What kind of information can we extract from this equation?

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Discussion Overview

The discussion revolves around the Friedmann equations in cosmology, specifically focusing on the equation relating the Hubble parameter to density parameters and scale factor. Participants explore the implications of varying these parameters and the information that can be extracted from the resulting function, H(z).

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant presents the Friedmann equation and expresses curiosity about the information that can be derived by evaluating H(z) for different density parameters.
  • Another participant suggests plotting the function in MATLAB as a method to explore the implications of varying parameters.
  • A later reply questions how changes in H(z) with respect to density parameters might reflect changes in the universe.
  • One participant argues that the equation primarily reveals properties of space on a large scale and its evolution, suggesting limitations in the conclusions that can be drawn.
  • Additional resources, including a Wikipedia link and seminar slides, are provided to support the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the extent of information that can be extracted from the equation, with some suggesting that it reveals significant insights while others believe it is limited to large-scale properties of space.

Contextual Notes

The discussion does not resolve the extent to which varying density parameters affect the universe, and assumptions regarding the implications of H(z) remain unaddressed.

Arman777
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In cosmology, we are using the Friedmann equations for the evolution of the universe. And we are using this equation a lot.

$$\frac{H^2}{H_0^2} = \Omega_ma^{-3} + \Omega_{\Lambda} + \Omega_ra^{-4}$$

If we write ##a(t)## in terms of z,

$$H(z) = H_0\sqrt{\Omega_m(1+z)^{3} + \Omega_{\Lambda} + \Omega_r (1+z)^{4}}$$

I wonder by evaluating this function, for different omega values, what kind of different information(s) we can obtain
 
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Perhaps you could try plotting it in MATLAB and see what you get.
 
jedishrfu said:
Perhaps you could try plotting it in MATLAB and see what you get.
Yes but how it can changes things. I mean basically I am asking that if H(z) changes differently (w.r.t density paramters) what changes in the universe.
 

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