Astronomy_ADF

From Big Bang to Galaxies In the beginning the universe was tinier than a spec, but with in a quarter of a mille second, it grew into humongous proportions. Particles are formed, atoms. After 1 second the temperature drops rapidly. A quarter of protons and neutrons have combined to make helium nuclei in 3 minutes. In the next 300 thousand years not much happens, and the temperature continues to drop. Finally when the temperature get s down to 300 degrees kelvin, atoms form without them being tor apart, and radiation can travel long distances around the universe. Formation of Galaxies 2 billion years after the big bang the formation of galaxies start. The galaxies and galaxy clusters are concentrated around shells and strings around huge empty voids. Galaxies are made by gases combining. Galaxies are classed by weather they are elliptical, spiral, and irregular. Collisions and emerges used to be common.

Structure of the Galaxy Where there is slight unevenness in the distribution of matter the action of gravity causes clumps to grow and get denser and the universe takes on a sponge-like structure.

Formation of the Planets Four very large masses form which become the planets we know to day. they grew discs of there own outof which millions condense. With about 10 times the earth's mass the gravitational pull was so strong, it attracted and held onto a thick atmosphere of gas form the surrounding nebula. Fo rmation of Moons, Rings, & Comets Moon was crated by heavy bombardment for the next million years. If icy planetesimal reach the warm facility of the sun they become comets. Rings around the sun are probably the result of broken planetesimal and comets being torn apart by gravity when they get too close.

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