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=== Tired Light === === Tired Light ===
{{ActiveDiscuss}} {{ActiveDiscuss}}
* Zwicky is associated with ']' theory - as coined so by ] - in ] as an alternative to ]'s and ]'s interpretation of the ]. LeMaître and Hubble believed that the cosmic red shift is caused by the stretching of light waves as they travel through expanding space. Fritz Zwicky believed that the cosmic red shift is caused by ]s gradually losing energy over distance, possibly due to resisting the gravitational fields between the source and the detector. The idea is that the photons transfer energy to massive bodies through the gravitational interaction by Planck's Law. At always constant velocity c a photon must fulfil the formula of ]: <math> \epsilon = h \nu \, </math>, where ''h'' is the ]. While photon's energy is only defined by its frequency <math> \nu \, </math>, a ] can result by a loss of ] of a photon by the second ]. Within any distributed masses, especially (interstellar) gas this theory is well supported by the ], (subsection "gravity"): "Applied to a gravitational field we get that the surface integral is -4πG times the mass inside, regardless of how the mass is distributed, and regardless of any masses outside". The effect was named ], considered as ] (see ]) or a kind of (]), mainly declared as a ] for photons, losing ] ]s centripetally to all passing masses.
Zwicky proposed that the ] apparent in distant galaxies was due to some physical process that caused photons to gradually lose energy as they traveled through space. This is called ]. He considered the most likely candidate process to be a gravitational drag effect; in which photons lose energy in some way to the gravitational fields through which they pass<ref>{{cite journal | last = Zwicky | first = F. | url = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1929PNAS...15..773Z | title = On the Red Shift of Spectral Lines through Interstellar Space | year = 1929 | journal = PNAS | volume = 15 | pages = 773&mdash;779}} </ref>.

The cosmological redshift is now understood to be a consequence of the cosmological expansion of space; a feature of ]. There are a handful of individuals who are still proposing variations of the ] model, but it is no longer something considered seriously within the mainstream of modern astronomy.



* Tired about colleagues not understanding a "light getting tired", Zwicky proposed in August 26, 1929 a modified Integration of the whole ] of the space in p.775; then cited p.777: "In regard to D (] of a ] for an integration by "divergenve theorem" above), it must be remarked that it should be as large as the dimension of the space over which masses are distributed, if those masses are regarded as independent from each other. But the masses are in reality coupled by gravitational forces and the effect of an external perturbation upon them must be computed by considering the system of the far distant masses as a whole.". In detail: While divergence theorem gives a summary of all (a whole shell (]) and the total sum of sources and sinks of its internal volume (]) are equal regardless of extern sources or sinks), Zwicky calculated similarly for single photons. He took the same basis, the local differential ]. He differentiated it by dt. So he got the ] (product of one small mass with its velocity v) instead, with a first result "2πlG2LD" = 4πG*lLD (see there) similar to -4πG*M above. Supposing that gravity waves have the velocity of light c, he used the theory of the ]s. Taking velocity of the light v = c with Planck mass m = h <math> \nu \ </math> /c² he got his approximation for redshifts of photons: “Light travelling a distance L then would lose the momentum... = l.4πfpDL/c²".


=== Morphological Analysis === === Morphological Analysis ===

Revision as of 14:00, 13 July 2007

File:Zwicky1.png
Fritz Zwicky

Fritz Zwicky (February 14 1898 – February 8 1974) was an American-based Swiss astronomer. He was an original thinker, with many important contributions in theoretical and observational astronomy.

Life and work

Fritz Zwicky was born in Varna, Bulgaria, to Swiss parents. His father was the Bulgarian ambassador to Norway. He received an advanced education in mathematics and experimental physics at the Swiss Federal Institute of Technology, located in Zürich, Switzerland and in 1925 emigrated to the United States to work with Robert Millikan at California Institute of Technology (Caltech). Zwicky had a reputation of being simultaneously brilliant and difficult to work with. He was responsible for positing numerous cosmological theories that have a profound impact on understanding of our universe today. He was appointed Professor of Astronomy at Caltech in 1942 and also worked as a research director/consultant for Aerojet Engineering Corporation (1943-1961) and staff member of Mount Wilson Observatory and Palomar Observatory for most of his career.

