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Is the Universe fine-tuned for life? A team of physicists is looking at the conditions necessary to the formation of carbon and oxygen two elements in the universe that are the foundation of life as we currently know it. They’ve found that when it comes to supporting life, the universe leaves very little margin for error. “The Hoyle state of carbon is key,” says NC State physicist Dean Lee. “If the Hoyle state energy was at 479 keV or more above the three alpha particles, then the amount of carbon produced would be too low for carbon-based life. The same holds true for oxygen,” he adds. “If the Hoyle state energy were instead within 279 keV of the three alphas, then there would be plenty of carbon. But the stars would burn their helium into carbon much earlier in their life cycle. As a consequence, the stars would not be hot enough to produce sufficient oxygen for life. In our lattice simulations, we find that more than a 2 or 3 percent change in the light quark mass would lead to problems with the abundance of either carbon or oxygen in the universe.” Both carbon and oxygen are produced when helium burns inside of giant red stars. Carbon-12, an essential element we’re all made of, can only form when three alpha particles, or helium-4 nuclei, combine in a very specific way. The key to formation is an excited state of carbon-12 known as the Hoyle state, and it has a very specific energy – measured at 379 keV (or 379,000 electron volts) above the energy of three alpha particles. Oxygen is produced by the combination of another alpha particle and carbon. The international team -- Lee and German colleagues Evgeny Epelbaum, Hermann Krebs, Timo Laehde and Ulf-G. Meissner-- had previously confirmed the existence and structure of the Hoyle state with a numerical lattice that allowed the researchers to simulate how protons and neutrons interact. These protons and neutrons are made up of elementary particles called quarks. The light quark mass is one of the fundamental parameters of nature, and this mass affects particles’ energies. In new lattice calculations done at the Juelich Supercomputer Centre the physicists found that just a slight variation in the light quark mass will change the energy of the Hoyle state, and this in turn would affect the production of carbon and oxygen in such a way that life as we know it wouldn’t exist.carbon and oxygen production and the viability of carbon-based life. In new lattice calculations done at the Juelich Supercomputer Center the physicists found that just a slight variation in the light quark mass will change the energy of the Hoyle state, and this in turn would affect the production of carbon and oxygen in such a way that life as we know it wouldn’t exist.
A team of scientists led by Harvard astronomer Guido Risaliti recounts its findings in the latest issue of Nature. The researchers accomplished the feat by measuring electromagnetic radiation emanating from the center of spiral galaxy NGC 1365. There — not unlike the center of our own Milky Way — a spherical region of spacetime more than 2 million miles in diameter whirls violently, its gravity so strong it actually schleps surrounding space along with it. Any matter that trespasses beyond the black hole's event horizon spirals inward and collects in what's known as an accretion disc, where it is subjected to so much friction it emits X-rays. Thanks to a joint effort by the ESA's XMM-Newton and NASA's recently launched NuSTAR (both X-ray observatories, positioned in Earth orbit), Risaliti and his colleagues were able to locate the inner boundary of the accretion disc. Sometimes known as the Innermost Stable Circular Orbit, the position of this accretion disc "edge" depends on the speed of the black hole's overall rotation. The astronomers used this relationship to calculate the spin rate of the black hole's surface, which they estimate is is traveling at nearly the speed of light — about 84% as fast, to be exact.
In a statement, Risaliti says that it is "the first time anyone has accurately measured the spin of a supermassive black hole," but insists that even more important is what his team's findings can tell us about this black hole's past, and the developmental history of its surrounding galaxy. The spin of a black hole is thought to be affected by the way it pulls in matter. It stands to reason, for example, that a black hole that subsumes gas and stars at random is more likely to fetter its angular momentum than add to it. According to Risaliti and his team, that the supermassive black hole at the center of NGC 1365 is spinning at speeds approaching the cosmic speed limit would suggest it acquired mass through ordered accretion, as opposed to multiple random events. For more details, visit SPACE.com, where Mike Wall has a great overview of the role that NASA's NuSTAR (launched in July of last year) has played in resolving a longstanding debate over the implications of X-ray emission patterns emanating from black holes. "It's the first time that we can really say that black holes are spinning," said study co-author Fiona Harrison in an interview with Wall. "The promise that this holds for being able to understand how black holes grow is, I think, the major implication."
