Comment Re:Dark matter (Score 1) 234
Assuming dark matter existed at from the big bang (the existence of which is required for all these models), it should have been no more or less likely to clump up than normal matter
False. Matter is interacting, that’s why planetary systems and galaxies form disk like shapes, they have angular momentum and due to matter matter interactions like gas collisions it naturally flattens into a disk as the momentum resolves into a uniform direction. If dark matter is simply a heavier right handed neutrino like particle the amount of interaction is so ridiculously small it passes through even degenerate matter like neutron stars, and perhaps even other like particles and as such would clump much like a gas does without particle particle interaction and only through gravity. In fact the equations for determining a dark halo shape are of the same form as you would use for a gas.
it should be present in the solar system and detectable here by its gravitational effects locally.
assuming a uniform distribution of the amount we have in the Milky Way that’s about 4 protons per cubic meter, we can’t measure that small amounts and the dust and particles in our solar system swamp it out, it literally totals the mass of a small asteroid for the entire solar system but uniformly spread out. To do some kind of detection like that we need technology far beyond what is feasible today.