Tag: Big Bang Theory

New from Space: Simulations and X-Rays Point to Dark Matter

center_universe2The cosmic hunt for dark matter has been turning up some interesting clues of late. And during the month of June, two key hints came along that might provide answers; specifically simulations that look at the “local Universe” from the Big Bang to the present day and recent studies involving galaxy clusters. In both cases, the observations made point towards the existence of Dark Matter – the mysterious substance believed to make up 85 per cent of the mass of the Universe.

In the former case, the clues are the result of new supercomputer simulations that show the evolution of our “local Universe” from the Big Bang to the present day. Physicists at Durham University, who are leading the research, say their simulations could improve understanding of dark matter due to the fact that they believe that clumps of the mysterious substance – or halos – emerged from the early Universe, trapping intergalactic gas and thereby becoming the birthplaces of galaxies.

universe_expansionCosmological theory predicts that our own cosmic neighborhood should be teeming with millions of small halos, but only a few dozen small galaxies have been observed around the Milky Way. Professor Carlos Frenk, Director of Durham University’s Institute for Computational Cosmology, said:

I’ve been losing sleep over this for the last 30 years… Dark matter is the key to everything we know about galaxies, but we still don’t know its exact nature. Understanding how galaxies formed holds the key to the dark matter mystery… We know there can’t be a galaxy in every halo. The question is: ‘Why not?’.

The Durham researchers believe their simulations answer this question, showing how and why millions of halos around our galaxy and neighboring Andromeda failed to produce galaxies. They say the gas that would have made the galaxy was sterilized by the heat from the first stars that formed in the Universe and was prevented from cooling and turning into stars. However, a few halos managed to bypass this cosmic furnace by growing early and fast enough to hold on to their gas and eventually form galaxies.

dark_matterThe findings were presented at the Royal Astronomical Society’s National Astronomy Meeting in Portsmouth on Thursday, June 26. The work was funded by the UK’s Science and Technology Facilities Council (STFC) and the European Research Council. Professor Frenk, who received the Royal Astronomical Society’s top award, the Gold Medal for Astronomy, added:

We have learned that most dark matter halos are quite different from the ‘chosen few’ that are lit up by starlight. Thanks to our simulations we know that if our theories of dark matter are correct then the Universe around us should be full of halos that failed to make a galaxy. Perhaps astronomers will one day figure out a way to find them.

Lead researcher Dr Till Sawala, in the Institute for Computational Cosmology, at Durham University, said the research was the first to simulate the evolution of our “Local Group” of galaxies, including the Milky Way, Andromeda, their satellites and several isolated small galaxies, in its entirety. Dr Sawala said:

What we’ve seen in our simulations is a cosmic own goal. We already knew that the first generation of stars emitted intense radiation, heating intergalactic gas to temperatures hotter than the surface of the sun. After that, the gas is so hot that further star formation gets a lot more difficult, leaving halos with little chance to form galaxies. We were able to show that the cosmic heating was not simply a lottery with a few lucky winners. Instead, it was a rigorous selection process and only halos that grew fast enough were fit for galaxy formation.

darkmatter1The close-up look at the Local Group is part of the larger EAGLE project currently being undertaken by cosmologists at Durham University and the University of Leiden in the Netherlands. EAGLE is one of the first attempts to simulate from the beginning the formation of galaxies in a representative volume of the Universe. By peering into the virtual Universe, the researchers find galaxies that look remarkably like our own, surrounded by countless dark matter halos, only a small fraction of which contain galaxies.

The research is part of a program being conducted by the Virgo Consortium for supercomputer simulations, an international collaboration led by Durham University with partners in the UK, Germany, Holland, China and Canada. The new results on the Local Group involve, in addition to Durham University researchers, collaborators in the Universities of Victoria (Canada), Leiden (Holland), Antwerp (Belgium) and the Max Planck Institute for Astrophysics (Germany).

ESO2In the latter case, astronomers using ESA and NASA high-energy observatories have discovered another possible hint by studying galaxy clusters, the largest cosmic assemblies of matter bound together by gravity. Galaxy clusters not only contain hundreds of galaxies, but also a huge amount of hot gas filling the space between them. The gas is mainly hydrogen and, at over 10 million degrees celsius, is hot enough to emit X-rays. Traces of other elements contribute additional X-ray ‘lines’ at specific wavelengths.

