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Baryon acoustic oscillations

What you are seeing: a high-density perturbation in the early universe (photons + baryons + dark matter). Photons drag baryons outward as a pressure wave at cs≈c/3(1+R)c_s \approx c/\sqrt{3(1+R)}. At recombination, the wave freezes at the "sound horizon" ∼150\sim 150 Mpc, leaving a baryon shell around each density peak.

Figure 1. Sound wave + baryon shell around a perturbation.
R baryon0.60

WHAT TO TRY

  • Vary each control and watch the rail readouts respond.
  • Compare the diagnostic plot against the live scene.