Jean-Pierre Petit

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Jean-Pierre Petit 2004

Jean-Pierre Petit (born April 5, 1937 in Choisy-le-Roi ) is a French astrophysicist and popular science author.

Petit graduated from the École nationale supérieure de l'aéronautique et de l'espace (ENSAE, Supaero) in 1961. He then worked on French ICBMs that were supposed to be shot down by submarines. From 1965 he was at the Institute for Fluid Mechanics (IMFM) of the CNRS in Marseille and dealt with experimental magnetohydrodynamics (MHD), among other things for the acceleration and control of aerodynamic flow (avoidance of shock waves) for aircraft and power generation (MHD generators). In 1972 he received his doctorate under Evry Schatzman . In 1974 he turned to astrophysics at the Observatoire de Marseille , but continued engineering research on MHD until the 1980s. 1977-1983 he was co-director of the Computing Center of the University of Provence . In 2003 he retired from CNRS.

He is known for popular science comic books, which he has published since 1979, a total of 18 titles in French, namely the series " Die Abenteuer des Anselm Wüßtegern " (French: "Les aventures d'Anselme Lanturlu").

Petit was also criticized for various unconventional views. He considers the visit of aliens for some UFO phenomena possible (he founded the organization UFO Science ), and speculated about secret projects of the US armed forces with MHD propulsion systems for aircraft and weapons with antimatter.

Petit developed a bimetric theory of gravitation in cosmology (called Janus model), in which field equations for positive and negative masses are coupled (for positive masses they are reduced to the field equations of general relativity). The model behind his equations are two twin universes with opposite time arrows and origin in a common singularity, which interact gravitationally and are connected via CPT symmetry. Andrei Sakharov investigated a similar model (and bimetric models were examined by Nathan Rosen in the 1940s) and Petit has been working on it since 1977. According to Petit, particles with masses of opposite signs repel and attract each other with the same sign, which according to him is the runaway problem which is usually cited as a main argument against negative masses ( Hermann Bondi 1957). His theories also predict a variation in fundamental natural constants. He sees this as an explanation for the accelerated expansion of the universe. His Janus model, however, met with little response and was heavily criticized by the well-known French astrophysicist Thibault Damour (physically and mathematically incoherent or contradictory). According to Damour, the ultimate cause is that Petit's field equations (for matter with positive and negative mass) follow two Bianchi identities with associated conservation laws.

Web links

Individual evidence

  1. ↑ In German, for example, Die Abenteuer des Anselm Wüßtegern : Das Schwarze Loch , Vieweg-Teubner 1995, Die Abenteuer des Anselm Wüßtegern , Das Geometrikon , Vieweg 1995. In the French original, his protagonist is Anselme Lanturlu, in English Archibald Higgins.
  2. ^ Petit, The missing mass problem, Il Nuovo Cimento B, Volume 109, 1994, pp. 697-709.
  3. ↑ Petit, Twin universes cosmology, Astrophysics and Space Science, Volume 227, 1995, pp. 273-307
  4. ↑ Petit, Gilles d'Agostini: Negative mass hypothesis in cosmology and the nature of dark energy, Astrophysics and Space Science, Volume 354, 2014, p. 611
  5. ↑ Petit, G. d'Agostini: Cosmological bimetric model with interacting positive and negative masses and two different speeds of light, in agreement with the observed acceleration of the Universe, Modern Physics Letters A, Volume 29, 2014, p. 1450182
  6. ↑ Petit, d'Agostini: Lagrangian derivation of the two coupled field equations in the Janus cosmological model, Astrophysics and Space Science, Volume 357, 2015, p. 67
  7. ↑ Articles in the Arxiv preprint server can be accessed online, e. B .: Bigravity as to interpretation of the cosmic acceleration (2007), Bigravity: a bimetric model of the Universe with variable constants, Including VSL (variable speed of light) (2008), Bigravity: A bimetric model of the Universe. Positive and negative gravitational lensings (2008), Can negative mass be considered in General Relativity? (2014)
  8. ↑ Bondi, Negative Mass in General Relativity, Rev. Mod. Phys., Volume 29, 1957, pp. 423-428. The paradoxical runaway solutions correspond to acceleration "out of nowhere". With Bondi, however, negative masses repel each other.
  9. ↑ Damour, Sur le "modèle Janus" de JPPetit , IHES, January 2, 2019 (pdf)
personal data
SURNAME Petit, Jean-Pierre
BRIEF DESCRIPTION French astrophysicist
DATE OF BIRTH April 5, 1937
PLACE OF BIRTH Choisy-le-Roi