Cosmology Archives

November 6, 2014December 23, 2015 by Tammy Plotner

ALMA Shows Off Baby Pictures… Baby Planets, That Is!

This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. These new ALMA observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system. Credit: ALMA (ESO/NAOJ/NRAO)

In a test of its new high resolution capabilities, the Atacama Large Millimeter/submillimeter Array (ALMA) is happily sharing some family snapshots with us. Astronomers manning the cameras have captured one of the best images so far of a newly-forming planet system gathering itself around a recently ignited star. Located about 450 light years from us in the constellation of Taurus, young HL Tau gathers material around it to hatch its planets and fascinate researchers.

Thanks to ALMA images, scientists have been able to witness stages of planetary formation which have been suspected, but never visually confirmed. This very young star is surrounded by several concentric rings of material which have neatly defined spacings. Is it possible these clearly marked gaps in the solar rubble disc could be where planets have started to gel?

“These features are almost certainly the result of young planet-like bodies that are being formed in the disk. This is surprising since HL Tau is no more than a million years old and such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image,” said ALMA Deputy Director Stuartt Corder.

“When we first saw this image we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disc appears to be full of forming planets. This one image alone will revolutionize theories of planet formation,” explained Catherine Vlahakis, ALMA Deputy Program Scientist and Lead Program Scientist for the ALMA Long Baseline Campaign.

Let’s take a look at what we understand about solar system formation…

Through repeated research, astronomers suspect that all stars are created when clouds of dust and gas succumb to gravity and collapse on themselves. As the star begins to evolve, the dust binds together – turning into “solar system soup” consisting of an array of different sized sand and rocks. This rubble eventually congeals into a thin disc surrounding the parent star and becomes home to newly formed asteroids, comets, and planets. As the planets collect material into themselves, their gravity re-shapes to structure of the disc which formed them. Like dragging a lawn sweeper over fallen leaves, these planets clear a path in their orbit and form gaps. Eventually their progress pulls the gas and dust into an even tighter and more clearly defined structure. Now ALMA has shown us what was once only a computer model. Everything we thought we knew about planetary formation is true and ALMA has proven it.

“This new and unexpected result provides an incredible view of the process of planet formation. Such clarity is essential to understand how our own solar system came to be and how planets form throughout the universe,” said Tony Beasley, director of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, which manages ALMA operations for astronomers in North America.

“Most of what we know about planet formation today is based on theory. Images with this level of detail have up to now been relegated to computer simulations or artist’s impressions. This high resolution image of HL Tauri demonstrates what ALMA can achieve when it operates in its largest configuration and starts a new era in our exploration of the formation of stars and planets,” says Tim de Zeeuw, Director General of ESO.

The major reason astronomers have never seen this type of structure before is easy to envision. The very dust which creates the planetary disc around HL Tau also conceals it to visible light. Thanks to ALMA’s ability to “see” at much longer wavelengths, it can image what’s going on at the very heart of the cloud. “This is truly one of the most remarkable images ever seen at these wavelengths. The level of detail is so exquisite that it’s even more impressive than many optical images. The fact that we can see planets being born will help us understand not only how planets form around other stars but also the origin of our own solar system,” said NRAO astronomer Crystal Brogan.

How does ALMA do it? According to the research staff, its new high-resolution capabilities were achieved by spacing the antennas up to 15 kilometers apart. This baseline at millimeter wavelengths enabled a resolution of 35 milliarcseconds, which is equivalent to a penny as seen from more than 110 kilometers away. “Such a resolution can only be achieved with the long baseline capabilities of ALMA and provides astronomers with new information that is impossible to collect with any other facility, including the best optical observatories,” noted ALMA Director Pierre Cox.

This is a composite image of the young star HL Tauri and its surroundings using data from ALMA (enlarged in box at upper right) and the NASA/ESA Hubble Space Telescope (rest of the picture). This is the first ALMA image where the image sharpness exceeds that normally attained with Hubble. Credit: ALMA (ESO/NAOJ/NRAO)

The long baselines spell success for the ALMA observations and are a tribute to all the technology and engineering that went into its construction. Future observations at ALMA’s longest possible baseline of 16 kilometers will mean even more detailed images – and an opportunity to further expand our knowledge of the Cosmos and its workings. “This observation illustrates the dramatic and important results that come from NSF supporting world-class instrumentation such as ALMA,” said Fleming Crim, the National Science Foundation assistant director for Mathematical and Physical Sciences. “ALMA is delivering on its enormous potential for revealing the distant universe and is playing a unique and transformational role in astronomy.”

Pass them baby pictures our way, Mama ALMA… We’re delighted to take a look!

Original Story Source: “Revolutionary ALMA Image Reveals Planetary Genesis” – ESO Press Release

November 4, 2014December 23, 2015 by Tim Reyes

The World is Not Enough: A New Theory of Parallel Universes is Proposed

Do we exist in a space and time shared by many worlds? And are all these infinite worlds interacting? (Credit: Do-Da)

Imagine if you were told that the world is simple and exactly as it seems, but that there is an infinite number of worlds just like ours. They share the same space and time, and interact with each other. These worlds behave as Newton first envisioned, except that the slightest interactions of the infinite number create nuances and deviations from the Newtonian mechanics. What could be deterministic is swayed by many worlds to become the unpredictable.

