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- The distance sound waves could have traveled in the time before recombination is called the sound horizon, rs. The sound horizon is a fixed physical scale at the surface of last scattering.
ned.ipac.caltech.edu/level5/Sept02/Reid/Reid5_2.htmlThe picture of our universe: A view from modern cosmology - D ...
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How accurate is a sound horizon?
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What is a horizon in physics?
The distance sound waves could have traveled in the time before recombination is called the sound horizon, r s. The sound horizon is a fixed physical scale at the surface of last scattering. The size of the sound horizon depends on the values of cosmological parameters.
Jun 8, 2021 · The sound horizon r⋆ is the comoving distance a sound wave could travel from the beginning of the universe to recombination, a standard ruler in any given model, and D (...
- Karsten Jedamzik, Levon Pogosian, Gong-Bo Zhao
- 2021
A cosmological horizon is a measure of the distance from which one could possibly retrieve information. This observable constraint is due to various properties of general relativity , the expanding universe , and the physics of Big Bang cosmology .
The particle horizon (also called the cosmological horizon, the comoving horizon (in Scott Dodelson 's text), or the cosmic light horizon) is the maximum distance from which light from particles could have traveled to the observer in the age of the universe.
This upper limit is called the “sound horizon”. What’s in it for cosmology? The main reason these oscillations are of great interest to cosmology is that astronomers can measure the apparent size of the sound horizon in the sky.
The sound horizon from our different measurements is r d = (137 ± 3 stat. ± 2 syst.) Mpc based on absolute distance calibration from gravitational lensing and the cosmic distance ladder. Depending on the adopted distance indicators, the combined tension in H 0 and r d ranges between 2.3 and 5.1 σ , and it is independent of changes to the low ...
This is a bit large, because the actual relevant horizon is the sound horizon rather than the light horizon, and they turn out to differ by a factor of 3, so 2.7° turns into 0.9°. Alternatively, you can say that in a matter-dominated flat universe H(t) 2 = H 0 2 /a 3 = H 0 2 × (1+z) 3 , so the Hubble distance c/H at redshift 1100 is given by c/(H 0 × (1+z) 3/2 ) = 380000 ly, divided by the ...