Black holes are created when a supernova explosion destroys a massive star. Scientists have discovered dozens of black holes, but all of them are already formed. So, when scientists recently saw different distorted remains of a supernova, they knew it something special. What the scientists believe they observed was the infant phases of a black hole, or the youngest black hole ever recorded in the Milky Way galaxy. Caught on film by NASA's Chandra X-ray Observatory, the "remnant," or W49B, is seen as a vibrant swirl of blues, greens, yellows, and pinks. As seen from Earth, it is about 1,000-years-old and is located roughly 26,000 light years away. A typical black hole, like SS433, is thought to be between 17,000- and 21,000-years-old, as seen from Earth. "W49B is the first of its kind to be discovered in the galaxy," Laura Lopez, who led a study on the remnant at the Massachusetts Institute of Technology, said in a statement. "It appears its parent star ended its life in a way that most others don't."
Arp 147 contains the remnant of a spiral galaxy (right) that collided with the elliptical galaxy on the left. This collision has produced an expanding wave of star formation that shows up as a blue ring containing in abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes. A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the Sun.
An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly-fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.
Infrared observations with NASA's Spitzer Space Telescope and ultraviolet observations with NASA's Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring. These estimates, combined with the use of models for the evolution of binary stars have allowed the authors to conclude that the most intense star formation may have ended some 15 million years ago, in Earth's time frame.
Using the CSIRO Australia Telescope Compact Array, scientists led by Sebastien Muller have made the most precise measurement ever of how the universe has cooled down during its 13.77 billion year history. The researchers studied molecules in clouds of gas in a distant galaxy, so far away that its light has taken half the age of the universe to reach us. To make the measurement they used the CSIRO Australia Telescope Compact Array, an array of six 22-metre radio telescopes in eastern Australia. “When we look at this galaxy with our telescopes, we see it as it was when the universe was younger – and warmer – than it is now”, says Sebastien Muller. The astronomers used a clever new method to measure the temperature of the cosmic microwave background – the very weak remnant of the heat of the Big bang that pervades the entire universe. They observed radio waves from molecules in a galaxy so far away that its light has taken 7.2 billion years to reach us. “The gas in this galaxy is so rarefied that the only thing keeping its molecules warm is the cosmic background radiation – what’s left of the Big bang”, says Sebastien Muller. Using a sophisticated computer model, the astronomers used these molecular signatures, left like fingerprints in the light from the quasar, to measure the temperature in the gas clouds in the intervening galaxy. The temperature of the cosmic background radiation they measured was 5.08 Kelvin (+/- 0.10 Kelvin). This is extremely cold, but significantly warmer than the temperature which scientists measure in today’s universe, 2.73 Kelvin. Scientists measure temperatures in Kelvin above absolute zero (0 Kelvin = -273 degrees Celsius). One Kelvin is the same size as one degree Celsius. “The temperature of the cosmic background radiation in the past has been measured before, at even larger distances. But this is the most precise measurement yet of the ambient temperature when the universe was younger than it is now”, says Alexandre Beelen, astronomer at the Institute for Space Astrophysics at the University of Paris, France. According to the Big bang theory, the temperature of the cosmic background radiation drops smoothly as the universe expands. “That’s just what we see in our measurements. The universe of a few billion years ago was a few degrees warmer than it is now, exactly as the Big bang theory predicts”, concludes Sebastien Muller.
An international team of astronomers, led by academics from the University of Central Lancashire (UCLan), has found the largest known structure in the universe. The large quasar group (LQG) is so large that it would take a vehicle travelling at the speed of light some 4 billion years to cross it. The team publish their results in the journal Monthly Notices of the Royal Astronomical Society.
Quasars are the nuclei of galaxies from the early days of the universe that undergo brief periods of extremely high brightness that make them visible across huge distances. These periods are 'brief' in astrophysics terms but actually last 10-100 million years. Since 1982 it has been known that quasars tend to group together in clumps or 'structures' of surprisingly large sizes, forming large quasar groups or LQGs. The team, led by Dr. Roger Clowes from UCLan's Jeremiah Horrocks Institute, has identified the LQG which is so significant in size it also challenges the Cosmological Principle: the assumption that the universe, when viewed at a sufficiently large scale, looks the same no matter where you are observing it from. The modern theory of cosmology is based on the work of Albert Einstein, and depends on the assumption of the Cosmological Principle. The Principle is assumed but has never been demonstrated observationally 'beyond reasonable doubt'. To give some sense of scale, our galaxy, the Milky Way, is separated from its nearest neighbour, the Andromeda Galaxy, by about 0.75 Megaparsecs (Mpc) or 2.5 million light-years. Whole clusters of galaxies can be 2-3 Mpc across but LQGs can be 200 Mpc or more across. Based on the Cosmological Principle and the modern theory of cosmology, calculations suggest that astrophysicists should not be able to find a structure larger than 370 Mpc. Dr. Clowes' newly discovered LQG however has a typical dimension of 500 Mpc. But because it is elongated, its longest dimension is 1200 Mpc (or 4 billion light years) - some 1600 times larger than the distance from the Milky Way to Andromeda.