120 Supernovae discoveries (record until now)

Together with colleague Walter Baade, Zwicky pioneered and promoted the use of the first Schmidt telescopes used in a mountain-top observatory in 1935. In 1934 he and Baade coined the term "supernova" and hypothesized that they were the transition of normal stars into neutron stars, as well as the origin of cosmic rays. It was a prescient insight that had tremendous impact in determining the size and age of the universe in subsequent decades. In support of this hypothesis, Zwicky started hunting for supernovae, and actually found a total of 120 by himself (and one more, SN 1963J, in concert with P. Wild) over a stretch of 52 years (SN 1921B through SN 1973K), a record which still stands as of 2006 (the current runner-up is Jean Mueller, with 98 discoveries and 9 co-discoveries).

Standard candles

In 1938, Zwicky's colleague Walter Baade proposed using supernovae as standard candles to estimate distances in deep space. Because light curves of many type Ia supernovae show a common peak luminosity, they establish a cosmological distance scale by a well known intrinsic brightness. Zwicky had been working closely with Baade in supernova investigations at this same time, but their relationship was strained by Zwicky's irascibility. By the time Baade's paper was written, Zwicky had already been accusing him of taking too much credit for their joint work, and Baade had moved to distance himself a bit from Zwicky, although they did continue to produce some other publications together.

Distant Type IA supernovae show a non linear Hubble relationship and scientists have explained this in terms of an acceleration in the expansion rate for the universe.

Gravitational Lenses

In 1937, Zwicky posited that galaxy clusters could act as gravitational lenses by the previously discovered Einstein effect. It was not until 1979 that this effect was confirmed by observation of the so-called "Twin Quasar" Q0957+561.

Dark matter

While examining the Coma galaxy cluster in 1933, Zwicky was the first to use the virial theorem to infer the existence of unseen matter, what is now called dark matter. He was able to infer the average mass of galaxies within the cluster, and obtained a value about 160 times greater than expected from their luminosity, and proposed that most of the matter was dark. The same calculation today shows a smaller factor, based on greater values for the mass of luminous material; but it is still clear that the great majority of matter is dark.

His suggestion was not taken very seriously at first, until some forty years later when studies of motions of stars within galaxies also implied the presence of a large halo of unseen matter extending beyond the visible stars. Zwicky's dark matter proposal is now confirmed also by studies of gravitational lensing and cosmological expansion rates.

Tired Light

Template:ActiveDiscuss

  • Zwicky is associated with 'tired light' theory - as coined so by Richard Tolman - in 1929 as an alternative to Georges LeMaître's and Edwin Hubble's interpretation of the cosmic red shift. LeMaître and Hubble believed that the cosmic red shift is caused by the stretching of light waves as they travel through expanding space. Fritz Zwicky believed that the cosmic red shift is caused by photons gradually losing energy over distance, possibly due to resisting the gravitational fields between the source and the detector. The idea is that the photons transfer energy to massive bodies through the gravitational interaction by Planck's Law. At always constant velocity c a photon must fulfil the formula of Planck: ϵ = h ν {\displaystyle \epsilon =h\nu \,} , where h is the Planck’s Constant. While photon's energy is only defined by its frequency ν {\displaystyle \nu \,} , a gravitational redshift can result by a loss of potential energy of a photon by the second Einstein effect. Within any distributed masses, especially (interstellar) gas this theory is well supported by the divergence theorem, (subsection "gravity"): "Applied to a gravitational field we get that the surface integral is -4πG times the mass inside, regardless of how the mass is distributed, and regardless of any masses outside". The effect was named Tired light, considered as Photon's friction (see Dynamical friction) or a kind of (Bremsstrahlung), mainly declared as a Compton effect for photons, losing Planck Quantums centripetally to all passing masses.
  • Tired about colleagues not understanding a "light getting tired", Zwicky proposed in August 26, 1929 a modified Integration of the whole Gravitational Potential of the space in - F.Zwicky: On the Red Shift of Spectral Lines through Interstellar Space p.775; then cited p.777: "In regard to D (diametre of a sphere for an integration by "divergenve theorem" above), it must be remarked that it should be as large as the dimension of the space over which masses are distributed, if those masses are regarded as independent from each other. But the masses are in reality coupled by gravitational forces and the effect of an external perturbation upon them must be computed by considering the system of the far distant masses as a whole.". In detail: While divergence theorem gives a summary of all (a whole shell (Surface integral) and the total sum of sources and sinks of its internal volume (Volume integral) are equal regardless of extern sources or sinks), Zwicky calculated similarly for single photons. He took the same basis, the local differential Poisson equation. He differentiated it by dt. So he got the Momentum (product of one small mass with its velocity v) instead, with a first result "2πlG2LD" = 4πG*lLD (see there) similar to -4πG*M above. Supposing that gravity waves have the velocity of light c, he used the theory of the retarded potentials. Taking velocity of the light v = c with Planck mass m = h ν   {\displaystyle \nu \ } /c² he got his approximation for redshifts of photons: “Light travelling a distance L then would lose the momentum... = l.4πfpDL/c²".

