordinary galaxies. All these stellar systems were found next to giant galaxies in centers of large clusters of galaxies. Numerical simulations demonstrated that these compact ellipticals could be the remnants of ancient larger galaxies, stripped out to the central core by tidal interactions with a massive galaxy after falling on it. In 2009 Igor Chilingarian discovered another 20 such rare galaxies.

However, in 2013, the first compact elliptical was found far away from any massive galaxy, so that it became unclear where it came from and whether it was formed through tidal stripping. It became clear that astronomers should search such objects not only in clusters of galaxies and groups, but also between them.

Astronomers think, that there are dozens of billions undetectable free floating planets that straggle along our Milky Way galaxy, being not gravitationaly bound to any star. Moreover, there are about two dozens known stars that escaped from our Galaxy at high velocities, and even one runaway star cluster hosting a million stars that fled the giant galaxy Messier 87 in the Virgo cluster.

All those objects have one thing in common - they have been thrown away from their home systems by gravitational perturbations. Two Russian astronomers, Igor Chilingarian and Ivan Zolotukhin of Sternberg Astronomical Institute, Moscow State University, who currently works at Harvard-Smithsonian Center for Astrophysics, USA and L'Institut de Recherche en Astrophysique et Planétologie, Toulouse, France, respectively, have shown that some galaxies can also be thrown away from their host clusters and groups by interacting with their neighbors.

The image below demonstrates several stages of the process of a close three-body encounter with a gravitation kick of a compact elliptical galaxy that explains the phenomenon of an isolated compact elliptical galaxy. (ESA/Hubble. Artwork by Andrey Zolotov).


Chilingarian and Zolotukhin have processed a huge amount of astronomical data, publicly available thanks to the Virtual Observatory initiative. They discovered almost 200 additional compact ellipticals. Most of them, as expected, were found inside massive clusters and groups of galaxies, but 11 are indeed isolated, flying free in space some millions of light years from nearest clusters.

"We asked ourselves, how we could explain them?", -- stated Igor Chilingarian, the first author of the paper that will appear in the journal Science. As far as isolated compact ellipticals and those found in clusters shared very similar properties, it looked like they must have had the common origin in the past. Initially, a massive galaxy in a cluster striped away outer parts of a an in-falling smaller galaxy, leaving behind only a compact core, and later, some other galaxy threw this core away into the inter-cluster space.

Similar processes are known to take place near Milky Way's center: a supermassive black hole can fling away one of two stars in a binary system, that came too close to it, and swallow the other one.

"This is the same phenomenon, but working on a different scale, a slingshot effect, when during a three-body encounter the lightest body flies away from the system", -- explained Zolotukhin. To support this statement, astronomers analyzed the velocity spread of compact ellipticals in galaxy clusters that shows that some of them are on a verge of escaping their host clusters.

"These small galaxies face a lonely future, exiled from galaxy clusters they were formed and used to live in", -- Igor Chilingarian said. But this helps them to survive, because otherwise they would spiral in and be devoured by their massive hosts in about a billion years.

To escape the Earth, a body must be thrown faster than 11 km/s, to leave the Solar system from the Earth's orbit that speed is over 42 km/s. A galaxy has to reach approximately 2500 km/s in order to run away, astronomers calculated. Chilingarian and Zolotukhin hope their discovery will shed light on the structure and evolution of compact elliptical galaxies, because they think that these galaxies don't contain dark matter that is thought keeps stable most galaxies of other types.

This is the first time when an astronomical discovery published in interdisciplinary journal made without a single new photon collected but based solely on publicly available observations. This is a new era in astronomy, when any Internet user can use observations in archives and make discoveries from her or his office without the need to travel to an observatory and collect the data.

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Sunday, 26 April 2015

"Far-Reaching Implications" -An Ancient Solar System Almost as Old as the Milky Way (Weekend Feature)


"There are far-reaching implications for this discovery," said Tiago Campante, from the University of Birmingham's School of Physics and Astronomy, who led the research. "We now know that Earth-sized planets have formed throughout most of the Universe's 13.8 billion year history, which could provide scope for the existence of ancient life in the Galaxy. By the time the Earth formed, the planets in this system were already older than our planet is today."

Thanks to the NASA Kepler mission, the scientists announced in January 2015 in The Astrophysical Journal the observation of a Sun-like star (Kepler-444) hosting 5 planets with sizes between Mercury and Venus, that was formed 11.2 billion years ago, when the Universe was less than 20% its current age. This is the oldest known system of terrestrial-sized planets in our Galaxy - 2 and a half times older than the Earth.

The University of Birmingham team carried out the research using asteroseismology - listening to the natural resonances of the host star which are caused by sound trapped within it. These oscillations lead to miniscule changes or pulses in its brightness which allow the researchers to measure its diameter, mass and age. The planets were then detected from the dimming that occurs when the planets transited, or passed across, the stellar disc. This fractional fading in the intensity of the light received from the star enables scientists to accurately measure the size of the planets relative to the size of the star.

"The first discoveries of exoplanets around other Sun-like stars in our Galaxy have fuelled efforts to find other worlds like Earth and other terrestrial planets outside our Solar System," said Bill Chaplin, also from the University of Birmingham who has been leading the team studying solar-type stars using asteroseismology for the Kepler Mission. " We are now getting first glimpses of the variety of Galactic environments conducive to the formation of these small worlds. As a result, the path towards a more complete understanding of early planet formation in the Galaxy is now unfolding before us.'

The image at the top of the page shows the Southern Cross, the Milky Way, and the Large Magellanic Cloud  shine above the Atacama Large Millimeter/submillimeter Array (ALMA C. Padilla, NRAO/AUI/NSF)

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Saturday, 25 April 2015

NASA: "There Might Be Civilizations Existing in Cold Dark Space Beyond Galaxies" (Weekend Feature)

Sn-galaxies (1)

“There might be people living out there, out in the middle of cold dark space, that don't have a Milky Way,” says Harvey Moseley, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Astronomers have spotted a faint cosmic glow, unseen until now, that may come from stars that float adrift between galaxies. The discovery suggests that as many as half of all stars in the universe lurk outside galactic boundaries.

