Retweeted by NASA and Inside Space!

Our watery Earth. Credit: NASA
Our watery Earth. Credit: NASA

Good news everyone! After about two months of working for Universe Today, it appears that some of what I say is actually being read by the big names in the bizz! It started three days ago when NASA Earth retweeted an article I wrote entitled “What Percentage of Earth is Water?“, which was part of UT’s Guide to Space section that deals with general knowledge questions about astronomy, geology, the universe, etc.

The second came yesterday when Inside Space retweeted an more recent article I did about the supermassive black hole at the center of our galaxy, and how scientists anticipate that they will be able to view it for the first time in the near future. They were doing a list of the top ten recent news stories of space in recent days, and apparently, my story made the list (I was number 9).

All in all, it’s been a pretty cool week! 🙂

Is the Universe One Big Hologram?

universe_nightsky“You know how I can tell we’re not in the Matrix?  If we were, the food would be better.” Thus spoke Sheldon Cooper, the socially-challenged nerd from The Big Bang Theory. And yet, there is actually a scientific theory that posits that the universe itself could be a 2D hologram that is painted on some kind of cosmological horizon and only pops into 3D whenever we observe it (aka. always).

And in what may be the most mind-boggling experiment ever, the US Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) seeks to test this theory for the first time. Their tool for this is the Holometer, a device which has been under construction for a couple of years. It is now operating at full power and will gather data for the next year or so, at which time it will seek to uncover if the universe is a hologram, and what it’s composed of.

big_bangThe current prevailing theories about how the universe came to be are the Big Bang, the Standard Model of particle physics, quantum mechanics, and classical physics. These hypotheses and models don’t fully answer every question about how the universe came to be or continues to persist – which is why scientists are always investigating other ideas, such as supersymmetry or string theory.

The holographic universe principle is part of string theory – or at least not inconsistent with it – and goes something like this: From our zoomed out vantage point, the universe seems to be a perfectly formed enclave of 4D spacetime. But what happens if you keep zooming in, past the atomic and subatomic, until you get down to the smallest possible unit that can exist in the universe?

fermi_holometer-3In explaining their theory, the scientists involved make much of the analogy of moving closer to an old-style TV until you can see the individual pixels. The holographic principle suggests that, if you zoom in far enough, we will eventually see the pixels of the universe. It’s theorized that these universal pixels are about 10 trillion trillion times smaller than an atom (where things are measured in Planck units).

The Holometer at Fermilab, which on the hunt for these pixels of the universe, is essentially an incredibly accurate clock. It consists of a twin-laser interferometer, which – as the name suggests – extracts information from the universe by measuring interference to the laser beams. Each interferometer directs a one-kilowatt laser beam at a beam splitter and then down two 40-m (130-ft) arms located at right-angles to one another.

holometer-interferometer-diagramThese beams are then reflected back towards the source, where they are combined and analyzed for any traces of interference. As Craig Hogan, the developer of the holographic noise theory and a director at Fermilab, explained:

We want to find out whether space-time is a quantum system just like matter is. If we see something, it will completely change ideas about space we’ve used for thousands of years.

After any outside influences are removed, any remaining fluctuations – measured by slightly different frequencies or arrival times – could be caused by the ever-so-slight quantum jitter of these universal pixels. If these universal pixels exist, then everything we see, feel, and experience in the universe is actually encoded in these 2D pixels. One major difficulty in such a test will be noise – aka. “Holographic noise” – which they expect to be present at all frequencies.

fermi_holometerTo mitigate this, the Holometer is testing at frequencies of many megahertz so that motions contained in normal matter are claimed not to be a problem. The dominant background noise of radio wave interference will be the most difficult to filter out, according to the team. As Holometer lead scientist Aaron Chou explained:

If we find a noise we can’t get rid of, we might be detecting something fundamental about nature – a noise that is intrinsic to space-time.

This would have some serious repercussions. For a start, it would mean that spacetime itself is a quantum system, just like matter. The theory that the universe consists of matter and energy would be annulled, replaced with the concept that the universe is made of information encoded into these universal pixels, which in turn create the classical concepts of matter and energy.

fermi_holometer-1And of course, if the universe is just a 3D projection from a 2D cosmological horizon, where exactly is that cosmological horizon? And does this mean that everything we know and love is just a collection of quantum information carrying 2D bits? And perhaps most importantly (from our point of view at least) what does that make us? Is all life just a collection of pixels designed to entertain some capricious audience?

All good and, if you think about it, incredibly time-honored questions. For has it not been suggested by many renowned philosophies that life is a deception, and death an escape? And do not the Hindu, Buddhist and Abrahamic religions tells us that our material existence is basically a facade that conceals our true reality? And were the ancient religions not all based on the idea that man was turned loose in a hostile world for the entertainment of the gods?

Well, could be that illusion is being broadcast in ultra-high definition! And getting back to The Big Bang Theory, here’s Leonard explaining the hologram principle to Penny, complete with holograms:


Sources:
extremetech.com, gizmag.com

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)

Evidence for the Big Bang

planck-attnotated-580x372The Big Bang Theory has been the dominant cosmological model for over half a century. According to the theory, the universe was created approximately 14 billion years ago from an extremely hot, dense state and then began expanding rapidly. After the initial expansion, the Universe cooled and began to form various subatomic particles and basic elements. Giant clouds of these primordial elements later coalesced through gravity to form stars, galaxies, and eventually planets.

