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Evidence record

What happens inside a black hole?

Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.

Last checked 24 September 2026.

  • A judgement, not a fact: 9
  • Source checked: 45
  • Partly checked: 1
  • Presented as open: 3

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.

What the question takes for granted

A physics question about a region no signal can leave. Nothing inside a black hole can be observed from outside, so every answer on the page is a prediction of a theory, and the two theories that apply disagree there.

  • Black holes exist

    Established

    Gravitational waves from merging black holes, images of two supermassive ones, and stellar orbits around the centre of the galaxy.

  • Answering it needs physics beyond general relativity

    Established

    General relativity predicts paths that end inside, which is widely taken as the classical theory failing where quantum effects matter.

  • There is an inside that can be described on its own

    Contested

    Black hole complementarity holds that a description of the inside together with the outside has no operational meaning. The page reports this as disputed.

  • Information is conserved

    Contested

    Standard quantum theory preserves it; Hawking argued black holes do not, and Unruh and Wald still defend that. Most of the recent evidence runs the other way, but it is not settled.

How the question is labelled

Claim: Black hole interiors

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Black holes

Kind
Framing. Signposting. It asserts nothing a source could check.

The question

Claim: Our two best theories of physics give different answers, and both may be wrong.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of what follows: general relativity predicts its own breakdown inside, and the information problem sets it against quantum theory. "Both may be wrong" is the page’s reading that a deeper theory is expected to replace both in this regime.

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: The black hole information paradox presents a sharp conflict between quantum theory and general relativity

  • Supports

    The 1965 Penrose singularity theoremsection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: A more up-to-date perspective would rather state that they provide very solid evidence of the need of (possibly quantum) corrections to GR when extreme gravity effects occur.

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: Black holes are observed, weighed, photographed and heard.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

"Heard" is a figure for the gravitational-wave detection; "photographed" for the EHT images, which are reconstructions from radio interferometry.

Later work looked for

Crossref, 2019 on, "tests of general relativity gravitational wave transient catalog" and "Event Horizon Telescope Sagittarius A*": later catalogues, test papers and a 2025 Living Reviews article on gravitational-wave tests of general relativity continue the programme (titles only, not read); nothing read that changes the claim.

Claim 4 · checked 24 September 2026 · AI-assisted audit

Claim: What happens past the horizon is where general relativity and quantum mechanics openly contradict each other.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

AMPS call the information paradox "a sharp conflict between quantum theory and general relativity". The sections on information and on the horizon set out where the conflict lies.

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: The black hole information paradox presents a sharp conflict between quantum theory and general relativity

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: They also contain a singularity in their interior. It is an anisotropic big crunch singularity, but it is also a situation where quantum gravity is necessary

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: A black hole is the one object where the two pillars of modern physics cannot both be right.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s framing. The review names the beginning of the universe as the other situation where quantum gravity is needed; that is an era rather than an object.

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: The black hole information paradox presents a sharp conflict between quantum theory and general relativity

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: They also contain a singularity in their interior. It is an anisotropic big crunch singularity, but it is also a situation where quantum gravity is necessary

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: Outside the horizon, general relativity works: the gravitational waves of merging black holes and the images of two of them match what it predicts.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Agreement within the precision of these measurements; the Sgr A* shadow, for example, matches the Schwarzschild size to about ten per cent.

Later work looked for

Crossref, 2019 on, "tests of general relativity gravitational wave transient catalog" and "Event Horizon Telescope Sagittarius A*": later catalogues, test papers and a 2025 Living Reviews article on gravitational-wave tests of general relativity continue the programme (titles only, not read); nothing read that changes the claim.

Corrected

24 September 2026. Previously: “Outside the horizon, general relativity works beautifully and has been confirmed to extraordinary precision.” The cited black-hole tests show agreement with general relativity, not extraordinary precision: the Sgr A* shadow matches its predicted size to about ten per cent. The sentence now says what the sources show.

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: Inside, it predicts a singularity: a place where its own description of space and time breaks down.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The 1965 Penrose singularity theoremsection 4, Theorem 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: If the space-time contains a non-compact Cauchy hypersurface Σ and a closed future-trapped surface, and if the convergence condition (6) holds for null uµ, then there are future incomplete null geodesics.

  • Supports

    The 1965 Penrose singularity theoremsection 8.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is widely accepted that the existence of classical singularities signal a breakdown of the classical theory at extreme conditions, which is precisely when gravitational quantum effects will become relevant.

  • Context

    Breakdown of predictability in gravitational collapseabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Theory

    The source reads: A singularity is a place where the classical concepts of space and time break down as do all the known laws of physics because they are all formulated on a classical space-time background.

What this does not establish

What the theorem proves is that some paths end; whether anything becomes infinite there is not established (see claim 19).

Corrected

24 September 2026. Previously: “Inside, it predicts a singularity: a point where its own equations stop producing meaningful numbers.” The singularity theorems prove incomplete paths, not a point, and say little about the singularity’s nature; the review describes singularities as signalling a breakdown of the classical theory. The page’s own later passage says so.

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: That is not a description of what is there.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the review: the theorems say only that some observer or light ray ends, and singularities are widely taken to mark where the classical theory fails.