New research has found that hypervelocity planets may be flung to the outer reaches of the galaxy by black holes at speeds matched only by subatomic particles, traveling at 1.5 to 30 million miles per hour. The finding builds on previous work on hypervelocity stars, which appear when a binary star system — two stars orbiting a central point — enter the gravitational well of a black hole, similar to the one at the center of our Milky Way galaxy. The black hole tears the stars apart, sending one of the stars hurtling from the galaxy at very high speeds while the other remains within the gravitational field of the black hole. Harvard's Avi Loeb, chair of the Harvard astronomy department, surmised that such planets could be seen through a telescope as “transits,” or traces, as they crossed a star’s light. He subsequently launched his collaboration with Dartmouth's Ginsburg to examine the possibility of such planets’ existence. “Once we realized that, it was clear to me that we could make a paper out of this,” Loeb said.Ginsburg and Loeb continued their collaborative research following Ginsburg’s move to Dartmouth to continue his studies. They developed computer simulations to explore the existence of hypervelocity planets, using facilities at both institutions, according to Ginsburg. The simulations placed the planets orbiting the binary stars in a binary planet system. When subjected to the same pressures that form hypervelocity stars, the models revealed that the planets would be similarly ejected at high speeds, Ginsburg said.
Magnets have practically become everyday objects. Earlier on, however, the universe consisted only of nonmagnetic elements and particles. Just how the magnetic forces came into existence has now been researched. Before the formation of the first stars, the luminous matter consisted only of a fully ionised gas of protons, electrons, helium nuclei and lithium nuclei which were produced during the Big Bang. "All higher metals, for example, magnetic iron could, according to today's conception, only be formed in the inside of stars," says Reinhard Schlickeiser. "In early times therefore, there were no permanent magnets in the Universe." The parameters that describe the state of a gas are, however, not constant. Density and pressure, as well as electric and magnetic fields fluctuate around certain mean values. As a result of this fluctuation, at certain points in the plasma weak magnetic fields formed -- so-called random fields. How strong these fields are in a fully ionised plasma of protons and electrons, has now been calculated by Prof. Schlickeiser, specifically for the gas densities and temperatures that occurred in the plasmas of the early universe.
The result: the magnetic fields fluctuate depending on their position in the plasma, however, regardless of time -- unlike, for example, electromagnetic waves such as light waves, which fluctuate over time. Everywhere in the luminous gas of the early universe there was a magnetic field with a strength of 10^-20 Tesla, i.e. 10 sextillionth of a Tesla. By comparison, the earth's magnetic field has a strength of 30 millionths of a Tesla. In MRI scanners, field strengths of three Tesla are now usual. The magnetic field in the plasma of the early universe was thus very weak, but it covered almost 100 percent of the plasma volume.
Stellar winds or supernova explosions of the first massive stars generated shock waves that compressed the magnetic random fields in certain areas. In this way, the fields were strengthened and aligned on a wide-scale. Ultimately, the magnetic force was so strong that it in turn influenced the shock waves. "This explains the balance often observed between magnetic forces and thermal gas pressure in cosmic objects," says Prof. Schlickeiser. The calculations show that all fully ionised gases in the early universe were weakly magnetised. Magnetic fields therefore existed even before the first stars. Next, the Bochum physicist is set to examine how the weak magnetic fields affect temperature fluctuations in the cosmic background radiation.
As far back in time as astronomers have been able to see, the universe has had some trace of heavy elements, such as carbon and oxygen. These elements, originally churned from the explosion of massive stars, formed the building blocks for planetary bodies, and eventually for life on Earth. Now researchers at MIT, the California Institute of Technology, and the University of California at San Diego have peered far back in time, to the era of the first stars and galaxies, and found matter with no discernible trace of heavy elements. To make this measurement, the team analyzed light from the most distant known quasar, a galactic nucleus more than 13 billion light-years from Earth. These quasar observations provide a snapshot of our universe during its infancy, a mere 750 million years after the initial explosion that created the universe. Analysis of the quasar's light spectrum provided no evidence of heavy elements in the surrounding gaseous cloud—a finding that suggests the quasar dates to an era nearing that of the universe's first stars. "The first stars will form in different spots in the universe … it's not like they flashed on at the same time," says Robert Simcoe, an associate professor of physics at MIT. "But this is the time that it starts getting interesting." Based on numerous theoretical models, most scientists agree on a general sequence of events during the universe's early development: Nearly 14 billion years ago, an immense explosion, now known as the Big Bang, threw off massive amounts of matter and energy, creating a rapidly expanding universe. In the minutes following the explosion, protons and neutrons collided in nuclear fusion reactions to form hydrogen and helium. Eventually, the universe cooled to a point where fusion stopped generating these basic elements, leaving hydrogen as the dominant constituent of the universe. Heavier elements, such as carbon and oxygen, would not form until the first stars appeared.
