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Chameleon Star Baffles Astronomers

Chameleon Star Baffles Astronomers | Amazing Science | Scoop.it

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.

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New 'Zombie Planet' images shock scientists - exoplanet's orbit around its sun takes 2,000 years to complete

New 'Zombie Planet' images shock scientists - exoplanet's orbit around its sun takes 2,000 years to complete | Amazing Science | Scoop.it

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.

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Einstein Was Right: Space-Time Is Smooth And Not Foamy

Einstein Was Right: Space-Time Is Smooth And Not Foamy | Amazing Science | Scoop.it
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.

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What’s going on around Andromeda? Curious structure made of dwarf galaxies puzzles scientists

What’s going on around Andromeda? Curious structure made of dwarf galaxies puzzles scientists | Amazing Science | Scoop.it

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.

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Relative masses of 7-billion-year-old protons and electrons confirmed to match those of today’s particles

Relative masses of 7-billion-year-old protons and electrons confirmed to match those of today’s particles | Amazing Science | Scoop.it

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.

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Biggest black holes potentially ten times more massive than thought

Biggest black holes potentially ten times more massive than thought | Amazing Science | Scoop.it

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.

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How has the expansion of the Universe changed over time (say the last 10 Billion years)?

How has the expansion of the Universe changed over time (say the last 10 Billion years)? | Amazing Science | Scoop.it

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.

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Most powerful black hole blast discovered - 100 times the energy of whole Milky Way ejected

Most powerful black hole blast discovered - 100 times the energy of whole Milky Way ejected | Amazing Science | Scoop.it

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.

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Milky Way's Age Narrowed Down - It Was Original Member Of The Early Universe!

Milky Way's Age Narrowed Down - It Was Original Member Of The Early Universe! | Amazing Science | Scoop.it

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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Universe, human brain and internet have similar structures, and similar dynamics govern these very different systems

Universe, human brain and internet have similar structures, and similar dynamics govern these very different systems | Amazing Science | Scoop.it
The structure of the universe and the laws that govern its growth may be more similar than previously thought to the structure and growth of the human brain and other complex networks, such as the Internet or a social network of trust relationships between people, according to a new study.

 

“By no means do we claim that the universe is a global brain or a computer,” said Dmitri Krioukov, co-author of the paper, published by the Cooperative Association for Internet Data Analysis (CAIDA), based at the San Diego Supercomputer Center (SDSC) at the University of California, San Diego.

 

“But the discovered equivalence between the growth of the universe and complex networks strongly suggests that unexpectedly similar laws govern the dynamics of these very different complex systems,” Krioukov noted. Having the ability to predict – let alone trying to control – the dynamics of complex networks remains a central challenge throughout network science. Structural and dynamical similarities among different real networks suggest that some universal laws might be in action, although the nature and common origin of such laws remain elusive.

 

By performing complex supercomputer simulations of the universe and using a variety of other calculations, researchers have now proven that the causal network representing the large-scale structure of space and time in our accelerating universe is a graph that shows remarkable similarity to many complex networks such as the Internet, social, or even biological networks. “These findings have key implications for both network science and cosmology,” said Krioukov.

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Cosmic Fatigue: Births of Stars Declining Sharply, Astronomers Say

Cosmic Fatigue: Births of Stars Declining Sharply, Astronomers Say | Amazing Science | Scoop.it

It’s evening in the universe. The rate at which the universe is producing stars has fallen continuously in the last 11 billion years. The stars we have are dying, and we’re not making new ones the way we used to. A group of British and American astronomers recently reported that the birthrate of stars in the universe has declined precipitously and continuously over the last 11 billion years.

 

The universe today is only producing stars one-thirtieth as fast as it was at its peak in the lusty primordial days when protogalaxies, all gas and spume, were bouncing around like pups in a closet, colliding and merging, popping with blazing bright new stars.

 

In a news release issued by the Royal Astronomical Society, the astronomer David Sobral of Leiden University in the Netherlands said, “You might say that the universe has been suffering from a long, serious crisis: cosmic G.D.P. output is now only 3 percent of what it used to be at the peak in star production.” Dr. Sobral and his colleagues published their paper in the Monthly Notices of the Royal Astronomical Society.

 

They calculated that the current consolidation rate of “starstuff” into stars amounts to about a half a trillion tons per year per cubic light-year. The Sun is about 2,000 trillion trillion tons. In a fundamental sense, this cosmic fatigue is not really new. Other surveys, including one led by the aptly named Alan Heavens of the University of Edinburgh a few years ago, have come to similar conclusions. But one detail of this new study hit me.