The work shows, reported by Nature, shows how little astronomers know about intergalactic space, and how it contributes to the energy budget of the Universe, says Juna Kollmeier, an astronomer at the Carnegie Observatories in Pasadena. In June, Kollmeier and her colleagues reported a ‘missing light’ problem: there are not nearly enough stars and galaxies to explain other observations in intergalactic space2. She calls the latest finding “provocative”, but is not convinced by the models the new study used to conclude that the light was coming from extragalactic stars

The stars were probably tossed there when galaxies collided (trail of stars from colliding galaxies shown in Hubble above). A team led by astrophysicist Michael Zemcov, of the California Institute of Technology (Caltech) in Pasadena, reports the discovery in the 7 November issue of Science1.

The findings come from the Cosmic Infrared Background Experiment (CIBER), which flew briefly into space in 2010 and 2012 aboard a sounding rocket. As CIBER soared above the atmosphere, it looked at five different regions in space for about a minute each, gathering as many particles of cosmic light as possible. The flights took place at different times of year, so that the astronomers could subtract the confounding effects of the zodiacal light, the glow of sunlight that is scattered off interplanetary dust.

CIBER was designed to look for fluctuations in infrared light to hunt for signs of some of the first galaxies that formed in the Universe. The light of these galaxies has been redshifted to infrared wavelengths because of the Universe's expansion.

But when Zemcov and his colleagues began to sift through CIBER’s data, they realized that the light it captured was not nearly red enough to have come from ancient galaxies. The light must be coming from something closer and more modern, they say — such as ordinary stars.

The scientists extrapolated from CIBER’s fields of view to the entire Universe, and concluded that there was much more light than could be explained by known galaxies. That means the light is probably coming from stars between galaxies, says team member Jamie Bock, an astrophysicist at Caltech. “These stars produce as much background light as the galaxies themselves,” he says. “That’s really exciting.”

Stars normally reside within galaxies, but can be yanked out by gravitational forces when galaxies collide. Bock suspects that a lot of these renegade stars could have come from relatively lightweight galaxies, which can lose hold of their stars more easily than more massive galaxies.

“If this is true, then there is an entire population of stars that's been sitting out there, but because they are individually so faint we can really only see them in ensemble,” says Moseley.

Bock and his colleagues are now building a follow-up experiment, CIBER2, which will look at visible rather than infrared wavelengths. They hope that it will reveal new information about the background glow and exactly what kinds of stars could be contributing to it.

The Hubble Image at the top of the page shows merging galaxies, like this pair called Arp 142, that may spew stars out into intergalactic space.

Nature doi:10.1038/nature.2014.16288

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Friday, 24 April 2015

The Yellowstone Supervolcano --New Discovery: It's 4.4 Times Larger Than Thought Prior

University of Utah seismologists announced this week that they discovered and made images of a reservoir of hot, partly molten rock 12 to 28 miles beneath the Yellowstone supervolcano, and it is 4.4 times larger than the shallower, long-known magma chamber.

The hot rock in the newly discovered, deeper magma reservoir would fill the 1,000-cubic-mile Grand Canyon 11.2 times, while the previously known magma chamber would fill the Grand Canyon 2.5 times, says postdoctoral researcher Jamie Farrell, a co-author of the study published online today in the journal Science.

"For the first time, we have imaged the continuous volcanic plumbing system under Yellowstone," says first author Hsin-Hua Huang, also a postdoctoral researcher in geology and geophysics. "That includes the upper crustal magma chamber we have seen previously plus a lower crustal magma reservoir that has never been imaged before and that connects the upper chamber to the Yellowstone hotspot plume below."

Contrary to popular perception, the magma chamber and magma reservoir are not full of molten rock. Instead, the rock is hot, mostly solid and spongelike, with pockets of molten rock within it. Huang says the new study indicates the upper magma chamber averages about 9 percent molten rock - consistent with earlier estimates of 5 percent to 15 percent melt - and the lower magma reservoir is about 2 percent melt.

So there is about one-quarter of a Grand Canyon worth of molten rock within the much larger volumes of either the magma chamber or the magma reservoir, Farrell says.

The researchers emphasize that Yellowstone's plumbing system is no larger - nor closer to erupting - than before, only that they now have used advanced techniques to make a complete image of the system that carries hot and partly molten rock upward from the top of the Yellowstone hotspot plume - about 40 miles beneath the surface - to the magma reservoir and the magma chamber above it.

"The magma chamber and reservoir are not getting any bigger than they have been, it's just that we can see them better now using new techniques," Farrell says.

Study co-author Fan-Chi Lin, an assistant professor of geology and geophysics, says: "It gives us a better understanding the Yellowstone magmatic system. We can now use these new models to better estimate the potential seismic and volcanic hazards."


The researchers point out that the previously known upper magma chamber was the immediate source of three cataclysmic eruptions of the Yellowstone caldera 2 million, 1.2 million and 640,000 years ago, and that isn't changed by discovery of the underlying magma reservoir that supplies the magma chamber.

"The actual hazard is the same, but now we have a much better understanding of the complete crustal magma system," says study co-author Robert B. Smith, a research and emeritus professor of geology and geophysics at the University of Utah.

Before the new discovery, researchers had envisioned partly molten rock moving upward from the Yellowstone hotspot plume via a series of vertical and horizontal cracks, known as dikes and sills, or as blobs. They still believe such cracks move hot rock from the plume head to the magma reservoir and from there to the shallow magma chamber.

The study in Science is titled, "The Yellowstone magmatic system from the mantle plume to the upper crust." Huang, Lin, Farrell and Smith conducted the research with Brandon Schmandt at the University of New Mexico and Victor Tsai at the California Institute of Technology. Funding came from the University of Utah, National Science Foundation, Brinson Foundation and William Carrico.

Yellowstone is among the world's largest supervolcanoes, with frequent earthquakes and Earth's most vigorous continental geothermal system.

The three ancient Yellowstone supervolcano eruptions were only the latest in a series of more than 140 as the North American plate of Earth's crust and upper mantle moved southwest over the Yellowstone hotspot, starting 17 million years ago at the Oregon-Idaho-Nevada border. The hotspot eruptions progressed northeast before reaching Yellowstone 2 million years ago.

Here is how the new study depicts the Yellowstone system, from bottom to top:

-- Previous research has shown the Yellowstone hotspot plume rises from a depth of at least 440 miles in Earth's mantle. Some researchers suspect it originates 1,800 miles deep at Earth's core. The plume rises from the depths northwest of Yellowstone. The plume conduit is roughly 50 miles wide as it rises through Earth's mantle and then spreads out like a pancake as it hits the uppermost mantle about 40 miles deep. Earlier Utah studies indicated the plume head was 300 miles wide. The new study suggests it may be smaller, but the data aren't good enough to know for sure.

