Cosmological Friction


by Fluxman
Tags: cosmological, friction
Fluxman
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#1
May24-08, 02:12 PM
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What is the force of "friction" (for want of a better word) between the two four-dimensional universes that have come together to create our three-dimensional surface (universe).

As a three-dimensional analog think of two rectangular solids moving toward each other.

One is moving right with it's bottom surface exactly the same height as the other's (moving left) top surface.

At some point (the beginning of our universe and time) they meet and form a "surface of friction".

They continue on in their initial direction creating a larger surface in contact and greater friction.
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cristo
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May24-08, 03:15 PM
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Quote Quote by Fluxman View Post
What is the force of "friction" (for want of a better word) between the two four-dimensional universes that have come together to create our three-dimensional surface (universe).
This doesn't sound too like any braneworld scenario that I have heard of. Perhaps you could give us a link, or a reference to a journal article describing the background info that you intend to discuss here? I should remind you that discussions at PF are limited to those based on published, peer reviewed articles: at least in the main technical forums, anyway.
Fluxman
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May25-08, 01:12 PM
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Quote Quote by cristo View Post
This doesn't sound too like any braneworld scenario that I have heard of. Perhaps you could give us a link, or a reference to a journal article describing the background info that you intend to discuss here? I should remind you that discussions at PF are limited to those based on published, peer reviewed articles: at least in the main technical forums, anyway.
For purposes of discussion, you can use:

http://cabierta.uchile.cl/revista/18...f/noticia1.pdf

as the link.

Of course, I have greatly simplified the concepts.

marcus
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#4
May25-08, 01:28 PM
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Cosmological Friction


Quote Quote by Fluxman View Post
For purposes of discussion, you can use:

http://cabierta.uchile.cl/revista/18...f/noticia1.pdf

as the link.

Of course, I have greatly simplified the concepts.
After several tries I got the link to work. It seemes to be a news item based mainly on 2002 work of Steinhardt Turok.

The general idea of two branes clashing together---as in Steinhardt Turok cylic or ekpyrotic scenarios---is generally familiar to me. I have heard about that. But the idea of two branes RUBBING together with something analogous to friction is completely unfamiliar to me!
Nor does this news item you gave help me, unfortunately. I see nothing new. I see no "friction" analog here. It is just the old Steinhardt Turok stuff plus some speculation. Show me if I am missing something.
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May25-08, 01:35 PM
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Downloaded the file without problems.

Not that I have read it. Just checked the link
cristo
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May25-08, 01:51 PM
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Quote Quote by Fluxman View Post
For purposes of discussion, you can use:

http://cabierta.uchile.cl/revista/18...f/noticia1.pdf

as the link.

Of course, I have greatly simplified the concepts.
Has this paper been published? If not, you're not allowed to discuss it here. If you indeed intend to talk about the ekpyrotic model, then please provide published links to that, and not to your own work.

I'm moving this to BTSM.
Fluxman
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May25-08, 01:57 PM
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The link is not to my work.
cristo
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May25-08, 02:02 PM
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Quote Quote by Fluxman View Post
The link is not to my work.
Ok, but has it been published?

If you wish to discuss a published model, then you may do so here, after providing a reference. But if you wish to speculate on an existing model, then the only place you can do that is the Independent Research forum.
marcus
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May25-08, 02:53 PM
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I think the link is one that Gorgos came up with, in the Penrose Lecture thread, and Fluxman adopted (faut de mieux) sort of at random.
A better discussion reference would probably be a 2002 Steinhardt Turok paper----going directly to the root of the matter.

this link to a University of Chile news item, if anyone is interested, is by Pablo Kittl and Gerardo E. Diaz (mechanical engineering and material science departments at UCSantiago).
They show a lively interest in cosmology and seem enthusiastic about the philosophical possibility of connecting the now unfashionable "Eternal Return" idea with the Steinhardt Turok cyclic universe.

Eternal Return is an old idea which was briefly revived by Nietzsche.
http://en.wikipedia.org/wiki/Eternal_return
the idea that everything perpetually repeats. Heidegger says that Nietzsche didn't claim that this actually HAPPENS but only examined the idea, the meaning of this old persistent idea going back to pre-christian Indian philosophy, the fascination with cycles, what it means about humans that they seem hypnotized by this idea etc etc etc.
Anyway no issue of physical reality.

Cyclic cosmology is something different. Steinhardt and Turok scenarios are just one kind of cyclic cosmology, and maybe not the most plausible or well worked out. Ashtekar's group have run other models where the universe keeps on going through crunch and bounce cycles indefinitely----and they don't have to assume branes or extra dimensions or anything much, and the models actually work. Perpetual bounce models are not rare. They just need to be tested by observation like any other model.

But they do not lead to a repetition in detail of our lives on this tiny planet.
There is nothing in cyclic models of cosmology that would appeal to Nietzsche. No affirmation of life or other spiritual content. If this our edition of spacetime ends and a new one starts the new one may not even have recognizable life. There are no guarantees that anything we care about repeats.

Or? Anybody think there are? Maybe we can forget about the "friction" issue which may be of only marginal interest and talk about what seems to be the main issue of interest here---and the likely reason that Steinhardt Turok scenario seems to appeal to people's fantasy.


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