Cosmology-Application of the friedmann equation

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SUMMARY

The discussion centers on applying the Friedmann equation to a matter-dominated universe, where the Hubble constant (H) is 75 km s-1 Mpc-1 and the constant density of matter is 10-26 kg m-3. The challenge is to determine the rate of hydrogen atom creation per unit volume to maintain this constant density as the universe expands. The solution involves calculating the derivative of the difference between the constant density (ρ0) and the time-dependent density (ρ(t)), which decreases over time.

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  • Understanding of the Friedmann equations in cosmology
  • Knowledge of Hubble's Law and the Hubble constant
  • Familiarity with concepts of density in cosmological models
  • Basic calculus, specifically differentiation
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  • Learn about the implications of the Hubble constant on the dynamics of the universe
  • Research the concept of matter density and its role in cosmological models
  • Explore advanced calculus techniques for solving differential equations in physics
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Astronomy students, cosmologists, and physicists interested in the dynamics of the universe and the application of the Friedmann equation to real-world scenarios.

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Homework Statement


The universe is expanding as shown by a Hubble constant H of 75 Km s^-1 Mpc^-1, but a constant density of matter of 10^-26 kg m^-3 is maintained by the continuous creation of hydrogen atoms as the universe expands. Find the rate of creation of hydrogen atoms per unit volume.
dont really know how to go about this

Homework Equations



for a matter dominated universe, a~t^2/3 and rho~a^-3


The Attempt at a Solution

 
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So you have ρ(t) given, which decreases with time, but you want to maintain a constant density ρ_0. The creation rate is just d/dt [ ρ_0 - ρ(t) ].
 

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