Quasars, Redshifts and Controversies

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Quasars, Redshifts and Controversies is a 1987 book by Halton Arp, an astronomer famous for his work on anomalous redshifts. Arp argued that many quasars with otherwise high redshift are somehow linked to close objects such as nearby galaxies, thus invalidating Hubble's law. Arp also argued that some galaxies showed unusual redshifts, and that redshifts themselves could be quantized - something which current theories cannot explain at macroscopic scales.

These are considered controversial views which do not accord with the standard model of the Universe, under which it is generally thought that the universe is undergoing expansion, and that redshifts observed in objects outside the Milky Way are a confirmation of this effect. Quasars, in particular, are high-redshift objects thought to be the very bright nuclei of very distant galaxies. The relationship between distance and redshift (interpreted as velocity) is known as Hubble's law, and is one of the fundamentals of modern cosmology.

Most astronomers reject Arp's interpretation of the data. Anomalous observations could be explained by perspective effects, these individuals argue. Reportedly, some of Arp's calculations seem to be simply "bad mathematics". Arp asserts that many questions he posed to the scientific establishment are still unanswered and that, even worse, his requests for more observation time have been systematically rejected.

His work is updated in his latest book, "Seeing Red: Redshifts, Cosmology and Academic Science", Aperion (August, 1998), ISBN 0968368905.

Halton Arp's proposal was an idea based on analyses done before the sky surveys increased the number of measured redshift by several orders of magnitude. The idea was that the cosmological redshift might be showing evidence of periodicity which would be difficult to explain in a Hubble's Law universe that had the feature of continuous expansion. However, most astronomers agree that the analysis suffers from poor methodology and small number statistics.

Another critique of cosmological redshift also came from Halton Arp, who continues to find empirical support in the existence of apparently connected objects with very different redshifts. Arp has interpreted these connections to mean that these objects are in fact physically connected. He has further hypothesized that the higher redshift objects are ejected from the lower redshift objects - which are usually active galactic nuclei (AGN)- and that the large observed redshifts of these "ejected" objects is dominated by a non-cosmological (intrinsic) component. Conventional cosmological models regard these as chance alignments and Arp's hypothesis has very few supporters within the research community.

Proponents of non-standard cosmologies have referred to other observed effects, such as Brillouin scattering, Compton scattering, Raman scattering and the Wolf effect which they claim can, under certain circumstances, mimic frequency shifts in certain bands of the electromagnetic spectrum. It is not generally thought that these effects could explain the observed cosmological redshift-distance relationship, although proponents of the Wolf effect have claimed that the Wolf effect might lead to small changes in the apparent redshift of some astronomical objects (particularly quasars).

Advocates of plasma cosmology have from time to time supported various redshift interpretations involving scattering, but these all suffer from being unable to adequately reproduce the Hubble Law on large scales.

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External links and references

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