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)

The Large Hadron Collider: We’ve Definitely Found the Higgs Boson

higgs-boson1In July 2012, the CERN laboratory in Geneva, Switzerland made history when it discovered an elementary particle that behaved in a way that was consistent with the proposed Higgs boson – otherwise known as the “God Particle”. Now, some two years later, the people working the Large Hadron Collider have confirmed that what they observed was definitely the Higgs boson, the one predicted by the Standard Model of particle physics.

In the new study, published in Nature Physics, the CERN researchers indicated that the particle observed in 2012 researchers indeed decays into fermions – as predicted by the standard model of particle physics. It sits in the mass-energy region of 125 GeV, has no spin, and it can decay into a variety of lighter particles. This means that we can say with some certainty that the Higgs boson is the particle that gives other particles their mass – which is also predicted by the standard model.

CERN_higgsThis model, which is explained through quantum field theory  – itself an amalgam of quantum mechanics and Einstein’s special theory of relativity – claims that deep mathematical symmetries rule the interactions among all elementary particles. Until now, the decay modes discovered at CERN have been of a Higgs particle giving rise to two high-energy photons, or a Higgs going into two Z bosons or two W bosons.

But with the discovery of fermions, the researchers are now sure they have found the last holdout to the full and complete confirmation that the Standard Model is the correct one. As Marcus Klute of the CMS Collaboration said in a statement:

Our findings confirm the presence of the Standard Model Boson. Establishing a property of the Standard Model is big news itself.

CERN_LHCIt is certainly is big news for scientists, who can say with absolute certainty that our current conception for how particles interact and behave is not theoretical. But on the flip side, it also means we’re no closer to pushing beyond the Standard Model and into the realm of the unknown. One of the big shortfalls of the Standard Model is that it doesn’t account for gravity, dark energy and dark matter, and some other quirks that are essential to our understanding of the universe.

At present, one of the most popular theories for how these forces interact with the known aspects of our universe – i.e. electromagnetism, strong and nuclear forces – is supersymmetry.  This theory postulates that every Standard Model particle also has a superpartner that is incredibly heavy – thus accounting for the 23% of the universe that is apparently made up of dark matter. It is hoped that when the LHC turns back on in 2015 (pending upgrades) it will be able to discover these partners.

CERN_upgradeIf that doesn’t work, supersymmetry will probably have to wait for LHC’s planned successor. Known as the “Very Large Hadron Collider” (VHLC), this particle accelerator will measure some 96 km (60 mile) in length – four times as long as its predecessor. And with its proposed ability to smash protons together with a collision energy of 100 teraelectronvolts – 14 times the LHC’s current energy – it will hopefully have the power needed to answer the questions the discovery of the Higgs Boson has raised.

These will hopefully include whether or not supersymmetry holds up and how gravity interacts with the three other fundamental forces of the universe – a discovery which will finally resolve the seemingly irreconcilable theories of general relativity and quantum mechanics. At which point (and speaking entirely in metaphors) we will have gone from discovering the “God Particle” to potentially understanding the mind of God Himself.

I don’t think I’ve being melodramatic!

Source: extremetech.com, blogs.discovermagazine.com

Looking for Dark Matter: The DarkSide-50 Project

darkmatter1If 2013 will go down in history as the year the Higgs Boson was discovered, then 2014 may very well be known as the year dark matter was first detected. Much like the Higgs Boson, our understanding of the universe rests upon the definitive existence of this mysterious entity, which alongside “dark energy” is believed to make up the vast majority of the cosmos.

Before 2014 rolled around, the Large Underground Xenon experiment (LUX) – located near the town of Lead in South Dakota – was seen as the best candidate for finding it. However, since that time, attention has also been directed towards the DarkSide-50 Experiment located deep underground in the Gran Sasso mountain, the highest peak in the Appennines chain in central Italy.

darkside-50This project is an international collaboration between Italian, French, Polish, Ukrainian, Russian, and Chinese institutions, as well as 17 American universities, which aims to pin down dark matter particles. The project team spent last summer assembling their detector, a grocery bag-sized device that contains liquid argon, cooled to a temperature of -186° C (-302.8° F), where it is in a liquid state.

According to the researchers, the active, Teflon-coated part of the detector holds 50 kg (110 lb) of argon, which provides the 50 in the experiment’s name. Rows of photodetectors line the top and bottom of the device, while copper coils collect the stripped electrons to help determine the location of collisions between dark matter and visible matter.

darkside-50-0The research team, as well as many other scientists, believe that a particle known as a WIMP (weakly interacting massive particle) is the prime candidate for dark matter. WIMP particles have little interaction with their surroundings, so the researchers are hoping to catch one of these particles in the act of drifting aloof. They also believe that these particles can be detected when one of them collides with the nucleus of an atom, such as argon.

