Dark matter as matter in parallel universes

[DavidMcC]

Uh huh, yet they predict and let us develop technology for all that it lacks the elegance you seem to want.

LQC also makes predictions (and could have done so before if it hadn't been prematurely abandoned). Eg, it predicts that neither WIMPS nor MACHOS, etc will be found, and that dark energy will ultimately go to zero (when there is nothing more to feed on in the parent universe), although the time-scale for this is unclear.
It is not that I "want elegance", it's just that I see inelegance elsewhere in physics, in which it is caused by external effects. Eg, if you didn't know that the Earth was slowly rotating, you would just have to accept that Newton's law of motion, F=ma, was a mess, needing to have some strange extra terms (the Coriolis force, etc) to make it correct.
As foir technology, comparing any theories should produce that, it's nothing to do with which is better.

 

[Chalnoth]

LQC also makes predictions (and could have done so before if it hadn't been prematurely abandoned). Eg, it predicts that neither WIMPS nor MACHOS, etc will be found, and that dark energy will ultimately go to zero (when there is nothing more to feed on in the parent universe), although the time-scale for this is unclear.

Er, what? Where does it make these predictions? And if so, how the hell does it explain our observations of dark matter?

 

[Misericorde]

Er, what? Where does it make these predictions? And if so, how the hell does it explain our observations of dark matter?

Ditto.

 

[David Elm]

The parallel universe part of your idea doesn't seem to hold water. If gravity was acting in more than 3 dimensions, then it would spread out faster than it currently does (1/r^2). I think this has been well measured and precluded.

On the other hand, I've seen some papers in the ArXive (xxx.lanl.gov) that indication that idea of self-interacting dark matter has some merit.

There is also a non-mainstream theory (developed by serious physicists, not fringe guys, but still not generally accepted) called "mirror matter" that proposes that there are two mutually invisible types of matter living in the same space. I don't know if I follow the argument that well, but it has to do with having two types of matter that violate CP conservation in opposite ways.

Other than the "mirror matter" development, I haven't seen much in the way of a theory of what that self interacting dark matter might be. One paper proposed an analogy to electrodynamics within dark matter, but they didn't go so far as to propose a different type of equivalent matter that was somehow different.

Perhaps these researchers are being deliberately cautious until they come across a good enough theory to hang their collective hats on.