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Showing votes from 2019-11-26 11:30 to 2019-11-29 12:30 | Next meeting is Tuesday Apr 15th, 10:30 am.
The spin pattern of a spiral galaxy is a matter of the perspective of the observer, and therefore galaxies with clockwise spin patterns are expected to be identical in their characteristics to galaxies with counterclockwise spin patterns. However, observations of a large number of galaxies show clear photometric differences between clockwise and counterclockwise spiral galaxies. In this study the magnitude difference between clockwise and counterclockwise spiral galaxies imaged by the space-based COSMOS survey is compared to galaxies imaged by the Earth-based SDSS and PanSTARRS around the same field. The comparison shows that the same asymmetry was identified by all three telescopes, providing strong evidence that the rotation direction of the galaxy affects its magnitude as measured from Earth. Analysis of a large number of galaxies from different parts of the sky shows that the differences between clockwise and counterclockwise galaxies are oriented around an axis such that the photometric asymmetry in one hemisphere is inverse to the photometric asymmetry in the opposite hemisphere. Due to the provocative nature of the observation, it is difficult to identify an immediate explanation. A possible explanation could be related to the large-scale structure of the universe, which leads to violation of the cosmological homogeneity assumption. Another possible explanation that does not require the violation of the cosmological principle is that the observation is driven by galaxy rotation. Due to relativistic beaming, such difference is indeed expected to be identified and peak at the galactic pole, but it is expected to be far smaller than the differences observed by all three telescopes. Therefore, if the asymmetry is driven by galaxy rotation, it corresponds to a much higher velocity than the actual measured rotational velocity of galaxies.
A recent preprint by Wang and Unruh [arXiv:1911.06110] contains a number of criticisms of my paper, "Hiding the cosmological constant" [Phys. Rev. Lett. 123 (2019) 131302, arXiv:1809.08277]. While Wang and Unruh suggest an interesting alternative scenario and raise an important conceptual question, most of their criticisms are incorrect, in part because of misunderstandings about averaging and about the nature of the "foamy" spacetimes considered in my paper.