By cramming the chamber of their detector with argon atoms, the team increases their chance of seeing a collision. The recoil from these collisions can be seen in a short-lived trail of light, which can then be detected using the chamber’s photodetectors. To ensure that background events are not interfering, the facility is located deep underground to minimize background radiation.

darkmatterTo aid in filtering out background events even further, the detector sits within a steel sphere that is suspended on stilts and filled with 26,500 liters (7000 gallons) of a fluid called scintillator. This sphere in turn sits inside a three-story-high cylindrical tank filled with 946,350 liters (250,000) of ultrapure water. These different chambers help the researchers differentiate WIMP particles from neutrons and cosmic-ray muons.

Since autumn of 2013, the DarkSide-50 project has been active and busy collecting data. And it is one of about three dozen detectors in the world that is currently on the hunt for dark matter, which leads many physicists to believe that elusive dark matter particles will be discovered in the next decade. When that happens, scientists will finally be able to account for 31.7% of the universe’s mass, as opposed to the paltry 4.9% that is visible to us now.

planck-attnotated-580x372Now if we could only account for all the “dark energy” out there – which is believed to make up the other 68.3% of the universe’s mass – then we’d really be in business! And while we’re waiting, feel free to check out this documentary video about the DarkSide-50 Experiment and the hunt for dark matter, courtesy of Princeton University:

Sources: gizmag.com, princeton.edu

Looking Forward: Science Stories to Watch for in 2014

BrightFutureThe year of 2013 was a rather big one in terms of technological developments, be they in the field of biomedicine, space exploration, computing, particle physics, or robotics technology. Now that the New Year is in full swing, there are plenty of predictions as to what the next twelve months will bring. As they say, nothing ever occurs in a vacuum, and each new step in the long chain known as “progress” is built upon those that came before.

And with so many innovations and breakthroughs behind us, it will be exciting to see what lies ahead of us for the year of 2014. The following is a list containing many such predictions, listed in alphabetical order:

Beginning of Human Trials for Cancer Drug:
A big story that went largely unreported in 2013 came out of the Stanford School of Medicine, where researchers announced a promising strategy in developing a vaccine to combat cancer. Such a goal has been dreamed about for years, using the immune system’s killer T-cells to attack cancerous cells. The only roadblock to this strategy has been that cancer cells use a molecule known as CD47 to send a signal that fools T-cells, making them think that the cancer cells are benign.

pink-ribbonHowever, researchers at Stanford have demonstrated that the introduction of an “Anti-CD47 antibody” can intercept this signal, allowing T-cells and macrophages to identify and kill cancer cells. Stanford researchers plan to start human trials of this potential new cancer therapy in 2014, with the hope that it would be commercially available in a few years time. A great hope with this new macrophage therapy is that it will, in a sense, create a personalized vaccination against a patient’s particular form of cancer.

Combined with HIV vaccinations that have been shown not only to block the acquisition of the virus, but even kill it, 2014 may prove to be the year that the ongoing war against two of the deadliest diseases in the world finally began to be won.

Close Call for Mars:
A comet discovery back in 2013 created a brief stir when researchers noted that the comet in question – C/2013 A1 Siding Springs – would make a very close passage of the planet Mars on October 19th, 2014. Some even suspected it might impact the surface, creating all kinds of havoc for the world’s small fleet or orbiting satellites and ground-based rovers.

Mars_A1_Latest_2014Though refinements from subsequent observations have effectively ruled that out, the comet will still pass by Mars at a close 41,300 kilometers, just outside the orbit of its outer moon of Deimos. Ground-based observers will get to watch the magnitude comet close in on Mars through October, as will the orbiters and rovers on and above the Martian surface.

Deployment of the First Solid-State Laser:
The US Navy has been working diligently to create the next-generation of weapons and deploy them to the front lines. In addition to sub-hunting robots and autonomous aerial drones, they have also been working towards the creation of some serious ship-based firepower. This has included electrically-powered artillery guns (aka. rail guns); and just as impressively, laser guns!

Navy_LAWS_laser_demonstrator_610x406Sometime in 2014, the US Navy expects to see the USS Ponce, with its single solid-state laser weapon, to be deployed to the Persian Gulf as part of an “at-sea demonstration”. Although they have been tight-lipped on the capabilities of this particular directed-energy weapon,they have indicated that its intended purpose is as a countermeasure against threats – including aerial drones and fast-moving small boats.

Discovery of Dark Matter:
For years, scientists have suspected that they are closing in on the discovery of Dark Matter. Since it was proposed in the 1930s, finding this strange mass – that makes up the bulk of the universe alongside “Dark Energy” – has been a top priority for astrophysicists. And 2014 may just be the year that the Large Underground Xenon experiment (LUX), located near the town of Lead in South Dakota, finally detects it.