This is the new theory about parallel universes explained by Australian and American theorists in a paper published in the journal Physics Review X. Called the “Many Interacting Worlds” theory (MIW), the paper explains that rather than standing apart, an infinite number of universes share the same space and time as ours. They show that their theory can explain quantum mechanical effects while leaving open the choice of theory to explain the universe at large scales. This is a fascinating new variant of Multiverse Theory that, in a sense, creates not just a doppelganger of everyone but an infinite number of them all overlaying each other in the same space and time.

Rather than island universes as proposed by other theories, Many Interacting Worlds (MIW) proposes many all lying within one space and time. (Photo Credit: Public Domain) — Rather than island universes as proposed by other multiverse theories, Many Interacting Worlds (MIW) proposes many all lying within one space and time.

Cosmology is a study in which practitioners must transcend their five senses. Einstein referred to thought experiments, and Dr. Stephen Hawking — surviving and persevering despite having ALS — has spent decades wondering about the Universe and developing new theories, all within his mind.

The “Many Interacting Worlds” theory, presented by Michael Hall and Howard Wiseman from Griffith University in Australia, and Dirk-André Deckert from the University of California, Davis, differs from previous multiverse theories in that the worlds — as they refer to universes — coincide with each other, and are not just parallel.

The theorists explain that while the interactions are subtle, the interaction of an infinite number of worlds can explain quantum phenomena such as barrier tunneling in solid state electronics, can be used to calculate quantum ground states, and, as they state, “at least qualitatively” reproduce the results of the double-slit experiment.

Schrödinger, in explaining his wave function and the interaction of two particles (EPR paradox) coined the term “entanglement”. In effect, the MIW theory is an entanglement of an infinite number of worlds but not in terms of a wave function. The theorists state that they were compelled to develop MIW theory to eliminate the need for a wave function to explain the Universe. It is quite likely that Einstein would have seen MIW as very appealing considering his unwillingness to accept the principles laid down by the Copenhagen interpretation of Quantum Theory.

While MIW theory can reproduce some of the most distinctive quantum phenomena, the theorists emphasize that MIW is in an early phase of development. They state that the theory is not yet as mature as long-standing unification theories. In their paper, they use Newtonian physics to keep their proofs simple. Presenting this new “many worlds” theory indicates they had achieved a level of confidence in its integrity such that other theorists can use it as a starter kit – peer review but also expand upon it to explain more worldly phenomena.

Hall compares MIW to the classical theory of ideal gases and partial pressures. He says:

Two worlds of many act as if they are two gases A & B within a volume of space. In the words of the theorists, “It would be as if the A gas and B gas were completely oblivious to each other unless every single A molecule were close to its B partner. Such an interaction is quite unlike anything in classical physics, and it is clear that our hypothetical A-composed observer would have no experience of the B world in its everyday observations, but by careful experiment might detect a subtle and nonlocal action on the A molecules of its world. Such action, though involving very many, rather than just two, worlds, is what we propose could lie behind the subtle and nonlocal character of quantum mechanics.”

Two of the perpetrators of the century long problem of unifying General Relativity Theory and Quantum Physics, A. Einstein, E. Schroedinger. — Two of the perpetrators of the century-long problem of unifying General Relativity Theory and Quantum Physics – Albert Einstein, Erwin Schroedinger.

The theorists continue by expounding that MIW could lead to new predictions. If correct, then new predictions would challenge experimentalists and observers to recreate or search for the effects. Such was the case for Einstein’s Theory of General Relativity. For example, the bending of the path of light by gravity and astronomer Eddington’s observing starlight bending around Sun during a total Solar Eclipse. Such new predictions and confirmation would begin to stand MIW theory apart from the many other theories of everything.

Hall, Deckert, and Wiseman continue – “Regarded as a fundamental physical theory in its own right, the MIW approach may also lead to new predictions arising from the restriction to a finite number of worlds. Finally, it provides a natural discretization of the Holland-Poirier approach, which may be useful for numerical purposes.”

Multiverse theories have gained notoriety in recent years through the books and media presentations of Dr. Michio Kaku of the City College of New York and Dr. Brian Greene of Columbia University, New York City. Dr. Green presented a series of episodes delving into the nature of the Universe on PBS called “The Fabric of the Universe” and “The Elegant Universe”. The presentations were based on his books such as “The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos.”

Hugh Everett’s reinterpretation of Dr. Richard Feynman’s cosmological theory, that the world is a weighted sum of alternative histories, states that when particles interact, reality bifurcates into a set of parallel streams, each being a different possible outcome. In contrast to Feynmann’s theory and Everett’s interpretation, the parallel worlds of MIW do not bifurcate but simply exist in the same space and time. MIW’s parallel worlds are not a consequence of “quantum behavior” but are rather the drivers of it.