-- Hot and partly molten rock rises in dikes from the top of the plume at 40 miles depth up to the bottom of the 11,200-cubic mile magma reservoir, about 28 miles deep. The top of this newly discovered blob-shaped magma reservoir is about 12 miles deep, Huang says. The reservoir measures 30 miles northwest to southeast and 44 miles southwest to northeast. "Having this lower magma body resolved the missing link of how the plume connects to the magma chamber in the upper crust," Lin says.

-- The 2,500-cubic mile upper magma chamber sits beneath Yellowstone's 40-by-25-mile caldera, or giant crater. Farrell says it is shaped like a gigantic frying pan about 3 to 9 miles beneath the surface, with a "handle" rising to the northeast. The chamber is about 19 miles from northwest to southeast and 55 miles southwest to northeast. The handle is the shallowest, long part of the chamber that extends 10 miles northeast of the caldera.

Scientists once thought the shallow magma chamber was 1,000 cubic miles. But at science meetings and in a published paper this past year, Farrell and Smith showed the chamber was 2.5 times bigger than once thought. That has not changed in the new study.

Discovery of the magma reservoir below the magma chamber solves a longstanding mystery: Why Yellowstone's soil and geothermal features emit more carbon dioxide than can be explained by gases from the magma chamber, Huang says. Farrell says a deeper magma reservoir had been hypothesized because of the excess carbon dioxide, which comes from molten and partly molten rock.

As with past studies that made images of Yellowstone's volcanic plumbing, the new study used seismic imaging, which is somewhat like a medical CT scan but uses earthquake waves instead of X-rays to distinguish rock of various densities. Quake waves go faster through cold rock, and slower through hot and molten rock.

For the new study, Huang developed a technique to combine two kinds of seismic information: Data from local quakes detected in Utah, Idaho, the Teton Range and Yellowstone by the University of Utah Seismograph Stations and data from more distant quakes detected by the National Science Foundation-funded EarthScope array of seismometers, which was used to map the underground structure of the lower 48 states.

The Utah seismic network has closely spaced seismometers that are better at making images of the shallower crust beneath Yellowstone, while EarthScope's seismometers are better at making images of deeper structures.

"It's a technique combining local and distant earthquake data better to look at this lower crustal magma reservoir," Huang says.

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"The Miss-Lonely-Heart Galaxies of the Universe" -A New Class of Rogue Blob Ellipticals

M32-DBaer (1)

We know of about two dozen runaway stars, and have even found one runaway star cluster escaping its galaxy forever. Now, astronomers have spotted 11 runaway galaxies that have been flung out of their homes to wander the void of intergalactic space.

"These galaxies are facing a lonely future, exiled from the galaxy clusters they used to live in," said astronomer Igor Chilingarian (Harvard-Smithsonian Center for Astrophysics/Moscow State University). Chilingarian is the lead author of the study, which is appearing in the journal Science.

An object is a runaway if it's moving faster than escape velocity, which means it will depart its home never to return. In the case of a runaway star, that speed is more than a million miles per hour (500 km/s). A runaway galaxy has to race even faster, traveling at up to 6 million miles per hour (3,000 km/s).

Chilingarian and his co-author, Ivan Zolotukhin (L'Institut de Recherche en Astrophysique et Planetologie/Moscow State University), initially set out to identify new members of a class of galaxies called compact ellipticals. These tiny blobs of stars are bigger than star clusters but smaller than a typical galaxy, spanning only a few hundred light-years. In comparison, the Milky Way is 100,000 light-years across. Compact ellipticals also weigh 1000 times less than a galaxy like our Milky Way.

Prior to this study, only about 30 compact elliptical galaxies were known, all of them residing in galaxy clusters. To locate new examples Chilingarian and Zolotukhin sorted through public archives of data from the Sloan Digital Sky Survey and the GALEX satellite.

Their search identified almost 200 previously unknown compact ellipticals. Of those, 11 were completely isolated and found far from any large galaxy or galaxy cluster.

"The first compact ellipticals were all found in clusters because that's where people were looking. We broadened our search, and found the unexpected," said Zolotukhin.

These isolated compact galaxies were unexpected because theorists thought they originated from larger galaxies that had been stripped of most of their stars through interactions with an even bigger galaxy. So, the compact galaxies should all be found near big galaxies.

Not only were the newfound compact ellipticals isolated, but also they were moving faster than their brethren in clusters.

"We asked ourselves, what else could explain them? The answer was a classic three-body interaction," stated Chilingarian.

A hypervelocity star can be created if a binary star system wanders close to the black hole at the center of our galaxy. One star gets captured while the other is thrown away at tremendous speed.

Similarly, a compact elliptical could be paired with the big galaxy that stripped it of its stars. Then a third galaxy blunders into the dance and flings the compact elliptical away. As punishment, the intruder gets accreted by the remaining big galaxy.

This discovery represents a prominent success of the Virtual Observatory - a project to make data from large astronomical surveys easily available to researchers. So-called data mining can result in finds never anticipated when the original data was collected.

"We recognized we could use the power of the archives to potentially unearth something interesting, and we did," added Chilingarian.

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Thursday, 23 April 2015

"Alien Light" --A Key to the Discovery of Habitable Worlds


“We’re combining techniques to discover new information about how planets form, their range of properties and what sorts of planets are most common, with the eventual goal of finding terrestrial planets and venues for life in the universe,” said James Graham, a UC Berkeley professor of astronomy who leads the new “Exoplanets Unveiled” project.

UC Berkeley astronomers will lead one of 16 new projects funded by NASA to coordinate different exoplanet searches to more efficiently find habitable planets around other stars, and perhaps extraterrestrial life itself. The project, led by Graham, will bring together researchers at UC Berkeley and Stanford University and coordinate their efforts with other researchers across the United States. The budget for the four-year project is $3.25 million.

The Berkeley and Stanford teams are involved in two major exoplanet searches: a highly successful search for exoplanets based on the wobble they produce in a star’s motion or the dimming they create when they transit in front of a star; and a newly launched survey by the Gemini Planet Imager to directly take pictures of planets by capturing the heat they give off.