  • Supports

    The 1965 Penrose singularity theoremsection 6.3

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: the singularity theorems don’t say all that, merely stating that for some unspecified reason some observer or light ray ends.

  • Supports

    The 1965 Penrose singularity theoremsection 8.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is widely accepted that the existence of classical singularities signal a breakdown of the classical theory at extreme conditions, which is precisely when gravitational quantum effects will become relevant.

Claim 9 · checked 24 September 2026 · AI-assisted audit

Claim: It is a theory announcing its own limit.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The review’s "up-to-date perspective": the theorems are evidence that general relativity needs (possibly quantum) corrections in extreme gravity.

  • Supports

    The 1965 Penrose singularity theoremsection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: A more up-to-date perspective would rather state that they provide very solid evidence of the need of (possibly quantum) corrections to GR when extreme gravity effects occur.

  • Supports

    The 1965 Penrose singularity theoremsection 8.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is widely accepted that the existence of classical singularities signal a breakdown of the classical theory at extreme conditions, which is precisely when gravitational quantum effects will become relevant.

Claim 10 · checked 24 September 2026 · AI-assisted audit

What the instruments show

Claim: What the instruments show

Kind
Framing. Signposting. It asserts nothing a source could check.

Black holes exist and we have several kinds of evidence

Claim: Black holes exist and we have several kinds of evidence

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2019 on, "tests of general relativity gravitational wave transient catalog" and "Event Horizon Telescope Sagittarius A*": later catalogues, test papers and a 2025 Living Reviews article on gravitational-wave tests of general relativity continue the programme (titles only, not read); nothing read that changes the claim.

Claim 12 · checked 24 September 2026 · AI-assisted audit

Claim: In 2015 LIGO detected gravitational waves from two black holes merging, matching general relativity’s predictions in detail.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Observation of Gravitational Waves from a Binary Black Hole Mergerabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Astronomical observation · Measurement

    The source reads: On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal.

  • Supports

    Observation of Gravitational Waves from a Binary Black Hole Mergerabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Astronomical observation · Measurement

    The source reads: It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole.

What this does not establish

Detected on 14 September 2015 and published in February 2016.

Later work looked for

Crossref, 2019 on, "tests of general relativity gravitational wave transient catalog" and "Event Horizon Telescope Sagittarius A*": later catalogues, test papers and a 2025 Living Reviews article on gravitational-wave tests of general relativity continue the programme (titles only, not read); nothing read that changes the claim.

Claim 13 · checked 24 September 2026 · AI-assisted audit

Claim: In 2019 the Event Horizon Telescope published an image of the shadow of the supermassive black hole in M87, and in 2022 of the one at the centre of our own galaxy.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The images are reconstructions from interferometric data, and the shadow is the dark region inside a ring of emission.

Later work looked for

Crossref, 2019 on, "tests of general relativity gravitational wave transient catalog" and "Event Horizon Telescope Sagittarius A*": later catalogues, test papers and a 2025 Living Reviews article on gravitational-wave tests of general relativity continue the programme (titles only, not read); nothing read that changes the claim.

Claim 14 · checked 24 September 2026 · AI-assisted audit

Claim: Decades of tracking stellar orbits around the galactic centre had already given its mass, about four million times the Sun’s, long before the picture existed.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Ghez and colleagues had 4.1 ± 0.6 million solar masses by 2008 from twelve years of Keck astrometry; the Sgr A* paper lists later values of 4.30 million (VLTI) and 3.95 million (Keck).

Later work looked for

Crossref, 2019 on, "Sagittarius A* mass stellar orbits GRAVITY": nothing relevant returned; the 2022 EHT paper itself lists the later stellar-orbit masses, 4.297 ± 0.013 million (VLTI) and 3.951 ± 0.047 million (Keck) solar masses, both about four million.

Claim 15 · checked 24 September 2026 · AI-assisted audit

Singularities are a prediction of the theory, not an observation

Claim: Singularities are a prediction of the theory, not an observation

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The 1965 Penrose singularity theoremsection 4, Theorem 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: If the space-time contains a non-compact Cauchy hypersurface Σ and a closed future-trapped surface, and if the convergence condition (6) holds for null uµ, then there are future incomplete null geodesics.

  • Supports

    The 1965 Penrose singularity theoremsection 6.3

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: the singularity theorems don’t say all that, merely stating that for some unspecified reason some observer or light ray ends.

What this does not establish

A prediction of classical general relativity under the theorem’s assumptions.

Claim 16 · checked 24 September 2026 · AI-assisted audit

Claim: Roger Penrose showed in 1965 that once collapse has produced a closed trapped surface, general relativity gives paths that simply stop: light rays that come to an end after a finite stretch and cannot be continued.

Kind
A proved result. A mathematical theorem, as its proof or a reference work states it. What it says about the world depends on how well the mathematics fits.
Review
Source checked. The cited passage was read, and it says this.

The "finite stretch" is a finite value of the ray’s own parameter, which is how the review defines an incomplete path.

  • Supports

    The 1965 Penrose singularity theoremsection 4, Theorem 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: If the space-time contains a non-compact Cauchy hypersurface Σ and a closed future-trapped surface, and if the convergence condition (6) holds for null uµ, then there are future incomplete null geodesics.