 

Dr. Sobral and his colleagues said that if this decline in breeding goes on, it means the universe has already made 95 percent of the star mass that it will ever make. As eternity goes on — and on and on — the cosmos, like Palm Springs, will be dominated by older and older stars.

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We live in a universe dominated by old stars - star formation is at only 1/30th of its peak

We live in a universe dominated by old stars - star formation is at only 1/30th of its peak | Amazing Science | Scoop.it

While parts of the world experience economic hardship, a team of Portuguese, UK, Japanese, Italian and Dutch astronomers has found an even bigger slump happening on a cosmic scale. In the largest ever study of its kind, the international team of astronomers has established that the rate of formation of new stars in the Universe is now only 1/30th of its peak and that this decline is only set to continue.

 

The accepted model for the evolution of the Universe predicts that stars began to form about 13.4 billion years ago, or around three hundred million years after the Big Bang. Many of these first stars are thought to have been monsters by today's standards, and were probably hundreds of times more massive than our Sun. Such beasts aged very quickly, exhausted their fuel, and exploded as supernovae within a million years or so. Lower mass stars in contrast have much longer lives and last for billions of years.


Much of the dust and gas from stellar explosions was (and is still) recycled to form newer and newer generations of stars. Our Sun, for example, is thought to be a third generation star, and has a very typical mass by today's standards. But regardless of their mass and properties, stars are key ingredients of galaxies like our own Milky Way. Unveiling the history of star formation across cosmic time is fundamental to understanding how galaxies form and evolve.

 

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Model-Dependent Realism

Model-Dependent Realism | Amazing Science | Scoop.it

When and how did the universe begin? Why are we here? Why is there something rather than nothing? What is the nature of reality? Why are the laws of nature so finely tuned as to allow for the existence of intelligent beings like ourselves? And, finally, is the apparent existence of our universe evidence of a "God-like structure", who has set all things in motion—or does science offer another explanation?

 

The most fundamental questions about the origins of the universe and of life itself, once the province of philosophy, now occupy the territory where scientists, philosophers, and theologians meet—if only to disagree. According to quantum theory, the cosmos does not have just a single existence or history, but rather the future influences the past and many histories of the universe exist simultaneously. When applied to the universe as a whole, this idea calls into question the very notion of cause and effect. But the “top-down” approach to cosmology would say that the fact that the past takes no definite form means that we create history by observing it, rather than that history creates us. We ourselves could just be the product of seemingly random quantum fluctuations in the very early universe. Part of the quantum theory predicts that the “multiverse”—ours own universe being just one of many universes—appeared spontaneously out of nothing, each multiverse possessing its own different laws of nature. A “model-dependent” theory of reality might be the best we can hope to find.

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Astronomers Measure the Temperature of the Universe 7.2 Billion Years Ago

Astronomers Measure the Temperature of the Universe 7.2 Billion Years Ago | Amazing Science | Scoop.it
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.

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Astronomers discover the largest structure in the universe - 4 Billion light years across

Astronomers discover the largest structure in the universe - 4 Billion light years across | Amazing Science | Scoop.it

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.



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Black-Hole-Powered Planets Could Reach Speeds Matched Only by SubAtomic Particles

Black-Hole-Powered Planets Could Reach Speeds Matched Only by SubAtomic Particles | Amazing Science | Scoop.it
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.

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Early universe: Magnetic fields created before the first stars

Early universe: Magnetic fields created before the first stars | Amazing Science | Scoop.it
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.

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5 Reasons We May Live in a Multiverse

5 Reasons We May Live in a Multiverse | Amazing Science | Scoop.it
Our universe may be one of many, according to numerous physics theories.

Via Leopoldo Benacchio, Guillaume Decugis, Belinda Suvaal
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Guillaume Decugis's curator insight, December 10, 2012 3:43 PM

A good high-level recap of all the different theories behind the multiple universes concept (yes there are also multiple theories of multiple universes: isn't that meta?).

Gestcash's curator insight, December 23, 2012 10:39 AM

The universe we live in may not be the only one out there. In fact, our universe could be just one of an infinite number of universes making up a "multiverse."

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The very first stars may have turned on when the universe was only 750 million years old

The very first stars may have turned on when the universe was only 750 million years old | Amazing Science | Scoop.it

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.