UC Berkeley’s “exoplanets unveiled” project is part of the NExSS (Nexus for Exoplanet System Science) initiative announced April 21 by NASA to bring together the “best and brightest,” according to a NASA press release. NExSS is conceived as a virtual institute marshalling the expertise of 10 universities, three NASA centers and two research institutes to better understand the various components of an exoplanet, as well as how the parent stars and neighboring planets interact to support life.

A unique aspect of the UC Berkeley-led project is the involvement of the Gemini Planet Imager (GPI), for which Graham is the project scientist. Bruce Macintosh, the principal investigator for GPI, is also part of the NASA team. GPI is a new instrument for the Gemini Observatory and began its exoplanet survey at the Gemini South Telescope in November 2014. GPI has already imaged two previously known exoplanets and disks of planetary debris orbiting young stars where planets recently formed.

“With GPI, we’ve already shown that we can see planets as they move month to month around their stars,” Macintosh said. “With this new collaboration, we will combine the strengths of imaging, Doppler and transits to characterize planets and their orbits.”

Gemini Planet Imager's first light image of the light scattered by a disk of dust orbiting the young star HR4796A is shown at the top of the page. This narrow ring is thought to be dust from asteroids or comets left behind by planet formation; some scientists have theorized that the sharp edge of the ring is defined by an unseen planet. The left image shows normal light, including both the dust ring and the residual light from the central star scattered by turbulence in the Earth's atmosphere. The right image shows only polarized light. Leftover starlight is unpolarized and hence removed from this image. The light from the back edge of the disk is strongly polarized as it scatters towards us

Collaborator Geoff Marcy, a UC Berkeley professor of astronomy, perfected the Doppler technique, which detects stellar wobble, and went on to discover more than 100 of the first known exoplanets. He is also part of the Kepler Mission team that has discovered nearly 2,000 exoplanets by the transit method. Both these techniques find planets that orbit near their star, while direct imaging via GPI is most sensitive to planets orbiting far from their star. Habitable, Earth-like planets lurk in-between.

“A principal goal is to focus on the overlap region where we can use all three techniques we now have to study planets,” Graham said.

“It is a wonderful confluence of multiple approaches to planet-hunting that allows us to detect planets that are both near and far from the host star,” Marcy said.

Aside from the Gemini South Telescope, the team plans to harness the adaptive-optics capabilities of the Keck Observatories in Hawaii and eventually the Thirty Meter Telescope planned for construction next door to Keck on Mauna Kea.

Paul Kalas, an adjunct professor of astronomy and co-PI for the project, noted that the goal of imaging Earth-size planets is still decades away, since direct imaging instruments like GPI would have to be sensitive enough to detect faint starlight reflected off the planet. Currently, GPI is able to see only hot, Jupiter-size planets that are bright because of their own infrared glow.

“The techniques and technologies developed for the Gemini Planet Imager will be used on future NASA planet-finding missions, such as the WFIRST telescope, which could see the reflected light from ‘super-Earth’ planets,” Macintosh said. The Wide-Field Infrared Survey Telescope (WFIRST) is a NASA observatory designed to perform wide-field imaging and spectroscopic surveys of the near infrared sky to explore exoplanets and dark energy. It is expected to be launched in about 10 years.

“If you could see reflected light, you might be able to see the signature of life,” Kalas said. “We are just now sowing the seeds to get to that point.”

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Life on Tau Ceti? --"Geology is Fundamental to the Habitability of Planets"


The Tau Ceti system, popularized in several fictional works, including Star Trek, has long been used in science fiction, and even popular news, as a very likely place to have life due to its proximity to Earth and the star's sun-like characteristics. Since December 2012 Tau Ceti has become even more appealing, thanks to evidence of possibly five planets orbiting it, with two of these - Tau Ceti e and f - potentially residing in the habitable zone.

As the search continues for Earth-size planets orbiting at just the right distance from their star, a region termed the habitable zone, the number of potentially life-supporting planets grows. In two decades we have progressed from having no extrasolar planets to having too many to search. Narrowing the list of hopefuls requires looking at extrasolar planets in a new way. Applying a nuanced approach that couples astronomy and geophysics, Arizona State University researchers report that from that long list we can sadly cross off cosmic neighbor Tau Ceti.

Using the chemical composition of Tau Ceti, the ASU team modeled the star's evolution and calculated its habitable zone. Although their data confirms that two planets (e and f) may be in the habitable zone it doesn't mean life flourishes or even exists there.

"Planet e is in the habitable zone only if we make very generous assumptions. Planet f initially looks more promising, but modeling the evolution of the star makes it seem probable that it has only moved into the habitable zone recently as Tau Ceti has gotten more luminous over the course of its life," explains astrophysicist Michael Pagano, ASU postdoctoral researcher and lead author of the paper appearing in the Astrophysical Journal. The collaboration also included ASU astrophysicists Patrick Young and Amanda Truitt and mineral physicist Sang-Heon (Dan) Shim.

Based upon the team's models, planet f has likely been in the habitable zone much less than 1 billion years. This sounds like a long time, but it took Earth's biosphere about 2 billion years to produce potentially detectable changes in its atmosphere. A planet that entered the habitable zone only a few hundred million years ago may well be habitable and even inhabited, but not have detectable biosignatures.

According to Pagano, he and his collaborators didn't pick Tau Ceti "hoping, wanting, or thinking" it would be a good candidate to look for life, but for the idea that these might be truly alien new worlds.

Tau Ceti has a highly unusual composition with respect to its ratio of magnesium and silicon, which are two of the most important rock forming minerals on Earth. The ratio of magnesium to silicon in Tau Ceti is 1.78, which is about 70% more than our sun.

The astrophysicists looked at the data and asked, "What does this mean for the planets?"

Building on the strengths of ASU's School of Earth and Space Exploration, which unites earth and space scientists in an effort to tackle research questions through a holistic approach, Shim was brought on board for his mineral expertise to provide insights into the possible nature of the planets themselves.

"With such a high magnesium and silicon ratio it is possible that the mineralogical make-up of planets around Tau Ceti could be significantly different from that of Earth. Tau Ceti's planets could very well be dominated by the mineral olivine at shallow parts of the mantle and have lower mantles dominated by ferropericlase," explains Shim.

