Tag: theoretical physics

Theoretical physics: The origins of space and time


Excerpt from nature.com
By Zeeya Merali


Many researchers believe that physics will not be complete until it can explain not just the behaviour of space and time, but where these entities come from.

“Imagine waking up one day and realizing that you actually live inside a computer game,” says Mark Van Raamsdonk, describing what sounds like a pitch for a science-fiction film. But for Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, Canada, this scenario is a way to think about reality. If it is true, he says, “everything around us — the whole three-dimensional physical world — is an illusion born from information encoded elsewhere, on a two-dimensional chip”. That would make our Universe, with its three spatial dimensions, a kind of hologram, projected from a substrate that exists only in lower dimensions.

This 'holographic principle' is strange even by the usual standards of theoretical physics. But Van Raamsdonk is one of a small band of researchers who think that the usual ideas are not yet strange enough. If nothing else, they say, neither of the two great pillars of modern physics — general relativity, which describes gravity as a curvature of space and time, and quantum mechanics, which governs the atomic realm — gives any account for the existence of space and time. Neither does string theory, which describes elementary threads of energy.

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Zeeya Merali discusses some of the theories that are trying to explain the origins of space and time.


Van Raamsdonk and his colleagues are convinced that physics will not be complete until it can explain how space and time emerge from something more fundamental — a project that will require concepts at least as audacious as holography. They argue that such a radical reconceptualization of reality is the only way to explain what happens when the infinitely dense 'singularity' at the core of a black hole distorts the fabric of space-time beyond all recognition, or how researchers can unify atomic-level quantum theory and planet-level general relativity — a project that has resisted theorists' efforts for generations.

“All our experiences tell us we shouldn't have two dramatically different conceptions of reality — there must be one huge overarching theory,” says Abhay Ashtekar, a physicist at Pennsylvania State University in University Park.

Finding that one huge theory is a daunting challenge. Here, Nature explores some promising lines of attack — as well as some of the emerging ideas about how to test these concepts...

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The Quantum Origins of Space & Time ~ A Wonderfully Thought Provoking Lecture by Renate Loll

Renate Loll from Utrecht University's Institute for Theoretical Physics delivers a lecture on Searching for the Quantum Origins of Space and Time. The lecture was recorded at the Perimeter Institute in Waterloo, Ontario, on May 5, 2010.Click to zoom

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Are There Hidden Dimensions in our Universe? Unraveling Hidden Mysteries with Harvard Professor Dr. Lisa Randall ~ Video Lecture

Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions is a book by Lisa Randall, published in 2005, about particle physics in general and additional dimensions of space (cf. Kaluza--Klein theory) in particular. The book has m...

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New invisibility cloak device can hide almost anything



invisible

digitaltrends.com

Hats off to scientists at the University of Rochester in New York, who have managed to produce a cheap ‘invisibility cloak’ effect using readily available materials and a lot of clever thinking. Through a combination of optical lenses, any object that passes behind a certain line of sight can be made to disappear from view.

‘The Rochester Cloak’, as it’s being dubbed, uses a simplified four-lens system that essentially bends light around any objects you put into the middle of the chain — you’re able to see the area in the background as normal, but not the item in the foreground. According to its inventors, it can be scaled up using any size of lens, and the team responsible for the setup has used standard, off-the-shelf hardware.

“People have been fascinated with cloaking for a very long time,” said John Howell, a Professor of Physics at the University. “It’s recently been a really popular thing in science fiction and Harry Potter… I think people are really excited about the prospect of just being invisible.”

“From what we know this is the first cloaking device that provides three-dimensional, continuously multidirectional cloaking,” said doctoral student Joseph Choi, one of the team who worked on the project, when speaking to Reuters. “I imagine this could be used to cloak a trailer on the back of a semi-truck so the driver can see directly behind him. It can be used for surgery, in the military, in interior design, art.”

What makes this system so interesting is that it’s simple, inexpensive and capable of working at multiple angles, as long as the object remains inside the series of lenses. Howell and Choi say it cost them $1,000 to get all of the necessary equipment together, but it can be done more cheaply. A patent is pending for their invention but the pair have put together instructions on making your own Rochester Cloak at home for less than $100.


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NASA Discovers Hidden Portals In Earth’s Magnetic Field

Our planet has come a long way in scientific breakthroughs and discoveries. Mainstream science is beginning to discover new concepts of reality that have the potential to change our perception about our planet and the extraterrestrial environment that surrounds it forever. Star gates, wormholes, and portals have been the subject of conspiracy theories and theoretical physics for decades, but that is all coming to an end as we continue to grow in our understanding about the t [...]

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