LUXLocated deep underground to prevent interference from cosmic rays, the LUX experiment monitors Weakly Interacting Massive Particles (WIMPs) as they interact with 370 kilograms of super-cooled liquid Xenon. LUX is due to start another 300 day test run in 2014, and the experiment will add another piece to the puzzle posed by dark matter to modern cosmology. If all goes well, conclusive proof as to the existence of this invisible, mysterious mass may finally be found!

ESA’s Rosetta Makes First Comet Landing:
This year, after over a decade of planning, the European Space Agency’s Rosetta robotic spacecraft will rendezvous with Comet 67P/Churyumov-Gerasimenko. This will begin on January 20th, when the ESA will hail the R0setta and “awaken” its systems from their slumber. By August, the two will meet, in what promises to be the cosmic encounter of the year. After examining the comet in detail, Rosetta will then dispatch its Philae lander, equipped complete with harpoons and ice screws to make the first ever landing on a comet.

Rosetta_and_Philae_at_comet_node_full_imageFirst Flight of Falcon Heavy:
2014 will be a busy year for SpaceX, and is expected to be conducting more satellite deployments for customers and resupply missions to the International Space Station in the coming year. They’ll also be moving ahead with tests of their crew-rated version of the Dragon capsule in 2014. But one of the most interesting missions to watch for is the demo flight of the Falcon 9 Heavy, which is slated to launch out of Vandenberg Air Force Base by the end of 2014.

This historic flight will mark the beginning in a new era of commercial space exploration and private space travel. It will also see Elon Musk’s (founder and CEO of Space X, Tesla Motors and PayPal) dream of affordable space missions coming one step closer to fruition. As for what this will make possible, well… the list is endless.

spaceX-falcon9Everything from Space Elevators and O’Neil space habitats to asteroid mining, missions to the Moon, Mars and beyond. And 2014 may prove to be the year that it all begins in earnest!

First Flight of the Orion:
In September of this coming year, NASA is planning on making the first launch of its new Orion Multi-Purpose Crew Vehicle. This will be a momentous event since it constitutes the first step in replacing NASA’s capability to launch crews into space. Ever since the cancellation of their Space Shuttle Program in 2011, NASA has been dependent on other space agencies (most notably the Russian Federal Space Agency) to launch its personnel, satellites and supplies into space.

orion_arrays1The test flight, which will be known as Exploration Flight Test 1 (EFT-1), will be a  short uncrewed flight that tests the capsule during reentry after two orbits. In the long run, this test will determine if the first lunar orbital mission using an Orion MPCV can occur by the end of the decade. For as we all know, NASA has some BIG PLANS for the Moon, most of which revolve around creating a settlement there.

Gaia Begins Mapping the Milky Way:
Launched on from the Kourou Space Center in French Guiana on December 19thof last year, the European Space Agency’s Gaia space observatory will begin its historic astrometry mission this year. Relying on an advanced array of instruments to conduct spectrophotometric measurements, Gaia will provide detailed physical properties of each star observed, characterising their luminosity, effective temperature, gravity and elemental composition.

Gaia_galaxyThis will effectively create the most accurate map yet constructed of our Milky Way Galaxy, but it is also anticipated that many exciting new discoveries will occur due to spin-offs from this mission. This will include the discovery of new exoplanets, asteroids, comets and much more. Soon, the mysteries of deep space won’t seem so mysterious any more. But don’t expect it to get any less tantalizing!

International Climate Summit in New York:
While it still remains a hotly contested partisan issue, the scientific consensus is clear: Climate Change is real and is getting worse. In addition to environmental organizations and agencies, non-partisan entities, from insurance companies to the U.S. Navy, are busy preparing for rising sea levels and other changes. In September 2014, the United Nations will hold another a Climate Summit to discuss what can be one.

United-Nations_HQThis time around, the delegates from hundreds of nations will converge on the UN Headquarters in New York City. This comes one year before the UN is looking to conclude its Framework Convention on Climate Change, and the New York summit will likely herald more calls to action. Though it’ll be worth watching and generate plenty of news stories, expect many of the biggest climate offenders worldwide to ignore calls for action.

MAVEN and MOM reach Mars:
2014 will be a red-letter year for those studying the Red Planet, mainly because it will be during this year that two operations are slated to begin. These included the Indian Space Agency’s Mars Orbiter Mission (MOM, aka. Mangalyaan-1) and NASA’ Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, which are due to arrive just two days apart – on September 24th and 22nd respectively.

mars_lifeBoth orbiters will be tasked with studying Mars’ atmosphere and determining what atmospheric conditions looked like billions of years ago, and what happened to turn the atmosphere into the thin, depleted layer it is today. Combined with the Curiosity and Opportunity rovers, ESA’s Mars Express,  NASA’s Odyssey spacecraft and the Mars Reconnaissance Orbiter, they will help to unlock the secrets of the Red Planet.

