So basically, since astronomers *assume* that redshift is caused by metaphysics rather than empirical physics, there's now about a 10 percent discrepancy between the expansion rate as it is calculated based on Planck data, and the metaphysical expansion rate as it is calculated by Hubble data, and the error rate of the later calculation has been reduced to about 2.5 percent. This means that there's only about 1 in 5000 chance that this isn't a "real" problem.Explaining a Vexing Discrepancy
Riess outlined a few possible explanations for the mismatch, all related to the 95 percent of the universe that is shrouded in darkness. One possibility is that dark energy, already known to be accelerating the cosmos, may be shoving galaxies away from each other with even greater - or growing - strength. This means that the acceleration itself might not have a constant value in the universe but changes over time in the universe. Riess shared a Nobel Prize for the 1998 discovery of the accelerating universe.
Another idea is that the universe contains a new subatomic particle that travels close to the speed of light. Such speedy particles are collectively called "dark radiation" and include previously known particles like neutrinos, which are created in nuclear reactions and radioactive decays. Unlike a normal neutrino, which interacts by a subatomic force, this new particle would be affected only by gravity and is dubbed a "sterile neutrino."
The first proposed "fix" for this problem is to claim that dark energy isn't just remaining constant during expansion, which is bad enough in terms of energy conservation, but rather to claim that 'dark energy' is "growing stronger" over time/distance/volume increases due to expansion.
The second proposed "fix" to this metaphysical kludge is to add yet *another* metaphysical fudge factor called "dark radiation" to the calculations, bringing the total number of invisible metaphysical fudge factors up to *five*, and relegating ordinary matter/energy to something *less* than it's currently measly 5 percent figure. Note also that the proposed 'sterile neutrino' fix has already been blown out of the water by the Ice Cube data:
IceCube telescope in Antarctica rules out sterile neutrinos
The third proposed 'fix' suggested in the article would be to modify the metaphysical properties of the fudge factor known as "dark matter" in spite of the fact that dark matter has already failed 10's of billions of dollars worth of lab "tests" to date, and failed many other observational "tests" including another one earlier this month.
Satellite galaxies of Centaurus A defy dark-matter model - physicsworld.com
What a metaphysical mess and a complete kludge! LCDM fails virtually every conceivable "test" on the books, yet astronomers are constantly trying to "save" it from what 'should be' a natural scientific death.
The *other* possibility of course which is *not* discussed in that article is that redshift is simply caused by *already empirically identified* processes in plasma like inelastic scattering, and none of the observed redshift is related to metaphysical nonsense.
Oy Vey. The LCDM model is falling apart of the metaphysical seams at this point. It's failed two major observatoinal "tests" of it's claims in the past month alone, and it's failed *billions* of dollars with of lab tests over the past decade.
LCDM is unfalsifiable dogmatic nonsense. It's like a bad metaphysical smell in physics that just won't go away.