Professor Howard Wiseman, Director of Griffith University's Centre for Quantum Dynamics and coauthor of the paper on the "Many Interacting World" theory. (Photo Credit: Griffith University) — Professor Howard Wiseman, Director of Griffith University’s Centre for Quantum Dynamics and coauthor of the paper on the “Many Interacting World” theory. (Photo Credit: Griffith University)

Hall states in the paper that simple Newtonian Physics can explain how all these worlds evolve. This, they explain, can be used effectively as a first approximation in testing and expanding on their theory, MIW. Certainly, Einstein’s Special and General Theories of Relativity completes the Newtonian equations and are not dismissed by MIW. However, the paper begins with the simpler model using Newtonian physics and even explains that some fundamental behavior of quantum mechanics unfolds from a universe comprised of just two interacting worlds.

So what is next for the Many Interacting Worlds theory? Time will tell. Theorists and experimentalists shall begin to evaluate its assertions and its solutions to explain known behavior in our Universe. With new predictions, the new challenger to Unified Field Theory (the theory of everything) will be harder to ignore or file away with the wide array of theories of the last 100 years. Einstein’s theories began to reveal that our world exudes behavior that defies our sensibility but he could not accept the assertions of Quantum Theory. Einstein’s retort to Bohr was “God does not throw dice.” The MIW theory of Hall, Deckert, and Wiseman might be what Einstein was seeking until the end of his life. For MIW theory, one world is not enough and for these many worlds their interactions might be compared to a martini shaken but not stirred.

References:

Quantum Phenomena Modeled by Interactions between Many Classical Worlds

October 29, 2014December 23, 2015 by Tammy Plotner

Double Disc Found Feeding Each Other In Binary Star System

This wide-field view shows the sky around the young multiple star system GG Tauri, which appears very close to the centre of this picture. This view also shows a dust cloud and evidence of star formation near the top of the picture. Credit: ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin

Deep within the Taurus Dark Cloud complex, one of the closest star-forming regions to Earth has just revealed one of its secrets – an umbilical cord of gas flowing from the expansive outer disc toward the interior of a binary star system known as GG Tau-A. According to the ESO press release, this never-before-seen feature may be responsible for sustaining a second, smaller disc of planet-forming material that otherwise would have disappeared long ago.

A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France and CNRS used the Atacama Large
Millimeter/submillimeter Array (ALMA) to observe the distribution of
dust and gas in the unusual GG Tau-A system. Since at least half of
Sun-like stars are the product of binary star systems, these type of
findings may produce even more fertile grounds for discovering
exoplanets. However, the 450 light year distant GG Tau system is even more complex than previously thought. Through observations taken with the VLTI, astronomers have discovered its primary star – home to the inner disc – is part of a more involved multiple-star system. The secondary star is also a close binary!

“We may be witnessing these types of exoplanetary systems in the midst of formation,” said Jeffrey Bary, an astronomer at Colgate University in Hamilton, N.Y., and co-author of the paper. “In a sense, we are learning why these seemingly strange systems exist.”

Let’s take a look…

This artist’s impression shows the dust and gas around the double star system GG Tauri-A. Researchers using ALMA have detected gas in the region between two discs in this binary system. This may allow planets to form in the gravitationally perturbed environment of the binary. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.

“Like a wheel in a wheel, GG Tau-A contains a large, outer disc
encircling the entire system as well as an inner disc around the main central star. This second inner disc has a mass roughly equivalent to that of Jupiter.” says the research team. “Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.”

Thanks to studies done with ALMA, the researchers made an exciting discovery in these disc structures… gas clumps located between the two. This observation could mean that material is being fed from the outer disc to feed the inner. Previously observations done with ALMA show that a single star pulls its materials inward from the outer disc. Is it possible these gas pockets in the double disc GG Tau-A system are creating a sustaining lifeline between the two?

“Material flowing through the cavity was predicted by computer
simulations but has not been imaged before. Detecting these clumps
indicates that material is moving between the discs, allowing one to
feed off the other,” explains Dutrey. “These observations demonstrate that material from the outer disc can sustain the inner disc for a long time. This has major consequences for potential planet formation.”

As we know, planets are created from the materials leftover from
stellar ignition. However, the creation of a solar system occurs at a snail’s pace, meaning that a debris disc with longevity is required for planet formation. Thanks to these new “disc feeding” observations from ALMA, researchers can surmise that other multiple-star systems behave in a similar manner… creating even more possibilities for exoplanet formation.

“This means that multiple star systems have a way to form planets, despite their complicated dynamics. Given that we continue to find interesting planetary systems, our observations provide a glimpse of the mechanisms that enable such systems to form,” concludes Bary.

During the initial phase of planetary searches, the emphasis was placed on Sun-like, single-host stars. Later on, binary systems gave rise to giant Jupiter-sized planets – nearly large enough to be stars on their own. Now the focus has turned to pointing our planetary discovery efforts towards individual members of multiple-systems.

