Fritz Zwicky
Fritz Zwicky | |
|---|---|
| Born | February 14, 1898 Varna, Bulgaria |
| Died | February 8, 1974 (aged 75) Pasadena, California, United States |
| Nationality | Swiss |
| Known for | Missing mass in the Coma cluster, supernovae and neutron stars, galaxies as gravitational lenses, the Catalogue of Galaxies and of Clusters of Galaxies, an early redshift mechanism without expansion |
| Scientific career | |
| Fields | Astrophysics, astronomy, jet propulsion |
| Institutions | California Institute of Technology, Mount Wilson and Palomar Observatories, Aerojet Engineering |
Fritz Zwicky (14 February 1898 – 8 February 1974) was a Swiss astrophysicist who spent his career at Caltech and the Mount Wilson and Palomar observatories. He is unusual among twentieth-century astronomers in being cited approvingly by both sides of the cosmological argument documented on this wiki: he originated the observation that became the case for dark matter, and he also published the first serious proposal that cosmological redshift might arise from something other than recession.
His observational record is formidable. With Walter Baade he introduced the term supernova in 1934 and proposed that such events mark the transition of an ordinary star into a neutron star, a suggestion made only two years after the neutron was identified and confirmed only with the discovery of pulsars in 1967; the same paper proposed supernovae as the source of cosmic rays. In 1937 he argued that clusters of galaxies should act as gravitational lenses, which was not observed until 1979. He personally discovered a large number of supernovae, compiled the six-volume Catalogue of Galaxies and of Clusters of Galaxies (1961–1968), catalogued compact galaxies, and during the Second World War worked on jet propulsion at Aerojet. He also promoted a general problem-solving method he called morphological analysis.
Two of his proposals matter directly to the material collected here.
The Coma cluster and dunkle Materie. In 1933 Zwicky applied the virial theorem to the velocity dispersion of galaxies in the Coma cluster and found the members moving far too fast to remain gravitationally bound by the mass visible in them. The shortfall he calculated was of order a hundredfold. He inferred a large quantity of unseen matter, which he called dunkle Materie — dark matter. This is the founding observation of the whole missing-mass literature.
An alternative to the expanding universe. In 1929, the same year Hubble published the redshift–distance relation, Zwicky proposed in the Proceedings of the National Academy of Sciences that photons might lose energy gradually in transit through a gravitational interaction with intervening matter — a kind of gravitational drag analogous to the Compton effect. Richard Tolman named the class of such proposals tired light in the early 1930s. Zwicky's own mechanism was shown to have difficulties, most seriously that a scattering interaction of that kind should blur distant images, and he did not press it in later years.
On this wiki
Zwicky appears here in two roles that pull in opposite directions, and the literature is careful to keep them apart.
He is the source of the dark matter problem but not of the dark matter solution. The Dark Matter article on this wiki sets out his Coma result accurately as the first line of evidence, and then records that almost none of the researchers catalogued here accept dark matter as a substance. The objections come from several directions: Cameron Rebigsol argues that the Newtonian calculation is misapplied to an extended rotating disc; William C Mitchell and Paul E Rowe argue that the missing mass is ordinary but unseen; Thierry De Mees argues in Deduction of Orbital Velocities in Disk Galaxies. "Dark Matter": a myth? that gravitomagnetic terms account for the discrepancy without new matter; and Stewart Ian Wells makes the continued laboratory non-detection of any dark matter particle the starting point of his critique. Tom Van Flandern classed dark matter among the standard model's ad hoc helper hypotheses.
He is also the originator of the tired-light programme, which is very much alive here. The Tired Light article traces the idea from Zwicky's 1929 paper through later variants, including Jean-Claude Pecker's A Possible Tired-Light Mechanism (1988), Lyndon E Ashmore's "New Tired Light" (see New Tired Light Correctly Predicts the Redshift of the CorBor Galaxy Cluster and Supernovae Ia Light Curves Show a Static Universe), John W Kierein's Compton-effect account, and Grote Reber's and Paul A LaViolette's work. Halton C Arp's discordant-redshift observations and the Intrinsic redshift hypothesis are a separate line of attack on the same assumption.
The honest summary is that Zwicky was right about a great deal — neutron stars, supernovae, lensing, the Coma discrepancy — and that the discrepancy he found remains real and unexplained on any account. What is disputed here is not his measurement but the inference from it, and mainstream physics itself concedes the central embarrassment: after decades of increasingly sensitive searches, no dark matter particle has been detected.