Is the Universe's Expansion Constant or Accelerating?

In summary, the universe is currently expanding at an accelerating rate, which was a major discovery of the 1990's. This acceleration is believed to be caused by Dark Energy, which has a high negative pressure. Contrary to intuition, adding positive pressure (the normal kind) actually increases the deceleration of the universe's expansion."
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TalonD
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1
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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  • #2
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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Related to Is the Universe's Expansion Constant or Accelerating?

1. What is the expanding universe theory?

The expanding universe theory states that the universe is constantly growing and getting larger. This means that galaxies and other celestial bodies are moving away from each other at an increasing rate.

2. How do we know that the universe is expanding?

Scientists have observed that the light from distant galaxies is shifted towards the red end of the light spectrum, known as redshift. This indicates that these galaxies are moving away from us, providing evidence for the expanding universe theory.

3. What is causing the universe to expand?

The exact cause of the expansion of the universe is still unknown, but it is believed to be driven by a force called dark energy. This force counteracts the effects of gravity, causing the universe to expand at an accelerating rate.

4. Will the universe continue to expand forever?

Based on current evidence and theories, it is believed that the universe will continue to expand indefinitely. However, the rate of expansion may change in the future and there is still much research being done to better understand the fate of the universe.

5. How does the expanding universe theory relate to the Big Bang theory?

The expanding universe theory is closely tied to the Big Bang theory, which states that the universe began as a single point of infinite density and has been expanding ever since. The redshift of light from distant galaxies is also used as evidence for the Big Bang theory.

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