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New String-Theory Notion Redefines the Big Bang
PhysOrg.com ^ | 31 March 2006 | Laura Mgrdichian

Posted on 03/31/2006 1:11:53 PM PST by PatrickHenry

String theory — the concept that all particles can be represented as strings or string-loops of incredibly minute length, oscillating at various frequencies — was initially developed to help explain why quarks, the tiny fundamental particles that make up protons and neutrons, are always confined within larger composite particles. However, string theory has evolved to allow scientists to deal with some wider issues. For example, they can use string theory to devise explanations for some grand problems in cosmology, such as the state of the universe — its shape, size, etc. — just after the Big Bang, when quarks roamed freely.

Along these lines, a group of theoretical physicists has recently published an interesting string-theory scenario that describes a new way to approach the development of the Big Bang. They propose that the universe began as a type of theoretical space-filling object called a “brane.”

This work was published in the January 27, 2006, online edition of Physical Review Letters.

“Perhaps the most ambitious problem in cosmology is the question of the initial conditions of the universe — what it looked like before expanding into the stars and planets we see today,” said a physicist involved in the study, Robert Leigh of the University of Illinois, to PhysOrg.com. “We propose that the universe, before expansion, was an unstable brane that decayed into innumerable string-loops to form the universe as we now know it.”

The conventional model for the expansion of the universe assumes that the universe once existed as a very small, point-like volume called a “singularity.” Then the Big Bang occurred, and the universe rapidly expanded. An extension of this, and one main competitor of the brane model, is the Big Crunch/Big Bang theory, which assumes that the universe was once vast, then “crunched” down to a singularity before expanding. The Big Bang/Big Crunch model implies that time existed before the Big Bang.

The problem with the Big Crunch/Big Bang model is that the mathematical laws of classical general relativity do not work at a singularity. And if scientists cannot mathematically understand the singularity, they cannot, in theory, fully understand the geometry of spacetime, either before the Big Crunch or after the Big Bang.

“Our brane model allows us to mathematically address what might have happened at the Big Bang, and also gives a novel interpretation of time in string theory,” said Leigh.

He and his group propose that time began when, via a Big Bang-like event, the brane decayed into closed strings (loops) that propagated off to create the ordinary matter that makes up the universe. This scenario, while avoiding the mathematical problems of a singularity, also helps explain some other issues. For example, to us, the universe looks the same in every direction. Within this brane model, the homogeneity of the universe could be explained as the result of an early universe with homogenous initial conditions, such as a brane that evenly filled space. Leigh and his colleagues may further explore this in additional studies.

Citation: “Brane Decay and an Initial Spacelike Singularity,” Phys. Rev. Lett. 96, 031301 (2006)


TOPICS: Culture/Society; Philosophy
KEYWORDS: cosmology
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To: RightWhale
But, either way, if it was unstable it must have been unstable before.

Not if there's no before. Which is a problem in itself, the way my brane brain works.

21 posted on 03/31/2006 1:50:31 PM PST by VadeRetro (I have the updated "Your brain on creationism" on my homepage.)
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To: VadeRetro

If something is unstable it must have existence in time. If time began with the Big Bang, then instability would not have been a factor.


22 posted on 03/31/2006 1:53:54 PM PST by RightWhale (Nothing can evolve which has not been involved)
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To: Red Badger
I'll be pondering the string theory of bikinis at the beach.......What would happen if I pulled that string?........

Sure hope its not the same as when you pull my finger.:)

23 posted on 03/31/2006 1:54:06 PM PST by taxesareforever (Never forget Matt Maupin)
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To: RightWhale
If time began with the Big Bang, then instability would not have been a factor.

Then nothing was unstable and nothing happened. Never mind.

24 posted on 03/31/2006 1:59:54 PM PST by VadeRetro (I have the updated "Your brain on creationism" on my homepage.)
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To: VadeRetro

Nothing happened. That's probably correct. Inflation and quantum microvariation probably explain some present observations, but that wouldn't imply that is necessarily what actually happened.


25 posted on 03/31/2006 2:03:57 PM PST by RightWhale (Nothing can evolve which has not been involved)
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To: MineralMan
Reading about string theory will give a guy a serious headache.

You're not kidding. How many dimensions are we up to now to make the math work, 10?, 11? I have enough trouble with 4 and that time dimension keeps speeding up.

26 posted on 03/31/2006 2:04:51 PM PST by DeFault User
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To: All
Here's a link to the abstract in Physical Review Letters, which isn't very informative. Getting the article itself requires a subscription:
Brane Decay and an Initial Spacelike Singularity.
27 posted on 03/31/2006 2:05:39 PM PST by PatrickHenry (Yo momma's so fat she's got a Schwarzschild radius.)
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To: DeFault User

It's 26 and time is not a dimension.


28 posted on 03/31/2006 2:06:22 PM PST by RightWhale (Nothing can evolve which has not been involved)
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To: llevrok
>The only string theory I know about is ...






I'm looking for grants
for string bikini research . . .
Big bang theory rules!

29 posted on 03/31/2006 2:10:57 PM PST by theFIRMbss
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To: MineralMan

String theory hurts my brane!


30 posted on 03/31/2006 2:15:36 PM PST by MooseMan
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To: PatrickHenry

Hoo, boy... Okay, how big was this brane before it decomposed? As big, or nearly as big, as the present universe -- or are they sticking with the mathematical point beginnings of the universe and superluminal expansion? Why was the brane unstable? Exactly HOW did it ("it" presumably being pure "unstable" space but not matter) decompose into an innumerable bunch of tiny closed strings (i.e., actual matter), etc.? Not annoyed at this new theory. Just fascinated and awed at it all.


31 posted on 03/31/2006 2:46:13 PM PST by LibWhacker
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To: PatrickHenry
A spacelike singularity at t0. Yes. That would do it, obviously.
32 posted on 03/31/2006 3:04:25 PM PST by VadeRetro (I have the updated "Your brain on creationism" on my homepage.)
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To: theFIRMbss

No mention of the black hole as this is a family site.


33 posted on 03/31/2006 3:27:02 PM PST by llevrok (Vote Conservative First.)
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To: PatrickHenry

this stuff always makes my head hurt


34 posted on 03/31/2006 3:33:46 PM PST by King Prout (many complain I am overly literal. this would not be a problem if so many were not under-precise)
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To: PatrickHenry

Not brand brand new...I've been stumbling over the occasional article leading in this direction.

We will see.

String theory. So much promise. So much frustration. It ties one up in knots.


35 posted on 03/31/2006 3:35:08 PM PST by Knitting A Conundrum (Act Justly, Love Mercy, and Walk Humbly With God Micah 6:8)
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To: LibWhacker; All
Would someone explain where the Void came from for all of this to occur in. If our Universal space has no boundary then how can anything else outside our universe exist? If there are borders to our universe, what happens when we reach the limit. One last question. Does time differ on a Universe, Galaxy, Solar System if it is expanding or contracting.
36 posted on 03/31/2006 4:13:27 PM PST by No2much3 (I did not ask for this user name, but I will keep it !)
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To: KevinDavis

ping


37 posted on 03/31/2006 9:36:31 PM PST by Wiz
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