And while it has its detractors, most of whom subscribe to the alternate Steady State Theory – which claims that new matter is continuously created as the universe expands – it has come to represent the scientific consensus as to how the universe came to be. And as usual, my ol’ pal and mentor in all things digital, Fraser Cain, recently released a video with the help of Universe Today discussing the particulars of it.

big_bangAddressing the particulars of the Big Bang Theory, Cain lists the many contributions made over the past century that has led this so-called theory to become the scientific consensus has come to exist. They are, in a nutshell:

  1. Cosmic Expanion: In 1912, astronomer Vesto Slipher calculated the speed and distance of “spiral nebulae” (galaxies) by measuring the light coming from them. He determined most were moving away. In 1924, Edwin Hubble determined that these galaxies were outside the Milky Way. He postulates that the motion of galaxies away from our own indicates a common point of origin.
  2. Abundance of Elements: Immediately after the big bang, only hydrogen existed and compressed into a tiny area of space under incredible heat and pressure. Like a star, this turned hydrogen into helium and other basic elements. Looking out into the universe (and hence back in time) scientists have found that great distances, the ratios of hydrogen to basic elements is consistent with what is found in star’s interiors.
  3. Cosmic Microwave Background (CMB) Radiation: In the 1960’s, using a radiotelescope, Arno Penzias and Robert Wilson discovered a background radio emission coming from every direction in the sky, day or night. This was consistent with the Big Bang Theory, which predicted that after the Big Bang, there would have been a release of radiation which then expanded billions of light years in all directions and cooled to the point that it shifted to invisible, microwave radiation.
  4. Large Scale Structure: The formation of galaxies and the large-scale structure of the cosmos are very similar. This is consistent with belief that after the initial Big Bang, the matter created would have cooled and began to coalesce into large collections, which is what galaxies, local galactic groups, and super-clusters are.

These are the four pillars of the Big Bang Theory, but they are no means the only points in its favor. In addition, there are numerous observational clues, such as how we have yet to observe a stars in the universe older than 13 billion years old, and fluctuations in the CMB that indicate a lack of uniformity. On top of that, there is the ongoing research into the existence of Dark Matter and Dark Energy, which are sure to bear fruit in the near future if all goes well.

big_bang1In short, scientists have a pretty good idea of how the universe came to be and the evidence all seems to confirm it. And some mysteries remain, we can be relatively confident that ongoing experimentation and research will come up with new and creative ways to shed light on the final unknowns. Little reason then why the Big Bang Theory enjoys such widespread support, much like Evolution, Gravity, and General Relativity.

Be sure to check out the full video, and subscribe to Universe Today for additional informative videos, podcasts, and articles. As someone who used to write for them, I can tell you that it’s a pretty good time, and very enlightening!

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

The Amplituhedron: Quantum Physics Decoded

amplutihedron_spanScientists recently made a major breakthrough that may completely alter our perceptions of quantum physics, and the nature of the universe itself. After many decades of trying to reformulate quantum field theory, scientists at Harvard University discovered of a jewel-like geometric object that they believe will not only simplify quantum science, but even challenge the notion that space and time are fundamental components of reality.

This jewel has been named the “amplituhedron”, and it is radically simplifying how physicists calculate particle interactions. Previously, these Interactions were calculated using quantum field theory – mathematical formulas that were thousands of terms long. Now, these interactions can be described by computing the volume of the corresponding amplituhedron, which yields an equivalent one-term expression.

theory_of_everythingJacob Bourjaily, a theoretical physicist at Harvard University and one of the researchers who developed the new idea, has this to say about the discovery:

The degree of efficiency is mind-boggling. You can easily do, on paper, computations that were infeasible even with a computer before.

This is exciting news, in part because it could help facilitate the search for a Grand Unifying Theory (aka. Theory of Everything) that manages to unify all the fundamental forces of the universe. These forces are electromagnetism, weak nuclear forces, strong nuclear forces, and gravity. Thus far, attempts at resolving these forces have run into infinities and deep paradoxes.

gravityWhereas the field of quantum physics has been able to account for the first three, gravity has remained explainable only in terms of General Relativity (Einstein’s baby). As a result, scientists have been unable to see how the basic forces of the universe interact on a grand scale, and all attempts have resulted in endless infinities and deep paradoxes.

The amplituhedron, or a similar geometric object, could help by removing two deeply rooted principles of physics: locality and unitarity. Locality is the notion that particles can interact only from adjoining positions in space and time, while unitarity holds that the probabilities of all possible outcomes of a quantum mechanical interaction must add up to one.

quantum_field_theoryThe concepts are the central pillars of quantum field theory in its original form, but in certain situations involving gravity, both break down, suggesting neither is a fundamental aspect of nature. As Nima Arkani-Hamed – a professor of physics at the Institute for Advanced Study in Princeton, N.J. and the lead author of the new work – put it: “Both are hard-wired in the usual way we think about things. Both are suspect.”

In keeping with this idea, the new geometric approach to particle interactions removes locality and unitarity from its starting assumptions. The amplituhedron is not built out of space-time and probabilities; these properties merely arise as consequences of the jewel’s geometry. The usual picture of space and time, and particles moving around in them, is a construct.

Photon_follow8And while the amplituhedron itself does not describe gravity, Arkani-Hamed and his collaborators think there might be a related geometric object that does. Its properties would make it clear why particles appear to exist, and why they appear to move in three dimensions of space and to change over time. This is because, as Bourjaily put it:

[W]e know that ultimately, we need to find a theory that doesn’t have [unitarity and locality]. It’s a starting point to ultimately describing a quantum theory of gravity.

Imagine that. After decades of mind-boggling research and attempts at resolving the theoretical issues, all existence comes down to a small jewel-shaped structure. I imagine the Intelligent Design people will have a field day with this, and I can foresee it making it into the new season of Big Bang Theory as well. Breakthroughs like this always do seem to have a ripple effect…

Source: simonsfoundation.org

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