Considering that ferropericlase is much less viscous, or resistant to flowing, hot, yet solid, mantle rock would flow more easily, possibly having profound effects on volcanism and tectonics at the planetary surface, processes which have a significant impact on the habitability of Earth.

"This is a reminder that geological processes are fundamental in understanding the habitability of planets," Shim adds.

"Tau Ceti has been a popular destination for science fiction writers and everyone's imagination as somewhere there could possibly be life, but even though life around Tau Ceti may be unlikely, it should not be seen as a letdown, but should invigorate our minds to consider what exotic planets likely orbit the star, and the new and unusual planets that may exist in this vast universe," says Pagano.

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Wednesday, 22 April 2015

The Hubble Effect's 25th Anniversary --"A Radical Transformation of Our Perception of the Universe"


"Equipped with his five senses, man explores the universe around him and calls the adventure Science, wrote Edwin Hubble. "At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed. The history of astronomy is a history of receding horizons."

Twenty-five years ago, NASA launched one of the most ambitious experiments in the history of astronomy: the Hubble Space Telescope, which has so radically changed and enlarged our picture and understanding of the cosmos and our place in it, is a cooperative project of NASA and ESA (European Space Agency), put into orbit in 1990 600 kilometers above the earth, allowing an unrivaled, undisturbed view into deep space.

During the past several years alone, the Hubble has delivered a goldmine of discoveries: from the mapping of cosmic-web of dark matter, to rich tapestries of evolving deep-space galaxies, to the very dawn of galaxies using mankind's deepest optical view of the universe, to evidence for Dark Energy in the young universe from Hubble Ultra Deep Field, to compelling evidence of monster black holes at the centers of galaxies.

Not by accident, the space-born telescope is named after one of the most fascinating men in the history of science. Born in 1889, ten years after Einstein (of whom he had little knowledge), few greats have had more effect on our knowledge of the cosmos than Edwin Hubble. A naturally-gifted track star, and scholar, the Missouri-born Hubble spent his life following a doctorate in astronomy from the University of Chicago answering two of the most fundamental and profound questions about our universe: how big is it, and how old?

When Hubble moved to California in 1919 to take up a position at the Mount Wilson Observatory near Los Angles, little was know about the size and age of the universe. The number of known galaxies at the time he first looked out to the cosmos from Mt Wilson was exactly one: the Milky Way. The Milky Way was thought to embrace the entire cosmos with everything else, distant puffs of celestial gas.

Hubble's great breakthrough came in 1923 when with a fresh eye he showed that a distant cloud of that peripheral celestial gas in the Andromeda Constellation known as M31 wasn't a gas cloud, but a maze of brilliant stars, a "nebulae" (Latin for "cloud") -a galaxy a 100,000 light years across and at least 900,000 light years distant from Earth.

This discovery led to his 1924 research paper "Cephids in Spiral Nebulae" (Hubble's term for galaxy) showing that the universe -which we now know houses some 130 billion galaxies- was made up of not just the Milky Way, but a myriad of "island universes," many far more distant and larger.

Hubble then turned to the next question of equally cosmic proportions,just how big is the universe, and made an equally striking discovery: that all the galaxies except for our local cluster are moving away from us at a speed and distance that are nearly proportional. In short, the more distant the galaxy, the faster it was moving.

The concept of an expanding universe destroyed the old, longstanding notion of a static steady-state universe, the wonder of which Stephen Hawking has exclaimed, was that it wasn't obvious before that a static universe would have collapsed in upon itself.

Hubble's ignorance of Einstein's General Theory of Relativity led to his nor being able to connect the dots between a universe that was expanding evenly in all directions (the "Hubble Constant") to a geometrical starting point, a "primeval atom, a Big Bang. That answer came several decades later with the discovery of cosmic background radiation from a hissing, constant, uniform low-frequency radio signal at a Bell Labs facility in rural New Jersey.

The Hubble image of beautiful spiral galaxy M66 lies a mere 35 million light-years away. About 100 thousand light-years across, the island universe is well known to astronomers as a member of the Leo Triplet of galaxies. In M66, pronounced dust lanes and young, blue star clusters sweep along spiral arms dotted with the tell-tale glow of pink star forming regions.The bright, spiky stars lie in the foreground, within our own Milky Way Galaxy, but many, small, distant background galaxies can be seen in the cosmic snapshot.

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"Hacking the Chemical Fingerprint of the Universe" --Detecting Organic Molecules in Space


The terahertz region of the spectrum is chock-full of information. Everything in the universe that is warmer than about 10 degrees Kelvin (-263 degrees Celsius) gives off terahertz radiation. Even at these very low temperatures molecules can rotate in space, yielding unique fingerprints in the terahertz. Astronomers using telescopes such as Caltech's Submillimeter Observatory, the Atacama Large Millimeter Array, and the Herschel Space Observatory are searching stellar nurseries and planet-forming disks at terahertz frequencies, looking for such chemical fingerprints to try to determine the kinds of molecules that are present and thus available to planetary systems. But in just a single chunk of the sky, it would not be unusual to find signatures of 25 or more different molecules.

To be able to definitively identify specific molecules within such a tangle of terahertz signals, scientists first need to determine exact measurements of the chemical fingerprints associated with various molecules. This requires a precise source of terahertz waves, in addition to a sensitive detector, and the terahertz frequency comb is ideal for making such measurements in the lab.

"When we look up into space with terahertz light, we basically see this forest of lines related to the tumbling motions of various molecules," says Finneran. "Unraveling and understanding these lines is difficult, as you must trek across that forest one point and one molecule at a time in the lab. It can take weeks, and you would have to use many different instruments. What we've developed, this terahertz comb, is a way to analyze the entire forest all at once."

Light can come in many frequencies, only a small fraction of which can be seen by humans. Between the invisible low-frequency radio waves used by cell phones and the high frequencies associated with infrared light lies a fairly wide swath of the electromagnetic spectrum occupied by what are called terahertz, or sometimes submillimeter, waves. Exploitation of these waves could lead to many new applications in fields ranging from medical imaging to astronomy, but terahertz waves have proven tricky to produce and study in the laboratory. Now, Caltech chemists have created a device that generates and detects terahertz waves over a wide spectral range with extreme precision, allowing it to be used as an unparalleled tool for measuring terahertz waves.

