Mon Apr 16, 2012, 01:28 PM
n2doc (34,520 posts)
Where Do Space and Time Come From? New Theory Offers Answers, If Only Physicists Can Figure It OutBy George Musser SANTA BARBARA—”Maybe we’re just too dumb,” Nobel laureate physicist David Gross mused in a lecture at Caltech two weeks ago. When someone of his level wonders whether the unification of physics will always be beyond mortal minds, it gets you worried. Since his lecture, I’ve been learning about a theory that seems to confirm Gross’s worry. It is so ridiculously hard that it could be the subject of an Onion parody. But at the same time, I’ve been watching how physicists are trying to power through their intimidation, because the theory promises a new way of understanding what space and time really are, at a deep level. The theory was put forward in the late 1980s by Russian physicists Mikhail Vasiliev and the late Efin Fradkin of the Lebedev Institute in Moscow, but is so mathematically complex and conceptually opaque that whenever someone brought it up, most theorists started talking about the weather, soccer, reality TV—anything but that theory. It became a subject of polite conversation only in the past couple of years, as math whizzes who take a peculiar pleasure in impossible problems dove in and showed that the theory is not impossible to grasp, merely almost impossible. Inspired by their bravery, I’m going to take a crack at explaining this strange beast, synthesizing lectures I’ve attended by Steve Shenker of Stanford University, Andy Strominger of Harvard, and Juan Maldacena of the Institute for Advanced Study, as well as informal chats with Joe Polchinski of the Kavli Institute for Theoretical Physics and Joan Simón of the University of Edinburgh. I’m sure they’ll set me straight if I get something wrong, and I’ll edit this blog post to reflect comments I receive. Vasiliev theory (for sake of a pithy name, physicists drop Fradkin’s name) takes to extremes the basic idea of modern physics: that the world around us consists of fields—the electrical and magnetic fields and a handful of others that represent the known forces of nature and types of matter. Vasiliev theory posits an infinite number of fields. They come in progressively more complicated varieties described by the quantummechanical property of spin. more http://blogs.scientificamerican.com/observations/2012/04/12/wheredospaceandtimecomefromnewtheoryoffersanswersifonlyphysicistscanfigureitout/

16 replies, 2324 views
16 replies  Author  Time  Post 
Where Do Space and Time Come From? New Theory Offers Answers, If Only Physicists Can Figure It Out (Original post) 
n2doc  Apr 2012  OP 
Vincardog  Apr 2012  #1  
Odin2005  Apr 2012  #13  
liberal N proud  Apr 2012  #2  
rurallib  Apr 2012  #3  
veganlush  Apr 2012  #4  
Odin2005  Apr 2012  #15  
drokhole  Apr 2012  #5  
Enrique  Apr 2012  #6  
GeorgeGist  Apr 2012  #7  
tama  Apr 2012  #8  
HopeHoops  Apr 2012  #9  
Jim__  Apr 2012  #10  
tama  Apr 2012  #11  
Odin2005  Apr 2012  #16  
RagAss  Apr 2012  #12  
Odin2005  Apr 2012  #14 
Response to n2doc (Original post)
Mon Apr 16, 2012, 01:49 PM
Vincardog (18,115 posts)
1. I read all the words. I wish I understood 1/2 the meaning
Response to Vincardog (Reply #1)
Tue Apr 17, 2012, 09:44 PM
Odin2005 (48,255 posts)
13. I understood it just fine.
Response to n2doc (Original post)
Mon Apr 16, 2012, 02:04 PM
liberal N proud (48,015 posts)
2. Not worried about where it comes from but where did it all go?
As time passes us by!

Response to n2doc (Original post)
Mon Apr 16, 2012, 02:05 PM
rurallib (36,119 posts)
3. this is where creationism comes in handy
all you have to do is answer 'God" and you pass the course.
Thanks for a mindbender of an article. 
Response to n2doc (Original post)
Mon Apr 16, 2012, 02:33 PM
veganlush (2,040 posts)
4. the what now?
?

Response to veganlush (Reply #4)
Tue Apr 17, 2012, 09:48 PM
Odin2005 (48,255 posts)
15. Repeat after me: antiDe Sitter Geometry.
Response to n2doc (Original post)
Mon Apr 16, 2012, 03:20 PM
drokhole (1,045 posts)
5. Reminds me of a quote from JBS Haldane...
(to paraphrase) "My own suspicion is that the universe is not only stranger than we think, but stranger than we can think."

Response to n2doc (Original post)
Mon Apr 16, 2012, 03:52 PM
Enrique (25,236 posts)
6. I once knew someone that understood this type of thing
Response to n2doc (Original post)
Tue Apr 17, 2012, 05:08 AM
GeorgeGist (14,090 posts)
7. Nothingness is impossible ...
after that it gets complicated.

