Personally I think that "dark matter" is not matter at all, but ripples that form valleys and hills in the space-time membrane like a plastic bag that has been

Personally I think that "dark matter" is not matter at all, but ripples that form valleys and hills in the space-time membrane like a plastic bag that has been stretched (by the big bang) and crumpled slightly back. But I am not a physicist so it is purely speculation from my part and I have no math to back it up. It's just the way I picture it in my head :)