Morphological Analysis

Zwicky developed a generalised form of morphological analysis, which is a method for systematically structuring and investigating the total set of relationships contained in multi-dimensional, usually non-quantifiable, problem complexes. He wrote a book on the subject in 1969, and claimed that he made many of his discoveries using this method.

Catalogue of Galaxies and Clusters, Gold Medal

In his later career, he compiled a Catalogue of Galaxies and of Clusters of Galaxies (CGCG) and won the Gold Medal of the Royal Astronomical Society in 1972. The asteroid 1803 Zwicky, the Zwicky lunar crater, and the galaxy I Zwicky 18 were all named in his honour.

Zwicky's publications

A large list of publications related to Zwicky is found in Proceedings of the National Academy of Sciences of the United States of America (PNAS) showing Zwicky's immense scale of knowledge, not only to interstellar problems:

Supernovae

  • Production of Atomic Rays and of Cosmic Rays in Supernovae, PNAS 1939; 25: 338-344,
  • On Super-novae, PNAS 1934; 20: 254-259.
  • Cosmic Rays from Super-novae, PNAS 1934; 20: 259-263.
  • An Expansion-Luminosity Relation for Novae, PNAS 1936; 22: 457-462.
  • Characteristic Temperatures in Super-Novae, PNAS 1936; 22: 557-561.

Interstellar problems

  • On the Formation of Clusters of Nebulae and the Cosmological Time Scale, PNAS 1940; 26: 116-117.
  • The Radial Velocities of Globular Clusters, PNAS 1930; 16: 111-118.
  • On the Physical Characteristics of the Perseus Cluster of Nebulae, PNAS 1942; 28: 355-361.
  • On a New Cluster of Nebulae in Pisces, PNAS 1937; 23: 251-256.
  • Remarks on the Pegasus Cluster of Nebulae, PNAS 1941; 27: 366-369.
  • Extraterrestrial Effects of Cosmic Rays, PNAS 1936; 22: 266-270.
  • Intrinsic Properties of Light and Corpuscles from Distant Sources, PNAS 1937; 23: 106-110.
  • On the Thermodynamic Equilibrium in the Universe, PNAS 1928; 14: 592-597.
  • On a Cluster of Nebulae in Hydra, PNAS 1941; 27: 264-269.
  • On the Physical Characteristics of the Hydra Cluster of Nebulae, PNAS 1942; 28: 150-155.
  • On the Formation of Clusters of Nebulae and the Cosmological Time Scale, PNAS 1939; 25: 604-609.
  • Absorption of Cosmic Rays in the Milky Way, PNAS 1936; 22: 182-186.
  • On the Perseus Cluster of Nebulae, PNAS 1942; 28: 317-320.
  • Further Remarks on the Cosmological Time Scale, PNAS 1940; 26: 332-333.

Physics

  • On the Red Shift of Spectral Lines through Interstellar Space, PNAS 1929; 15: 773-779
  • Remarks on Superconductivity, PNAS 1933; 19: 818-823.
  • On the Imperfections of Crystals, PNAS 1929; 15: 253-259.
  • Transfer of Energy from Electrons to Atoms, PNAS 1926; 12: 466-470.
  • On the Reflection of Electrons from Crystal Lattices, PNAS 1927; 13: 518-525.
  • Why Crystals Exist, PNAS 1931; 17: 524-532.
  • Ionization in Gases by Ions and Atoms, PNAS 1932; 18: 314-318.
  • The Quantum Theory and the Behavior of Slow Electrons in Gases, PNAS 1926; 12: 461-466.
  • On Mosaic Crystals, PNAS 1929; 15: 816-822.
  • Theory of the Specific Heat of Electrolytes, PNAS 1926; 12: 86-92.
  • On the Possible Influence of the Mosaic Structure of Crystals on the Determination of Avogadro's Number", PNAS 1930; 16: 211-215.
  • Superconductivity: August 11, 1933, p.881: Remarks on Superconductivity. On Cooperative Phenomena in Metals, according to Herzfeld: "The so-called Lorentz field causes a self-perpetuating polarization in any substance whose molar refraction satisfies a certain condition.".