  • Supports

    The 1965 Penrose singularity theoremsection 4.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: A singularity in a Lorentzian manifold is an incomplete endless curve. These curves cannot be continued regularly within the space-time despite they reach only finite values of their canonical parameter.

  • Supports

    The 1965 Penrose singularity theoremabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: We review the first modern singularity theorem, published by Penrose in 1965. This is the first genuine post-Einstenian result in General Relativity, where the fundamental and fruitful concept of closed trapped surface was introduced

  • Context

    Gravitational Collapse and Space-Time SingularitiesCrossref record

    Cited · Link answered, 19 October 2026 · Catalogue record only, 24 September 2026

    Penrose’s paper was not readable here; the theorem is checked against the 2015 review’s statement of it.

Corrected

24 September 2026. Previously: “light rays that run out of spacetime to travel through after a finite distance.” A light ray has no length in the ordinary sense; the review defines incompleteness as a curve that cannot be continued although its parameter reaches only finite values.

Claim 17 · checked 24 September 2026 · AI-assisted audit

Claim: The theorem does not assume spherical symmetry, which is what the earlier collapse models had relied on.

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The 1965 Penrose singularity theoremsection 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Penrose wanted to prove that deviations from spherical symmetry were not able to prevent the formation of singularities, such as those described in the Oppenheimer-Snyder collapse, within the GR theory.

  • Supports

    The 1965 Penrose singularity theoremsection 4, Theorem 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: If the space-time contains a non-compact Cauchy hypersurface Σ and a closed future-trapped surface, and if the convergence condition (6) holds for null uµ, then there are future incomplete null geodesics.

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: It does assume other things, and what it proves is that those paths are incomplete, not that curvature anywhere becomes infinite.

Kind
A proved result. A mathematical theorem, as its proof or a reference work states it. What it says about the world depends on how well the mathematics fits.
Review
Source checked. The cited passage was read, and it says this.

The assumptions are a non-compact Cauchy hypersurface, a closed trapped surface and an energy condition on null directions.

  • Supports

    The 1965 Penrose singularity theoremsection 4, Theorem 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: If the space-time contains a non-compact Cauchy hypersurface Σ and a closed future-trapped surface, and if the convergence condition (6) holds for null uµ, then there are future incomplete null geodesics.

  • Supports

    The 1965 Penrose singularity theoremsection 4.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: one can put a limit on the curvature growth when approaching the end of an incomplete geodesic predicted by the theorems, but one does not know whether the curvature will diverge at all!

  • Supports

    The 1965 Penrose singularity theoremsection 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: one must choose among one of the following possibilities: (6) is violated for null vectors, or the concept of space-time loses its meaning at extreme conditions (maybe quantum effects), or some null geodesics are not complete.

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: It is widely read as evidence that general relativity is incomplete rather than as evidence that infinities are physically real.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The 1965 Penrose singularity theoremsection 8.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is widely accepted that the existence of classical singularities signal a breakdown of the classical theory at extreme conditions, which is precisely when gravitational quantum effects will become relevant.

  • Supports

    The 1965 Penrose singularity theoremsection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: A more up-to-date perspective would rather state that they provide very solid evidence of the need of (possibly quantum) corrections to GR when extreme gravity effects occur.

  • Supports

    The 1965 Penrose singularity theoremsection 3

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: even though infinite values of physical observables must not be accepted in physical reality, one must be prepared to probe the limits of any particular theory

Later work looked for

Crossref, 2019 on, "loop quantum gravity black hole singularity resolution": work on replacing the singularity continues within candidate theories (titles only), consistent with the reading; nothing that changes it.

Claim 20 · checked 24 September 2026 · AI-assisted audit

Black holes are thermodynamic objects

Claim: Black holes are thermodynamic objects

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Studies of black holes in the ’70s showed that black holes behave as thermal objects. They have a temperature that leads to Hawking radiation. They also have an entropy given by the area of the horizon.

  • Supports

    Particle creation by black holesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: quantum mechanical effects cause black holes to create and emit particles as if they were hot bodies ... where K is the surface gravity of the black ... This thermal emission leads to a slow decrease in the mass of the black hole and to its eventual disappearance

What this does not establish

A theoretical result: the temperature and entropy are derived, not measured.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: Hawking showed in 1975 that black holes radiate, with a temperature set by their surface gravity, and therefore lose mass and can eventually disappear.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Particle creation by black holesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: quantum mechanical effects cause black holes to create and emit particles as if they were hot bodies ... where K is the surface gravity of the black ... This thermal emission leads to a slow decrease in the mass of the black hole and to its eventual disappearance

What this does not establish

A calculation of quantum fields on a classical curved spacetime, not an observation. Hawking notes that the approximation fails where curvature reaches the Planck scale, which is where evaporation ends.

Corrected

24 September 2026. Previously: “and therefore evaporate over enormous timescales.” The paper describes a slow loss of mass and eventual disappearance, and says a black hole of the Sun’s mass is at present gaining mass, not evaporating. The next sentence now says so.

Claim 22 · checked 24 September 2026 · AI-assisted audit

Claim: For a black hole of the Sun’s mass that temperature is far below the cosmic microwave background’s, so for now it takes in more than it gives off.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Particle creation by black holessection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: this temperature is much lower than the 3 °K temperature of the cosmic microwave background. Thus black holes of this size would be absorbing radiation faster than they emitted it and would be increasing in mass.