Unmanned Aircraft Testing:
A lot of the action for the year ahead is in the area of unmanned aircraft, building on the accomplishments in recent years on the drone front. For instance, the US Navy is expected to continue running trials with the X-47B, the unmanned technology demonstrator aircraft that is expected to become the template for autonomous aerial vehicles down the road.

X-47BThroughout 2013, the Navy conducted several tests with the X-47B, as part of its ongoing UCLASS (Unmanned Carrier Launched Airborne Surveillance and Strike) aircraft program. Specifically, they demonstrated that the X-47B was capable of making carrier-based take offs and landings. By mid 2014, it is expected that they will have made more key advances, even though the program is likely to take another decade before it is fully realizable.

Virgin Galactic Takes Off:
And last, but not least, 2014 is the year that space tourism is expected to take off (no pun intended!). After many years of research, development and testing, Virgin Galactic’s SpaceShipTwo may finally make its inaugural flights, flying out of the Mohave Spaceport and bringing tourists on an exciting (and expensive) ride into the upper atmosphere.

spaceshiptwo-2nd-flight-2In late 2013, SpaceShipTwo and passed a key milestone test flight when its powered rocket engine was test fired for an extended period of time and it achieved speeds and altitudes in excess of anything it had achieved before. Having conducted several successful glide and feathered-wing test flights already, Virgin Galactic is confident that the craft has what it takes to ferry passengers into low-orbit and bring them home safely.

On its inaugural flights, SpaceShipTwo will carry two pilots and six passengers, with seats going for $250,000 a pop. If all goes well, 2014 will be remembered as the year that low-orbit space tourism officially began!

Yes, 2014 promises to be an exciting year. And I look forward to chronicling and documenting it as much as possible from this humble little blog. I hope you will all join me on the journey!

Sources: Universetoday, (2), med.standford.edu, news.cnet, listosaur, sci.esa.int

Creating Dark Matter: The DarkLight Project

https://i2.wp.com/scienceblogs.com/startswithabang/files/2011/08/dark_matter_millenium_simulation.jpegFor several decades now, the widely accepted theory is that almost 27% of the universe is fashioned out of an invisible, mysterious mass known as “dark matter”. Originally theorized by Fritz Zwicky in 1933, the concept was meant to account for the “missing mass” apparent in galaxies in clusters. Since that time, many observations have suggested its existence, but definitive proof has remained elusive.

Despite our best efforts, no one has ever observed dark matter directly (nor dark energy, which is theorized to make up the remaining 68% of the universe). It’s acceptance as a theory has been mainly due to the fact that it makes the most sense, beating out theories like Modified Newtonian Dynamics (MOND), which seek to redefine the laws of gravity as to why the universe behaves the way it does.

https://i1.wp.com/www.extremetech.com/wp-content/uploads/2013/04/cdms.jpgLuckily, MIT recently green-lighted the DarkLight project – a program aimed at creating tiny tiny amounts of dark matter using a particle accelerator. In addition to proving that dark matter exists, the project team has a more ambitious goal of figuring out dark matter behaves – i.e. how it exerts gravitational attraction on the ordinary matter that makes up the visible universe.

The leading theory for dark matter used to be known as WIMPs (weakly interacting massive particles). This theory stated that dark matter only interacted with normal matter via gravity and the weak nuclear force, making them very hard to detect. However, a recent research initiative challenged this view and postulates that dark matter may actually consist of massive photons that couple to electrons and positrons.

https://i0.wp.com/www.extremetech.com/wp-content/uploads/2013/10/prototype-a-prime-dark-matter-detector.jpgTo do this, DarkLight will use the particle accelerator at the JeffersonJefferson Lab’s Labs Free-Electron Laser Free Electron Lase in Virginia to bombard an oxygen target with a stream of electrons with one megawatt of power. This will be able to test for these massive photons and, it is hoped, create this theorized form of dark matter particles. The dark matter, if it’s created, will then immediately decay into two other particles that can be (relatively) easily detected.

At this point, MIT estimates that it will take a couple of years to build and test the DarkLight experiment, followed by another two years of smashing electrons into the target and gathering data. By then, it should be clear whether dark matter consists of A prime particles, or whether scientists and astronomers have barking up the wrong tree these many years.

https://i2.wp.com/scienceblogs.com/startswithabang/files/2012/12/sim3dnew.pngBut if we can pinpoint the basis of dark matter, it would be a monumental finding that would greatly our enhance our understanding of the universe, and dwarf even the discovery of the Higgs Boson. After that, the only remaining challenge will be to find a way to observe and understand the other 68% of the universe!

Source: extremetech.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