12/31/2023 0 Comments Dark matter outer space phenomenaVera Rubin and Kent Ford published their first rotational curve in paper. Past a certain distance though (when increasing a distance from the massive center of galaxy does not enclose adequately bigger amounts of mass), the effective force of gravity should decline (as R 2 will increase faster than the mass enclosed in a sphere of a radius being that distance from the center so the force of gravity will decline) which should result in lower orbital velocities. When being close to the center of the galaxy, the plot agrees with what one would expect: the rotational curve increases rapidly that reflects an obvious fact that the velocity of a test object (a “star”) increases as the effective gravitational force is growing (at a given radius, only the mass enclosed within a sphere of that radius is relevant in terms of excreting gravitational force-Newton’s Shell Theorem). Credit: PhilHibbs, Wikipedia,, Creative Commons Attribution-Share Alike 3.0 Unported license.įigure 1 illustrates this discrepancy. It turned out that the shapes of the curves did not comply with the theoretical predictions based on the mount of matter estimated due to the emitted light.įigure schematically representing discrepancy between observed (B) and predicted (A) rotational curves of galaxies that indicates presence of dark matter in halos of such galaxies. Rotational curve of a galaxy is a plot presenting how the orbital velocity of objects in this galaxy changes with increasing distance from the galaxy’s center (see Figure 1). Rubin studied rotational curves of galaxies. And only findings of Vera Rubin, some 40 years later, led to the formulation of the fundamental and still unresolved problem. These findings seemingly intriguing by themselves had not been taken seriously by scientific community. Zwicky claimed then that the gravitational attraction exerted by the luminous matter was not enough to hold the cluster together and if there wasn’t some kind of additional, nonluminous matter that provide extra gravity force, the galaxies would fly apart. It turned out that such an amount of ( luminous) matter wasn’t large enough to explain the trajectories and velocities of those galaxies. Studying the Coma cluster (of galaxies) located 320 million light-years away, Zwicky estimated masses of the galaxies that make up this cluster based on the amount of light they emit. The term “dark matter” (DM) was introduced due to the contribution by Fritz Zwicky as early as in 1930s of the twentieth century. Obtained rotational curve is flat which indicates the presence of dark matter in the halo of our galaxy. There appear to exist galaxies devoided of dark matter-then what about MOND predictions? This contribution is completed with the rotational curve of the Milky Way determined with 3 m in diameter radio telescope in the Astronomical Observatory of the Jagiellonian University. Yet such an approach seems to be in tension with recent findings of van Dokkum et al. Milgrom in 1983 is a phenomenological approach attempting to provide explanation of rotation of galaxies without invoking hidden matter at all. Modified Newtonian dynamics (MOND) proposed by M. On different grounds stands the idea of modifying gravity in low acceleration regime. This idea has rather been discredited as the abundance and masses of such objects are too small comparing to the amount of the matter that is missing. Another attempt of explaining the problem of missing matter was based on the assumption of existence of astrophysical objects such as black hole or dim brown dwarfs. In order to detect such particle, sensitive detectors are built, but still final conclusion has not been made. The most important property of such particle would be that it is not a subject to electromagnetic force hence the dark matter is invisible in all electromagnetic wavelengths. One such idea is to find a particle to possibly complete the standard model. Various attempts to resolve the problem of the existence of a mysterious form of matter, dark matter, have been taken ever since. Today we know that most of the matter in the Universe is dark. Research of Vera Rubin discovered that the galaxies rotate in a way that cannot be explained by taking into account visible, luminous matter. Only 40 years later in 1970s the problem was rediscovered and concerned almost all of the galaxies. However, there was no response for that finding. The content of the luminous matter was estimated form the amount of light emitted by the cluster. Galaxy cluster studied by Zwicky appeared to contain some 400 times more matter than an ordinary, visible, i.e., luminous matter. In 1933 Fritz Zwicky indicated a problem related to the galaxy cluster Coma.
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