eng Science and Education Publishing International Journal of Physics 2333-4576 2020-12-21 9 1 36 41 10.12691/ijp-9-1-4 IJP2021914 article Jos¨¦ Lu¨ªs Pereira Rebelo Fernandes rebelofernandes@sapo.pt 1 Independent Researcher since 2005, Engineer, graduated from the University of Porto To understand the rotation of galaxies, the idea of the existence of dark matter was created. Through a better observation of reality, analyzing the distribution of matter, we conclude that this distribution is very close to that proportional to the radius cube, thus remembering the spherical distribution. With the appearance of the accretion disk, it retained a large part of the matter that gravitated the gravitational sphere of the galaxy, maintaining its distribution proportional to the cube of the radius, part of the total matter will be contained in the Accretion Disc and the rest will continue to gravitate to the galaxy. Given the large size of the galaxy, the latter may be practically printable given its dispersion in the total volume of the galaxy. We conclude that the idea of the existence of dark matter is not necessary to justify the rotation of the galaxy. http://pubs.sciepub.com/ijp/9/1/4/ijp-9-1-4.pdf universe gravitation potential gravity velocity mass physics variable