Parallel universe attracting galactic clusters

Naty1

On the Science Channel, US cable TV (7/11/2011): A NASA astronomer has discovered that a number of galactic clusters are all UNEXPECTEDLY drifting in a uniform manner (not directly away from earth) suggesting that something is attracting them all in a particular direction. [The astronomer was SHOCKED when he saw the data and initially did not believe it himself.]
An English theoretical physicst heard about the observations: She has a theory about a nearby parallel universe attracting matter in our universe...and her calculations match the observations from NASA! They have teamed up for further study and the NASA astronomer hopes to have some 2,000 galactic cluster drifts documented during the next two years. [According to the program, this "drift" is currently disputed by others.]

I happen to be rereading Michio Kaku's Hyperspace (1994) and noticed this comment about Hugh Everett's many worlds theory:

So I am wondering if anyone can point me to some discussion of the drift and or explain any details. And I am wondering if Kaku's comment is now out of date and if so why do we believe gravity can pass between parallel universes.

All I have read is that it has been theorized that gravity may be weak in our universe because maybe it leaks into the curled up dimensions in string theory.

(Sorry I don't have the physicsts names..)
Thanks.

Oldfart

Wouldn't things be simpler (and a bit less sensational) to assume that the source of gravitational pull were within our universe but outside of our observable universe? Maybe a very distant monster cluster of galaxies or something like that?

Tanelorn

I have to agree with Oldfart that we should consider the simplest explanation first. If these galaxies are nowhere close to the limit of the observable universe and you cant see the massive attractor then you might be on to something.

Drakkith

There is also the possibility of dark matter causing this to happen.

phinds

I believe this is what's called "dark flow" (yeah, another "dark" ... just what we need) if you want to poke around for more about it, but I have not heard of any answers, just questions. The questions, when reduced to laymen's terms seem to be on the order of "NOW WTF???"

Actually, I exaggerate ... there HAVE been some interesting hypotheses (but not any answers)

Tanelorn

Explanations for this may cause problems for homogeneity theories.

Chronos

Wait and see. Such conclusions are highly suspect until observationally supported. The data to date is inconclusive. Claims such as this usually fade into obscurity when put under the microscope.

Chalnoth

Looks like this is probably nothing:
http://arxiv.org/abs/0910.4233

skydivephil

I wonder what PLanck will have to say about this, they should be reporting cosmological results about 1-2 years from now.

JonDE

I dont think this is new, as I think he is referring to the great attractor theory which has been around since the 70's and has sort of evolved into dark flow theory. More information can be found at these 3 sites, although I have no idea how accurate wikipedia's information is.
http://en.wikipedia.org/wiki/Great_Attractor
http://en.wikipedia.org/wiki/Shapley_supercluster
http://en.wikipedia.org/wiki/Dark_flow

phinds

My impression is distinctly that "dark flow", whatEVER it is (if it is even real) is NOT the great attractor, which as you say has been know for quite a while. This IS something new.

JonDE

sorry if my response caused some confusion, I guess I should have explained myself further. According to the articles, the first theory that came out was called the great attractor, later it was theorized that the "great attractor" was itself moving in the same general direction, hence the great attractor is not what is attracting us. The theory that replaced the great attractor is called "dark flow" although I have no idea how credible this theory is in real science.

Naty1

"Explanations for this may cause problems for homogeneity theories."

It's observed...so there would have to bee some new apparatus inferred that would cause deviations just beyond our visibility....not so attractive, but possible.

Chalnoth: Thanks for the paper....Kashlinsky may be the NASA scientist ...he sure had a heavy accent in the documentary......

Thanks all for the comments.

Naty1

I think that was mentioned in the TV dialogue...thanks....

IsometricPion

I think Kaku was referring to the fact that quantum mechanics is linear. So, no matter the interpretation, the independent components of superpositions cannot interact physically. When applied to the many worlds interpretation (MWI), this translates to worlds not being able to physically interact with one another. Since quantum mechanics (both relativistic and non-relativistic) is built on the concepts of linear operators, any theory that would allow such interaction would be a qualitatively different theory. In addition, I am not sure if the concept of "many worlds" even makes sense if they can interact (wouldn't they all be more or less physical parts of the same world?).

The "many worlds" of the MWI exist in an abstract probability space, there is no notion (even if the worlds could interact) that they exist at a spatial or temporal location different from that of the observed universe/"world". This is in contrast to the sort of parallel universe that is postulated to be responsible for "dark flow". That sort of parallel universe is thought to exist near our own in space (where the distance would be in the direction described by one of the extra dimensions in (a form of) string theory or some such theory that involves extra dimensions).

Edward Solomo

Of course, if we assume that gravity moves at the speed of light, than any gravity from such a massive object interacting with other observable objects would imply that the unknown object itself must be within the observable universe, otherwise we would not be able to observe it communicating with other galaxies.

You must remember that the present state to an observer of a distant object is the past state of the object; and that the present state of an object is the future state of the object to the observer.

Think of it this way, if one object A is near the edge of the particle horizon, then we are looking at the object near the start of the Big Bang. Now take another object beyond the particle horizon. If photons cannot have arrived to us from beyond the particle horizon, then these photons have not yet interacted with Object A to the observer. Therefore, gravity cannot have interacting with Object A either.

Also (I may be wrong about this), if objects A and B are actually communicating to the present state of the observer, this would imply that they started communicating before the Big Bang.

I believe it is more likely that Dark Matter is not homogeneously distributed as regular matter is.