•Key points – we are
pretty darn certain it is present
in larger quantities than baryons.
•Can provide the
extra gravity, extra unseen perturbation,
to let galaxies grow from the small
observed temperature fluctuations.
•Unknown what it is!
Recall our previous class discussion
(chapter 2).
•Terminology in this
game describes “hot” and “cold”
dark matter, indicating whether or not particles are relativistic when they decouple.
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