Giant Galactic Blobs: Uncovering Dark Matter?

[ohwilleke]

If there is a shielding effect, one would expect that it would be pretty localized and not have a big effect on large scale dynamics. Why? Because most of the universe is empty space. Even in a typical galaxy, there isn't much line of sight/geodesic line interference.

Also, given the small OOM of the proposed allais effect, and the huge masses necessary to produce the effect (planetary), gravitational shielding seems like it would be pretty much a curiosity only.

 

[turbo]

Good points, ohwilleke, however if the Allais effect is experimentally verified, it will by no means be a curiosity. A very basic and important implication of the Allais effect (if proven) is that the mechanics of gravitation is inadequately described by GR. GR says that masses warp space-time. If the gravitational effect of the Sun, as measured at any place on the Earth can be moderated by placing our very modest-sized moon directly between the Sun and that location (solar eclipse), then we will have to admit that the GR mathematical model of space-time curvature is only a handy approximation, and is not "real" in and of itself. The shielding effect proposed by Allais begs for a true mechanical (kinetic/dynamical) model of gravitation, which is where LQG is currently stuck - trying to reconcile flat-field quantum physics with the curved space-time of GR.

I will shut up now, lest I be accused of hand-waving by those much wiser and more perceptive than myself.

 

[ohwilleke]

A very basic and important implication of the Allais effect (if proven) is that the mechanics of gravitation is inadequately described by GR.

Good point. And, of course, new physics is always interesting, even when it isn't very useful.

 

[ohwilleke]

Along this line, McGaugh (a MOND guy) has a paper describing constraints on the distribution of DM is you say MOND is wrong on DM is right.

Another paper in a similar vein is here: http://cul.arxiv.org/abs/astro-ph/0406487

 

[Chronos]

If there is a shielding effect, one would expect that it would be pretty localized and not have a big effect on large scale dynamics. Why? Because most of the universe is empty space. Even in a typical galaxy, there isn't much line of sight/geodesic line interference.

Also, given the small OOM of the proposed allais effect, and the huge masses necessary to produce the effect (planetary), gravitational shielding seems like it would be pretty much a curiosity only.

I agree entirely. I can't picture how such an effect would have any large scale consequences. I was merely thinking it might be interesting to see what, if anything, would happen if you plugged the effect into an N-body simulation - assuming of course the effect is real and could be quantified.