A new survey recently reported in Nature found a supermassive black hole (mass~17 billions of solar masses) at the center of a relatively "light" galaxy. This wouldn't be a surprise if the mass of the black hole wasn't more than half the mass of the buldge of the hosting galaxy. The black line shows the mass–luminosity relation for galaxies with a directly measured black-hole mass. NGC 1277 is a significant positive outlier. Indeed, we already know that most galaxies -- including our own Milky Way -- host supermassive black holes which lurk at the galactic center. Also, the mass of the black hole is believed to be tightly connected with the properties of the hosting galaxy. Several models of galaxy dynamics and mergers predict a black hole mass VS bulge luminosity relation similar to that shown in the Figure above and this has important implications in the understanding of the galaxy evolution and of black hole population models. Typically, the mass of the black hole is about 0.1 per cent of the mass of the stellar bulge of the galaxy and the maximum mass fraction observed so far was about 10%. The discovery of NGC 1277, a compact, lenticular galaxy with a mass of roughly 1.2x10^11 solar masses, is particularly interesting because this galaxy hosts a black hole of mass about 1.7x10^10 solar masses, that is, roughly 59% of the total bulge mass. Indeed, it's evident in the Figure above how NGC 1277 deviates from the expected empirical behavior. This discovery seems confirmed by other observations of galaxies that host oversized black holes and it might suggest a failure (or the need of some improvement) in current models.
Astronomers were puzzled earlier this year when NASA's Hubble Space Telescope spotted an overabundance of dark matter in the heart of the merging galaxy cluster Abell 520. This observation was surprising because dark matter and galaxies should be anchored together, even during a collision between galaxy clusters. Astronomers have abundant evidence that an as-yet-unidentified form of matter is responsible for 90 percent of the gravity within galaxies and clusters of galaxies. Because it is detected via its gravity and not its light, they call it "dark matter." Now, a new observation of Abell 520 from another team of astronomers using a different Hubble camera finds that the core does not appear to be over-dense in dark matter after all. The study findings were published in The Astrophysical Journal. "The earlier result presented a mystery. In our observations we didn't see anything surprising in the core," said study leader Douglas Clowe, an associate professor of physics and astronomy at Ohio University. "Our measurements are in complete agreement with how we would expect dark matter to behave." Hubble observations announced earlier this year by astronomers using Hubble's Wide Field Planetary Camera 2 suggested that a clump of dark matter was left behind during a clash between massive galaxies clusters in Abell 520, located 2.4 billion light-years away. The dark matter collected into a "dark core" that contained far fewer galaxies than would be expected if the dark and luminous matter were closely connected, which is generally found to be the case. Because dark matter is not visible, its presence and distribution is found indirectly through its gravitational effects. The gravity from both dark and luminous matter warps space, bending and distorting light from galaxies and clusters behind it like a giant magnifying glass. Astronomers can use this effect, called gravitational lensing, to infer the presence of dark matter in massive galaxy clusters. Both teams used this technique to map the dark matter in the merging cluster.
Gravitational waves are ripples in the fabric of spacetime caused by cataclysmic events such as neutron stars colliding and black holes merging. The biggest of these events, and the easiest to see, are the collisions between supermassive black holes at the centre of galaxies. So an important question is how often these events occur. Sean McWilliams and a couple of pals at Princeton University say that astrophysicists have severely underestimated the frequency of these upheavals. Their calculations suggest that galaxy mergers are an order of magnitude more frequent than had been thought. Consequently, collisions between supermassive black holes must be more common too. That has important implications for the ability of today's gravitational wave observatories to see them. There is an intense multi-million dollar race to be first to spot gravitational waves but if McWilliams and pals are correct the evidence may already be in the data collected by the first observatories. The evidence that McWilliams and co rely on is various measurements of galaxy size and mass. This data shows that in the last 6 billion years, galaxies have roughly doubled in mass and quintupled in size. Astrophysicists know that there has been very little star formation in that time so the only way for galaxies to grow is by merging, an idea borne out by various computer simulations of the way that galaxies must evolve. These simulations suggest that galaxy mergers must be far more common than astronomers had thought. That raises an interesting prospect--that the supermassive black holes at the centre of these galaxies must be colliding more often too. McWilliams and co calculate that black hole mergers must be between 10 and 30 times more common than expected and that the gravitational wave signals from these events are between 3 and 5 times stronger. That has important implications for astronomers’ ability to see these signals. Astrophysicists are intensely interested in these waves since they offer an entirely new way to study the cosmos.