Monographs

(This incomplete list was obtained from an Amazon author search, retrieved 2007-07-10.)

Private Life

In April 1932, the Pasadena Star News reported that, "Pasadena Society and science circles were given a big surprise yesterday in the form of little announcement from Mrs. Egbert James Gates, a member of one of Pasadena's first families." The announcement revealed that Fritz Zwicky and Dorothy Vernon Gates were married in Santa Cruz, with family and very close friends attending. Dorothy Vernon Gates was the daughter of State Senator, Egbert Gates, secretary to Colonel Green on Wall Street and a successful businessman and railroad man. She was an alumna of Miss Porter's School for Girls and Stanford. Extremely intelligent, independent, private, rich and beautiful, she dropped out of Pasadena Society after her marriage to Zwicky, never to return. Her money was instrumental in the funding of Palomar in the Depression. Zwicky and Dorothy divorced amicably, and she admired his intellect until her death in 1988. {Mueller Science, Bio of Zwicky also based on personal knowledge of D.V.G.) Zwicky was the brother-in-law of Nicholas Roosevelt, who married Dorothy's sister, Tirzah Gates.

Zwicky was married in Switzerland to Anna Margaritha Zurcher, and had three daughters, Margrit, Franziska, and Barbarina. His grandchildren are Christian Thomas Pfenninger, Ariella Frances Pfenninger, and Christian Alexander Fritz Zwicky. He is interred in Switzerland in his home canton of Glarus. The Zwicky Museum at the Landesbibliothek, Glarus, houses many of his papers and scientific work. The Fritz Zwicky Foundation in Switzerland represents and encompasses the work of this great visionary.

Notes and References

  1. Baade, W.; Zwicky, F. (1934), "On Super-Novae", PNAS, 20: 254–259
  2. List of Supernovae, retrieved 2007-07-10 (provided by )
  3. Baade, W. (1938), "The Absolute Photographic Magnitude of Supernovae", Astrophysical Journal, 88: 285–304
  4. Miller, A.I. (2005), Empire of the Stars: Obsession, Friendship, and Betrayal in the Quest for Black Holes, p. 155, ISBN 061834151X {{citation}}: Unknown parameter |published= ignored (help)
  5. Perlmutter, S. (2003), "Supernovae, Dark Energy, and the Accelerating Universe" (PDF), Physics Today, 56 (4): 53–60 {{citation}}: Unknown parameter |month= ignored (help)
  6. Zwicky, F. (1937), "Nebulae as Gravitational Lenses", Physical Review, 51 (4): 290 {{citation}}: Unknown parameter |month= ignored (help)
  7. Walsh, D.; Carswell, R.F.; Weymann, R.J. (1979), "0957 + 561 A, B - Twin quasistellar objects or gravitational lens", Nature, 279 (5712): 381–384 {{citation}}: Unknown parameter |day= ignored (help); Unknown parameter |month= ignored (help)
  8. Zwicky, F. (1933). "Die Rotverschiebung von extragalaktischen Nebeln". Helvetica Physica Acta. 6: 110–127. See also Zwicky, F. (1937). "On the Masses of Nebulae and of Clusters of Nebulae". Astrophysical Journal. 86: 217.
  9. Some details of Zwicky's calculation and of more modern value are given in Using the virial theorem: the mass of a cluster of galaxies, retrieved 2007-07-10 {{citation}}: |first= missing |last= (help); Unknown parameter |Last= ignored (|last= suggested) (help).
  10. Ritchey, T. (2002), General Morphological Analysis: A General Method for Non-Quantified Modelling (PDF), retrieved 2007-07-10 {{citation}}: Check date values in: |accessdate= (help)
  11. Zwicky, F. (1969), Discovery, Invention, Research Through the Morphological Approach, Toronto: The Macmillian Company
  12. Zwicky's catalog is still maintained and updated today. The latest version is The Updated Zwicky Catalog of Galaxies (UZC), retrieved 2007-07-10 at the Harvard-Smithsonian Center for Astrophysics.

External links

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