Emmanuel Di Folco, co-author of the paper, concludes: “Almost half the Sun-like stars were born in binary systems. This means that we have found a mechanism to sustain planet formation that applies to a significant number of stars in the Milky Way. Our observations are a big step forward in truly understanding planet formation.”

Original Story Source: Planet-forming Lifeline Discovered in a Binary Star System ALMA Examines Ezekiel-like “Wheel in a Wheel” of Dust and Gas – ESO Science News Release.

October 17, 2014December 23, 2015 by Tim Reyes

Hawking Radiation Replicated in a Laboratory?

In honor of Dr. Stephen Hawking, the COSMOS center will be creating the most detailed 3D mapping effort of the Universe to date. Credit: BBC, Illus.: T.Reyes

Dr. Stephen Hawking delivered a disturbing theory in 1974 that claimed black holes evaporate. He said black holes are not absolutely black and cold but rather radiate energy and do not last forever. So-called “Hawking radiation” became one of the physicist’s most famous theoretical predictions. Now, 40 years later, a researcher has announced the creation of a simulation of Hawking radiation in a laboratory setting.

The possibility of a black hole came from Einstein’s theory of General Relativity. Karl Schwarzchild in 1916 was the first to realize the possibility of a gravitational singularity with a boundary surrounding it at which light or matter entering cannot escape.

This month, Jeff Steinhauer from the Technion – Israel Institute of Technology, describes in his paper, “Observation of self-amplifying Hawking radiation in an analogue black-hole laser” in the journal Nature, how he created an analogue event horizon using a substance cooled to near absolute zero and using lasers was able to detect the emission of Hawking radiation. Could this be the first valid evidence of the existence of Hawking radiation and consequently seal the fate of all black holes?

This is not the first attempt at creating a Hawking radiation analogue in a laboratory. In 2010, an analogue was created from a block of glass, a laser, mirrors and a chilled detector (Phys. Rev. Letter, Sept 2010); no smoke accompanied the mirrors. The ultra-short pulse of intense laser light passing through the glass induced a refractive index perturbation (RIP) which functioned as an event horizon. Light was seen emitting from the RIP. Nevertheless, the results by F. Belgiorno et al. remain controversial. More experiments were still warranted.

The latest attempt at replicating Hawking radiation by Steinhauer takes a more high tech approach. He creates a Bose-Einstein condensate, an exotic state of matter at very near absolute zero temperature. Boundaries created within the condensate functioned as an event horizon. However, before going into further details, let us take a step back and consider what Steinhauer and others are trying to replicate.

Artists illustrations of black holes are guided by descriptions given from theorists. There are many illustrations. A black hole has never been seen up close. However, to have Hawking radiation all the theatrics of accretion disks and matter being funneled off a companion star are unnecessary. One just needs a black hole in the darkness of space. (Illustration: public domain) — Artists illustrations of black holes are guided by descriptions given to them by theorists. There are many illustrations. A black hole has never been seen up close. However, to have Hawking radiation, all the theatrics of accretion disks and matter being funneled off a companion star are unnecessary. Just a black hole in the darkness of space will do. (Illustration: public domain)

The recipe for the making Hawking radiation begins with a black hole. Any size black hole will do. Hawking’s theory states that smaller black holes will more rapidly radiate than larger ones and in the absence of matter falling into them – accretion, will “evaporate” much faster. Giant black holes can take longer than a million times the present age of the Universe to evaporate by way of Hawking radiation. Like a tire with a slow leak, most black holes would get you to the nearest repair station.

So you have a black hole. It has an event horizon. This horizon is also known as the Schwarzchild radius; light or matter checking into the event horizon can never check out. Or so this was the accepted understanding until Dr. Hawking’s theory upended it. And outside the event horizon is ordinary space with some caveats; consider it with some spices added. At the event horizon the force of gravity from the black hole is so extreme that it induces and magnifies quantum effects.

All of space – within us and surrounding us to the ends of the Universe includes a quantum vacuum. Everywhere in space’s quantum vacuum, virtual particle pairs are appearing and disappearing; immediately annihilating each other on extremely short time scales. With the extreme conditions at the event horizon, virtual particle and anti-particles pairs, such as, an electron and positron, are materializing. The ones that appear close enough to an event horizon can have one or the other virtual particle zapped up by the black holes gravity leaving only one particle which consequently is now free to add to the radiation emanating from around the black hole; the radiation that as a whole is what astronomers can use to detect the presence of a black hole but not directly observe it. It is the unpairing of virtual particles by the black hole at its event horizon that causes the Hawking radiation which by itself represents a net loss of mass from the black hole.

So why don’t astronomers just search in space for Hawking radiation? The problem is that the radiation is very weak and is overwhelmed by radiation produced by many other physical processes surrounding the black hole with an accretion disk. The radiation is drowned out by the chorus of energetic processes. So the most immediate possibility is to replicate Hawking radiation by using an analogue. While Hawking radiation is weak in comparison to the mass and energy of a black hole, the radiation has essentially all the time in the Universe to chip away at its parent body.

