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Hubble tension

CC-BY-4.0vfr_9caed35d1222c706

id: vfr_9caed35d1222c706
license: CC-BY-4.0
findings: 131
accepted core: 12
contested: 3

131

findings

81

links

127

sources

131

evidence

3

contested

0.83

avg conf

recordoverview state sources proofenginereviewbodygraph

Finding bundle

The Tip of the Red Giant Branch (TRGB) distance indicator relies on the observation that all metal-poor globular clusters reach a sharp luminosity cutoff at nearly identical absolute magnitude (M_V ≈ −4.0 ± 0.1) when they transition from the red giant branch to the asymptotic giant branch, providing a standardizable 'cosmic rung' for nearby galaxies.

1contested3inferred

id: vf_b84cdcc718019d73
frontier: Hubble tension
version: 1
confidence: 0.92

record state

frontier-owned

Review status

This finding is part of accepted frontier state. Review events, reviewable changes, and proof state explain how it can change.

unreviewed

finding statement

finding type

mechanism

No entity list is declared.

evidence

source-bound

1 atoms

theoretical · manual state transition

proof impact

packet context

2 events

1 reviewable changes and 0 evaluation records are attached to this finding id.

Evidence and conditions

method

manual state transition

evidence type

theoretical

conditions

species_unverified
species_verified
text: Requires high-resolution imaging (HST-quality) to resolve individual TRGB stars; metallicity bias (population with [Fe/H] ≤ −1.5) must be accounted for; limiting distance ~4–5 Mpc for current facilities

Provenance

source title

Bellazzini et al. (1999), Whitelock & Feast (2000), established TRGB calibration literature

authors

reviewer:will-blair

Source records

1

source record

Bellazzini et al. (1999), Whitelock & Feast (2000), established TRGB calibration literature

vs_2fe147f360243b0e

title:Bellazzini et al. (1999), Whitelock & Feast (2000), established TRGB calibration literature

1999manual_curation

inspect source →

Evidence atoms

1

vea_2056187c4a3d4c74theoretical · unknown
The Tip of the Red Giant Branch (TRGB) distance indicator relies on the observation that all metal-poor globular clusters reach a sharp luminosity cutoff at nearly identical absolute magnitude (M_V ≈ −4.0 ± 0.1) when they transition from the red giant branch to the asymptotic giant branch, providing a standardizable 'cosmic rung' for nearby galaxies.
vs_2fe147f360243b0e · manual_curation

Typed links

5

outgoing

dependsvf_1fa79dc0b965c889
TRGB absolute magnitude precision depends critically on metallicity calibration
dependsvf_92a4abc490ebaf6c
TRGB metallicity calibration anchored to LMC globular clusters via Gaia parallaxes

incoming

The Red Clump (RC), a core helium-burning phase with stable absolute magnitude (M_I ≈ −0.2 to −0.5 depending on metallicity), offers an alternative distance indicator to TRGB with ~0.15 mag precision in the infrared, applicable to galaxies up to ~10 Mpc.
supersedes · vf_0a14b8c5cb712d65
The luminosity of the Horizontal Branch (HB) is measurably correlated with metallicity and age, making unambiguous HB distance determinations difficult; when calibrated against globular cluster parallaxes, HB distances show ~0.2 mag scatter relative to TRGB, limiting standalone utility.
contradicts · vf_e739510dadf9b39a
Mira variables in nearby galaxies (LMC, SMC, M31, M33) have been recalibrated using Gaia EDR3 parallaxes, yielding period-luminosity relations with ±0.12 mag uncertainty, offering an independent local distance ladder rung competing with TRGB.
supports · vf_5d29534a41579659

Review, event, and evaluation records

3

events

vev_d05f08f7b1f0867efinding.asserted
Manual finding added to frontier state
reviewer:will-blair · 2026-05-29
vev_32790c1b837b7a3bfinding.dependency_invalidated
Upstream finding vf_92a4abc490ebaf6c retracted; cascade depth 1
reviewer:will-blair · 2026-05-29

reviewable changes

vpr_20f3448497ce7471finding.add
Manual finding added to frontier state
applied · reviewer:will-blair · 2026-05-29

evaluations

No evaluation record targets this finding id.