VISIBLE MATTER. “Baryons, however, are tightly coupled to photons until decoupling, at tdec ≈ 0.4 Myr and therefore perturbations in baryons can only grow after decoupling. Consequently in a universe without non-baryonic DM the initial density perturbations have to be larger, and produce larger temperature fluctuations in the CMB, ∆T/T ∼ 10(-4), for observed structures to form.” (DM = dark matter; CMB = cosmic microwave background).
https://lnkd.in/e6ifiQMn
linkedin post 2022-06-29 05:12:48
Nigel Fleming
September 21, 2022