Is the Universe's Expansion Constant or Accelerating?

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SUMMARY

The universe's expansion is currently understood to be accelerating, a conclusion drawn from observations of distant Supernovae Type 1a in the 1990s. This acceleration is attributed to Dark Energy, which exerts a high negative pressure. Unlike positive pressure, which increases gravitational effects and decelerates expansion, negative pressure facilitates the acceleration of the universe's expansion.

PREREQUISITES
  • Understanding of Supernovae Type 1a and their role in cosmology
  • Familiarity with the concept of Dark Energy and its properties
  • Knowledge of gravitational effects related to pressure types
  • Basic principles of cosmic expansion and its measurements
NEXT STEPS
  • Research the implications of Dark Energy on cosmic structure formation
  • Explore the methods used to measure distances to Supernovae Type 1a
  • Study the role of negative pressure in cosmological models
  • Investigate current theories regarding the fate of the universe based on expansion rates
USEFUL FOR

Astronomers, physicists, and students of cosmology interested in the dynamics of the universe's expansion and the underlying forces driving it.

TalonD
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reading thru some of the posts I havn't really found the answer. The universe is expanding but is it a constant rate or is it an accelerating rate?
 
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At present the expansion appears to be accelerating.

This was a major discovery of the 1990's deduced from the fainter than expected distant Supernovae Type 1a.

The acceleration is thought to be due to Dark Energy that has a high negative pressure.

Note: adding positive pressure (the normal kind) acts like adding energy and produces extra gravitation, which counter intuitively increases the deceleration of the universe's expansion. Negative pressure has the opposite effect.

Garth
 
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