Are Nesting Universes Possible and How Does Gravity Fit In?

[RickBman]

nesting universes...

Im just curious as to what people think on this matter...is it really a possibility? the more i read up on it the more i like the idea. The only thing i dnt get is how time would 'translate' through the different levels if this makes sense.And is this a infinate theory or does this have boundries? maybe stupid questions again from me but never mind...

 

[Simon Bridge]

The answers will depend on how the nesting is modeled ... i.e. in the "fecund universes" model, the daughter universes get their dimensions, pretty much, from the parent. The "time axis" in the daughter would depend on the space-time geometry about/in the black hole.

It's really difficult to talk about multiverse theories ... it may not be terribly useful to think of the universes being nested like matyoshka ... maybe more like splitting off like "spawning". But to count as a Universe, it should really be separate in some important way - "you can't get there from here" would be a start.

If you can get information out of it, as in Gregory Benford's Cosm, then, is it actually a separate Universe or is it part of ours?

I want you to realize two things though:
1. This field is speculative, even for cosmology, so we need to be careful talking about it in these forums.
2. The attractiveness of an idea does not say anything about how likely it is to be true.

 

[RickBman]

Is theory and speculative talk prohibited in this site??

Is see what you mean, the idea of it being a multiverse on the nesting universe theory doesn't really make sense as in theory it would be the same universe. I kinda like to think in my little brain anyway :) that the universe is infinatly cone shaped if that makes sense...with the step down between each visible 'existance' something like 10▲10000 of an atom or something like that. My only thing is time...how would it work? Would the parent existence have to be traveling exponentially faster than the daughter? Also could this also explain why gravity is so weak and almost acts like leakage from other universes as it distributed throughso many levels?

 

[Simon Bridge]

Is theory and speculative talk prohibited in this site??

Theory is fine - personal theory and speculation isn't. See the Physics Forums Global Guidelines for details.

Is see what you mean, the idea of it being a multiverse on the nesting universe theory doesn't really make sense as in theory it would be the same universe.

You'd be talking about regions within our own universe which have some sort of special separation perhaps -

I kinda like to think in my little brain anyway :) that the universe is infinatly cone shaped if that makes sense...

Well, yes and no... dependse what you mean by "shape". (and "sense" ;) )
http://en.wikipedia.org/wiki/Shape_of_the_Universe

..with the step down between each visible 'existance' something like 10▲10000 of an atom or something like that.

That doesn't make any sense.

None of the other questions can be answered without some clarity on the model - can you come up with a reference in a peer reviewed journal?

I'm curious about why you think the weakness of gravity is something that needs to be explained.

 

[RickBman]

Ok.. cone shape may not be the best description, i find it hard to expkain what i mean but as its personal theory its probably best being left there anyway.

With reference to having clarity in the model ill get back to you on that and see what you have to say :) i am, as I am sure uve gathered fairly new to this.

Gravities weakness...i think it does need explaining yes. Why is it so weak? Is the gravity we experience mearly leakage from another dimension? Another question i have is...if gravity doesn't have the strength to hold galaxies together and dark matter is the scaffolding for the galactic web... why is this not in the standard model...apologies if this is a stupid question

 

[Mordred]

this thread has a large discussion on various multiverse theories. s Simon pointed out if our spacetime interacts with a region that is in your definition a separate universe then its part of our universe. Universe is loosely defined as everything that is.
To count as a separate universe we would not be able to see, measure or interact with the other universe directly. However we may be able to measure a multiverse influence. Common proposals are influences on the CMB.
As far as gravity goes, their are proposals only, that gravity is a multi dimensional force. This is one of the proposals of sting theory. Though no evidence

https://www.physicsforums.com/showthread.php?t=697051

 

[Simon Bridge]

Gravities weakness...i think it does need explaining yes. Why is it so weak?

"Why" is tricky to answer - can you provide an example of what sort of answer would work?
It kind-of implies that gravity could be otherwise than it is but for some sort of constraint ... I think standard cosmology pretty much has gravity separate off quite early so it's strength would be set by the symmetry of the early Universe.

Is the gravity we experience mearly leakage from another dimension?

That's the kind of leading question you get in infomercials: "could it be that the Enerwave^(TM) sets up a resonating force field that energizes your entire core to strengthen and balance your whole being?..."

... you can string words together and make all kinds of cool-sounding sentences but it is much more helpful if it means something.
eg. are universes a kind of container that gravity fills like water in a plastic bag?
If gravity is weak because we are just getting the leakage - then doesn't that beg the question of why the strong nuclear force is so strong?

However you reply, the original question just turns into why gravity leaks so much and other forces less so and you are back to where you started!

Occams razor will have us get rid of the multi-universe thing in that case.

Another question i have is...if gravity doesn't have the strength to hold galaxies together and dark matter is the scaffolding for the galactic web... why is this not in the standard model...apologies if this is a stupid question

The standard model is for particle physics - small scale - and does not handle gravity.
There are proposals for how gravity may fit into the standard model, but none have been verified.