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If you want your pet black hole to be visible, you must feed it regularly. Only when a black hole gorges on a steady diet of gas or other matter does it shine. The disk of matter that orbits it heats up and emits large amounts of light, especially in X-rays. If you have one of the supermassive black holes at the centers of galaxies, feeding it matter can create one of the brightest objects in the Universe. But the smaller ones should also be pretty visible. And while astronomers expect and have observed black holes comparable in mass to stars, their numbers are fewer than expected, even after decades of searching. Perhaps, as a new paper suggests, this is because many black holes are hidden by an opaque, donut-shaped disk of matter. J. M. Corral-Santana and colleagues based this hypothesis on a detailed study of a relatively faint, fluctuating X-ray source in the Milky Way. Their observations in X-ray and visible light revealed the signs of a binary system: an ordinary star in orbit around a black hole, similar to other systems, but with some key differences. For one, the star and black hole were so close together that the orbital period of the system was only 2.8 hours. For another, the matter being drawn off the star was obscuring the black hole when viewed from Earth. The authors hypothesized that many other black holes may be similarly hidden, and future searches should take that possibility into account. Stellar-mass black holes are the remnants of the cores of stars which exploded in supernovae and are at least 20 times the mass of the Sun. Black holes in this mass range have been discovered in binary systems, where their companion is an ordinary star. The transfer of mass from the companion onto the black hole creates an accretion disk: a hot, rapidly rotating platter that emits a great deal of X-ray light. The first black hole discovered, Cygnus X-1, was found through these emissions. However, in nearly 50 years of X-ray observations, only about 50 black holes candidates have been known in the Milky Way, of which only 18 are confirmed. None of them exhibit eclipses, where the companion star or accretion disk block the X-ray emission. That's a somewhat surprising result, as it may imply we're only identifying systems we see from a privileged angle, one where our telescopes peer "down" onto the system. Since a bright black hole system that undergoes eclipses was identified in the M33 (Triangulum) galaxy, astronomers know it does happen.
When matter is compressed beyond a certain density, a black hole is created. It is called black because no light can escape from it. Some black holes are the tombstones of what were once massive stars. An enormous black hole is thought to lurk at the center of the Milky Way galaxy. All the mass of a black hole is concentrated into a point at its center called the singularity. Gravity surrounding the singularity is so strong, you would have to travel faster than light to escape. This creates a spherical zone surrounding the singularity called the event horizon from which nothing can escape. At about one and a half times the diameter of the event horizon, photons become trapped in circular orbits around the black hole. All the mass of a black hole is concentrated into a point at its center called the singularity. Gravity surrounding the singularity is so strong, you would have to travel faster than light to escape. This creates a spherical zone surrounding the singularity called the event horizon from which nothing can escape. In theory, a black hole of any size could exist. A black hole with the mass of our sun would be 3.7 miles (6 km) in diameter. In practice, the death of a star like the sun does not compress the material enough to form a black hole. Stars with about two times the sun’s mass or more form black holes. Astronomers recognize two major types. Stellar-mass black holes have the mass of several sun-sized stars. They form when a dying star explodes in a supernova, then collapses under its own gravity. Matter drawn toward the black hole forms an accretion disc. Supermassive black holes can have billions of times our sun’s mass. Matter drawn toward a supermassive black hole is compressed, heats up and may be blasted out into jets thousands of light-years long. Stellar-mass black holes are scattered throughout the galaxy. A supermassive black hole lies at the core of many galaxies, including our own. The Milky Way’s supermassive black hole is called SgrA* (Sagittarius A-star), and it is seen from Earth in the constellation Sagittarius. The supermassive black hole is about 26,000 light-years away, and has a mass of at least 4 million times the mass of our sun. The powerful gravity of a black hole distorts light, space and time. One effect is gravitational lensing. A black hole between us and a distant galaxy will bend the rays of light, causing our view of the galaxy to be warped. We have yet to photograph a black hole in detail, but simulations suggest that the supermassive black hole at the Milky Way’s center might appear to be a distorted crescent.