Examining observations by ESA’s XMM-Newton and NASA’s Chandra spaceborne telescopes of these characteristic lines in 73 galaxy clusters, astronomers stumbled on an intriguing faint line at a wavelength where none had been seen before. The astronomers suggest that the emission may be created by the decay of an exotic type of subatomic particle known as a ‘sterile neutrino’, which is predicted but not yet detected.

dark_matter_blackholeOrdinary neutrinos are very low-mass particles that interact only rarely with matter via the so-called weak nuclear force as well as via gravity. Sterile neutrinos are thought to interact with ordinary matter through gravity alone, making them a possible candidate as dark matter. As Dr Esra Bulbul – from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, USA, and lead author of the paper discussing the results – put it:

If this strange signal had been caused by a known element present in the gas, it should have left other signals in the X-ray light at other well-known wavelengths, but none of these were recorded. So we had to look for an explanation beyond the realm of known, ordinary matter… If the interpretation of our new observations is correct, at least part of the dark matter in galaxy clusters could consist of sterile neutrinos.

The surveyed galaxy clusters lie at a wide range of distances, from more than a hundred million light-years to a few billion light-years away. The mysterious, faint signal was found by combining multiple observations of the clusters, as well as in an individual image of the Perseus cluster, a massive structure in our cosmic neighborhood.

The supermassive black hole at the center of the Milky Way galaxy.The implications of this discovery may be far-reaching, but the researchers are being cautious. Further observations with XMM-Newton, Chandra and other high-energy telescopes of more clusters are needed before the connection to dark matter can be confirmed. Norbert Schartel, ESA’s XMM-Newton Project Scientist, commented:

The discovery of these curious X-rays was possible thanks to the large XMM-Newton archive, and to the observatory’s ability to collect lots of X-rays at different wavelengths, leading to this previously undiscovered line. It would be extremely exciting to confirm that XMM-Newton helped us find the first direct sign of dark matter. We aren’t quite there yet, but we’re certainly going to learn a lot about the content of our bizarre Universe while getting there.

Much like the Higgs Boson, the existence of Dark Matter was first theorized as a way of explaining how the universe appears to have mass that we cannot see. But by looking at indirect evidence, such as the gravitational influence it has on the movements and appearance of other objects in the Universe, scientists hope to one day confirm its existence. Beyond that, there is the mystery of “Dark Energy”, the hypothetical form of energy that permeates all of space and is believed to be behind accelerations in the expansion of the universe.

As with the discovery of the Higgs Boson and the Standard Model of particle physics, detecting these two invisible forces will at last confirm that the Big Bang and Cosmological theory are scientific fact – and not just working theories. When that happens, the dream of humanity finally being able to understand the universe (at both the atomic and macro level) may finally become a reality!

Source: sciencedaily.com, (2)

News from Space: Universe’s Evolution Mapped in Detail

universe_expansionScientists have come up with the best computer model to date of the universe, one which maps the evolution of the cosmos in unprecedented detail. Known as Illustris, this virtual cosmos – which was created by U.S., English and German researchers using a network of supercomputers – includes details never before achieved in a simulation. All told, the numerical-based model covers the 13-billion-year evolution of the universe, beginning just 12 million years after the Big Bang took place.

While cosmologists have been developing and employing computer models of the universe for several decades, the outcome is usually a rough approximation of the universe that scientists observe in reality.  Illustris, however, has produced a universe that looks uncannily like the real on.  Among other things, it models how the universe expands, how galaxies are formed, their composition and distribution, and the mechanics of how stars and black holes are formed.

planck-attnotated-580x372Given all the recent breakthroughs in physics and cosmology, this ultra-detailed virtual model should come as no surprise. For example, this past April, scientists made not only made the first-ever observation of gravitational waves, they also processed data that is believed to be the first real indication of the existence of Dark Matter. In addition, the ESA’s Planck mission released the most detailed thermal imaging map of the universe last year that placed an accurate date on the universe’s age and confirmed the validity of the Big Bang Theory.