The new device is an example of what is known as a frequency comb, which uses ultrafast pulsed lasers, or oscillators, to produce thousands of unique frequencies of radiation distributed evenly across a spectrum like the teeth of a comb. Scientists can then use them like rulers, lining up the teeth like tick marks to very precisely measure light frequencies. The first frequency combs, developed in the 1990s, earned their creators (John Hall of JILA and Theordor Hánsch of the Max Planck Institute of Quantum Optics and Ludwig Maximilians University Munich) the 2005 Nobel Prize in physics. These combs, which originated in the visible part of the spectrum, have revolutionized how scientists measure light, leading, for example, to the development of today's most accurate timekeepers, known as optical atomic clocks.

The team at Caltech combined commercially available lasers and optics with custom-built electronics to extend this technology to the terahertz, creating a terahertz frequency comb with an unprecedented combination of spectral coverage and precision. Its thousands of "teeth" are evenly spaced across the majority of the terahertz region of the spectrum (0.15-2.4 THz), giving scientists a way to simultaneously measure absorption in a sample at all of those frequencies.

The work is described in a paper that appears in the online version of the journal Physical Review Letters and will be published in the April 24 issue. The lead author is graduate student and National Science Foundation fellow Ian Finneran, who works in the lab of Geoffrey A. Blake, professor of cosmochemistry and planetary sciences and professor of chemistry at Caltech.

Blake explains the utility of the new device, contrasting it with a common radio tuner. "With radio waves, most tuners let you zero in on and listen to just one station, or frequency, at a time," he says. "Here, in our terahertz approach, we can separate and process more than 10,000 frequencies all at once. In the near future, we hope to bump that number up to more than 100,000."

After the device generates its tens of thousands of evenly spaced frequencies, the waves travel through a sample--in the paper, the researchers provide the example of water vapor. The instrument then measures what light passes through the sample and what gets absorbed by molecules at each tooth along the comb. If a detected tooth gets shorter, the sample absorbed that particular terahertz wave; if it comes through at the baseline height, the sample did not absorb at that frequency.

"Since we know exactly where each of the tick marks on our ruler is to about nine digits, we can use this as a diagnostic tool to get these frequencies really, really precisely," says Finneran. "When you look up in space, you want to make sure that you have such very exact measurements from the lab."

In addition to the astrochemical application of identifying molecules in space, the terahertz comb will also be useful for studying fundamental interactions between molecules. "The terahertz is unique in that it is really the only direct way to look not only at vibrations within individual large molecules that are important to life, but also at vibrations between different molecules that govern the behavior of liquids such as water," says Blake.

Additional coauthors on the paper, "Decade-Spanning High-Precision Terahertz Frequency Comb," include current Caltech graduate students Jacob Good, P. Brandon Carroll, and Marco Allodi, as well as recent graduate Daniel Holland (PhD '14). The work was supported by funding from the National Science Foundation.

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The First Alien Planet Detected in Visible Light


A new technique has been developed that does not depend on finding a planetary transit, so it can potentially be used to study many more exoplanets. It allows the planetary spectrum to be directly detected in visible light, which means that different characteristics of the planet that are inaccessible to other techniques can be inferred. The challenge is similar to trying to study the faint glimmer reflected off a tiny insect flying around a distant and brilliant light.

The exoplanet 51 Pegasi b lies some 50 light-years from Earth in the constellation of Pegasus, discovered in 1995 and will forever be remembered as the first confirmed exoplanet to be found orbiting an ordinary star like the Sun. It is also regarded as the archetypal hot Jupiter -- a class of planets now known to be relatively commonplace, which are similar in size and mass to Jupiter, but orbit much closer to their parent stars.

Since that landmark discovery, more than 1900 exoplanets in 1200 planetary systems have been confirmed, but, in the year of the twentieth anniversary of its discovery, 51 Pegasi b returns to the ring once more to provide another advance in exoplanet studies. Both 51 Pegasi b and its host star 51 Pegasi are among the objects available for public naming in the IAU's NameExoWorlds contest.

The team that made this new detection was led by Jorge Martins from the Instituto de Astrofísica e Ciências do Espaço (IA) and the Universidade do Porto, Portugal, who is currently a PhD student at ESO in Chile. They used the HARPS instrument on the ESO 3.6-metre telescope at the La Silla Observatory in Chile.

Currently, the most widely used method to examine an exoplanet's atmosphere is to observe the host star's spectrum as it is filtered through the planet's atmosphere during transit -- a technique known as transmission spectroscopy. An alternative approach is to observe the system when the star passes in front of the planet, which primarily provides information about the exoplanet's temperature.

The host star's spectrum is used as a template to guide a search for a similar signature of light that is expected to be reflected off the planet as it describes its orbit. This is an exceedingly difficult task as planets are incredibly dim in comparison to their dazzling parent stars.

The signal from the planet is also easily swamped by other tiny effects and sources of noise. In the face of such adversity, the success of the technique when applied to the HARPS data collected on 51 Pegasi b provides an extremely valuable proof of concept.

"This type of detection technique is of great scientific importance, as it allows us to measure the planet's realmass and orbital inclination, which is essential to more fully understand the system," says Jorge Martins. "It also allows us to estimate the planet's reflectivity, or albedo, which can be used to infer the composition of both the planet's surface and atmosphere."

51 Pegasi b was found to have a mass about half that of Jupiter's and an orbit with an inclination of about nine degrees to the direction to the Earth [4]. The planet also seems to be larger than Jupiter in diameter and to be highly reflective. These are typical properties for a hot Jupiter that is very close to its parent star and exposed to intense starlight.

HARPS was essential to the team's work, but the fact that the result was obtained using the ESO 3.6-metre telescope, which has a limited range of application with this technique, is exciting news for astronomers. Existing equipment like this will be surpassed by much more advanced instruments on larger telescopes, such as ESO's Very Large Telescope and the future European Extremely Large Telescope.

"We are now eagerly awaiting first light of the ESPRESSO spectrograph on the VLT so that we can do more detailed studies of this and other planetary systems," concludes Nuno Santos, of the IA and Universidade do Porto, who is a co-author of the new paper.

ESPRESSO on the VLT, and later even more powerful instruments on much larger telescopes such as the E-ELT, will allow for a significant increase in precision and collecting power, aiding the detection of smaller exoplanets, while providing an increase in detail in the data for planets similar to 51 Pegasi b.

