Natural astrophysical extensions of gravity.

by Prof. Sergio Mendoza (UNAM - Ciudad de Mexico - Mexico)

Tuesday 26 Jun 2018, 15:00 → 16:00 Europe/Rome

2N22 (Dipartimento di Fisica)

Abstract:
Newtonian gravity and its relativistic extension, the general theory of
relativity, are extremely well tested in our solar system.  Both proposals
were built with solar system dynamics provided in Kepler's laws for the
motion of planets.  When the scales of mass and length associated to a
particular astrophysical system greatly exceed the solar system values in such a way that the gravitational acceleration on a given test particle is less or about 10^{-10} m /s^2, either non-baryonic dark matter is required or Kepler's third law of motion requires a modification (the Tully-Fisher law).  In this talk I will discuss non-relativistic and relativistic developments for extending gravity based on the Tully-Fisher law, which in its simplest form yields the basic MOdified Newtonian Dynamics (MOND) formula.  I will also show that this prescription has so far been adequate to explain dynamics of systems from scales to solar system up to galaxy clusters and the accelerated expansion of the universe. Also, I will explain how these ideas are in very good agreement with the deflection of light and gravitational lensing in individual, groups and clusters of galaxies.