  Recent advancements have shown tensions between observations and our current
understanding of the Universe. Such observations may include the Ho tension, as
well as massive and mature galaxies at high redshifts that according to the
existing models are older than the Universe itself. Since these observations
are based on the redshift as the primary distance indicator, a bias in the
redshift may explain these tensions. While the redshift follows an established
model, when applied to astronomy it is based on the assumption that the
rotational velocity of the Milky Way relative to the rotational velocity of the
observed galaxies has a negligible effect on the redshift. But given the
mysterious nature of the physics of galaxy rotation, that assumption should be
tested. The test is done by comparing the redshift of galaxies that rotate in
the same direction relative to the Milky Way to the redshift of galaxies that
rotate in the opposite direction relative to the Milky Way. The results show
that the mean redshift of galaxies that rotate in the same direction relative
to the Milky Way is significantly higher than the mean redshift of galaxies
that rotate in the opposite direction. Additionally, the redshift difference
becomes larger as the redshift gets higher. The consistency of the analysis was
verified by comparing data collected by three different telescopes, annotated
using four different methods, released by three different research teams, and
cover both the Northern and Southern ends of the galactic pole. All datasets
are in excellent agreement with each other, showing consistency in the observed
redshift bias. Given the "reproducibility crisis" in science, all datasets used
in this study are publicly available, and the results can be easily reproduced.
The observation could be a first direct observation for the Zwicky's
"tired-light" model.
