The eighteen problems
Below: every problem the standard cosmological model accumulates, with its current status under ISST. The list is the lab's living checklist (canon/problems.md); status updates only when backed by verified work, never by promise.
- DISSOLVED
- 9
- PARTIAL
- 6
- CONSISTENT
- 1
- INHERITED
- 1
- NOT STARTED
- 1
Big Five
The dark sector and the Hubble & S₈ tensions — what most people mean by ‘the cosmological problems’.
Problem 1
DISSOLVEDDark matter identity
Standard: 26% undetected. WIMP null.
Mechanism + derivation
Problem 2
DISSOLVEDDark energy / Lambda
Standard: 69% accelerates. No mechanism.
Mechanism + derivation
Problem 3
DISSOLVEDCC problem
Standard: QFT vacuum energy 10^120 too large.
Mechanism + derivation
Problem 4
DISSOLVEDHubble tension
Standard: CMB 67.4 vs local 73.0. 5 sigma.
Summary + sources
Problem 5
PARTIALS8 tension
Standard: Lensing < Planck prediction. 3+ sigma.
Summary + sources
Structure
Galactic and cluster-scale problems where the standard fix is a particle nobody has ever seen.
Problem 6
PARTIALGalaxy rotation curves
Standard: Flat rotation curves. Need DM halos.
Summary + sources
Problem 7
PARTIALCluster mass deficit
Standard: Clusters need 5x visible mass.
Summary + sources
Problem 8
PARTIALBullet Cluster
Standard: Lensing offset from gas. "Proof" of CDM.
Summary + sources
Problem 9
PARTIALJWST impossible galaxies
Standard: 100x too many massive galaxies at z>10.
Summary + sources
Problem 10
DISSOLVEDWIMP null detection
Standard: All DM detectors: nothing.
Summary + sources
Early Universe
Flatness, horizon, and BBN — the inflation-shaped questions, plus the lithium anomaly.
Problem 11
DISSOLVEDFlatness problem
Standard: Omega_k ~ 0 to 0.4%. Why?
Summary + sources
Problem 12
DISSOLVEDHorizon problem
Standard: CMB uniform over causally disconnected regions.
Summary + sources
Problem 13
CONSISTENTBBN concordance
Standard: Five measurements agree on 26% DM.
Summary + sources
Problem 14
INHERITEDLithium problem
Standard: BBN predicts 3x too much Li-7.
Summary + sources
Deep
Foundational questions: the arrow of time, the gravity-vs-other-forces hierarchy, the measurement problem.
Problem 15
DISSOLVEDArrow of time
Standard: Why does entropy increase? Past Hypothesis.
Summary + sources
Problem 16
DISSOLVEDFine-tuning / hierarchy
Standard: Gravity 10^38 weaker than other forces.
Summary + sources
Problem 17
NOT STARTEDBaryon asymmetry
Standard: More matter than antimatter.
Summary + sources
Problem 18
PARTIALMeasurement problem
Standard: QM collapse. What causes it?
Summary + sources