Brane Theory

[surreptitious57]

In the brane hypothesis of Steinhardt and Turok where two collided to create

the Big Bang is there a force of attraction such as gravity operating between

them or was the collision entirely random? Why are collisions between them

supposedly rare? What are they actually made of - matter / energy / strings?

So if the Universe does actually reside up on one or two of them would it not

be evidence of their existence? Could this be determined and if not why not?

What would have existed between these two branes before they collided with

each other - space / time / spacetime? Were these two branes part of another

Universe before they collided or did they exist out side of them? Do they exist

at the quantum or at the classical level? How did they originally come to exist?

How popular is brane theory among physicists? Does it have any major flaws?

[mathematic]

Answers to all your questions are purely speculative.

[ajb]

... was the collision entirely random? Why are collisions between them

supposedly rare?

If I recall correctly the models they propose the collisions are random. Some further work by Warren Perkins (I think) showed that the probaility of a collision does not decrease in time. So in principle we could be struck by another brane at any moment... doomsday indeed.

 

Do they exist at the quantum or at the classical level?

Understanding the quantum theory of interacting branes is difficult and I would say work in progress.

 

How popular is brane theory among physicists?

It depends what you mean here exactly. D-branes and F-branes are taken very seriously by those who work in string theory. We also have the M2 and M5 branes of M-theory, which again is taken quite seriously by those in the string community.

[mathematic]

String (and M) theories are all speculative. There has been a lot of mathematical development, but no definitive connection to the real world.

[ajb]

String (and M) theories are all speculative. There has been a lot of mathematical development, but no definitive connection to the real world.

Still that does not mean we should simply dismiss the opening questions. (Not that I have answered them all)

 

There are people in physics and mathematics departments working on strings and branes, thus the questions are valid.

[Moontanman]

I was under the impression that branes were gravitationally attracted to each other and after they collide the energy of collision drives them apart until gravity takes back over and drags them back together...

 

https://en.wikipedia.org/wiki/Ekpyrotic_universe

[vexedvixen]

I was under the impression that branes were gravitationally attracted to each other and after they collide the energy of collision drives them apart until gravity takes back over and drags them back together...

 

https://en.wikipedia.org/wiki/Ekpyrotic_universe

If that were true, then wouldn't a calculation be able to accurately predict the next collision/big bang and render the doomsday point moot? Although, I have no letters beside my name, I was under the impression that Brane theory (for simplicity sake) is an explanation of the origin of the big bang and the notion that bangs are happening all over the place at all points in time. I am curious, what is the thread that ties String Theory, Brane Theory and M-Theory together? (pardon the pun) I have found my Nirvana in these forums and cannot read enough. If I cannot be a fly on the wall at the Perimeter Institute, than I shall be one here!

[Moontanman]

If that were true, then wouldn't a calculation be able to accurately predict the next collision/big bang and render the doomsday point moot? Although, I have no letters beside my name, I was under the impression that Brane theory (for simplicity sake) is an explanation of the origin of the big bang and the notion that bangs are happening all over the place at all points in time. I am curious, what is the thread that ties String Theory, Brane Theory and M-Theory together? (pardon the pun) I have found my Nirvana in these forums and cannot read enough. If I cannot be a fly on the wall at the Perimeter Institute, than I shall be one here!

 

 

I'm not sure why being attracted to each other by gravity would make them detectable, by the way both branes contain matter.

[vexedvixen]

 

 

I'm not sure why being attracted to each other by gravity would make them detectable, by the way both branes contain matter.

First let me say that I did not choose my words carefully. I am not a scientist, nor do I have any formal education that would give me the framework I need to clearly communicate my thoughts. I am simply a person who has been obsessed with all of these marvelous areas of study. As a young girl in the 70's, my favorite past time was watching Nova and Cosmos. At 18 I began a decade long subscription to Scientific American. At 20, I met Stephen Hawking after attending one of his lectures. It is a lonely feeling to be so passionate about such things and to never find other people who even find it remotely interesting. It is also difficult in that due to many circumstances, I was not able to get the education and genuine knowledge needed to fully understand these subjects and discuss them with people who do.

 

Whew! That being said, I just found this forum today and my excitement got the best of me. I will be more careful from now on.

 

I remember reading about Steinhardt and Turok quite some time ago and the piece that stuck with me was the Brane collisions that explained the origin of the bang/bounce idea and how it was able to account for dark energy and the acceleration of the expanding universe. I was trying to say that they would be able to come up with a calculation and thereby be able to predict when the next collision would happen.

 

Sorry I came across like a jerk.