The stability of galaxies in an expanding universe obtained by Newtonian dynamics

Abstract

The dynamics of galaxies in an expanding universe is often determined for gravitational and dark matter in an Einstein-de Sitter universe, or alternatively by modifying the gravitational long-range attractions in the Newtonian dynamics (MOND). Here the time evolution of galaxies is determined by simulations of systems with pure gravitational forces by classical Molecular Dynamic simulations. A time reversible algorithm for formation and aging of gravitational systems by self-assembly of baryonic objects, recently derived (Eur. Phys. J. Plus 2022, 137:99), is extended to include the Hubble expansion of the space. The algorithm is stable for billions of time steps without any adjustments. The algorithm is used to simulate simple models of the Milky Way with the Hubble expansion of the universe, and the galaxies are simulated for times which corresponds to more than 25 Gyr. The rotating galaxies lose bound objects from time to time, but they are still stable at the end of the simulations. The simulations indicate that the explanation for the dynamics of galaxies may be that the universe is very young in cosmological times. Although the models of the Milky Way are rather stable at 13-14 Gyr, which corresponds to the cosmological time of the universe, the Hubble expansion will sooner or later release the objects in the galaxies. But the simulations indicate that this will first happen in a far away future.

arXiv comment18 pages, 6 figures

References in corpus (31)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• Clumps and streams in the local dark matter distribution
• The physics driving the cosmic star formation history
• The Horizon-AGN simulation: morphological diversity of galaxies promoted by AGN feedback
• A huge reservoir of ionized gas around the Milky Way: Accounting for the Missing Mass?
• The Milky Way's Stellar Disk
• Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation
• HD 140283: A Star in the Solar Neighborhood that Formed Shortly After the Big Bang
• Black hole evolution: III. Statistical properties of mass growth and spin evolution using large-scale hydrodynamical cosmological simulations
• From galactic bars to the Hubble tension: weighing up the astrophysical evidence for Milgromian gravity
• The Extended Distribution of Baryons Around Galaxies
• The Parallax of Omega Centauri Measured from Gaia EDR3 and a Direct, Geometric Calibration of the Tip of the Red Giant Branch and the Hubble Constant
• Dark matters on the scale of galaxies
• On the Dynamical Stability of the Solar System
• Spurious heating of stellar motions in simulated galactic disks by dark matter halo particles
• Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data
• The Edge of the Galaxy
• Galaxy merging in MOND
• Loss of mass and stability of galaxies in MOND
• Discrete Newtonian Cosmology
• Long-term dynamics of the solar system inner planets
• N-body simulations of the Carina dSph in MOND
• Simulation techniques for modified gravity
• Median Statistics Estimate of the Galactic Rotational Velocity
• Discrete Newtonian Cosmology: Perturbations
• The outermost edges of the Milky Way halo from galaxy kinematics
• The MOND External Field Effect on the Dynamics of the Globular Clusters: General Considerations and Application to NGC 2419
• Discrete dynamics versus analytic dynamics