The Illustris creators say it represents “a significant step forward in modelling galaxy formation”, and provides a good visual representation of our ever-expanding (no pun!) understanding of the universe. A recent article that appeared last Wednesday in the journal Nature describes Illustris, and several videos (like those below) have been released that show the simulation in action. Check them out below:

 


Sources: cbc.ca, IO9.com

News From Space: Cosmic Inflation and Dark Matter

big bang_blackholeHello again! In another attempt to cover events that built up while I was away, here are some stories that took place back in March and early April of this year, and which may prove to be some of the greatest scientific finds of the year. In fact, they may prove to be some of the greatest scientific finds in recent history, as they may help to answer the most fundamental questions of all – namely, what is the universe made of, and how did it come to exist?

First up, in a development that can only be described as cosmic in nature (pun intended), back in March, astrophysicists at the Harvard-Smithsonian Center announced the first-ever observation of gravitational waves. This discovery, which is the first direct evidence of the Big Bang, is comparable to significance to CERN’s confirmation of the Higgs boson in 2012. And there is already talk about a Nobel Prize for the Harvard crew because of their discovery.

big_bangThis theory, which states that the entire universe sprung into existence from a tiny spot in the universe some 13.8 billion years ago, has remained the scientific consensus for almost a century. But until now, scientists have had little beyond theory and observations to back it up. As the name would suggest, gravitational waves are basically ripples in spacetime that have been propagating outward from the center of the universe ever since the Big Bang took place.

Originally predicted as part of Einstein’s General Theory of Relativity in 1916, these waves are believed to have existed since a trillionth of a trillionth of a trillionth of a second after the Big Bang took place, and have been propagating outward for roughly 14 billion years. The theory also predicts that, if we can detect some gravitational waves, it’s proof of the initial expansion during the Big Bang and the continued inflation that has been taking place ever since.

bicep2-640x425Between 2010 and 2012, the BICEP2 – a radio telescope situated at the Amundsen–Scott South Pole Station (pictured above) – the research team listened to the Cosmic Microwave Background (CMB). They were looking for hints of B-mode polarization, a twist in the CMB that could only have been caused by the ripples of gravitational waves. Following a lot of data analysis, the leaders announced that they found that B-mode polarization.

The work will now be scrutinized by the rest of the scientific community, of course, but the general consensus seems confident that it will stand up. In terms of scientific significance, the confirmation of gravitational waves would be the first direct evidence that the universe started out as nothing, erupted into existence 13.8 billion years ago, and has continued to expand ever since. This would confirm that cosmic inflation really exists and that the entire structure of the universe was decided in the beginning by the tiniest flux of gravitational waves.

planck-attnotated-580x372And that’s not only discovery of cosmic significance that was made in recent months. In this case, the news comes from NASA’s Fermi Gamma-ray Space Telescope, which has been analyzing high-energy gamma rays emanating from the galaxy’s center since 2008. After pouring over the results, an independent group of scientists claimed that they had found an unexplained source of emissions that they say is “consistent with some forms of dark matter.”

These scientists found that by removing all known sources of gamma rays, they were left with gamma-ray emissions that so far they cannot explain. And while they were cautious that more observations will be needed to characterize these emissions, this is the first time that potential evidence has been found that may confirm that this mysterious, invisible mass that accounts for roughly 26.8% of the universe actually exists.

darkmatter1To be fair, scientists aren’t even sure what dark matter is made of. In fact, it’s very existence is inferred from gravitational effects on visible matter and gravitational lensing of background radiation. Originally, it was hypothesized to account for the discrepancies that were observed between the calculations of the mass of galaxies, clusters and entire universe made through dynamical and general relativistic means, and  the mass of the visible “luminous” matter.

