"Hubble constant"

My note. This is always a fun constant in nature to watch the reporting values found.

Ref - Observations of type 1a supernovae are consistent with a static universe,

https://arxiv.org/abs/0901.4172, 2009. "Analysis of type 1a supernovae observations out to a redshift of z=1.6 shows that there is good agreement between the light-curve widths and (1+z) which is usually interpreted as a strong support for time dilation due to an expanding universe...provides a Hubble constant of 63.1±2.5 kms^−1 Mpc^−1."

My note. This result is very interesting in view of the measurement obtained using the Moon. Ref - Worry No More, The Hubble Tension is Relieved: A Truly Direct Measurement of the Hubble Constant from Mooniversal Expansion,

https://arxiv.org/abs/2203.16551, March 2022. "Using sedimentary and eclipse-based measurements of the lunar recession velocity, we derive a new local-Universe measurement of the Hubble constant (H0) from the recession rate of Earth's Moon. Taking into account the effects of tides, we find a value of H0 = 63.01 ± 1.79 km s^−1 Mpc^−1,.."

My note. So in 2009 using Type 1a SN with redshifts out to z=1.6, H0=63.1 km/s/Mpc. Using the March 2022 report for the Moon, H0 = 63.01 km/s/Mpc. Perhaps this is just a fluke

Ref - Cosmological Results from the RAISIN Survey: Using Type Ia Supernovae in the Near Infrared as a Novel Path to Measure the Dark Energy Equation of State,

https://arxiv.org/abs/2201.07801, "The largest systematic errors are the redshift-dependent SN selection biases and the properties of the NIR mass step. We also use these data to measure H0=75.4±2.4 km s^−1 Mpc^−1 from stars with geometric distance calibration in the hosts of 8 SNe Ia observed in the NIR versus H0=65.9±3.4 km s^−1 Mpc^−1 using an inverse distance ladder approach tied to Planck."

My note. H0 = 75.4 km/s/Mpc now compared to Planck H0 = 65.9 km/s/Mpc using the CMBR. My thinking, using the CMBR is biased because the postulated redshift, z ~ 1100 is not spectroscopically determined.

Ref - Measurements of the Hubble Constant with a Two Rung Distance Ladder: Two Out of Three Ain't Bad,

https://arxiv.org/abs/2204.10866, April 2022. "Modeling these assumptions yields central values ranging from H0 = 71.8 to 77.0 km/s/Mpc. Combining the four best fitting selection models yields H0 = 73.1 (+2.6/-2.3) km/s/Mpc as a fiducial result, at 2.6σ tension with Planck."

My note. Just in these small samples cited I find H0 values ranging 63 to 77 km/s/Mpc. Early reports in the 1920s-1930s showed H0 = 500 km/s/Mpc. Plugging in different values for H0 into the cosmology calculators will show some surprising age differences for the Universe

Ref - Study of the Virgo Cluster Using the B-Band Tully-Fisher Relation,

https://ui.adsabs.harvard.edu/abs/1997ApJS..108..417Y/abstract, Feb-1997. "The distances to spiral galaxies of the Virgo cluster are estimated using the B-band Tully-Fisher (TF) relation, and the three-dimensional structure of the cluster is studied. The analysis is made for a complete spiral sample taken from the Virgo Cluster catalog of Binggeli, Sandage, & Tammann. The sample contains virtually all spiral galaxies down to MBT=-15 mag at 40 Mpc…Finally, we infer the Hubble constant to be 82 +/- 10 km s^-1 Mpc^-1."

My note. Now I see another value, H0 = 82 km/s/Mpc