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Is Dark Matter Flattened by Gravity and Rotation?

6 Nov 2016, 21:33 UTC
Is Dark Matter Flattened by Gravity and Rotation?
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Question: When gravity and rotating motion get together they usually result in a flattened disc. For example, the spiral galaxies, the solar system, the rings of Saturn, and the different diameters of the Earth, around the equator and around the poles. Yet all pictures of the dark matter halo around spiral galaxies show a fairly spherical smudge around the galactic center. If dark matter is moving/rotating and subject to gravity, why does it not flatten like baryonic matter? This only depends on gravity and motion, not interaction with electromagnetic radiation. — Tom
Answer: Since the actual distribution of dark matter, to my knowledge, has not been imaged before I believe that the haloes of dark matter represented around galaxies are all artists conceptions. Note, though, that these artists conceptions are based on theoretical models for what the dark matter halo around a galaxy might look like. One of the main pieces of evidence for the existence of dark matter in galaxies is the fact that many galaxies have a flat rotation curve as a function of distance from the center of the galaxy. If the galaxy’s mass is completely determined by its visible stars, gas, and dust its rotation curve ...

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