The most widely accepted explanation for these phenomena is that dark matter exists and that it is most probably composed of Weakly Interacting Massive Particles (WIMPs) that interact only through gravity and the weak force. If this is true, then dark matter could produce gamma rays in ranges that Fermi could detect. Also, the location of the radiation at the galaxy’s center is an interesting spot, since scientists believe that’s where dark matter would lurk since the insofar invisible substance would be the base of normal structures like galaxies.

fermi_gamma-raysThe galactic center teems with gamma-ray sources, from interacting binary systems and isolated pulsars to supernova remnants and particles colliding with interstellar gas. It’s also where astronomers expect to find the galaxy’s highest density of dark matter, which only affects normal matter and radiation through its gravity. Large amounts of dark matter attract normal matter, forming a foundation upon which visible structures, like galaxies, are built.

Dan Hooper, an astrophysicist at Fermilab and lead author of the study, had this to say on the subject:

The new maps allow us to analyze the excess and test whether more conventional explanations, such as the presence of undiscovered pulsars or cosmic-ray collisions on gas clouds, can account for it. The signal we find cannot be explained by currently proposed alternatives and is in close agreement with the predictions of very simple dark matter models.

Hooper and his colleagues suggest that if WIMPs were destroying each other, this would be “a remarkable fit” for a dark matter signal. They again caution, though, that there could be other explanations for the phenomenon. Writing in a paper submitted to the journal Physical Review D, the researchers say that these features are difficult to reconcile with other explanations proposed so far, although they note that plausible alternatives not requiring dark matter may yet materialize.

CERN_LHCAnd while a great deal more work is required before Dark Matter can be safely said to exist, much of that work can be done right here on Earth using CERN’s own equipment. Tracy Slatyer, a theoretical physicist at the Massachusetts Institute of Technology and co-author of the report, explains:

Dark matter in this mass range can be probed by direct detection and by the Large Hadron Collider (LHC), so if this is dark matter, we’re already learning about its interactions from the lack of detection so far.This is a very exciting signal, and while the case is not yet closed, in the future we might well look back and say this was where we saw dark matter annihilation for the first time.

Still, they caution that it will take multiple sightings – in other astronomical objects, the LHC, or direct-detection experiments being conducted around the world – to validate their dark matter interpretation. Even so, this is the first time that scientists have had anything, even tentative, to base the existence of Dark Matter’s on. Much like until very recently with the Big Bang Theory, it has remained a process of elimination – getting rid of explanations that do not work rather than proving one that does.

So for those hoping that 2014 will be the year that the existence of Dark Matter is finally proven – similar to how 2012 was the year the Higgs Boson was discovered or 2013 was the year the Amplituhedron was found – there are plenty of reasons to hope. And in the meantime, check out this video of a gamma-ray map of the galactic center, courtesy of NASA’s Goddard Space Center.


Sources: extremetech.com, IO9.com, nasa.gov, cfa.harvard.edu, news.nationalgeographic.com

News From Space: Big Bang Vs. Black Hole

big bang_blackholeFor decades, the Big Bang Theory has remained the accepted theory of how the universe came to be, beating out challengers like the Steady State Theory. However, many unresolved issues remain with this theory, the most notable of which is the question of what could have existed prior to the big bang. Because of this, scientists have been looking for way to refine the theory.

Luckily, a group of theoretical physicists from the Perimeter Institute (PI) for Theoretical Physics in Waterloo, Ontario have announced a new interpretation on how the universe came to be. Essentially, they postulate that the birth of the universe could have happened after a four-dimensional star collapsed into a black hole and began ejecting debris.

big_bangThis represents a big revision of the current theory, which is that universe grew from an infinitely dense point or singularity. But as to what was there before that remain unknown, and is one of a few limitations of the Big Bang. In addition, it’s hard to predict why it would have produced a universe that has an almost uniform temperature, because the age of our universe (about 13.8 billion years) does not give enough time to reach a temperature equilibrium.

Most cosmologists say the universe must have been expanding faster than the speed of light for this to happen. But according to Niayesh Afshordi, an astrophysicist with PI who co-authored the study, even that theory has problems:

For all physicists know, dragons could have come flying out of the singularity. The Big Bang was so chaotic, it’s not clear there would have been even a small homogenous patch for inflation to start working on.

black_holeThe model Afshordi and her colleagues are proposing is basically a three-dimensional universe floating as a membrane (or brane) in a “bulk universe” that has four dimensions. If this “bulk universe” has four-dimensional stars, these stars could go through the same life cycles as the three-dimensional ones we are familiar with. The most massive ones would explode as supernovae, shed their skin and have the innermost parts collapse as a black hole.