This is where the convergence of the growing understanding of black holes led to Dr. Hawking’s seminal work. Theorists including Hawking realized that despite the Quantum and Gravitational theory that is necessary to describe a black hole, black holes also behave like black bodies. They are governed by thermodynamics and are slaves to entropy. The production of Hawking radiation can be characterized as a thermodynamic process and this is what leads us back to the experimentalists. Other thermodynamic processes could be used to replicate the emission of this type of radiation.

Using the Bose-Einstein condensate in a vessel, Steinhauer directed laser beams into the delicate condensate to create an event horizon. Furthermore, his experiment creates sound waves that become trapped between two boundaries that define the event horizon. Steinhauer found that the sound waves at his analogue event horizon were amplified as happens to light in a common laser cavity but also as predicted by Dr. Hawking’s theory of black holes. Light escapes from the laser present at the analogue event horizon. Steinhauer explains that this escaping light represents the long sought Hawking radiation.

Publication of this work in Nature underwent considerable peer review to be accepted but that alone does not validate his findings. Steinhauer’s work will now withstand even greater scrutiny. Others will attempt to duplicate his work. His lab setup is an analogue and it remains to be verified that what he is observing truly represents Hawking radiation.

References:

“Observation of self-amplifying Hawking radiation in an analogue black-hole laser“, Nature Physics, 12 October 2014

“Hawking Radiation from Ultrashort Laser Pulse Filaments”, F. Belgiorno, et al., Phys. Rev. Letter, Sept 2010

“Black hole explosions?”, S. W. Hawking, et al., Nature, 01 March 1974

“The Quantum Mechanics of Black Holes”, S. W. Hawking, Scientific American, January 1977

October 16, 2014December 23, 2015 by Shannon Hall

Distant Galaxies Reveal 3D Cosmic Web for the First Time

3D map of the cosmic web at a distance of 10.8 billion light years from Earth. The map was generated from imprints of hydrogen gas observed in the spectrum of 24 background galaxies, which are located behind the volume being mapped. This is the first time that large-scale structures in such a distant part of the Universe have been mapped directly. The coloring represents the density of hydrogen gas tracing the cosmic web, with brighter colors representing higher density. Credit: Casey Stark (UC Berkeley) and Khee-Gan Lee (MPIA)

On the largest scales, networks of gaseous filaments span hundreds of millions of light-years, connecting massive galaxy clusters. But this gas is so rarified, it’s impossible to see directly.

For years, astronomers have used quasars — brilliant galactic centers fueled by supermassive black holes rapidly accreting material — to map the otherwise invisible matter.

But now, for the first time, a team of astronomers led by Khee-Gan Lee, a post-doc at the Max Planck Institute for Astronomy, has managed to create a three-dimensional map of the large-scale structure of the Universe using distant galaxies. And the advantages are numerous.

The science has always gone a little something like this: as the bright light from a distant quasar travels toward Earth, it encounters the intervening clouds of hydrogen gas and is partially absorbed. This leaves dark absorption lines in the quasar’s spectrum.

Artist's impression illustrating the technique of Lyman-alpha tomography: as light from distant background galaxies (yellow arrows) travels through the Universe towards Earth, hydrogen gas in the foreground leaves a characteristic imprint ("absorption signature"). From this imprint, astronomers can reconstruct which clouds the light has encountered as it traverses the "cosmic web" of dark matter and gas that accounts for the biggest structures in our universe. By observing a number of background galaxies in a small patch of the sky, astronomers were able to create a 3D map of the cosmic web using a technique similar to medical computer tomography (CT) scans. The coloring represents the density of hydrogen gas tracing the cosmic web, with brighter colors representing higher density. The rendition of the cosmic web in this image is based on a supercomputer simulation of cosmic structure formation. Credit: Khee-Gan Lee (MPIA) and Casey Stark (UC Berkeley) — Artist’s impression illustrating how a distant quasar’s or galaxy’s spectrum becomes clouded with absorption lines from intervening hydrogen gas. Credit: Khee-Gan Lee (MPIA) and Casey Stark (UC Berkeley)

If the Universe were static, the dark absorption lines would always be located at the same spot (121 nanometers for the so-called Lyman-alpha line) in the quasar’s spectrum. But because the Universe is expanding, the distant quasar is flying away from the Earth at a rapid speed. This stretches the quasar’s light, such that each intervening hydrogen gas cloud imprints its absorption signature on a different region of the quasar’s spectrum, leaving a forest of lines.

Therefore detailed measurements of multiple quasars’ spectra close together can actually reveal the three-dimensional nature of the intervening hydrogen clouds. But galaxies are nearly 100 times more numerous than quasars. So in theory they should provide a much more detailed map.

The only problem is that galaxies are also about 15 times fainter than quasars. So astronomers thought they were simply not bright enough to see well in the distant universe. But Lee carried out calculations that suggested otherwise.

