Why does general relativity break down at high energies?

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Discussion Overview

The discussion revolves around the concept of general relativity (GR) breaking down at high energies, exploring the implications of this breakdown, the definitions of "high energies," and the relationship between GR and quantum gravity. Participants engage in clarifying the context and meaning of these terms, as well as the reasons behind the perceived limitations of GR.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants question what is meant by "high energies" in the context of GR breaking down, suggesting a need for clearer definitions.
  • There is a discussion about the relationship between high-energy collisions and the breakdown of GR, with some participants asserting that this breakdown is related to quantum effects.
  • Participants note that singularities are often cited as a reason for the need for a theory of quantum gravity, but they differentiate this from the concept of high energies.
  • Some participants express skepticism about vague references to claims regarding GR's limitations, emphasizing the need for specific citations to support such statements.
  • One participant points out that while singularities may indicate a failure of GR, this does not directly equate to the concept of high energies.
  • There is a call for references to substantiate claims about GR breaking down at high energies, with some participants expressing frustration over general statements without backing.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions and implications of "high energies" in relation to the breakdown of GR. There are competing views on the relationship between singularities, high energies, and the need for quantum gravity theories.

Contextual Notes

The discussion highlights limitations in definitions and the need for specific references to support claims. There is an ongoing uncertainty regarding the terminology and implications of high energies in the context of GR.

KleinMoretti
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TL;DR
what does it mean for general relativity to break down at high energies
more specifically what does high energies mean in this context, does it actually mean a high amount of energy? I can intuitively understand why it breaks down at small scales where quantum effects take place. for example it is said that high speed collisions produce a lot of energy and general relativity will break down as (part) of the description of such collisions, but why is that
 
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KleinMoretti said:
what does it mean for general relativity to break down at high energies
Why do you think it does?

KleinMoretti said:
it is said
Where? Please give a reference.
 
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PeterDonis said:
Why do you think it does?
isn't it said that one of the reasons a theory of quantum gravity is needed is because GR breaks down at some point for example singularities
 
KleinMoretti said:
isn't it said
Said where? Again, please give a reference.
 
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KleinMoretti said:
one of the reasons a theory of quantum gravity is needed is because GR breaks down at some point for example singularities
That is a reason that is given for looking for a theory of quantum gravity. But "singularities" is not the same thing as "high energies".
 
PeterDonis said:
But "singularities" is not the same thing as "high energies".
okay but they do signal a failure of the theory and you were asking why I thought GR breaks down, and that's why im asking what does high energies mean in this context
 
PeterDonis said:
Said where? Again, please give a reference.
I meant that as general statement
 
PeterDonis said:
Said where? Again, please give a reference.
'This raises an important point: though we think of general relativity and quantum theory as ‘nice’ theories from the point of view of philosophical investigation, in a very real sense they are not the whole story and break down at extreme scales."

Quantum Gravity

 
KleinMoretti said:
they do signal a failure of the theory
They might. It's not a proven fact, just an opinion.

KleinMoretti said:
that's why im asking what does high energies mean in this context
And until you can give some specific reference that even uses the term "high energies" in this context, there is no point in even asking.

KleinMoretti said:
I meant that as general statement
Vague general statements about what "is said" are not a valid basis for discussion here. If you're going to claim that something "is said", you need to give a specific, valid reference that says it.

KleinMoretti said:
'This raises an important point: though we think of general relativity and quantum theory as ‘nice’ theories from the point of view of philosophical investigation, in a very real sense they are not the whole story and break down at extreme scales."

Quantum Gravity

This is a philosophy website, not a physics textbook or peer-reviewed paper.
 
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