Problem Area


Hubble Tension

4 σ - 6σ Possible Modeling or Systematic Error or failure in Lambda CDM, Possible error in Standardising candles

Lensing Anomaly

Possible Systematic Error/Positive Curvature/Closed Universe

Accelerated Expansion

Astrophysical Observations/Possibly New Explanations


Theoretical necessity (CMB observations)

Dark Matter

Theoretical necessity/Astrophysical Observations

Dark Energy

Theoretical Necessity/Astrophysical Observations


Patchwork to SMC based on CMB and Astrophysical Observations/Debatable. Needs explanations and more evidence

Conformal Cyclic Cosmology

Alternative to inflation/Mathematically and aesthetically appealing/Needs more evidence and theoretical work

Giant Arc

New Explanations needed

Lepton Universality Violation

New Explanations needed

Energy Density ~0 (>0)

New Explanations needed

Critical Mass Density (~1)

New Explanations needed