Intrinsic redshift

Scientific Theory
Name	Intrinsic redshift
Type	Cosmological hypothesis
Author(s)	Halton C Arp, William Tifft, Geoffrey Burbidge, Jayant Narlikar and others
Keywords	redshift, quasars, discordant associations, redshift quantization, variable mass, Big Bang
Year	1966 onward

Intrinsic redshift is the hypothesis that a significant part of the redshift observed in some astronomical objects — particularly quasars — is not caused by cosmological expansion or by motion away from the observer, but is instead a property intrinsic to the object itself. If true, redshift would cease to be a reliable measure of distance, and the distance scale on which modern cosmology and the Big Bang model rest would require fundamental revision.

The hypothesis is most closely associated with the astronomer Halton C Arp, whose observations of apparently connected objects with wildly differing redshifts formed its principal evidence, and with William Tifft, who reported that galaxy redshifts fall into preferred, quantized values. It remains firmly rejected by mainstream astronomy, but is a central topic in the critical-thinkers literature catalogued on this wiki.

The standard interpretation of redshift

In conventional astronomy an object's redshift is understood as the sum of three effects: the cosmological redshift produced by the expansion of space, the Doppler shift due to the object's own motion, and a usually small gravitational redshift. Because the cosmological term dominates at large distances, redshift is used directly as a distance indicator through Hubble's law — the foundation of the extragalactic distance scale. On this view there is no additional, object-specific component, and a high redshift necessarily means a great distance.

Discordant redshift associations

Arp's case against that assumption rested on objects that appear to be physically connected yet have very different redshifts. Working from photographs and spectra taken with the large telescopes at Mount Wilson and Palomar, he compiled numerous such pairings, published in his Catalogue of Discordant Redshift Associations (2003). Two became emblematic:

• NGC 4319 and Markarian 205 — a nearby spiral galaxy and a high-redshift quasar-like object that Arp argued are joined by a luminous bridge of material.
• NGC 7603 and NGC 7603B — a galaxy from Arp's own Atlas of Peculiar Galaxies whose companion has a much higher redshift, apparently connected to it by an anomalous luminous arm.

Arp further argued that high-redshift quasars are found in excess around active, relatively nearby galaxies, and proposed that they are ejected from those galaxies — beginning life with a large intrinsic redshift that decreases as they age and evolve into ordinary companion galaxies. Together with Geoffrey Burbidge, he held that the redshift disparities of quasars reflect this evolutionary process rather than distance.

Redshift quantization

A second and independent line of evidence came from William Tifft, who reported from the 1970s onward that galaxy redshifts are not smoothly distributed but cluster around preferred values — a periodicity he set out in work on "global redshift quantization" (1984). Since a genuine velocity distribution would be expected to be continuous, proponents argue that such periodicity points to a non-velocity, intrinsic component in redshift. See Redshift quantization.

Proposed mechanisms

No single mechanism is agreed upon among proponents, but several have been advanced:

• Variable Mass Hypothesis (VMH) — developed within the Hoyle–Narlikar framework, in which particle masses depend on the age of the matter. Newly created matter has very low mass, and the resulting atomic transitions are shifted toward the red. On this account a quasar's excess redshift arises from the youth and low mass of its matter rather than from any great recession velocity — a natural fit with Arp's ejection picture.
• Tired light — the older proposal that photons lose energy progressively in transit; see Tired Light.
• Wave-propagation and plasma effects — various authors have proposed that redshift can be produced by interaction with intervening plasma or by wave-optical effects, without recession.

Reception

Mainstream astronomy rejects intrinsic redshift. The standard objection to Arp's associations is that they are chance superpositions: in a sky containing enormous numbers of faint background quasars, some will inevitably appear close to, or seem connected with, foreground galaxies. Statistical re-analyses of Arp's samples have disputed their significance, and in several celebrated cases higher-resolution imaging was held to show that the apparent bridges are projection effects or artefacts. Redshift quantization has likewise been attributed to selection effects and small-sample statistics, and later large surveys were argued not to reproduce it.

Proponents reply that the objections are applied selectively, that the number and quality of the associations exceed what chance allows, and that the professional resistance the work encountered was institutional rather than evidential — the argument Arp set out at length in Seeing Red: Redshifts, Cosmology and Academic Science (1998).

Criticisms from researchers on this wiki

The rejection of intrinsic redshift by mainstream astronomy is itself the subject of sustained criticism by researchers catalogued here, who argue that the observational case has never been answered on its merits:

• Halton C Arp — the central figure, whose Catalogue of Discordant Redshift Associations (2003) documents the associations directly, and whose Seeing Red: Redshifts, Cosmology and Academic Science (1998) argues that the evidence was dismissed for institutional rather than scientific reasons.
• William G Tifft — whose reports of quantized redshifts provide an independent line of evidence for a non-velocity component; see Redshift quantization.
• William L Raddatz — examines the mechanism directly in A Brief and Elementary Note on Redshift and A Note of Widening on the Redshift Mechanism.
• Cosmological and Intrinsic Redshifts — addresses the central question of how the two components are to be separated.
• A New Non-Doppler Redshift — proposes a redshift mechanism unrelated to recession.
• The Karlsson Peaks in the Quasar's Redshift Distribution as an Indication for Circling Light in a Non-Expanding Universe — reads the quasar periodicities as evidence against expansion altogether.
• Cosmological Models and Redshift-Distance Relations and Towards an Absolute Cosmic Distance Gauge by using Redshift Spectra from Light Fatigue — reconsider the redshift–distance relation on which the standard interpretation depends.

The shared position is that redshift is a composite quantity, and that treating it as a pure distance indicator builds an unexamined assumption into the foundations of cosmology. Further material is indexed under Category:Cosmology.

See also

• Halton C Arp
• Redshift quantization
• Atlas of Peculiar Galaxies
• Big Bang
• Tired Light
• Category: Cosmology