April 2, 2018
velocity, virial theorem, gravity, elliptical galaxies, disc galaxies, kinematics, kinetic energy, poten- tial energy
The virial theorem is a method that is used to evaluate the mass of a dynamic system under certain conditions. It is used in astronomy beyond its scope of validity, as it will be shown here. Moreover, it will be shown that the derivation for the evaluation of the system’s mass is plain wrong as well due to erroneous physical attributions to the mathematical equations, especially in the frame of gravitational systems, including rotating and non-rotating systems. For a studied case of a simple disc galaxy, values of potential energy and mass are found that are up to 4.31 times as large as when estimated by the Virial Theorem. Due to that, “dark matter” has been erroneously postulated for gravitational systems, which indeed include the elliptical- and the disc galaxies.