Dark Energy May Lurk In Hidden Dimensions

Magdalene writes in to let us know about a sketch of an idea, that might one day become a theory, to explain the dark energy that is making the universe flee faster and faster apart. It posits that dark energy may be the result of a new kind of neutrino wandering in tiny extra dimensions above our familiar three. She adds, "There is no word yet on whether Sphere or Square are available for comment." From the article: "The mysterious cosmic presence called dark energy, which is accelerating the expansion of the universe, might be lurking in hidden dimensions of space. This idea would explain how the dimensions of space remain stable — one of the biggest problems for the unified scheme of physics called 'string theory'... To get the same amount of acceleration seen by astronomers, Greene and Levin calculate that the extra dimensions should have a scale of about 0.01 millimeter."

Comments

Now that...

[jd]

...dark energy has fallen into an interdimensional rift in the fabric of space/time, can we shove the astrophysicists who insist on inventing the unobservable to fix their theories in with them, and get on with fixing whatever the error in the models really is? Please?

There is nothing worse than a scientist who fixes the observation to meet their theory, to paraphrase the illustrious but equally fictional Sherlock Holmes.

Re:Now that...

[perturbed1]

What part of such an LHC-observation scenario do you find as "total nonsense"? Afterall, physics (especially the LHC) needs two things: 1) a multitude of theories to debunk and 2) money. There are theorists which will "die" if the LHC does not observe large extra dimensions. So most such theorists say: "if this theory is correct, then large extra dimensions must be small enough so that we havent observed them before but are large enough to be observed at the LHC." I can see nothing that can be called total nonsense here -- as long as the clause "if this theory is correct" is included.

And I am an experimentalist. With very little taste for things that theorists believe to be true. So there you go... I spend my days hoping to reproduce a mini-singularity one day... ;)

Re:Huh?

[Anonymous Coward]

You must have meant Roland is getting tired, so there was no Roland post to pick from. kdawson seems to be still doing his 'job' :)

Re:"Sphere or Square" reference...

[MichaelSmith]

In case you haven't read it, Flatland (The first non-wiki link in google) is the tale of a square named (conveniently) A. Square

I haven't read that one but I loved The Planiverse

Funniest title ever

[suv4x4]

Dark Energy May Lurk In Hidden Dimensions

So.. let me get that straight. We solve the problem of energy we can't detect and dimensions we can't prove exist? Simple! We tuck the one into the other and thus explain everything in a single shot. Brilliant!

Now allow me walk away for today as I am laughing my guts out.

Re:How does a dimension have a scale?

[eyebits]

I suppose part of my problem is that I think of dimensionality in a cartesian sense. If I have a dimension curve back on itself (form a circle) I am conceptualizing that I have to go through another dimension to do it. So, if I have a line in one dimension I need to go through a second dimension to curve the line into a circle. Circles are two dimensional...and yet they are being used to describe a single dimension. I must somehow convince myself to think differently about what a dimension is I suppose.

>"Each time you travel a certain distance in the z-direction, you come back to where you started."

This implies, I think, that a dimension can be (is) in some sense bounded. And, in order for this bound to not generate a sharp end ( in the sense of end of the universe, edge of the world, etc.) the notion of coming back around to the original position is needed.

So, I am not sure if I am to accept that a dimension as a circle requires thinking about more than 1 dimension at a time to conceptualize a dimension or if I need to get my head to wrap around a model of a single dimension having curvature without the requirement for a second dimension.

This makes me think of the 1-D ant walking on what the ant thinks is a straight line when in fact when viewed from higher number of dimensions the ant could be walking on a circle, ellipse, mobius or any number of other forms. The thing is...from the perspective of the ant all the various traversals appear to happen in one dimension. But, that does not belie the "reality" from higher dimensions that the circle and the ellipse are two dimensional even if the ant doesn't know it.

I can see that if I had two dimensions and both were conceptualized as circular then a sphere would form whose surface would be a two dimensional "plane". A 2D creature could crawl all over that 2D plane with the only weirdness being that if it traveled far enough in any direction it would end up back where it started. The issue for me is... to conceptualize this 2D plane I need to have an added third dimension to see it. Is the third dimension that lets me see it "real" or does it only exist conceptually? I think it is interesting that I have to place my 2D curved world in a 3D cartesian space to "see" how it works.

No doubt, I need to take some courses in topology...

Thanks for the responses.

Re:0.01 millimeter?

[bill_mcgonigle]

0.01 millimeter?

That's actually a very interesting result, as it's on a similar scale to some other theories of large hidden dimensions. Doesn't mean it's right, but it's at least interesting when multiple theories arrive at similar results coming from different angles.

Re:How does a dimension have a scale?

[Anonymous Coward]

Basically, the "scale" of a dimension is how far you have to travel before you have crossed the entire universe in that dimension and come back to where you started.

So, if our universe has these extra dimensions, the size of our universe is:

Dimension X: X gazillion light years

by

Dimension Y: Y gazillion light years

by

Dimension Z: Z gazillion light years

by

Extra Dimension 1: 0.01 mm

by

Extra Dimension 2: 0.01 mm

etc etc.

The idea is that while the dimensions actually exist, it is only X, Y, and Z in which the universe began to expand during the Big Bang. Who knows? Perhaps these other dimensions are expanding as well, only much more slowly.

re - Dark Energy May Lurk In Hidden Dimensions

[MM-Telco-Emp]

Has anyone considered that dark energy may be the emissions created by Black-Holes swallowing up everything. Whilst nothing including light escapes, perhaps Dark Energy doesn't obey the same rules as the emission is becomes anti-gravity - heavy gravity repelling heavy anti-gravity?