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According to physicist Vlatko Vedral's appealing new book, it is made, at bottom, of information. In other words, if you break the universe into smaller and smaller pieces, the smallest pieces are, in fact, bits. With this theme in mind, Vedral embarks on an exuberant romp through physics, biology, philosophy, religion and even personal finance.
http://www.newscientist.com/article/mg20527520.600-the-universe-is-a-quantum-computer.html
“We view the speed of light as simply a conversion factor between time and space in spacetime,” Shu writes. “It is simply one of the properties of the spacetime geometry. Since the universe is expanding, we speculate that the conversion factor somehow varies in accordance with the evolution of the universe, hence the speed of light varies with cosmic time.”
As Shu writes in his paper, the newly proposed models have four distinguishing features:
• The speed of light and the gravitational “constant” are not constant, but vary with the evolution of the universe.
• Time has no beginning and no end; i.e., there is neither a big bang nor a big crunch singularity.
• The spatial section of the universe is a 3-sphere [a higher-dimensional analogue of a sphere], ruling out the possibility of a flat or hyperboloid geometry.
• The universe experiences phases of both acceleration and deceleration.
He tested one of the models against current cosmological observations of Type Ia supernovae that have revealed that the universe appears to be expanding at an accelerating rate. He found that, because acceleration is an inherent part of his model, it fits the redshift data of the observed supernovae quite well. In contrast, the currently accepted big bang model does not fit the data, which has caused scientists to search for other explanations such as dark energy that theoretically makes up 75% of the mass-energy of the universe.
http://www.physorg.com/news199591806.html
That's not to say Shu's theory is perfect. Far from it. One of the biggest problems he faces is explaining the existence and structure of the cosmic microwave background, something that many astrophysicists believe to be the the strongest evidence that the Big Bang really did happen. The CMB, they say, is the echo of the Big bang.
http://www.technologyreview.com/blog/arxiv/25492/
So Horava did the unthinkable and amended Einstein’s equations in a way that removed Lorentz symmetry. To his delight, this led to a set of equations that describe gravity in the same quantum framework as the other fundamental forces of nature: gravity emerges as the attractive force due to quantum particles called gravitons, in much the same way that the electromagnetic force is carried by photons. He also made another serious change to general relativity. Einstein’s theory does not have a preferred direction for time, from the past to the future. But the universe as we observe it seems to evolve that way. So Horava gave time a preferred direction (Physical Review D, vol 79, p 084008). With these modifications in place, he found that quantum field theories could now describe gravity at microscopic scales without producing the nonsensical results that plagued earlier attempts. “All of a sudden, you have new ingredients for modifying the behaviour of gravity at very short distances,” Horava says. Since Horava published his work in January 2009, it has received an astonishing amount of attention. Already, more than 250 papers have been written about it. Some researchers have started using it to explain away the twin cosmological mysteries of dark matter and dark energy. Others are finding that black holes might not behave as we thought.
http://theinformativereport.com/2010/08/09/the-end-of-space-time-rethinking-einstein/
The theories Igor Smolyaninov has in mind are those that have to do with parallel universes or dimensions of space and time that we don't experience in this world. In these lines of thought, different dimensions become "compactified" early in the Universe's life, leaving the three dimensions of space and one of time that we understand today.
Now Smolyaninov thinks we can take the idea to new heights. In the same way gravity bends light, metamaterials can bend electrical and magnetic fields to create a metamaterial version of relativity. We can, he says, create metamaterials with electromagnetic spaces that possess compactified dimensions.
Not only that, but we could create metamaterials in which the number of dimensions and compactified dimensions changes from region to region, with wormholes transiting from space to space. We might even be able to witness the birth of photons in these metamaterials, the transition of which would in some ways represent the spawning of a new universe within the metamaterial itself. We could even create a metamaterial multiverse in which different universes have different properties, or wherein different physical laws apply.
Put another, perhaps simpler, way, Smolyaninov thinks it’s possible to recreate several of our most out-there cosmological ideas within metamaterials, observing how they work and perhaps informing our search for the real meaning of how space and time work to make up the fabric of existence. We could even witness our own tiny Big Bang by engineering an optical “photon blockade” device in which topological transitions within the metamaterial resemble the birth of a universe
http://www.popsci.com/science/article/2010-05/metamaterials-multiverses-how-create-universes-lab
String theorists Neil Turok of Cambridge University and Paul Steinhardt, Albert Einstein Professor in Science and Director of the Princeton Center for Theoretical Science at Princeton believe that the cosmos we live in was actually created by the cyclical trillion-year collision of two universes (which they define as three-dimensional branes plus time) that were attracted toward each other by the leaking of gravity out of one of the universes.
Turok and Steinhardt were inspired by a lecture given by Burt Ovrut who imagined two branes, universes like ours, separated by a tiny gap as tiny as 10-32 meters. There would be no communictaion between the two universes except for our parallel sister universe's gravitational pull, which could cross the tiny gap.
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