الصف :الثاني عشر - العام الدراسي :2015/2016
Astrophysicists now know that 80% of the matter in the universe is `Dark Matter' which is the most vexing mystery OF ALL THE MANY MYSTERIES of modern astronomy. Most astronomers believe in the existence of the Dark Matter and some are not The Dark Matter problem arose because of a mismatch in the masses of galaxies and larger cosmic structures. The constituents of these systems—stars and gas in the case of galaxies, gas and galaxies in the case of galaxy clusters—move about but do not escape, because they are checked by the gravitational pull from the rest of the system. The laws of physics tell us how much mass has to be present to counterbalance the motions and thereby prevent the dispersal of the system. Disconcertingly, the tally of mass that astronomers actually observe falls far short of that. I will summarize how the astronomers calculate its mass and explain why some of them disbelieve in the existence of Dark Matter by searching for mistakes in the calculation method of dark matter.
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حلقة بحث95Does the Dark Matter really exist-