“I was surprised to find that existing large telescopes should already be able to collect sufficient light from these faint galaxies to map the foreground absorption, albeit at a lower resolution than would be feasible with future telescopes,” said Lee in a news release. “Still, this would provide an unprecedented view of the cosmic web which has never been mapped at such vast distances.”

Lee and his colleagues used the 10-meter Keck I telescope on Mauna Kea, Hawaii to take a look a closer look at the distant galaxies and the forest of hydrogen absorption embedded in their spectra. But even the weather in Hawaii can turn ugly.

“We were pretty disappointed as the weather was terrible and we only managed to collect a few hours of good data,” said coauthor Joseph Hennawi, also from the Max Planck Institute for Astronomy. “But judging by the data quality as it came off the telescope, it was already clear to me that the experiment was going to work.”

The team was only able to collect data for four hours. But it was still unprecedented. They looked at 24 distant galaxies, which provided sufficient coverage of a small patch of the sky and allowed them to combine the information into a three-dimensional map.

The map reveals the large-scale structure of the Universe when it was only a quarter of its current age. But the team hopes to soon parse the map for more information about the structure’s function — following the flows of cosmic gas as it funneled away from voids and onto distant galaxies. It will provide a unique historical record on how the galaxy clusters and voids grew from inhomogeneities in the Big Bang.

The results have been published in the Astrophysical Journal and are available online.

October 14, 2014December 30, 2015 by Jason Major

On Scarves, Squirrels, and the Fate of the Universe

Are you scared of the dark, personal failure, or just feeling a tad nihilistic? Maybe you’re worried about asteroids, solar flares, or the heat death of the Universe… or perhaps you’ve just misplaced your favorite winter accessory and it’s driving you… er, nuts. If any of these are applicable (or even if none is) be sure to watch the ridiculously award-winning video above by animator Eoin Duffy. (And if you’re wondering why I’m sharing this on Universe Today, well… you’ll see.)

Click. Play. Now.

Credit: Eoin Duffy. HT to the Observation Deck @io9.

October 7, 2014December 23, 2015 by Elizabeth Howell

How to Turn Your Phone Into A Cosmic Ray Detector

Artist's impression of cosmic rays striking Earth (Simon Swordy/University of Chicago, NASA)

Quick, do you have an Android phone in your pocket? A few small changes and you could help physicists probe more of the curious nature of cosmic rays, high-energy particles that emanate from outside our solar system.

Just download an app, cover up your phone’s camera with duct tape, then place it somewhere (running idle) with the screen facing up. If a particle “event” happens, the information will be logged in a central database.

The project (called Distributed Electronic Cosmic-ray Observatory or DECO) aims to record secondary particles called muons that occur when cosmic rays hit the Earth’s atmosphere. Scientists believe cosmic rays are created in black holes and supernovas, but more studies are needed.

Screenshot of an Android app developed at the University of Wisconsin-Madison that aims to capture cosmic rays. Credit: Justin Vandenbroucke

Researchers at the Wisconsin IceCube Particle Astrophysics Center (WIPAC), led by Justin Vandenbroucke, note that there are things about cosmic rays that confuse physicists. Their paths in space change as they go across magnetic fields, and it makes searching for other astronomy events difficult. That’s where they hope the phone study will be useful.

“Smartphone cameras use silicon chips that work through what is called the photoelectric effect, in which particles of light, or photons, hit a silicon surface and release an electric charge,” the University of Wisconsin-Madison wrote in a press release.

“The same is true for muons. When a muon strikes the semiconductor that underpins a smartphone camera, it liberates an electric charge and creates a signature in pixels that can be logged, stored and analyzed.”

For more details on how to run and use the app, consult this page (it’s the second item).

Source: University of Wisconsin-Madison

September 25, 2014December 23, 2015 by Tammy Plotner

Hubble Vision: Galaxy DDO 68 – Young Or Old?

Only astronomers know for sure… Or do they? In this assembly of images taken with Hubble’s Advanced Camera for Surveys, scientists have utilized both visible and infrared light to survey a most unusual galaxy. When looking for a newly formed galaxy in our “cosmic neighborhood”, they spied DDO 68 (a.k.a. UGC 5340). Normally to witness galactic evolution, we have to look over great distances to see back in time… but this particular collection of gas and stars seems to break the rules!

Researching galactic evolution isn’t a new concept. Over the last few decades astronomers have increased our understanding of how galaxies change with time. One of the most crucial players in this game has been the NASA/ESA Hubble Space Telescope. Through its eyes, scientists can see over almost incomprehensible distances – studying light that has taken billions of years to reach us. We are essentially looking back in time.

While this is great news on its own, studying progressively younger galaxies can sometimes pose more questions than it answers. For example, all the newly created galaxies reside a huge distance from us and thereby appear small and faint when imaged. On the other side of the coin, galaxies which are close to us appear to be far more mature.