What this does not establish

A prediction from the calculated temperature; the radiation has not been observed from any black hole.

Corrected

24 September 2026. Previously: “” Added: the page said black holes evaporate, and Hawking’s own paper says one of stellar mass is at present absorbing more than it emits.

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: The result combines quantum field theory with curved spacetime,

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Particle creation by black holessection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: the matter fields, such as scalar, electro-magnetic, or neutrino fields, obey the usual wave equations with the Minkowski metric replaced by a classical space-time metric

What this does not establish

Quantum fields on a fixed classical spacetime: an approximation, which Hawking expected to fail only near the Planck scale, not a theory of quantum gravity.

Claim 24 · checked 24 September 2026 · AI-assisted audit

Claim: and it has become the best-known test that candidate theories of quantum gravity are held to,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: the most notable “test” of quantum theories of gravity imposed by the community to date involves a phenomenon which has never been observed, the so-called Hawking radiation from black holes

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: String theory gets the number right for a not-particularly-physically-realistic subset of black holes called near-extremal black holes, while loop quantum gravity gets it right for generic black holes, but only up to an overall constant.

Corrected

24 September 2026. Previously: “and is regarded as one of the most important theoretical results in physics,” No cited source said it is regarded as one of the most important results in physics. The SEP entry says it is the most notable test the community imposes on quantum theories of gravity.

Claim 25 · checked 24 September 2026 · AI-assisted audit

Claim: although the radiation itself has never been observed.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: the most notable “test” of quantum theories of gravity imposed by the community to date involves a phenomenon which has never been observed, the so-called Hawking radiation from black holes

Later work looked for

Crossref, 2019 on, "Hawking radiation detection black hole": titles on analogue systems and quantum simulations of Hawking radiation, none reporting it from a black hole; the SEP entry, revised in February 2024, still says it has never been observed.

Claim 26 · checked 24 September 2026 · AI-assisted audit

Where the two theories collide

Claim: Where the two theories collide

Kind
Framing. Signposting. It asserts nothing a source could check.

Whether information is destroyed

Claim: Whether information is destroyed

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Quantum mechanics requires that information about a system be preserved.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: the time evolution of any system from a given initial state is described unambiguously by a unitary transformation ... there is never any loss of fundamental, fine grained information

  • Supports

    The entropy of Hawking radiationsection 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: An important property is that it is invariant under unitary time evolution

  • Qualifies

    Information losssection V.A

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: (i) Conservation of probability. (ii) Evolution from pure states to pure states.

What this does not establish

This is unitary evolution of a closed system, as ordinarily formulated. Unruh and Wald distinguish conservation of probability from pure states evolving to pure states, and argue that losing the second is innocuous when part of the system is lost from view.

Claim 29 · checked 24 September 2026 · AI-assisted audit

Claim: Hawking radiation appears to depend only on a black hole’s mass, charge and spin,

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Particle creation by black holessection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: the rate of emission would not depend on details of the collapse process except through the mass, angular momentum and charge of the resulting black hole. I shall show that this is indeed the case

  • Context

    Breakdown of predictability in gravitational collapseabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Theory

    The source reads: about which the observer has only limited information such as the mass, angular momentum, and charge

What this does not establish

Spin is angular momentum in the sources.

Claim 30 · checked 24 September 2026 · AI-assisted audit

Claim: so when a black hole finishes evaporating, everything that fell in would seem to be gone.

Kind
An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: He argued that a black hole would destroy quantum information

  • Context

    Breakdown of predictability in gravitational collapseabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Theory

    The source reads: Because part of the information about the state of the system is lost down the hole, the final situation is represented by a density matrix rather than a pure quantum state.

Claim 31 · checked 24 September 2026 · AI-assisted audit

Claim: Hawking drew that conclusion himself in 1976 and proposed that predictability fails.

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    Breakdown of predictability in gravitational collapseabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Theory

    The source reads: In this paper it is claimed that this breakdown is not merely a result of our ignorance of the correct theory but that it represents a fundamental limitation to our ability to predict the future

  • Supports

    Breakdown of predictability in gravitational collapseabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Theory

    The source reads: Instead one has to introduce a new operator, called the superscattering operator, which maps density matrices describing the initial situation to density matrices describing the final situation.

What this does not establish

Only the abstract was read. The abstract says the paper claims the breakdown is a fundamental limit on prediction, and replaces the S matrix with a superscattering operator.

Claim 32 · checked 24 September 2026 · AI-assisted audit

Claim: It is now widely believed that information escapes somehow, though not by everyone.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Gauge/gravity duality has provided some insight, giving strong evidence that all information is carried away by the Hawking radiation. It is widely believed that an external observer sees this information emitted by complicated dynamics at or very near the horizon

  • Supports

    The entropy of Hawking radiationsection 3

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: We can view it as an unproven assumption about the properties of a full theory of quantum gravity. It is also something that is not accepted by some researchers. In fact, Hawking famously objected to it.

  • Supports

    Information losssection I

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Our belief is that information is lost into black holes

What this does not establish

No survey measures how widely; AMPS and the review describe the view as widely held, and the review says some researchers reject it.

