Singularity prevented by repulsive force?

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Discussion Overview

The discussion explores the concept of whether a hypothetical repulsive force among hadrons could prevent the formation of a singularity during the collapse of a massive star. It touches on theoretical implications, general relativity, and the nature of forces in physics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that if hadrons carried a new kind of charge that exerted a short-range repulsive force, it could potentially prevent singularity formation during stellar collapse.
  • Others argue that there are no theoretical reasons to believe that no more forces exist in nature, but emphasize the need for experimental evidence before postulating new forces.
  • A participant mentions a theorem in general relativity suggesting that once matter collapses within its Schwarzschild radius, no force can halt its collapse towards a singularity.
  • One participant questions whether dark energy, which is gravitationally repulsive, could counteract the curvature of space leading to a singularity.
  • Another participant notes that the strong force is repulsive at very short distances, prompting a discussion about its nature and whether this applies to direct or residual strong force.
  • A participant introduces the Pauli exclusion principle as a factor in preventing collapse for identical spin 1/2 particles and references classical gravitational problems that may avoid singularity issues.

Areas of Agreement / Disagreement

Participants express differing views on the potential for new forces to exist and their implications for singularity formation. The discussion remains unresolved, with multiple competing perspectives on the role of existing forces and theoretical constructs.

Contextual Notes

There are limitations regarding the assumptions made about the nature of forces and the applicability of general relativity in extreme conditions. The discussion also reflects varying levels of knowledge among participants, particularly concerning general relativity and particle physics.

kurious
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If hadrons carried a new kind of charge that exerted a significant
force only over very short distances so that hadrons repel hadrons at
close range,this force could stop the formation of a singularity when
a massive star collapses. There is no evidence for the existence of
such a force, but are there theoretical reasons for believing that
there can be no more forces in nature?
 
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kurious said:
If hadrons carried a new kind of charge that exerted a significant force only over very short distances so that hadrons repel hadrons at close range,this force could stop the formation of a singularity when a massive star collapses. There is no evidence for the existence of
such a force, but are there theoretical reasons for believing that
there can be no more forces in nature?

There are no theoretical reasons for believing there are no more forces in nature. But we don't postulate something unless we have experimental evidence for it; otherwise we could write down theories for infinitely many forces with any behavior we wanted.
My knowledge of general relativity is much weaker than that of particle physics, but I don't think such a force can stop the collapse to a singularity. I think there is a theorem in GR that once some matter collapses inside its own Schwarzschild radius, no force, however strong, can stop its collapse towards the singularity. The space is curved to such a degree that all timelike paths lead towards the singularity so unless the particles move faster than light, they cannot escape.
 
Zefram:
The space is curved to such a degree that all timelike paths lead towards the singularity

Kurious:
Can dark energy oppose this curvature - it is gravitationally repulsive?
 
kurious said:
If hadrons carried a new kind of charge that exerted a significant
force only over very short distances so that hadrons repel hadrons at
close range,this force could stop the formation of a singularity when
a massive star collapses. There is no evidence for the existence of
such a force, but are there theoretical reasons for believing that
there can be no more forces in nature?

The strong force is repulsive at very short distances.

Njorl
 
kurious said:
Can dark energy oppose this curvature - it is gravitationally repulsive?
My knowledge of GR is limited, as I've said. Try the astronomy or cosmology forums for this one.
 
Njorl said:
The strong force is repulsive at very short distances.
I did not know this, but it makes more sense now. Does this refer to the direct or residual strong force. I thought that the strong force was an HO force at the smallest distances.
 
Pauli principle amounts to impenetrability for identical spin 1/2 particles. That is the main trick.

On a related note, some famous problems actually bypass the singularity problem. Between them, I have read, the classical gravitational three body problem has a perturbative expansion that avoids the singularity in origin.
 

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