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This video begins with a ground based view of the night sky, before zooming in on dwarf galaxy DDO 68 as the NASA/ESA Hubble Space Telescope sees it. This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks? Credit: NASA/ESA

DDO 68, imaged here by the NASA/ESA Hubble Space Telescope, would seem to be the best example of a nearby newly-formed galaxy. Just how nearby? Estimates place it at about 39 million light years distant. While this might seem like a very long way, it is still roughly 50 times closer than other galactic examples. Studying galaxies of different ages is important to our understanding of how the Universe works. Astronomers have discovered that young galaxies are quite different than those which have aged. In this case, DDO 68 gives off the appearance of being young. These findings come from examining its structure, appearance and composition. However, researchers question their findings. It is possible this galaxy may be considerably older than initial findings indicate.

“All of the available data are consistent with the fact that DDO 68 is a very rare candidate for young galaxies.” says S. A. Pustilnik (et al). “The bulk of its stars were formed during the recent (with the first encounter about 1 Gyr ago) merger of two very gas-rich disks.”

These common events – mergers and collisions – are part of galactic life and are generally responsible for older galaxies being more bulky. These “senior citizens” are normally laced with a wide variety of stellar types – young, old, large and small. The chemistry is also different, too. Very young galaxies are rich in hydrogen and helium, making them tantalizingly similar in composition to the primordial matter created by the Big Bang. Older galaxies have more experiences. Numerous stellar events have happened within them over their lifetimes, making them rich in heavy elements. This is what makes DDO 68 very exciting! It is the best local candidate found so far to be low in heavier elements.

“DDO 68 (UGC 5340) is the second most metal-poor star-forming galaxy,” explains Pustilnik. “Its peculiar optical morphology and its HI distribution and kinematics are indicative of a merger origin. We use the u, g, r, and i photometry based on the SDSS images of DDO 68 to estimate its stellar population ages.”

Step into the light? You bet. The Hubble observations were meant to examine the properties of this mysterious galaxy’s light – determine whether or not it contains any older stars. If they are discovered, which seems to be the case, this would disprove the theory that DDO 68 is singularly comprised of younger stars. If not, it will validate the unique nature of this nearby neighbor. While more computer modeling and studies are needed, we can still enjoy this incredible look at another cosmic enigma!

Original Story Source: A Galaxy Of Deception – Hubble/ESA

September 24, 2014December 23, 2015 by Brian Koberlein

New Results from Planck: It Doesn’t Look Good For BICEP2

Dust map of the Universe. The region studied by BICEP2 is indicated by the rectangle in the right circle. Credit: Planck Collaboration

One of the recent sagas in cosmology began with the BICEP2 press conference announcing evidence of early cosmic inflation. There was some controversy since the press release was held before the paper was peer reviewed. The results were eventually published in Physical Review Letters, though with a more cautious conclusion than the original press release. Now the Planck team has released more of their data. This new work hasn’t yet been peer reviewed, but it doesn’t look good for BICEP2.

As you might recall, BICEP2 analyzed light from the cosmic microwave background (CMB) looking for a type of pattern known as B-mode polarization. This is a pattern of polarized light that (theoretically) is caused by gravitational waves produced by early cosmic inflation. There’s absolutely no doubt that BICEP2 detected B-mode polarization, but that’s only half the challenge. The other half is proving that the B-mode polarization they saw was due to cosmic inflation, and not due to some other process, mainly dust. And therein lies the problem. Dust is fairly common in the Milky Way, and it can also create B-mode polarization. Because the dust is between us and the CMB, it can contaminate its B-mode signal. This is sometimes referred to as the foreground problem. To really prove you have evidence of B-mode polarization in the CMB, you must ensure that you’ve eliminated any foreground effects from your data.

When the BICEP2 results were first announced, the question of dust was immediately raised. Some researchers noted that dust particles caught in magnetic fields could produce stronger B-mode effects than originally thought. Others pointed out that part of the data BICEP2 used to distinguish foreground dust wasn’t very accurate. This is part of the reason the final results went from “We found inflation!” to “We think we’ve found inflation! (But we can’t be certain.)”

Dust effects seen by Planck (shaded region) compared with inflation results of BICEP2 (solid line). Credit: Planck Collaboration — Dust effects seen by Planck (shaded region) compared with inflation results of BICEP2 (solid line).
Credit: Planck Collaboration

The new results from Planck chip at that claim even further. Whereas BICEP2 looked at a specific region of the sky, Planck has been gathering data across the entire sky. This means lots more data that can be used to distinguish foreground dust from a CMB signal. This new paper presented a map of the foreground dust, and a good summary can be seen in the figure. The shaded areas represents the B-mode levels due to dust at different scales. The solid line represents the B-mode distribution due to inflation as seen by BICEP2. As you can see, it matches the dust signal really well.

The simple conclusion is that the results of BICEP2 have been shown to be dust, but that isn’t quite accurate. It is possible that BICEP2 has found a mixture of dust and inflation signals, and with a better removal of foreground effects there may still be a real result. It is also possible that it’s all dust.