Corrected

24 September 2026. Previously: “Most theorists now believe information escapes somehow.” "Most theorists" is a count no source gives. AMPS say it is widely believed; the review calls it an unproven assumption not accepted by some researchers; Unruh and Wald hold the opposite view.

Claim 33 · checked 24 September 2026 · AI-assisted audit

Claim: Much of the case comes from string theory,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 3.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Though we said that the “central dogma” is an unproven assumption, there is a great deal of very non-trivial evidence from string theory.

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Results from the ’90s using string theory, a theory of quantum gravity, provided some precise ways to study this problem for very specific gravity theories. These results strongly suggest that information does indeed come out.

Corrected

24 September 2026. Previously: “Two results are why:” The review gives more than two reasons, and the most cited, the AdS/CFT duality, was missing. The passage now names it.

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: which counted the microscopic states of certain black holes and got exactly the Bekenstein-Hawking entropy,

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Microscopic origin of the Bekenstein-Hawking entropyabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: The Bekenstein-Hawking area-entropy relation SBH = A/4 is derived for a class of five-dimensional extremal black holes in string theory ... the degeneracy of BPS soliton bound states.

  • Supports

    The entropy of Hawking radiationsection 3.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: One big piece of evidence was the computation of black hole entropy for special extremal black holes in supersymmetric string theories ... In these cases one can reproduce the Bekenstein-Hawking formula from an explicit count of microstates.

  • Qualifies

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: String theory gets the number right for a not-particularly-physically-realistic subset of black holes called near-extremal black holes, while loop quantum gravity gets it right for generic black holes, but only up to an overall constant.

What this does not establish

Five-dimensional extremal black holes in supersymmetric string theory, not astrophysical ones. The SEP entry notes loop quantum gravity also reproduces the entropy, for generic black holes up to a constant.

Claim 35 · checked 24 September 2026 · AI-assisted audit

Claim: and whose duality between gravity and ordinary quantum systems points the same way.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 3.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Another piece of evidence comes from the AdS/CFT correspondence [54–56], which is a conjectured relation between the physics of AdS and a dual theory living at its boundary.

  • Supports

    The entropy of Hawking radiationsection 3.1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: In this case, the black hole and its whole exterior can be represented in terms of degrees of freedom living at the boundary.

  • Supports

    Black holes: complementarity or firewalls?section 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: The discovery of gauge/gravity duality pointed to purity

  • Qualifies

    Information losssection V.C

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: The AdS/CFT correspondence is a conjecture.

What this does not establish

The duality is a conjecture, established for spacetimes with a negative cosmological constant. Unruh and Wald argue it has not been formulated precisely enough to settle the question.

Claim 36 · checked 24 September 2026 · AI-assisted audit

Claim: More recently, calculations of how the radiation’s entanglement entropy evolves have reproduced a curve consistent with nothing being lost.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: The final result differs from Hawking’s result and is consistent with unitary evolution.

  • Supports

    The entropy of Hawking radiationsection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: as suggested by D. Page [60,61], the entropy of the radiation would need to follow the curve indicated in figure 7, as opposed to the Hawking curve.

  • Supports

    The entropy of Hawking radiationabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: This technique reveals large corrections needed for the entropy to be consistent with unitary black hole evaporation.

What this does not establish

The calculations give the entropy of the radiation, not its state, and rely on a gravitational path integral whose definition the review says is not yet clear.

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: There is no agreed mechanism.

Kind
Open question. Something the page says is not known.
Review
Presented as open. The page says this is unresolved, and the review found that it is.

  • Context

    The entropy of Hawking radiationsection 11.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Therefore the current discussion leaves an important problem unresolved. ... we have discussed how to compute the entropy of Hawking radiation, but not how to compute its precise quantum state.

  • Context

    The entropy of Hawking radiationsection 11.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: rely on the Euclidean path integral. It is not clear how this is defined precisely in gravity.

Claim 38 · checked 24 September 2026 · AI-assisted audit

What the horizon is like

Claim: What the horizon is like

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: General relativity says nothing locally special happens at the horizon of a large black hole: an infalling observer would notice nothing.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 2.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Therefore according to a free-falling observer, the event horizon r = rs is not special. It is just like any other point in a smooth spacetime

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: an observer falling through the horizon encounters nothing special there

What this does not establish

A statement of the classical theory; whether it survives quantum effects is the question the rest of the passage takes up.

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: In 2012 Almheiri, Marolf, Polchinski and Sully argued that this cannot be held together with a pure final state and with the information leaving from near the horizon, and that the most conservative way out is that the infalling observer burns.

Kind
An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Black holes: complementarity or firewalls?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: the following three statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon ... and (iii) the infalling observer encounters nothing unusual at the horizon.

    First posted to arXiv in July 2012 (arXiv:1207.3123, the version read is v4 of April 2013); published in JHEP in February 2013.

  • Supports

    Black holes: complementarity or firewalls?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Perhaps the most conservative resolution is that the infalling observer burns up at the horizon.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: They proposed it as the least bad option, not as a finding.

Kind
An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Black holes: complementarity or firewalls?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Perhaps the most conservative resolution is that the infalling observer burns up at the horizon.