A field that permeates the universe and gives rise to a new force, or "fifth force," between massive objects may be a candidate for dark energy and an explanation for why the expansion of the universe is accelerating. This field, called the symmetron field, is so named because it has a symmetry in regions of high density, while in regions of low density, such as a vacuum, the symmetry is broken and the field mediates the new force. Currently, the symmetron concept is purely theoretical. But in a new study, physicist Amol Upadhye at Argonne National Laboratory in Argonne, Illinois, has calculated that a previously unexplored symmetron regime near the dark energy scale will give rise to a fifth force at submillimeter distances. He proposes that short-range gravity experiments can search for the fifth force at these distances and possibly reveal if dark energy is in fact a symmetron field.
"Much of my work has focused on chameleon dark energy theories, and I really only started thinking about symmetrons last summer," Upadhye said. "Modern experimental techniques and technologies have advanced enough to search for new physics at distances of interest for dark energy theories." As Upadhye explained, a symmetron field could fulfill the role of dark energy by acting as a negative pressure. "Dark energy in general can be described by a constant (or slowly varying) vacuum energy density, such as that due to a field whose potential is minimized at a small, positive value," he said. "In the presence of such an energy density, Einstein's equation of General Relativity (GR) predicts that the universe will expand at an accelerating rate. In GR, pressure gravitates; positive pressures contribute to the decelerating expansion of the universe. Dark energy acts as a negative pressure which leads to an accelerating expansion. "The simplest model of a dark energy is Einstein's cosmological constant, a constant vacuum energy density which explains all available data. The big question in cosmology is whether or not the dark energy is just a cosmological constant. Alternative theories predict that the vacuum energy density evolves with time, or that new ('fifth') forces exist between known particles.
Pulsars — tiny spinning stars, heavier than the sun and smaller than a city — have puzzled scientists since they were discovered in 1967. Now, new observations by an international team, including University of Vermont astrophysicist Joanna Rankin, make these bizarre stars even more puzzling. Like the universe’s most powerful lighthouses, pulsars shine beams of radio waves and other radiation for trillions of miles. As these highly magnetized neutron stars rapidly rotate, a pair of beams sweeps by, appearing as flashes or pulses in telescopes on Earth. Using a satellite X-ray telescope, coordinated with two radio telescopes on the ground, the team observed a pulsar that was previously known to flip on and off every few hours between strong (or “bright”) radio emissions and weak (or “quiet”) radio emissions. Monitoring simultaneously in X-rays and radio waves, the team revealed that this pulsar exhibits the same behavior, but in reverse, when observed at X-ray wavelengths. This is the first time that a switching X-ray emission has been detected from a pulsar. Flipping between these two extreme states — one dominated by X-ray pulses, the other by a highly organized pattern of radio pulses — “was very surprising,” says Rankin. “As well as brightening in the X-rays we discovered that the X-ray emission also shows pulses, something not seen when the radio emission is bright,” said Rankin, who spearheaded the radio observations. “This was completely unexpected.” No current model of pulsars is able to explain this switching behavior. All theories to date suggest that X-ray emissions would follow radio emissions. Instead, the new observations show the opposite. “The basic physics of a pulsar have never been solved,” Rankin says.
New images from the Hubble Space Telescope have captured a surprising development in the "zombie planet" orbiting the Fomalhaut star. On Tuesday, NASA released images captured by the Hubble Space Telescope which show a massive debris ring and mysterious planet orbiting the Fomalhaut star. The planet, which is officially known as Fomalhaut b, but is commonly dubbed "the zombie planet", has appeared and disappeared from view over time. Astronomers now believe that the planet's "hide and seek" activity is due to its extreme orbit. According to a Hubble Telescope news release, the unusual orbit of the planet will bring it to within 4.6 billion miles of its star at one point, while later being as far as 27 billion miles from the star. The extreme orbit means it takes the planet 2,000 years to completely orbit its sun. The Earth is 92.96 million miles from the sun, and a complete orbit only takes 365 days. Pluto, the most distant planet in our solar system, has an orbit of 3.67 billion miles away from the sun and a complete orbit takes 248 years.
