Black Hole

Black Hole

History of the black hole The concept of a body so massive that even light could not escape was put forward by the geologist John Michell in a letter written to Henry Cavendish in 1783….

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Random walk of Photon

Random walk

Consider a starting position at some zero point. We toss a coin that tells a man to move forward or backward. He ends up at either the +1 or the -1 position, the next toss…

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Dark Matter

Dark matter

Dark matter is material that gravitates but does not emit very much light. It is undetectable by its emitted radiation but whose presence can be inferred from gravitational effects on visible matter. Dark matter is…

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Hubble law and age of the Universe

E. Hubble determined that there is a relation between the distance of various galaxies and their radial velocity. The radial velocity was derived from the Doppler shift of absorption lines in the spectrum of the…

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Galaxy Merger

The galaxy mergers can occur when two or more galaxies collide. They are the most violent type of galaxy interaction. Although galaxy merger doesn’t involve stars or system of stars in actual collision due to…

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