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Tuesday, 21 April 2015

"Earth May Have Experienced Dark-Matter Triggered Extinction Events" (Today's Most Popular)


"We are fortunate enough to live on a planet that is ideal for the development of complex life," says New York University Biology Professor Michael Rampino. "But the history of the Earth is punctuated by large scale extinction events, some of which we struggle to explain. It may be that dark matter - the nature of which is still unclear but which makes up around a quarter of the universe - holds the answer. As well as being important on the largest scales, dark matter may have a direct influence on life on Earth."

Rampino's model of dark matter interactions with the Earth as it cycles through the Galaxy could have a broad impact on our understanding of the geological and biological development of Earth, as well as other planets within the Galaxy.

He concludes that Earth's infrequent but predictable path around and through our Galaxy's disc may have a direct and significant effect on geological and biological phenomena occurring on Earth. In a new paper in Monthly Notices of the Royal Astronomical Society, he concludes that movement through dark matter may perturb the orbits of comets and lead to additional heating in the Earth's core, both of which could be connected with mass extinction events.

The Galactic disc is the region of the Milky Way Galaxy where our solar system resides. It is crowded with stars and clouds of gas and dust, and also a concentration of elusive dark matter--small subatomic particles that can be detected only by their gravitational effects.

Previous studies have shown that Earth rotates around the disc-shaped Galaxy once every 250 million years. But the Earth's path around the Galaxy is wavy, with the Sun and planets weaving through the crowded disc approximately every 30 million years. Analyzing the pattern of the Earth's passes through the Galactic disc, Rampino notes that these disc passages seem to correlate with times of comet impacts and mass extinctions of life. The famous comet strike 66 million ago that led to the extinction of the dinosaurs is just one example.

What causes this correlation between Earth's passes through the Galactic disc, and the impacts and extinctions that seem to follow?

While traveling through the disc, the dark matter concentrated there disturbs the pathways of comets typically orbiting far from the Earth in the outer Solar System, Rampino observes. This means that comets that would normally travel at great distances from the Earth instead take unusual paths, causing some of them to collide with the planet.

But even more remarkably, with each dip through the disc, the dark matter can apparently accumulate within the Earth's core. Eventually, the dark matter particles annihilate each other, producing considerable heat. The heat created by the annihilation of dark matter in Earth's core could trigger events such as volcanic eruptions, mountain building, magnetic field reversals, and changes in sea level, which also show peaks every 30 million years. Rampino therefore suggests that astrophysical phenomena derived from the Earth's winding path through the Galactic disc, and the consequent accumulation of dark matter in the planet's interior, can result in dramatic changes in Earth's geological and biological activity.

In the future, he suggests, geologists might incorporate these astrophysical findings in order to better understand events that are now thought to result purely from causes inherent to the Earth. This model, Rampino adds, likewise provides new knowledge of the possible distribution and behaviour of dark matter within the Galaxy.

The Hubble image above is an artist's view of night sky from a hypothetical planet within a young Milky Way-like galaxy 10 billion years ago, the sky are ablaze with star birth.

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Monday, 20 April 2015

"Supermassive Black Hole Exists Where It Shouldn't Be" --Inside a Blob Galaxy


Henize 2-10 is a small irregular galaxy that is not too far away in astronomical terms -- 30 million light-years. "This is a dwarf starburst galaxy -- a small galaxy with regions of very rapid star formation -- about 10 percent of the size of our own Milky Way," says co-author Ryan Hickox, an assistant professor in Dartmouth's Department of Physics and Astronomy. "If you look at it, it's a blob, but it surprisingly harbors a central black hole."

Hickox says there may be similar small galaxies in the known universe, but this is one of the only ones close enough to allow detailed study. Lead author Thomas Whalen, Hickox and a team of other researchers have now analyzed a series of four X-ray observations of Henize 2-10 using three space telescopes over 13 years, providing conclusive evidence for the existence of a black hole. The galaxy Henize 2-10 is shown above as seen with the Hubble telescope. The color scale has been adjusted to show the details in the center of the galaxy. (Credit: N. Bergvall & T. Marquart)

Their findings appear as an online preprint to be published in The Astrophysical Journal Letters. A PDF also is available on request.

Suspicions about Henize 2-10 first arose in 2011 when another team, that included some of the co-authors, first looked at galaxy Henize 2-10 and tried to explain its behavior. The observed dual emissions of X-ray and radio waves, often associated with a black hole, gave credence to the presence of one. The instruments utilized were Japan's Advanced Satellite for Cosmology and Astrophysics (1997), the European Space Agency's XMM-Newton (2004, 2011) and NASA's Chandra X-ray Observatory (2001).


"The galaxy was bright in 2001, but it has gotten less bright over time," says Hickox. "This is not consistent with being powered only by star formation processes, so it almost certainly had to have a small supermassive black hole -- small compared to the largest supermassive black holes in massive elliptical galaxies, but is still a million times the mass of the sun."

A characteristic of supermassive black holes is that they do change with time -- not a huge amount, explains Hickox, "and that is exactly what Tom Whalen found," he says. "This variability definitely tells us that the emission is coming from a compact source at the center of this system, consistent with it being a supermassive black hole."

While supermassive black holes are typically found in the central bulges of galaxies, Henize 2-10 has no bulge. "All the associations that people have made between galaxies and black holes tell us there ought to be no black hole in this system," says Whalen, but the team has proven otherwise. Whalen, a recent Dartmouth graduate, is now a member of the Chandra X-ray Center team at the Harvard-Smithsonian Center for Astrophysics.

A big question is where black holes come from. "When people try to simulate where the galaxies come from, you have to put in these black holes at the beginning, but we don't really know what the conditions were. These dwarf starburst galaxies are the closest analogs we have in the universe around us now, to the first galaxies early in the universe," says Whalen.

The authors conclude: "Our results confirm that nearby star-forming galaxies can indeed form massive black holes and that by implication so can their primordial counterparts."

"Studying those to get some sense of what might have happened very early in the universe is very powerful," says Hickox.

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"Pulsing Lights of the Universe" --May Signal Gravitational Waves from Merging Black Holes


As two galaxies enter the final stages of merging, scientists have theorized that the galaxies' supermassive black holes will form a "binary," or two black holes in such close orbit they are gravitationally bound to one another. In a new study, astronomers at the University of Maryland present direct evidence of a pulsing quasar, which may substantiate the existence of black hole binaries.