  • Supports

    Black holes: complementarity or firewalls?section 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Our work again seems to present some sharp and perhaps unpalatable alternatives: a firewall at the horizon, or novel and probably nonlocal dynamics extending a macroscopic distance outside the horizon.

Claim 42 · checked 24 September 2026 · AI-assisted audit

Claim: Both pictures cannot be right.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the AMPS argument: if their three statements cannot all hold, a smooth horizon and their resolution cannot both describe the same black hole.

  • Supports

    Black holes: complementarity or firewalls?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: the following three statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon ... and (iii) the infalling observer encounters nothing unusual at the horizon.

Claim 43 · checked 24 September 2026 · AI-assisted audit

Claim: A 2021 review by Almheiri and colleagues argues that the horizon stays smooth and the paradox is resolved another way;

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationappendix A

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: According to this review, the paradox is resolved by dropping the assumption that the interior is also described by the same degrees of freedom that describe it as viewed from outside.

  • Supports

    The entropy of Hawking radiationappendix A

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: This is different than the resolution proposed in AMPS. With this resolution, the horizon is smooth.

Corrected

24 September 2026. Previously: “Both pictures cannot be right, and the disagreement remains unresolved.” The page did not report the newer proposal. The review cited on the page resolves the AMPS paradox with a smooth horizon; the page now says so and that it is a proposal.

Claim 44 · checked 24 September 2026 · AI-assisted audit

Claim: the disagreement is not settled.

Kind
Open question. Something the page says is not known.
Review
Presented as open. The page says this is unresolved, and the review found that it is.

The review’s own resolution depends on assumptions it lists as not yet understood.

  • Context

    The entropy of Hawking radiationsection 11.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: rely on the Euclidean path integral. It is not clear how this is defined precisely in gravity.

  • Context

    Information lossabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: Semiclassical arguments strongly suggest that, in the process of black hole ... a pure quantum state will evolve to a mixed state ... There has been considerable controversy over this issue for more than 40 years.

Claim 45 · checked 24 September 2026 · AI-assisted audit

Past the horizon

Claim: Past the horizon

Kind
Framing. Signposting. It asserts nothing a source could check.

What is actually at the centre

Claim: What is actually at the centre

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: A theory of quantum gravity would be required to say.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The entropy of Hawking radiationsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: They also contain a singularity in their interior. It is an anisotropic big crunch singularity, but it is also a situation where quantum gravity is necessary

  • Supports

    The 1965 Penrose singularity theoremsection 8.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is widely accepted that the existence of classical singularities signal a breakdown of the classical theory at extreme conditions, which is precisely when gravitational quantum effects will become relevant.

Later work looked for

The SEP entry read is the current revision (February 2024); Crossref, 2019 on, "loop quantum gravity black hole singularity resolution" found no experimental test of a candidate theory; nothing that changes the claim.

Claim 48 · checked 24 September 2026 · AI-assisted audit

Claim: There is no experimentally confirmed theory of quantum gravity.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophyopening

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: Quantum Gravity, broadly construed, is a physical theory (still ‘under construction’ after over 100 years) incorporating both the principles of general relativity and quantum theory.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophyopening

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: This scale is so remote from current experimental capabilities that the empirical testing of quantum gravity proposals along standard lines is rendered near-impossible, though there have been some recent developments that suggest the outlook might be more optimistic than previously surmised

Later work looked for

The SEP entry read is the current revision (February 2024); Crossref, 2019 on, "loop quantum gravity black hole singularity resolution" found no experimental test of a candidate theory; nothing that changes the claim.

Claim 49 · checked 24 September 2026 · AI-assisted audit

Claim: Candidates exist, and none has been tested: the scale at which quantum gravity is expected to matter is far beyond any present experiment.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophyopening

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: This scale is so remote from current experimental capabilities that the empirical testing of quantum gravity proposals along standard lines is rendered near-impossible, though there have been some recent developments that suggest the outlook might be more optimistic than previously surmised

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophyopening

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: Such a theory is expected to be able to provide a satisfactory description of the microstructure of spacetime at the so-called Planck scale

What this does not establish

The entry notes recent proposals that may make some tests possible.

Later work looked for

The SEP entry read is the current revision (February 2024); Crossref, 2019 on, "loop quantum gravity black hole singularity resolution" found no experimental test of a candidate theory; nothing that changes the claim.

Corrected

24 September 2026. Previously: “Candidates exist and make different predictions; none has been tested.” The passage had no source. The SEP entry carries the absence of tests and the reason for it; "make different predictions" was not something a cited source stated and was dropped.

Claim 50 · checked 24 September 2026 · AI-assisted audit

Whether the interior is even a meaningful question

Claim: Whether the interior is even a meaningful question

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Black hole complementarity, proposed by Susskind, Thorlacius and Uglum in 1993, holds that the inside and the outside are two descriptions of one thing and that no observer ever sees both,

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: there is complementarity between observations made by infalling observers who cross the event horizon and those made by distant observers.

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Such a state can describe correlations which have no operational ... since an observer who passes behind the event horizon can never communicate the result of any experiment performed inside the black hole

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Only when we try to give a combined ... with a standard quantum theory valid for both observers, do we encounter

What this does not establish

A proposed principle, advocated rather than derived; AMPS argue it is not enough to keep the horizon smooth.

