But as I understand it, it was linear. The values measured that led to DM hypothesis appears to be irregular. It would mean the constant isn't constant?
The Cosmological Constant (CC) accounts for Dark
Energy (DE), not Dark
Matter (DM) which is a separate issue:
According to the conventional cosmology, the Universe began in the Big Bang with only ~30% of required critical closure mass-energy density in the form of any kind of matter
Assumedly (?), 15% was matter and 15% was anti-matter
For some reason, all of the antimatter (15%) and 2/3
rds of the matter (10%) annihilated into "super-massive (sterile) neutrinos" or something (= WIMPs, "Weakly Interacting Massive Particles")
leaving only 5% of critical closure density surviving in the form of normal "baryonic" matter we know & love
of that 5%, 80% is intergalactic space plasma (amidst galaxies in groups, clusters, and Large Scale Structures (LSSs)), 10% is in detectably luminous bright stars (in detected galaxies), <1% is in "heavy metals" (Lithium on up) in the stars & space plasma in & amongst the galaxies, and the rest is in Cosmic Background microwave frequency photons (CMB) & normal (non-sterile) Cosmic Background neutrinos (CNB)
Professional astronomers avidly deny that much mass density resides in "dim matter" like rogue planets & Brown Dwarves (BDs) and compact objects like NSs & BHs -- if all DM were "dim matter" then there'd have to be 50x more mass out there in rogue planets & sub-stellar BDs (and NSs & BHs) than in detectably bright luminous stellar objects
(non-sterile neutrinos, including "left-handed" neutrinos = spin angular momentum points backwards anti-parallel to their velocity vector & "right-handed" anti-neutrinos = spin forward parallel to velocity, are able to interact via the Weak force... "opposite-handed" neutrinos & anti-neutrinos cannot even interact Weakly, forever isolated from any known forceful interactions... so I understand DM is not really "W-IMPs" but rather "Non-IMPs")