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The universe will expand exponentially when dark energy completely dominates the energy density of the universe. To clarify, does that make the present expansion 'quasi-exponential'?
Exponential expansion and the Cosmological Constant
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In summary, the conversation discusses the expansion of the universe and the role of dark energy. The question of whether the present expansion is "quasi-exponential" is raised, but deemed meaningless without a clear definition. The idea of speaking in tautologies is mentioned as a way to increase accuracy, but it is also noted that this may result in a loss of content. The topic of dark energy dominating the energy density of the universe is also mentioned.
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Unless you define what you mean by "quasi-exponential" the question lacks meaning.
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In the sense of tending toward being eventually exponential.Orodruin said:
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Bandersnatch
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With that definition, your question reads: 'The universe tends towards exponential expansion. Does that make the present expansion tend towards exponential expansion?'
I.e. it's tautologically true.
I.e. it's tautologically true.
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PAllen
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Speaking in tautologies is great. The gain in accuracy offsets the loss of content. Unless it doesn’t.
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I don't know. Sounds a bit tautological to me ...PAllen said:Speaking in tautologies is great. The gain in accuracy offsets the loss of content. Unless it doesn’t.
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mathman
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At present dark energy is approximately 70% of the universe. Dominates?
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Bandersnatch
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You just can't go wrong with a tautology.PAllen said:Speaking in tautologies is great. The gain in accuracy offsets the loss of content. Unless it doesn’t.
Related to Exponential expansion and the Cosmological Constant
1. What is exponential expansion and the cosmological constant?
Exponential expansion refers to the rapid and continuous increase in the size and scale of the universe. The cosmological constant is a term in Einstein's theory of general relativity that represents the energy density of empty space and is thought to contribute to the acceleration of the universe's expansion.
2. How does the cosmological constant affect the expansion of the universe?
The cosmological constant is believed to play a significant role in the acceleration of the universe's expansion. It is thought to counteract the pull of gravity and cause the expansion to accelerate at an exponential rate.
3. What evidence supports the existence of exponential expansion and the cosmological constant?
Observations of distant supernovae, the cosmic microwave background radiation, and the distribution of galaxies all provide evidence for the existence of exponential expansion and the cosmological constant. These observations show that the expansion of the universe is accelerating, which is consistent with the effects of the cosmological constant.
4. Can the cosmological constant change over time?
The value of the cosmological constant is thought to be constant over time. However, some theories suggest that it may vary slightly over extremely long periods of time. This is still a topic of ongoing research and debate among scientists.
5. How does the concept of dark energy relate to exponential expansion and the cosmological constant?
Dark energy is a term used to describe the unknown force driving the acceleration of the universe's expansion. The cosmological constant is one of the leading theories for what dark energy may be, as it fits well with observations of the universe. However, there are other theories and ongoing research attempting to better understand the nature of dark energy and its relationship to exponential expansion.
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