Claim 52 · checked 24 September 2026 · AI-assisted audit

Claim: so asking what is in there independently of the outside is not a question the theory answers.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s gloss of the paper’s point that a state describing inside and outside together has no operational meaning.

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Such a state can describe correlations which have no operational ... since an observer who passes behind the event horizon can never communicate the result of any experiment performed inside the black hole

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Only when we try to give a combined ... with a standard quantum theory valid for both observers, do we encounter

Claim 53 · checked 24 September 2026 · AI-assisted audit

Claim: Whether that is deep insight or a change of subject is itself disputed.

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

  • Supports

    The stretched horizon and black hole complementaritysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: Only when we try to give a combined ... with a standard quantum theory valid for both observers, do we encounter

  • Supports

    Black holes: complementarity or firewalls?section 2 title

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Complementarity is not enough

  • Supports

    Black holes: complementarity or firewalls?section 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: the absence of drama for the infalling observer – have in particular been incorporated into the axioms of black hole complementarity

Other readings

Susskind, Thorlacius and Uglum hold that trouble arises only when one insists on a combined description; AMPS argue that complementarity is not enough to save a smooth horizon.

Claim 54 · checked 24 September 2026 · AI-assisted audit

Candidate answers

Claim: Candidate answers

Kind
Framing. Signposting. It asserts nothing a source could check.

Information is encoded on the horizon

Claim: Information is encoded on the horizon

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The world as a hologramabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: According to ’t Hooft the combination of quantum mechanics ... requires the three dimensional world to be an image of data that can be ... on a two dimensional projection much like a holographic image.

  • Supports

    The world as a hologramsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: by a set of degrees of freedom which reside on the surface bounding V

What this does not establish

A proposal, not an observation.

Claim 56 · checked 24 September 2026 · AI-assisted audit

Claim: The holographic principle, proposed by ’t Hooft and developed by Susskind in 1995, holds that everything inside a region can be described by information on its boundary.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The world as a hologramabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: According to ’t Hooft the combination of quantum mechanics ... requires the three dimensional world to be an image of data that can be ... on a two dimensional projection much like a holographic image.

  • Supports

    The world as a hologramsection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: by a set of degrees of freedom which reside on the surface bounding V

What this does not establish

A principle proposed for quantum gravity, not a tested result.

Corrected

24 September 2026. Previously: “The holographic principle, argued by Susskind in 1995, proposes that” Susskind’s own abstract attributes the proposal to ’t Hooft and describes his paper as developing it.

Claim 57 · checked 24 September 2026 · AI-assisted audit

Claim: A conjecture by Maldacena gave it a concrete form for one particular kind of universe, with a negative cosmological constant.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The large-N limit of superconformal field theories and supergravityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: We conjecture that compactifications of M/string ... on various Anti-deSitter spacetimes is dual to various conformal field theories.

  • Supports

    Anti de Sitter space and holographyabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: it has been proposed by Maldacena that large N limits of certain conformal field theories in d dimensions can be described in terms of supergravity

  • Supports

    Anti de Sitter space and holographysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: expresses a string theory on AdS5 × S5 in terms of a theory on the boundary. This correspondence is thus “holographic,”

  • Supports

    Anti de Sitter space and holographysection 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: the Einstein equations (with a negative cosmological constant as we are on AdSd+1)

What this does not establish

A conjecture with much supporting evidence, not a proof; Maldacena’s paper does not use the word holographic, and Witten’s paper made the connection.

Corrected

24 September 2026. Previously: “Maldacena made it concrete for one particular kind of universe,” Maldacena’s paper states a conjecture, and the holographic reading and the negative cosmological constant are both in Witten 1998, now cited.

Claim 58 · checked 24 September 2026 · AI-assisted audit

Claim: Ours does not appear to be one of those,

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The 1965 Penrose singularity theoremsection 8

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Astronomical observation · Review of the field

    The source reads: Inflation as well as the acceleration of the expansion of the Universe are closely related to the existence of a positive cosmological constant Λ > 0

  • Supports

    Anti de Sitter space and holographysection 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory

    The source reads: the Einstein equations (with a negative cosmological constant as we are on AdSd+1)

What this does not establish

The accelerating expansion is what points to a positive cosmological constant; the review states that link.

Later work looked for

Crossref, 2019 on, "DESI dark energy baryon acoustic oscillations cosmological constraints": the titles returned concern whether dark energy evolves over time (not read); nothing read suggests a negative cosmological constant for our universe.

Claim 59 · checked 24 September 2026 · AI-assisted audit

Claim: and no version of the principle has been established for it.

Kind
Open question. Something the page says is not known.
Review
Presented as open. The page says this is unresolved, and the review found that it is.

  • Context

    The entropy of Hawking radiationsection 11.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: unclear whether we should think of the cosmological horizon as a quantum system in the sense of the central dogma for black holes.

  • Context

    Information losssection V.C

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: The AdS/CFT correspondence is a conjecture.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Quantum gravity replaces the singularity

Claim: Quantum gravity replaces the singularity

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: bringing quantum field theory and general relativity together might serve to cure their respective singularity problems ... This hope does seem to have been borne out in many of the current approaches.

