William Straub
Sep 8, 2018 · 1 min read

Proponents of dark matter (including Siegel) note that galaxies tend to exhibit centralized, spherical DM haloes resulting from the accumulation of DM under gravity, the only force believed to influence its distribution. If that were strictly true, then in time DM would collapse around galactic cores, perhaps getting eaten by supermassive black holes.

Wait, say the proponents, since DM does not experience any pressure from itself or ordinary matter, then the haloes would persist indefinitely, with DM material orbiting forever around the galactic cores. But the proponents neglect to explain how DM came to be compacted in the first place. Wait again, they say, star formation might be heating up DM material and preventing its compaction, resulting in a kind of hydrostatic equilibrium with gravity. But this would require DM to interact with its environment, again defeating the notion that only gravity influences its behavior.

I simply cannot see how DM haloes can form without ultimately collapsing into black holes, since sooner or later all DM material would be swept onto the event horizons.

    William Straub

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