Friedmann Equation and the age of empty universe

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SUMMARY

The Friedmann Equation demonstrates that the age of an empty universe, characterized by an average density of zero, is given by τ = 1/H₀, where H₀ represents the current value of Hubble's Constant. The discussion highlights a common confusion regarding the spatial curvature parameter, k, which can indeed be negative, indicating an open universe. Participants clarified that the presence of a constant in front of 1/H₀ may arise from additional factors in the equation. Understanding these nuances is crucial for accurately applying the Friedmann Equation in cosmological models.

PREREQUISITES
  • Friedmann Equation fundamentals
  • Understanding of Hubble's Constant (H₀)
  • Concept of spatial curvature (k)
  • Basic cosmology principles
NEXT STEPS
  • Research the implications of negative curvature in cosmology
  • Study the derivation and applications of the Friedmann Equation
  • Explore the relationship between density parameters and the universe's fate
  • Learn about the role of cosmological constants in Friedmann models
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Astronomers, cosmologists, and physics students interested in understanding the dynamics of the universe and the implications of the Friedmann Equation on cosmological models.

darkar
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Got stuck in this question, the question asked to use friedmann equation to show that the age of an empty universe (average density = 0) is

τ=1/H₀

where H₀ is the present day value of Hubble's Constant.

Well, i got the friedmann equation by put the value ρ(average)=0 but the trouble is that u have H₀^2 = - kc^2/R^2. which mean k has to be an imaginary number. But i am kind of not accepting it. Did i miss out something?
 
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Does spatial curavture have to be positive?

Regards,
George
 
Ummm, rite. Just recheck, K can be negative and it mean the universe is open.

Btw, still i will get some constand infront 1/H₀
 

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