  • Supports

    Quantum geometry and the Schwarzschild singularityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: shown to lead to a resolution of the Schwarzschild singularity

What this does not establish

Shown only within candidate theories, none of them tested.

Claim 61 · checked 24 September 2026 · AI-assisted audit

Claim: In several candidate theories the singularity is smoothed into something finite, such as a bounce or a region where spacetime stops being classical.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophysection 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: bringing quantum field theory and general relativity together might serve to cure their respective singularity problems ... This hope does seem to have been borne out in many of the current approaches.

  • Supports

    Quantum geometry and the Schwarzschild singularitysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: there would be a quantum bounce to another large classical region

  • Supports

    Quantum geometry and the Schwarzschild singularitysection V

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: In the Planck regime, quantum fluctuations do indeed become so strong that the classical description breaks down.

What this does not establish

Results within candidate theories and simplified models.

Corrected

24 September 2026. Previously: “smoothed into something finite: a bounce, a dense core, or a region where spacetime stops being classical.” "A dense core" was not carried by any cited source and was removed; the bounce and the non-classical region are in Ashtekar and Bojowald, and the SEP entry supports "several candidate theories".

Claim 62 · checked 24 September 2026 · AI-assisted audit

Claim: Ashtekar and Bojowald found one such resolution of the Schwarzschild singularity in a simplified model built on the quantum geometry of loop quantum gravity.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Quantum geometry and the Schwarzschild singularityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: shown to lead to a resolution of the Schwarzschild singularity

  • Supports

    Quantum geometry and the Schwarzschild singularitysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: theory of the Kantowski-Sachs mini-superspace using connection-dynamics

  • Supports

    Quantum geometry and the Schwarzschild singularitysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: we emphasize that the results of this note constitute only initial steps for a more complete theory

What this does not establish

A symmetry-reduced (Kantowski-Sachs) model; the authors call the results only initial steps.

Corrected

24 September 2026. Previously: “Ashtekar and Bojowald showed one such resolution of the Schwarzschild singularity using the quantum geometry of loop quantum gravity.” The result is in a symmetry-reduced model, which the authors describe as initial steps toward a complete theory.

Claim 63 · checked 24 September 2026 · AI-assisted audit

Claim: These are calculations within unverified frameworks, not descriptions of observed objects.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the SEP entry on the absence of tests and the authors’ own caveat.

  • Supports

    Quantum geometry and the Schwarzschild singularitysection 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: we emphasize that the results of this note constitute only initial steps for a more complete theory

  • Supports

    Quantum Gravity, in the Stanford Encyclopedia of Philosophyopening

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: This scale is so remote from current experimental capabilities that the empirical testing of quantum gravity proposals along standard lines is rendered near-impossible, though there have been some recent developments that suggest the outlook might be more optimistic than previously surmised

Claim 64 · checked 24 September 2026 · AI-assisted audit

Black holes evaporate completely and take nothing with them

Claim: Black holes evaporate completely and take nothing with them

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Information losssection I

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Our belief is that information is lost into black holes

  • Supports

    Particle creation by black holesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model

    The source reads: quantum mechanical effects cause black holes to create and emit particles as if they were hot bodies ... where K is the surface gravity of the black ... This thermal emission leads to a slow decrease in the mass of the black hole and to its eventual disappearance

Other readings

The view that information escapes is more widely held; see claims 33 to 37.

Claim 65 · checked 24 September 2026 · AI-assisted audit

Claim: The original conclusion (that information really is lost) has not been refuted, and it still has defenders.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

The review, which argues for unitarity, allows that in some theories of gravity Hawking’s picture is accurate.

  • Supports

    The entropy of Hawking radiationsection 11.2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: It is possible that some theories of gravity include replica wormhole saddles and black holes evaporate unitarily, while in other theories of gravity they do not contribute to the path integral, the central dogma fails, and Hawking’s picture is accurate.

  • Supports

    Information losssection I

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Our belief is that information is lost into black holes

Corrected

24 September 2026. Previously: “The original conclusion (that information really is lost) has not been formally refuted, only widely disbelieved.” The page left out that the view has named defenders; Unruh and Wald argued for it in 2017.

Claim 66 · checked 24 September 2026 · AI-assisted audit

Claim: Its critics argue that it would violate fundamental principles of physics.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Information losssection I

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field

    The source reads: it has been argued on a variety of grounds that such pure state to mixed state evolution would violate fundamental principles of physics

Corrected

24 September 2026. Previously: “It would require modifying quantum mechanics, which is why almost nobody wants it.” Stated as fact, this was one side of a live dispute, and "almost nobody" is a count no source gives. Unruh and Wald argue that pure-to-mixed evolution violates no fundamental principle; the page now reports both sides.

Claim 67 · checked 24 September 2026 · AI-assisted audit

Claim: Unruh and Wald, who defend it, argued in 2017 that it violates none.

Kind
An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Information losssection I

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: to argue that such pure to mixed evolution does not violate any fundamental principles of physics.

  • Supports

    Information losssection V.A

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument

    The source reads: Such a failure of unitarity is entirely innocuous.

Claim 68 · checked 24 September 2026 · AI-assisted audit

What was read