While this seems like bad news, it actually answers a mystery in the BICEP2 results. The level of inflation claimed by BICEP2 was actually quite large. Much larger than expected than many popular models. The fact that a good chuck of the B-mode polarization is due to dust means that inflation can’t be that large. So small inflation models are back in favor. It should also be emphasized that even if the BICEP2 results are shown to be entirely due to dust, that doesn’t mean inflation doesn’t exist. It would simply mean we have no evidence either way.

It’s tempting to look at all this with a bit of schadenfreude. Har, har, the scientists got it wrong again. But a more accurate view would be of two rival sports teams playing an excellent game. BICEP2 almost scored, but Planck rallied an excellent defense. Both teams want to be the first to score, but the other team won’t let them cheat to win. And we get to watch it happen.

Anyone who says science is boring hasn’t been paying attention.

Here’s the paper from the Planck team.

September 19, 2014April 8, 2018 by Tammy Plotner

Lazy Giant Galaxies Gain Mass By Ingesting Smaller Neighbors

Some of the many thousands of merging galaxies identified within the GAMA survey. Credit: Professor Simon Driver and Dr Aaron Robotham, ICRAR.

The Anglo-Australian Telescope in New South Wales has been watching how lazy giant galaxies gain size – and it isn’t because they create their own stars. In a research project known as the Galaxy And Mass Assembly (GAMA) survey, a group of Australian scientists led by Professor Simon Driver at the International Centre for Radio Astronomy Research (ICRAR) have found the Universe’s most massive galaxies prefer “eating” their neighbors.

According to findings published in the journal “Monthly Notices of the Royal Astronomical Society”, astronomers studied more than 22,000 individual galaxies to see how they grew. Apparently smaller galaxies are exceptional star producers, forming their stellar members from their own gases. However, larger galaxies are lazy. They aren’t very good at stellar creation. These massive monsters rarely produce new stars on their own. So how do they grow? They cannibalize their companions. Dr. Aaron Robotham, who is based at the University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), explains that smaller ‘dwarf’ galaxies were being consumed by their heavyweight peers.

“All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” he said. “Then every now and then they get completely cannibalized by some much larger galaxy.”

So how does our home galaxy stack up to these findings? Dr. Robotham, who led the research, said the Milky Way is at a tipping point and is expected to now grow mainly by eating smaller galaxies, rather than by collecting gas.

“The Milky Way hasn’t merged with another large galaxy for a long time but you can still see remnants of all the old galaxies we’ve cannibalized,” he said. “We’re also going to eat two nearby dwarf galaxies, the Large and Small Magellanic Clouds, in about four billion years.” Robotham also added the Milky Way wouldn’t escape unscathed. Eventually, in about five billion years, we’ll encounter the nearby Andromeda Galaxy and the tables will be turned. “Technically, Andromeda will eat us because it’s the more massive one,” he said.

Andromeda and the Milky Way Collide! from ICRAR on Vimeo.

This simulation shows what will happen when the Milky Way and Andromeda get closer together and then collide, and then finally come together once more to merge into an even bigger galaxy.

Simulation Credit: Prof Chris Power (ICRAR-UWA), Dr Alex Hobbs (ETH Zurich), Prof Justin Reid (University of Surrey), Dr Dave Cole (University of Central Lancashire) and the Theoretical Astrophysics Group at the University of Leicester. Video Production Credit: Pete Wheeler, ICRAR.

What exactly is going on here? Is it a case of mutual attraction? According to Dr. Robotham when galaxies grow, they acquire a heavy-duty gravitational field allowing them to suck in neighboring galaxies with ease. But why do they stop producing their own stars? Is it because they have exhausted their fuel? Robotham said star formation slow downs in really massive galaxies might be “because of extreme feedback events in a very bright region at the center of a galaxy known as an active galactic nucleus.”

“The topic is much debated, but a popular mechanism is where the active galactic nucleus basically cooks the gas and prevents it from cooling down to form stars,” Dr. Robotham said.

Will the entire Universe one day become just a single, large galaxy? In reality, gravity may very well cause galaxies groups and clusters to congeal into a limited number of super-giant galaxies, but that will take many billions of years to occur.

“If you waited a really, really, really long time that would eventually happen, but by really long I mean many times the age of the Universe so far,” Dr. Robotham said.

While the GAMA survey findings didn’t take billions of years, it didn’t happen overnight either. It took seven years and more than 90 scientists to complete – and it wasn’t a single revelation. From this work there have been over 60 publications and there are still another 180 in progress!

Original Story Souce: Monster galaxies gain weight by eating smaller neighbours – ICAR

Further reading: ‘Galaxy and Mass Assembly (GAMA): Galaxy close-pairs, mergers and the future fate of stellar mass’ in the Monthly Notices of the Royal Astronomical Society. Published online 19/9/2014 at: http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stu1604 . Preprint version accessible at: http://arxiv.org/abs/1408.1476 .