A new study supports Einstein's view over that of some quantum theorists. A team of researchers came to this conclusion after tracing the long journey three photons took through intergalactic space. The photons were blasted out by an intense explosion known as a gamma-ray burst about 7 billion light-years from Earth. They finally barreled into the detectors of NASA's Fermi Gamma-ray Space Telescope in May 2009, arriving just a millisecond apart. Their dead-heat finish strongly supports the Einsteinian view of space-time, researchers said. The wavelengths of gamma-ray burst photons are so small that they should be able to interact with the even tinier "bubbles" in the quantum theorists' proposed space-time foam. If this foam indeed exists, the three protons should have been knocked around a bit during their epic voyage. In such a scenario, the chances of all three reaching the Fermi telescope at virtually the same time are very low, researchers said. So the new study is a strike against the foam's existence as currently imagined, though not a death blow. "If foaminess exists at all, we think it must be at a scale far smaller than the Planck length, indicating that other physics might be involved," study leader Robert Nemiroff, of Michigan Technological University, said in a statement. The Planck length is an almost inconceivably short distance, about one trillionth of a trillionth the diameter of a hydrogen atom. "There is a possibility of a statistical fluke, or that space-time foam interacts with light differently than we imagined," added Nemiroff, who presented the results Wednesday (Jan. 9) at the 221st meeting of the American Astronomical Society in Long Beach, Calif.
Thirteen dwarf galaxies are playing a cosmic-scale game of Ring Around Andromeda, forming an enormous structure astronomers have never seen before and are hard-pressed to explain with current theories of how galaxies form and evolve. According to current theories, the small galaxies, which contain as many as a few tens of billions of stars each, should be randomly arranged around the Andromeda galaxy. Instead, they orbit Andromeda within a plane more than 1 million light-years across and about 30,000 light-years thick. For comparison, the latest estimates of Andromeda's girth put its diameter at more than 220,000 light-years. The ring, if it can be called that, represents "the largest organized structure in what we call the local group of galaxies," says Michael Rich, a research astronomer at the University of California at Los Angeles. The local group consists of more than 54 galaxies, including dwarfs, about 10 million light-years across. Such rings don't appear when astrophysicists run their models of galaxy evolution, or when they model the local group's formation, he says. In addition, Andromeda and the Milky Way, the two most massive galaxies in the group, appear to be headed for a collision in about 4.5 billion years. The two galaxies are but 2.5 million light-years away and closing.
By peering at alcohol molecules in a distant galaxy, astronomers have determined that a fundamental constant of nature has hardly changed at all over the age of the universe. The constant — the ratio of the mass of a proton to the mass of an electron — has changed by only one hundred thousandth of a percent or less over the past 7 billion years, the observations show. The scientists determined this by pointing the Effelsberg 100-m radio telescope at a distant galaxy that lies 7 billion light-years away, meaning its light has taken that long to reach Earth. Thus, astronomers are seeing the galaxy as it existed 7 billion years ago. The telescope looked for special light features that reflect the absorption of methanol, a simple form of alcohol that contains carbon, hydrogen and oxygen. If the ratio of the mass of the protons and electrons inside those atoms were different than it is here and now in our own galaxy, the scientists would be able to detect this in the properties of the light. "This idea makes the methanol molecule an ideal probe to detect a possible temporal variation in the proton-electron mass ratio," astrophysicist Wim Ubachs of VU University Amsterdam said in a statement. "We proposed to search for methanol molecules in the far-distant universe, to compare the structure of those molecules with that observed in the present epoch in laboratory experiments." Their observations confirmed that the proton-electron mass ratio has changed by no more than 10E-7 over the past 7 billion years. The universe itself is 13.7 billion years old.
Composite X-ray, visible light, and radio image of the bright massive galaxy PKS 0745. Based on X-ray and radio emissions, this black hole could be as much as ten times more massive than previously estimated. Most large galaxies host a supermassive black hole, ranging from millions to billions of times the mass of the Sun. Based on the study of many systems, astronomers discovered a correlation between certain properties of a galaxy and the mass of its central black hole. This relationship seems universal, but we've only been able to examine a subset of the galaxies out there. Black hole masses have only been measured for some of the biggest galaxies in the local Universe—the bright, massive galaxies that sit at the centers of galaxy clusters. A recent study has used an independent means of estimating black hole masses, based on their brightness in X-rays and radio light. J. Hlavacek-Larrondo, A. C. Fabian, A. C. Edge, and M. T. Hogan examined the massive central galaxies in 18 galaxy clusters and found that previous measurements could be off by as much as a factor of ten. In other words, if the luminosity-based measurements are correct, a black hole currently thought to be 6 billion times the mass of the Sun could actually be 60 billion times more massive than our local star.