The 4-D black hole would then have an “event horizon”, the boundary between the inside and the outside of a black hole. In a 3-D universe, an event horizon appears as a two-dimensional surface; but in a 4-D universe, the event horizon would be a 3-D object called a hypersphere. And when this 4-D star blows apart, the leftover material would create a 3-D brane surrounding a 3-D event horizon, and then expand.

planck-attnotated-580x372To simplify it a little, they are postulating that the expansion of the universe was triggered by the motion of the universe through a higher-dimensional reality. While it may sound complicated, the theory does explain how the universe continues to expand and is indeed accelerating. Whereas previous theories have credited a mysterious invisible force known as “dark energy” with this, this new theory claims it is the result of the 3-D brane’s growth.

However, there is one limitation to this theory which has to do with the nearly uniform temperature of the universe. While the model does explain how this could be, the ESA’s Planck telesceop recently mapped out the universe and discovered small temperature variations in the cosmic microwave background (CBM). These patches were believed to be leftovers of the universe’s beginnings, which were a further indication that the Big Bang model holds true.

big_bang1The PI team’s own CBM readings differ from this highly accurate survey by about four percent, so now they too are going back to the table and looking to refine their theory. How ironic! However, the IP team still feel the model has worth. While the Planck observations show that inflation is happening, they do not show why the inflation is happening.

Needless to say, we are nowhere near to resolving how the universe came to be, at least not in a way that resolves all the theoretical issues. But that’s the things about the Big Bang – it’s the scientific equivalent of a Hydra. No matter how many times people attempt to discredit it, it always comes back to reassert its dominance!

Source: universetoday.com, perimeterinstitute.ca

More News in Quantum Computing!

quantum-computers-The-Next-GenerationRecently, a team of researchers at the University of Rochester conducted an experiment where they managed to suspend a nano-sized diamond in free space with a laser. The purpose of the experiment was to measure the amount of light emitted from the diamond, but had the added bonus of demonstrating applications that could be useful in the field of quantum computing.

For those unfamiliar with the concept, quantum computing differs from conventional computing since it does not rely on sending information via a series of particles (electrons) through one-way channels. Instead, quantum computing relies on the process of beaming the states of particles (i.e. a photons quantum properties) from one location to the next.

nanodiamondSince this process occurs faster than the speed of light (as no movement takes place) and qubits (quantum bits) have the ability to be in more than one state simultaneously, computations done using this model would be exponentially faster. But despite many advancements made in recent years, the field remains largely theoretical and elusive.

To conduct their experiment, the researchers focused a laser into a 25 cm (10 inch) chamber and then sprayed an aerosol containing dissolved nanodiamonds inside. These nanodiamonds were attracted to the laser in a technique known as “laser trapping”, until a single particle was isolated and made to levitate. Once the tiny gem was levitating in free space, the researchers used another laser to make defects within the diamond emit light at given frequencies.

nanodiamond1This process is known as photoluminescence – a form light emission that is caused by defects in the tiny diamond that allows for the absorptions of photons. When the system is excited, it changes the spin; and when the it relaxes after the change, other photons are emitted. This occurs because nitrogen atoms replace some of the carbon atoms in the diamond. Once the nitrogen is nested in the diamond’s atomic structure, it is possible to excite electrons with a laser.

According to the researchers, this photoluminescence process has the potential to excite the system and cause what is known as Bohr spin quantum jumps, which are changes in spin configuration of the internal defect. This occurs because nitrogen atoms replace some of the carbon atoms in the diamond. Once the nitrogen is nested in the diamond’s atomic structure, it is possible to excite electrons with a laser.

????????????????????In addition, the potential also exists to turn the nanodiamond into an optomechanical resonator. According to Nick Vamivakas, an assistant professor of optics at the University of Rochester, these are structures in which the vibrations of the system can be controlled by light. Optomechanical resonators have the potential to be used as incredibly precise sensors, which could lead to uses in microchips.

