Schwarzschild radius of the Universe

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Discussion Overview

The discussion revolves around the concept of the Schwarzschild radius in relation to the universe, exploring whether the mass of the observable universe can be plugged into the Schwarzschild radius equation to yield meaningful insights. Participants examine implications for cosmology, dark matter, and dark energy, as well as the validity of claims made by popular physicists.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that calculating the Schwarzschild radius using the mass of the observable universe yields a radius that corresponds to what we observe, though they note it is not exactly so and will vary over time.
  • Others argue that the Schwarzschild radius is not applicable to the universe as a whole, stating that the universe does not possess a Schwarzschild geometry.
  • A participant questions whether dark matter and dark energy are included in these calculations, to which others confirm they are, but with varying implications based on the model used.
  • There is a discussion about the nature of dark energy, with some suggesting it remains constant while others express uncertainty about how to define the total energy of the universe in cosmological spacetimes.
  • Some participants express skepticism about the validity of claims made by popular physicists, suggesting that such statements may be oversimplified or misleading.
  • One participant mentions the potential for a simpler model of the universe without dark energy, which could lead to a direct correlation with the Schwarzschild radius.
  • Concerns are raised about the implications of an accelerating universe and whether that suggests an increasing total energy, with no clear resolution on this point.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the applicability of the Schwarzschild radius to the universe or the implications of dark energy. Multiple competing views remain regarding the interpretation of these concepts and their mathematical underpinnings.

Contextual Notes

Participants highlight limitations in defining total energy in cosmological contexts, noting that current understanding is primarily based on asymptotically flat spacetimes, which may not apply to the universe as a whole.

  • #31
Ivan Seeking said:
This article is not at all reliable. At one point it says the radius of the entire universe (not observable, entire) is 23 trillion light years across, but at another point it says our universe is open, which means it would be spatially infinite. (Our actual best current model says our universe is spatially flat, which is different from both.)

At another point it says that SR says "time stops" at the speed of light, which is a common pop science misstatement.

The article references no actual scientific papers, just other pop science sources.

In short: this article is not a valid basis for PF discussion. The main claim made in the OP has been refuted. This thread is closed.
 
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