Value for redshift change in acceleration

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SUMMARY

The discussion centers on the transition of the universe from deceleration to acceleration, estimated to have occurred approximately 5 billion years ago. This shift is attributed to the dominance of dark energy over dark matter and baryons. As the universe expands, the density of dark matter decreases more rapidly than that of dark energy, leading to a scenario where dark energy becomes the prevailing force. Specifically, when the universe's volume doubles, dark matter density is halved while dark energy density remains constant, illustrating the fundamental differences in their behaviors.

PREREQUISITES
  • Understanding of cosmological concepts such as dark energy and dark matter
  • Familiarity with the expansion of the universe and its implications
  • Knowledge of density dynamics in cosmology
  • Basic grasp of the cosmological constant and its significance
NEXT STEPS
  • Research the implications of dark energy on cosmic expansion
  • Study the role of dark matter in the early universe
  • Explore models of cosmic acceleration and their predictions
  • Learn about observational evidence supporting the acceleration of the universe
USEFUL FOR

Astronomers, cosmologists, and physics students interested in the dynamics of the universe's expansion and the roles of dark energy and dark matter.

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If the universe was decelarating and then started to accelerate can we calculate when this happened, and if so how can we do this?
 
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Cosmologists estimate that the acceleration began roughly 5 billion years ago. Before that, it is thought that the expansion was decelerating, due to the attractive influence of dark matter and baryons. The density of dark matter in an expanding universe decreases more quickly than dark energy, and eventually the dark energy dominates. Specifically, when the volume of the universe doubles, the density of dark matter is halved but the density of dark energy is nearly unchanged (it is exactly constant in the case of a cosmological constant).
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The above is from Wikipedia

http://en.wikipedia.org/wiki/Dark_energy
 

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