Scientific works

Recent publications in Astrophysics :

- Gravity and dual gravity: proposals for an inhomogeneous expanding universe, on this site (2020)

- Cosmic expansion acceleration and negative matter, Physics Essays 32, 2 (2019)

- New expansion dynamics applied to the planar structures of satellite galaxies and space structuration,

Journal of Modern Physics, Vol.07 No.16(2016), Article ID:72940

- Expansion as a consequence of a rest-mass erosion theory, Astrophys Space Sci (2015) 357:68, DOI 10.1007/s10509-015-2253-3

- Towards a new generalized space expansion dynamics applied to the rotation of galaxies and Tully Fisher law, Astrophys. Space Sci., 350-2 (2014),769 doi:10.1007/s10509-014-1797-y

According to the classical gravitation laws, the rotation velocity of an object around a center of mass should decrease when the orbit radius increases (it is the case of the planets around the sun). But concerning galaxies, it appears that the rotation velocity of stars remains approximately constant as a function of radius.

Essentially, two explanations have been attempted :

  • the MOND theory postulates that the Newton force should be actually modified for large distances.

  • the  black matter hypothesis assumes that besides visible matter, the galaxy includes a special and unseen black matter , which would   account for those  phenomena. The problem is that much more black matter would be needed, much more than the whole mass of existing ordinary matter. Furthermore, this famous black matter has been searched for decades…

In order to explain the galactic flat rotation curves without resorting  to some  hypothetical black matter, I first proposed to add a new (very weak) force to Newton's force. Then, I showed that this force could also allow us to replace the black energy hypothesis by a mass erosion process. This force has also been applied to the question of Dwarf Satellite Galaxies trajectories. Then I showed that it is equivalent to a negative mass repartition.

Abstracts (in chronological order):

Towards a new generalized expansion dynamics applied to the rotation of galaxies and Tully Fisher law,cs Fleuret

Astrophysics and Space Science

April 2014, Volume 350, Issue 2, pp 769-775

Up to now, the rotational velocities of galaxies are not clearly understood and the experimental Tully Fisher rule, linking the total galactic mass to the fourth power of the velocity, through an acceleration coefficient of about 10−10 m/s2 has not found a deep theoretical explanation. Tentative proposals (MOND theory of a modified Newton’s law and extraneous dark matter) do not bring a definite clarification. We propose here a new approach to this problem, without exotic matter and using the classical Newton force. But we introduce a new additional universal acceleration, which could represent a universal expansion law valid at the scale level of a galaxy. We show that this hypothesis leads to a good description of the observed variations of the galactic transverse velocity. It can be considered as a consequence of the Scale Expansion Cosmos theory (SEC) introduced by J. Masreliez, but we postulate that the space expansion acceleration universally applies at any scale. We obtain a formal derivation of the Tully Fisher law, linking the constant galactic transverse velocity to its total mass, via the universal minimum acceleration. We derive a good estimate of the TF acceleration coefficient and show that expansion should be proportional to the square root of the local volumic mass density. Our conjecture is in fact a new dynamics principle which could be applied to many other physical problems at different scales. Applying it to the range of the solar planet system confirms the well known Kepler laws, at least as a valid approximation for the order of magnitude of the solar system.

Publication available at:



Expansion as a consequence of a rest-mass erosion theory,

Astrophysics and Space Science

18 April 2015, 357:68

I propose a new paradigm to understand expansion. In a non-preserving mass theory, space expansion is driven by a slow continuous mass (or energy) erosion process. I show that this proposal is formally equivalent to an additional cosmic “evolution” force, which was suggested previously to explain the flat rotation curves of spiral galaxies.

The energy equation shows how expansion is related to gravitation and mass erosion.

According to this theory, the fundamental rectilinear movement is exponential in time. More generally, it is also shown how space, time and mass are inter-dependent. A cosmological equation is then obtained, similar to the FRW equation. This proposal confirms Masreliez’s SEC theory and is a candidate to replace dark matter and dark energy hypotheses.



Publication available at:

New expansion dynamics applied to the planar structures of satellite galaxies and space structuration,

Journal of Modern Physics, Vol.07 No.16(2016), Article ID:72940

Recent observations of Dwarf Satellite Galaxies (DSG) show that they have a clear tendency to stay in particular planes. Explanations with standard physics remain controversial.

Recently, I proposed a new explanation of the galactic flat rotation curves, introducing a new cosmic acceleration due to expansion.  In this paper, I apply this new acceleration to the dynamics of DSG’s (without dark matter). I show that this new acceleration implies planar structures for the DSG trajectories. More generally, it is shown that this acceleration produces a space structuration around any massive center. It remains a candidate to explain several cosmic observations without dark matter.


Publication available at:

Cosmic expansion acceleration and negative matter,

Physics Essays 32, 2 (2019)

To explain galactic flat rotation curves, I proposed in a previous paper to introduce a new “cosmic expansion acceleration”, with Newton’s gravity being unchanged. In this paper, this acceleration is applied to 3D radially symmetric systems. It is found that it is equivalent to a precise negative mass repartition, acting as a Newtonian (anti-) gravity. It is shown that the transverse velocity remains constant, due to the transverse part of the acceleration.

The model can be applied to (expanding or imploding) radial systems made of gas, dust, stars or galaxies.

Concerning the universe, it is applied in the two cases of exponential expansion and accelerated expansion. It is shown that the model is in conformity with the present observed data, and the needed mass densities are computed.

The energy balance is also examined (showing that the expansion acceleration work and mass erosion combine to contribute to the increase of the total mass), together with the proportion of radial/lateral force works.

The model predicts an equal amount of positive and negative masses in the “inner” regions of the universe, but an excess of negative masses in the outskirts, which could explain the observed bubbles with “empty” spaces in the large scale regions.

It opens the way to easiest simulation of the expansion acceleration influence.

More generally, this proposal appears to be an alternative to the other models used to describe the same phenomena, such as: dark matter and energy, MOND, etc.

Publication available at:

Gravity and dual gravity: proposals for an inhomogeneous expanding universe,

J. Fleuret website, dec.2020

I proposed a new expansion force to explain the flat rotation curves of plane galaxies, in a Newtonian approach in 2016. This force is validated here in General Relativity for an inhomogeneous radially symmetrical universe. It can be deduced from the solution of Einstein’s equation with a cosmological constant. A pseudo-Schwarzschild “twin-potential” metric is considered, with two different potentials for the space and time dimensions. The expansion force results as a repulsive dual gravity. Negative masses are needed. The necessary mass repartitions are computed, in connection with the radial dynamics and the expansion rate’s evolution. A linear model and a quadratic model are studied, connected with the observation representations of a universe in accelerated expansion. It is a first step towards a better representation of an inhomogeneous universe. The framework can be applied to deduce the universe mass repartition form the measured values of the expansion rate variation.

Publication available at:  

Other publications 


Du malaise à l'espoir, J. Fleuret, Amazon ed., 2016 :

Bouddhisme et Psychologie de la Motivation, l'Harmattan, 2013 :

Optique et télécommunications, A. Cozannet, J. Fleuret, H. Maitre, M. Rousseau, Eyrolles, Collection CNET, 1981

Scientific publications & communications:

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