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Since 1990 , based on the Type Ia Supernova  observations, it was established that our universe is dominant with some unknown quantities which generally referred to as Dark Matter and Dark Energy . The term dark has been used to represent the form of quantity which does not interact with light or mainly any known particles. Since, the unknown substance is electromagneticaly neutral, hence the unknown sector has been dubbed as a dark sector. The dark matter is referred to as a form of substance which is essential for structure formation and found to be pressureless. This form of matter can be considered as a gravitating system, which behaves as a dust matter. While the form of dark energy can exhibit a repulsive effect (opposite to the gravitational force), that can generate negative pressure, making universe to grow bigger and bigger with an acceleration. It has been found that the major constituents of our universe is dark energy which is 70%, then dark matter 26% and then rest ...

What Is Dark Matter? Roughly 80% of the mass of the universe is made up of material that scientists cannot directly observe. Known as dark matter, this bizarre ingredient does not emit light or energy. So why do scientists think it dominates? Since at least the 1920s, astronomers have hypothesized that the universe contains more matter than seen by the naked eye. Support for dark matter has grown since then, and although no solid direct evidence of dark matter has been detected, there have been strong possibilities in recent years. "Motions of the stars tell you how much matter there is," Pieter van Dokkum, a researcher at Yale University, said in a statement. "They don't care what form the matter is, they just tell you that it's there." Van Dokkum led a team that identified the galaxy Dragonfly 44, which is composed almost entirely of dark matter. The familiar material of the universe, known as baryonic matter, is composed of protons, neutrons and electrons...