Dark_ME - Defnition oF Dark Matter Matter whose presence...

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Unformatted text preview: Defnition oF Dark Matter Matter whose presence cannot be detected by either emission or absorption oF electromagnetic radiation at any accessible wave- Length (I.e. cant be seen), but whose presence can defnitely be traced by the gravitational attraction exerted by it on other observable masses. Dark matter could be ordinary matter in highly compact, low- luminosity Form: e.g. black holes, neutron stars, white dwarFs, brown dwarFs, dark planet-sized objects, very hot gas,. We call this: BARYONIC DARK MATTER Dark matter can also be in the Form oF weakly interacting, massive particles (WIMPs) leFt over From the Big Bang. We call this: NON-BARYONIC DARK MATTER What is the evidence for Dark Matter? First detection of Dark Matter was reported by Fritz Zwicky in the 1930s. He supported his claim by observations of the orbital velocities of galaxies in giant clusters of galaxies. Zwicky found that galaxies in clusters move much faster than expected, if the mass of the clusters was made up solely by the observable mass of the stars in the galaxies themselves. The true mass appeared to be about 50 times larger, a huge difference. No one believed Zwicky. Nevertheless, he turned out to be correct in the end. So how does this work? Zwicky applied something called the Virial Theorem to deduce that there must be dark matter in galaxy clusters. In this case, the Virial theorem relates the average kinetic energy and the graviational potential energy of a stable system. A key fact that allows this to work is that the galaxies in a cluster are gravitationally...
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Dark_ME - Defnition oF Dark Matter Matter whose presence...

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