Infinite brightness in the singularity?

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Discussion Overview

The discussion revolves around the concept of "infinite brightness" near singularities, specifically in the context of black holes and the Big Bang singularity. Participants explore the implications of brightness as perceived by different observers, particularly in relation to gravitational effects and acceleration.

Discussion Character

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

Main Points Raised

  • One participant suggests that black holes exhibit infinite brightness near their singularities, questioning if the Big Bang singularity shares this characteristic.
  • Another participant seeks clarification on what is meant by "infinite brightness."
  • A reference is made to a source indicating that the universe appears increasingly bright as one approaches the event horizon of a black hole, tending towards infinite brightness at the horizon.
  • It is noted that this phenomenon applies to static observers, and that free-falling observers or those accelerating away from the black hole would not experience the same infinite brightness.
  • One participant argues that the perception of infinite brightness is more related to the observer's acceleration rather than an intrinsic property of the black hole itself.
  • Further examples are provided, suggesting that an observer accelerating in flat spacetime could also perceive a similar effect of approaching infinite brightness.
  • Clarifications are made regarding the limitations of observing the universe's history from within the event horizon, emphasizing that one must remain outside the horizon to witness the universe unfold over time.

Areas of Agreement / Disagreement

Participants express differing views on the nature of infinite brightness, with some attributing it to observer effects while others suggest it is a property of black holes. The discussion remains unresolved regarding the implications for the Big Bang singularity.

Contextual Notes

Limitations include the dependence on the observer's frame of reference and the complexities of gravitational effects on perception. The discussion does not resolve the mathematical or physical implications of infinite brightness.

DavidGahan
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Since the black hole has infinite brightness near the singularity just below the photon sphere, would the big bang singularity also possesses such characteristic?
 
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DavidGahan said:
Since the black hole has infinite brightness near the singularity just below the photon sphere
What do you mean infinite brightness?
 
Passionflower said:
What do you mean infinite brightness?

According to this site: http://jila.colorado.edu/~ajsh/insidebh/schw.html

"The Universe appears brighter and brighter as you approach the horizon, tending to infinite brightness at the horizon."
 
Note that this applies only for the static observer - i.e. the original quote is:

Click on the image at left (with the horizon grid) or right (without the horizon grid) for an animation of the appearance of the outside Universe as you lower yourself slowly to the horizon. The Universe appears brighter and brighter as you approach the horizon, tending to infinite brightness at the horizon. But again, no one with any sense would do this.

An observer free-falling through the black hole, or even an observer accelerating away from the black hole with a finite acceleration while falling through the event horizon, would not see the same infinite brightness. So it's a bit of a mistake to think of the infinite brightness as a property of the black hole.

Also note that an observer with infinite acceleration in a flat space-time would see the universe in a similar way. More precisely, an observer accelerating in a flat space-time (say with a rocketship) would also see the universe appear visually to abberate, approaching in the limit of infinite acceleration a single point of infinite brightness in front of the rocket ship.

So it's better to think of the infinite brightness as being due to the observer's acceleration than it is to think of it as being due to the black hole.

See for instance http://casa.colorado.edu/~ajsh/singularity.html

(another website from colorado.edu)

Answer to the quiz question 5: False. You do NOT see all the future history of the world played out. Once inside the horizon, you are doomed to hit the singularity in a finite time, and you witness only a finite (in practice rather short) time pass in the outside Universe.

In order to watch the history of the Universe unfold, you would have to remain outside the horizon, the Schwarzschild surface. One way to watch all the history of the Universe would be to stay just above the horizon, firing your rockets like crazy just to stay put. The Universe would then appear not only speeded up, but also highly blueshifted (probably roasting you in gamma rays), and concentrated in a tiny piece of the sky just above you.
 

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