In addition, these resonator systems have the potential to create Schrödinger Cat states, which are typically not found in microscopic objects. As anyone who’ familiar with Futurama or Big Bang Theory may recall, this refers to the thought experiment where a cat is inside a box with poison, and until someone opens the box and determines its whereabouts, the cat could be considered simultaneously both alive and dead.

^Being able to stimulate matter so that it can exist in more than one state at any given time is not only revolutionary, it is a clear step towards the creation of machines that exploit this principle to perform computations. According to Nick Vamivakas, an assistant professor of optics at the University of Rochester, explained:

Cat or cat-like states contradict our everyday experiences since we do not see common things in quantum states. The question is: where is this boundary between microscopic and macroscopic? By generating quantum states of larger and larger objects, we can hone in on a boundary … if there is one.

Naturally, the Rochester team is still a long way from achieving their big breakthrough, and Vamivakas himself admits that he does not know how far away a quantum computing truly is. In terms of this latest experiment, the team still needs to cool the crystal better, which they are hoping can be achieved with a few technical improvements. And then they hope to find a better way of running the experiment than spraying nanodiamond dust into a tube.

In the meantime, check out this video of the experiment. It promises to be “illuminating” (sorry!):


Source: gizmag.com

Big Bang Theory Flash Mob!

My thanks to Rami for bringing this one to my attention. Man, I can be so out of it when it comes to pop culture sometimes! But I think you’ll agree, this is not something any fan of Big Bang Theory, or flash mobs for that matter, could afford to miss. Downright awesome in terms of its sheer suddeness, choreography and presentation. One has to wonder how you organize something like this considering all the people and coordinating dancing involved.

Be sure to watch to the end too. Not only do they cover many different songs, but the finish caps it off with hilarity! And the cast themselves, they got some sweet-ass dance moves. Mainly I just watching Penny – God, is she hot! – but Howard, Raj, Leonard and Bernadette bust a few too. Man, that’s a good show. Enjoy the clip!

Three-Man Soyuz Crew Headed for ISS

I just came across this news story on cnet.com, of how a Russian Soyuz rocket departed Earth to deposit a team of two rookies and one veteran cosmonaut on the International Space Station. Hmm, a three man crew is heading for the ISS aboard a Russian-built Soyuz rocket? That sound familiar to you? Provided you’re a fan of Big Bang Theory, it damn well ought to seeing as how this is exactly how the last season ended.

In any case, this mission has a somewhat unusual profile: to test the effect of zero-g on aquariums and aquatic life forms contained therein. I kind you not. The Soyuz craft, which lifted off at 4:51 p.m. (local time) from the Baikonur Cosmodrome in Kazakhstan, was carrying with it a tank with 32 medaka fish that were bound for a zero-gravity research aquarium aboard the ISS’s lab complex.

At the same time, the crew will be shuttling supplies to the station and conducting routine maintenance on the station’s spacewalk while they are aboard. This will consist of fixing a leak in the coolant system of the station’s far left-side solar array, which is responsible for dissipating heat within the station. The mission is expected to last a total of 143 days, with the three man crew returning to Earth in March 2013. Personally, I can’t imagine being in space, or anywhere, for that long! I hope they packed plenty of digital devices, and at least have an internet hookup up there 😉

Higgs Boson, by Sheldon Cooper!

In honor of the recent news about the discovery of the Higgs Boson, I thought I’d post this funny clip from the Big Bang Theory. In it, Dr. Sheldon Cooper (who I swear is a friend of mine in disguise) tries to use it as the keyword in a game of charades. Not only is this one of my favorite shows around (it speaks to me!), they also manage to sneak in a fair bit of real science from time to time. Heck, if it weren’t for them, I never would have been sent scrambling to my laptop to look up the concept of “Loop Quantum Gravity”.

It almost makes we want to write about real science, unrelated to fiction and literature and such. Articles dedicated to the graviton, neutrinos, Relativity, and the mysteries of space and time. But then again, who has that kind of time, who would want to read it, and most importantly, would I really get any enjoyment out of writing about all that stuff? After all, I’m a geek, not a nerd 🙂

Enjoy!