"We believe we have observed two supermassive black holes in closer proximity than ever before," said Suvi Gezari, assistant professor of astronomy at the University of Maryland and a co-author of the study. "This pair of black holes may be so close together that they are emitting gravitational waves, which were predicted by Einstein's theory of general relativity.

Black holes typically gobble up matter, which accelerates and heats up, emitting electromagnetic energy and creating some of the most luminous beacons in the sky called quasars. When two black holes orbit as a binary, they absorb matter cyclically, leading theorists to predict that the binary's quasar would respond by periodically brightening and dimming.

The researchers conducted a systematic search for so-called variable quasars using the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) Medium Deep Survey. This Haleakala, Hawaii-based telescope imaged the same patch of sky once every three days and collected hundreds of data points for each object over four years.

In that data, the astronomers found quasar PSO J334.2028+01.4075, which has a very large black hole of almost 10 billion solar masses and emits a periodic optical signal that repeats every 542 days. The quasar's signal was unusual because the light curves of most quasars are arrhythmic. To verify their finding, the research team performed rigorous calculations and simulations and examined additional data, including photometric data from the Catalina Real-Time Transient Survey and spectroscopic data from the FIRST Bright Quasar Survey.

"The discovery of a compact binary candidate supermassive black hole system like PSO J334.2028+01.4075, which appears to be at such close orbital separation, adds to our limited knowledge of the end stages of the merger between supermassive black holes," said UMD astronomy graduate student Tingting Liu, the paper's first author.

The researchers plan to continue searching for new variable quasars. Beginning in 2023, their search could be aided by the Large Synoptic Survey Telescope, which is expected to survey a much larger area and could potentially pinpoint the locations of thousands of these merging supermassive black holes in the night sky.

"These telescopes allow us to watch a movie of how these systems evolve," said Liu. "What's really cool is that we may be able to watch the orbital separation of these supermassive black holes get smaller and smaller until they merge."

This study was published online April 14, 2015, in the Astrophysical Journal Letters. The discovery could shed light on how often black holes get close enough to form a gravitationally bound binary and eventually merge together.

The image at the top of the page shows thev galaxy known as Markarian 739, which is actually two galaxies in the midst of merging. The two bright spots at the center are the cores of the two original galaxies, each of which harbors a supermassive black hole. (SDSS).

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Mystery of Largest Structure Ever Identified in the Universe --The Eridanus Supervoid and Cold Spot

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Getting through a supervoid can take millions of years, even at the speed of light, so this measurable effect, known as the Integrated Sachs-Wolfe (ISW) effect, might provide the first explanation one of the most significant anomalies found to date in the CMB, first by a NASA satellite called the Wilkinson Microwave Anisotropy Probe (WMAP), and more recently, by Planck, a satellite launched by the European Space Agency.

In 2004, astronomers examining a map of the radiation leftover from the Big Bang (the cosmic microwave background, or CMB) discovered the Cold Spot, a larger-than-expected unusually cold area of the sky. The physics surrounding the Big Bang theory predicts warmer and cooler spots of various sizes in the infant universe, but a spot this large and this cold was unexpected.

Now, a team of astronomers led by Dr. Istvan Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa may have found an explanation for the existence of the Cold Spot, which Szapudi says may be "the largest individual structure ever identified by humanity."

If the Cold Spot originated from the Big Bang itself, it could be a rare sign of exotic physics that the standard cosmology (basically, the Big Bang theory and related physics) does not explain. If, however, it is caused by a foreground structure between us and the CMB, it would be a sign that there is an extremely rare large-scale structure in the mass distribution of the universe.

Using data from Hawaii's Pan-STARRS1 (PS1) telescope located on Haleakala, Maui, and NASA's Wide Field Survey Explorer (WISE) satellite, Szapudi's team discovered a large supervoid, a vast region 1.8 billion light-years across, in which the density of galaxies is much lower than usual in the known universe. This void was found by combining observations taken by PS1 at optical wavelengths with observations taken by WISE at infrared wavelengths to estimate the distance to and position of each galaxy in that part of the sky.

The Cold Spot area resides in the constellation Eridanus in the southern galactic hemisphere. The insets in the image above show the environment of this anomalous patch of the sky as mapped by Szapudi's team using PS1 and WISE data and as observed in the cosmic microwave background temperature data taken by the Planck satellite. The angular diameter of the vast supervoid aligned with the Cold Spot, which exceeds 30 degrees, is marked by the white circles.

Earlier studies, also done in Hawaii, observed a much smaller area in the direction of the Cold Spot, but they could establish only that no very distant structure is in that part of the sky. Paradoxically, identifying nearby large structures is harder than finding distant ones, since we must map larger portions of the sky to see the closer structures. The large three-dimensional sky maps created from PS1 and WISE by Dr. András Kovács (Eötvös Loránd University, Budapest, Hungary) were thus essential for this study. The supervoid is only about 3 billion light-years away from us, a relatively short distance in the cosmic scheme of things.

Imagine there is a huge void with very little matter between you (the observer) and the CMB. Now think of the void as a hill. As the light enters the void, it must climb this hill. If the universe were not undergoing accelerating expansion, then the void would not evolve significantly, and light would descend the hill and regain the energy it lost as it exits the void. But with the accelerating expansion, the hill is measurably stretched as the light is traveling over it. By the time the light descends the hill, the hill has gotten flatter than when the light entered, so the light cannot pick up all the energy it lost upon entering the void. The light exits the void with less energy, and therefore at a longer wavelength, which corresponds to a colder temperature.

While the existence of the supervoid and its expected effect on the CMB do not fully explain the Cold Spot, it is very unlikely that the supervoid and the Cold Spot at the same location are a coincidence. The team will continue its work using improved data from PS1 and from the Dark Energy Survey being conducted with a telescope in Chile to study the Cold Spot and supervoid, as well as another large void located near the constellation Draco.

The study is being published online on April 20 in Monthly Notices of the Royal Astronomical Society by the Oxford University Press. In addition to Szapudi and Kovács, researchers who contributed to this study include UH Manoa alumnus Benjamin Granett (now at the National Institute for Astrophysics, Italy), Zsolt Frei (Eötvös Loránd), and Joseph Silk (Johns Hopkins).

Founded in 1967, the Institute for Astronomy at the University of Hawaii at Manoa conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Maunakea. The Institute operates facilities on the islands of Oahu, Maui, and Hawaii.

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