For the past five-billion years, the expansion of the universe has been powered by a mysterious repulsive force known as "dark energy." Now, thanks to a new technique for measuring the three-dimensional structure of the distant universe, scientists in an international team within the Sloan Digital Sky Survey (SDSS-III), including an astronomer at Penn State University, have made the first measurement of the rate of this cosmic expansion as it was just three-billion years after the Big Bang. "Observations in the past 15 years have revealed that the expansion rate of the universe is accelerating," said Donald Schneider, Distinguished Professor of Astronomy and Astrophysics at Penn State, a coauthor of the study. "Most cosmological models predict that when the universe was young, dark energy had little influence on the expansion; at that time the evolution of the large-scale structure of the universe was dominated by gravitation, which is an attractive force that acted to slow the expansion. The new SDSS-III observations are an important probe of this early era." Schneider is the Sloan Digital Sky Survey's survey coordinator and scientific publications coordinator. The above graph shows how the universe's expansion rate has changed over the last 10-billion years. Until recently, three-dimensional maps by BOSS and other surveys were able to measure the regular distribution of galaxies back to only about five-and-a-half-billion years ago, a time when the expansion of the universe was already accelerating. The numbers along the bottom of the graph show the time in the universe's past, in billions of years. The vertical scale (y-axis) shows the expansion rate of the universe; higher means the universe was expanding faster.These older measurements appear as data points toward the right of the graph. The new SDSS-III measurements, shown as the data point to the far left, have now probed the structure of the early universe at a time when expansion was still slowing down.
Astronomers analysed the energy being carried away from a huge quasar – the bright centres of distant galaxies which are powered by supermassive black holes and spew out vast amounts of matter. Scientists have long claimed that extraordinarily powerful quasars must exist and play a key role in the formation of new galaxies, but until now none had been discovered which came close to their predictions.
Now measurements of a quasar known as SDSS J1106+1939 have established that it releases energy with about two million million times the power output of the Sun – the type of very high energy proposed by theorists. The team of scientists, who made their observations using the European Southern Observatory's Very Large Telescope (VLT), calculated that a mass equivalent to 400 Suns is given off by the quasar each year, at a speed of 800km per second. Dr. Nahum Arav of Virginia Tech University, who led the study, said: “We have discovered the most energetic quasar outflow known to date ... I’ve been looking for something like this for a decade, so it’s thrilling to finally find one of the monster outflows that have been predicted."
Theorists claim that the existence of quasars with such a powerful outflow of energy could solve a number of unanswered questions in cosmology, such as how the central black hole mass of galaxies helps determine the overall mass of the galaxy, and why the universe has so few very large galaxies.
Until now it was unclear whether quasars were powerful enough to produce such vast galaxies as some seen in the distant universe, but the researchers established that both SDSS J1106+1939 and one other quasar each have tremendous outflows.
They are now studying a further 12 similar quasars to determine whether the same is true of other luminous quasars spread across the universe.
A new estimate of the age of our Milky Way Galaxy suggests it was an original member of the universe, having been born just about as early on as was possible. The overall universe is about 13.7 billion years old. That figure, after decades of wildly varying estimates, was pinned down last year to within 200 million years of accuracy. Scientists used space-based observations of a microwave background radiation that had been unleashed as a dense fog cleared, shortly after the universe's formation. The background radiation also suggested that the first stars formed about 200 million years after the Big Bang, theorists say, just as the fog lifted on the initial dark ages. Astronomers have known that the Milky Way is among the oldest of galaxies. The new observations suggest it was indeed one of the first to get under construction. The study puts its age at 13.6 billion years, give or take 800 million years. Further studies will be needed to reduce that margin of error. A key to generating the new number was knowledge that the earliest stars formed almost entirely from hydrogen. They lived short lives and exploded violently, spewing new and heavier elements into their surroundings. The new age estimate is based on measurements of the element beryllium in two stars within a globular cluster of stars called NGC 6397. The amount of Beryllium, one of the lightest elements, increased with time and serves as a sort of "cosmic clock," according to the team, led by Luca Pasquini of the European Southern Observatory. The stars were found to be roughly 13.4 billion years old. The researchers added to that an interval of about 200 million years they say it took for previous generations of stars in the Milky Way to form, explode, and seed the fledgling galaxy with the goods necessary to forge the types of stars found in NGC 6397.
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how fast should we be working to replace our old poluting technologys with substainable ones, with the speed that global warming change is happening the sooner the better I think !