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Super-massive black hole with a mass half the size of its hosting galaxy

Super-massive black hole with a mass half the size of its hosting galaxy | Amazing Science | Scoop.it

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.

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Scientists report new dark matter finding from merging galaxy cluster

Scientists report new dark matter finding from merging galaxy cluster | Amazing Science | Scoop.it
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.

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Astrophysicists On The Verge Of Spotting Gravitational Waves

Astrophysicists On The Verge Of Spotting Gravitational Waves | Amazing Science | Scoop.it

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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Puts it all in perspective » Interactive Graphics: Magnifying the Universe

Puts it all in perspective » Interactive Graphics: Magnifying the Universe | Amazing Science | Scoop.it

A joint project of Killer Infographics and Mandril Design. Interactivity creates greater reader engagement, which, in turn, generates interest and educates a wide spectrum of people. This particular interactive infographic was picked up by hundreds of websites, including National Geographic!

 

The precision of the interactive scalability highlight the importance of accuracy in successful infographics - Killer Infographics will never publish any data they won't stand behind!

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Szabolcs Kósa's comment, November 24, 2012 4:19 PM
amazing.
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New mark for oldest, furthest galaxy - just 420 million years after the Big Bang

New mark for oldest, furthest galaxy - just 420 million years after the Big Bang | Amazing Science | Scoop.it

Astronomers have caught a glimpse of a galaxy that sets a new record for the furthest, and thus oldest, yet discovered - 13.3 billion light years from Earth. The star cluster was observed in its infancy - as it looked when the universe was just three per cent of its present age, according to NASA and the European Space Agency.

 

"We see the newly discovered galaxy, named MACS0647-JD, as it was 420 million years after the Big Bang" that created the Universe 13.7 billion years ago, a statement says. "Its light has travelled 13.3 billion years to reach Earth."

 

The astronomers, grouped under the joint American-European CLASH project, use the orbiting Hubble and Spitzer telescopes as well as employing massive galaxy clusters as cosmic magnifiers to find distant galaxies. The process, known as gravitational lensing, allows astronomers to see galaxies that emit light with a brightness weaker than that of a candle on the Moon, thus undetectable directly by telescopes on Earth.

 

The newly discovered cluster is so small, less than 600 light years across, that scientists believe it may still be in the first stages of galaxy formation. As a point of reference, our own Milky Way is 150,000 light years across.

 

"The estimated mass of this baby galaxy is roughly equal to 100 million or a billion suns, or 0.1 to 1.0 per cent of our Milky Way's stars," the statement says. In September, the CLASH scientists said they had spotted the Universe's oldest and furthest galaxy, using the same technique - the previous record-holding 13.2 billion light years away. With gravitational lensing, theorised by Albert Einstein himself, astronomers use younger galaxies that lie closer to Earth to magnify older ones lurking in the distance by bending the light they emit.

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H3+ of Interstellar Space - One of the Most Important Molecules in Existence

H3+ of Interstellar Space - One of the Most Important Molecules in Existence | Amazing Science | Scoop.it

The molecule known as H3+ is believed to have had a vital role in cooling down the first stars of the universe, and may still play an important part in the formation of current stars. The unassuming molecule known as a triatomic hydrogen ion, or H3+, may hold secrets of the formation of the first stars after the Big Bang. In the presence of the radiation that pervades interstellar space, H3+ can gain energy that causes it to vibrate and lose its symmetry. Here, the electrons are shared among only two of the hydrogen atoms. Asymmetries such as these allow the molecule to emit light and cool down forming stars.


"Most of the universe consists of hydrogen in various forms," said Ludwik Adamowicz, a professor in the University of Arizona''s department of chemistry and biochemistry, but the H3+ ion is the most prevalent molecular ion in interstellar space. It's also one of the most important molecules in existence."

 

Believed to be critical to the formation of stars in the early days of the universe, H3+ also is the precursor to many types of chemical reactions, said Adamowicz, including those leading to compounds such as water or carbon, which are essential for life.

 

Early stars would have become hotter and hotter until they exploded before they ever formed, according to Michele Pavanello, who led the groundbreaking research, unless there was a way to release some of that pent-up energy.

 

"There wouldn't be any star formation if there weren't molecules that slowly cool down the forming star by emitting light," said Pavanello. Not many molecules can do that, he added, partly because very few molecules existed in the early days of the universe. "Astronomers think that the only molecule that could cool down a forming star in that particular time is H3+."

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