Response to n2doc (Original post)
Tue Apr 17, 2012, 09:55 AM
tama (9,137 posts)
8. Scalar fields again
with holographic principle or some form of it. Those seem to be the central themes of all promising GUT and TOE candidates these days, and IMO the most advanced and promising of such approaches is Matti Pitkänen's TGD. Spin fields identified with rational numbers sounds to my very limited comprehension like a limited case of Pitkänen's more general idea about rational numbers as common areas between padic and real areas, and then some of which I understand even less.

Response to n2doc (Original post)
Tue Apr 17, 2012, 10:28 AM
HopeHoops (47,675 posts)
9. The book of Genesis explains it all quite clearly.

Response to n2doc (Original post)
Tue Apr 17, 2012, 03:09 PM
Jim__ (9,469 posts)
10. Is the article giving us 3 different options for the nature of the universe? Or 2 different options?
Or am I completely misunderstanding what it is saying?
The article talks about 2 different holograpic universes and then about our spacetime emerging from the primordial universe as higher spin symmetries broke. One holographic universe, under an antide Sitter geometry (?), has a 3D spacetime reality with a 2 dimensional space and a 1 dimensional time where a 3rd (pseudo)space dimension emerges: ... Higherspin fields promise to flesh out the holographic principle, which is a way to explain the origin of space and gravity. Suppose you have a hypothetical threedimensional spacetime (two space dimensions, one time dimension) filled with particles that interact solely by a soupedup version of the strong nuclear force; there is no gravity. In such a setting, objects can behave in a very structured way. Objects of a given size can interact only with objects of comparable size, just as objects can interact only if they are spatially adjacent. Size plays exactly the same role as spatial position; you can think of size as a new dimension of space, materializing from particle interactions like a figure in a popup book. The original threedimensional spacetime becomes the boundary of a fourdimensional spacetime, with the new dimension representing the distance from this boundary. Not only does a spatial dimension emerge, but so does the force of gravity. In the jargon, the strong nuclear force in 3D spacetime (the boundary) is “dual” to gravity in 4D spacetime (the bulk).
The other holographic universe, under a de Sitter universe, has a real 3D space dimensions lying in an infinite future and a 4th holographic dimension of time: ... In the real universe, dark energy has a positive density, for a de Sitter geometry or some approximation thereof. Extending the holographic principle to such a geometry is fraught. The boundary of 4D de Sitter spacetime is a 3D space lying in the infinite future. The emergent dimension in this case would not be of space but of time, which is hard even for theoretical physicists to wrap their minds around. But if they succeed in formulating a version of the holographic principle for a de Sitter geometry, it would not only apply to the real universe, but would also explain what time really is. A lack of understanding of time is at the root of almost every deep problem in fundamental physics today.
And then there is the emergence of our spacetime from the primordial universe: ... Matter and spacetime geometry are so thoroughly entwined that it becomes impossible to tease them apart, and our usual picture of matter as residing in spacetime becomes completely untenable. In the primordial universe, where Vasiliev theory reigned, the universe was an amorphous blob. As the higherspin symmetries broke—for instance, as the higher harmonics of quantum strings become too costly to set into motion—spacetime emerged in its entirety.
Are these 3 different options? Or, if our universe emerged from a primordial amorphous blob, did it emerge into one of the holograpic universes described above  which one depending on the underlying geometry? 
Response to Jim__ (Reply #10)
Tue Apr 17, 2012, 04:02 PM
tama (9,137 posts)
11. b
http://en.wikipedia.org/wiki/Holographic_principle
http://en.wikipedia.org/wiki/De_Sitter_universe The 3D space time is as said, hypothetical, and I assume just for presentation purpose, as also Minkowski space is normally presented as 3D projection of two spacetime cones. The application of holographic principle to real 4D spacetime needs a spatial boundary where the information theoretical and thermodynamic bekenstein boundary that "holography" seems to refer here, would be observable, and that is impossible with the infinite dimension of time. The hope or promise is that in ndimensional de Sitter space the holographic principle could be formulated. The primordial amorphous blob refers to "superposition" of the "supersymmetric" spin scalars that by some spontaneous symmetry break broke down to 4Dspace time. So to my understanding these are not 3 different options, but attempt to unify QM and Relativity at the more general levels of spin scalars and ndimensional de Sitter spaces. The question remains, does this model suffer from the same landscaping problem as string/M theories and predict a vast multitude of possible universes, or is it more limiting case of World of Classical Worlds. 
Response to tama (Reply #11)
Tue Apr 17, 2012, 09:51 PM
Odin2005 (48,255 posts)
16. That's the impression I got, too.
Response to n2doc (Original post)
Tue Apr 17, 2012, 06:36 PM
RagAss (13,815 posts)
12. We create space and time. It is the process with which we perceive reality.
Disagree with me and you're a Teabagger !

Response to n2doc (Original post)
Tue Apr 17, 2012, 09:46 PM
Odin2005 (48,255 posts)