Cosmos 6: The Cosmic Background Radiation, the Cosmic Temperature, and Recombination

Don't Panic

Sections

  1. The Cosmic Microwave Background Surf

  1. The Cosmic Microwave Background (CMB) Surf

    2. We're just going to surf the Web.

    1. CMB plot: See CMB features: T_0=2.7260(13) K (Fixsen 2009). The CMB is a nearly perfect blackbody spectrum: maybe almost the most perfect in nature. For reference, see Wikipedia: Cosmic microwave background (CMB).
    2. Keywords: Diffuse extragalactic background radiation (DEBRA) inverse centimeter (cm**(-1)), jansky (Jy) = 10**(-26) W/(m**2*Hz), microwave band (fiducial range 0.1--100 cm, 0.01--10 cm**(-1)) Wien's law (see wien_law.html), etc..
    3. CMB all sky: In Mollweide projection (see Wikipedia: Cosmic microwave background: Microwave background observations). The fluctuations are about 1/10*85 or 18 μK (see Wikipedia: Cosmic microwave background: Features. This distorations result from primordial density fluctations at the recombination era.
    4. Optical depth τ since reionization: Most modern value 0.0561(71) which means I_modern=I_recombination*exp(-τ) ≅ I_recombination*(1-τ) ≅ 0.94*I_recombination. So most CMB has not been scattered by free free electrons by Thomson scattering which randomize its direction. Randomization would erase our ability to know about know of the primordial density fluctuations at the recombination era. About the same amount of scattering has occurred to diffuse extragalactic background radiation (DEBRA).
    5. Diffuse extragalactic background radiation (DEBRA): See Schematic DEBRA (2007), Barry Madore DEBRA (c.2000), Southampton DEBRA (c.2018?).
      Keywords: Compton scattering, DEBRA, dex → factor of 10, extragalactic background light (EBL), inverse Compton scattering, Sachs-Wolfe effect (Non-integrated Sachs-Wolfe effect, integrated Sachs-Wolfe effect, Sunyaev-Zel'dovich effect, Thomson scattering, etc..
    6. Cosmic temperature evolution from 1e-10 s to 1e+16 s = 0.3 Gyr.
    7. wien_law.html
    8. cmb_dipole_anisotropy.html.
    9. cmb_wmap.html
    10. cmb_power_spectrum.html.
    11. blackbody radiation, blackbody spectrum
    12. horizon_problem.html: For CMB coming from all directions from the near the particle horizon and the horizon problem.
    13. Cahill 2017, The eras of radiation, matter, and dark energy: new information from the Planck Collaboration:
    14. recombination era: Wikipedia: Recombination: Rough estimate from equilibrium theory.
    15. * | Future Evolution of Nearby Large-Scale Structure in a Universe Dominated by a Cosmological Constant: Kentaro Nagamine, Abraham Loeb, arXiv 2002, Nov12, 14 pages: Research: On the future of the observable universe assuming the cosmological constant and the concordance model.
      --- Keywords: cold dark matter (CDM), concordance model, concordance model parameters, concordance model distance measures graph, cosmology, dark energy, dark matter, galaxies, intergalactic medium (IGM), IOP cosmological parameters summary: bit dated, large-scale structure of the universe, Universe in Problems: lots of solutions, etc.