The purpose of the present paper is to assume that the expanding spacetime of our cosmos was created by the big bang. It then follows that there exists a finite instantaneous radial extent dRU to spacetime as observed from anywhere in spacetime by comoving observers. The consequences for gravity are explored by first considering the scalar field of a central mass that defines the dynamic properties of a circular orbit for each radius R ≤ dRU under the postulate of weak equivalence. These properties include an orbital velocity and an escape velocity. For a central mass of galactic proportion, the escape velocity becomes large even at cosmological distances. By considering the dynamics of a smaller mass occupying the last orbit, we find that the established laws of physics lead to different rotation curves than they do when applied to the solar system. Since galactic rotation curves reveal the existence of dark matter, this is anticipated to have some consequences for our understanding of dark matter.
A. Allen, "Finite Gravity: From the Big Bang to Dark Matter," International Journal of Astronomy and Astrophysics, Vol. 3 No. 2, 2013, pp. 180-182. doi: 10.4236/ijaa.2013.32020.
[1] K. G. Begeman, “HI Rotation Curves of Spiral Galaxies,” Astronomy and Astrophysics, Vol. 223, No. 1-2, 1989, pp. 47-60. [2] S. M. Kent, “Dark Matter in Spiral Galaxies. I. Galaxies with Optical Rotation Curves,” Astrophysical Journal, Vol. 91, No. 6, 1986, pp. 1301-1327. [3] T. S. van Albada, J. N. Bahcall, K. Begeman, and R. Sanscisi, “Distribution of Dark Matter in The Spiral Galaxy NGC 3198,” Astrophysical Journal, Vol. 295, 1985, pp. 305-313. [4] J. Kormendy and D. Richstone, “Inward Bound―The Search for Supermassive Black Holes in Galactic Nuclei,” Annual Review of Astronomy and Astrophysics, Vol. 33, 1995, pp. 581-624. [5] J. Kormendy, “Evidence for a Supermassive Black Hole in the Nucleus of M31,” Astrophysical Journal, Vol. 325, 1988, pp. 128-141. [6] B. M. S. Giambastiani, “Evoluzione Idrologica ed Idrogeologica Della Pineta di San Vitale (Ravenna),” Ph.D. Thesis, Bologna University, Bologna, 2007.