AdvancedIOAA style, adapted

Matter radiation equality

Today $\Omega_m = 0.31$ and the radiation density (photons plus neutrinos) is $\Omega_r = 9.0\times10^{-5}$ . Find the redshift of matter radiation equality and the CMB temperature at that epoch ( $T_0 = 2.725$ K).

Saved in this browser only, no account needed.

Reading resources

Material that covers the physics behind this problem.

An Introduction to Modern AstrophysicsCarroll & Ostlie
The standard reference for olympiad-level astrophysics. Chapters 1-3 cover the celestial sphere, orbits and the magnitude system.
Textbook
Ohio State Astronomy Lecture NotesOhio State University
Clear university-level notes on stars, galaxies and cosmology with derivations you can follow line by line.
Lecture notes
Cosmology CalculatorEdward L. Wright (UCLA)
Converts redshift into distances, lookback time and scale factors. Use it to sanity-check cosmology answers.
Website