Cosmology Of The Universe"The most beautiful thing we can experience is the mysterious. It's the source of all true art and science. He to whom this emotion is a stranger, who can no longer wonder and stand rapt in awe, is as good as dead." ~ Albert Einstein (1930)Overview Of Cosmology The cosmology of the universe is based upon the discovery that the universe is expanding. This discovery was made by two astronomers Hubble and Huminson in the 1930's. Their evidence was based on the doppler effect on light from stars. Light travels in waves in space about 186,000 miles. If light is traveling towards you it appears blue, but if it's traveling away from you it appears red. Hubble and Huminson discovered that no matter where you looked in the universe all galaxies appeared to be red shifted. Thus they concluded the universe is expanding. 20th century cosmology of the universe is based on this finding. There are three theories of the cosmology of the universe: steady state, big bang, and oscillating universes. The Big Bang Theory In this theory of cosmology the universe began as an explosion. All matter in the universe was compressed down to the size of a large star which violently exploded sending dust and gas outwards in all directions. Eventually the dust and gasses formed all of the stars and all of the galaxies. These galaxies are still expanding and may do so forever. The Oscillating Universe An oscillating universe starts out the same way as a big bang universe except that it does not expand forever. It slows down and eventually begins to collapse back to its origional large star form. Eventually the whole process is repeated again. This type of universe goes through an endless amount of life death cycles. This type of universe is an Einsteinian concept of cosmology in that space in this type of universe has a positive curvature which makes it a closed universe. You may also safely assume that if the universe is closed than it is just one of the many universes that make up an even larger universes, perhaps from the infinetly smallest to the infinetly largest. The Cosmology Of Stars "All the elements (atoms, molecules) that make up our bodies and the Earth itself come from the inside of stars. "We are made of starstuff" ~ Carl Sagan (Cosmos - 1980) Birth Death Cycle Of Stars Stars go through a kind of stellar reincarnation. They go through an endless amount of life death cycles. After about 10 billion years a star will use up all its nuclear fuel. When this happens it will begin to collapse due to chain-reactions in its core. Finally it will blow apart. The mass of the star will determine how bad the explosion will be. If a star is small it will turn into a white dwarf, that is the core will still remain, in a cooled down state, surrounded by a cloud of dust and gas. If a star is large it will be completely destroyed, and all that will be left is a large cloud of dust and gasses. New stars are born out of the dust and gasses of stars that have died. This happens over a period of billions of years after the dust and gasses are condensed together. The Atomic Universe Everything in the universe is composed of atoms (energy). An atom consists of a nucleus (the center), protons (postive charges inside the nucleus), neutrons (neutral charges in the nucleus), and electrons (negative charges) which orbit outside around the nucleus. Atoms are chiefly composed of nothing (empty space), but as the electrons revolve around the nucleus it forms a shell around it. In this same sense all matter in the universe is chiefly composed of nothing. According to the first law of physics atoms (energy) can neither be created nor destroyed. All matter is made up of atoms. The Shape Of Space And Time Not until Einstein did anyone think of space as a substance having a shape of its own. Before Einstein sciencetists always thought of space as nothing or the absence of matter. According to Einstein's theory of relativety he states that space is a real entity that has a definite shape. He believed that time warped the fabric of space and caused it to be 4th dimensional (height, width, depth are the first 3 dimensions). He also felt that matter or the lack of matter could warp the physical universe. If there wasn't very much matter in the universe, it would be an open (negatively curved) universe. If there was enough matter in the universe it would be a closed (positively curved). So on one hand you have an open infinite universe that will go on expanding forever, and on the other hand you will have a closed or finite universe, that will eventually collapse. My own personal theory for the cosmology of the universe is that the universe is infinite, no begining and no end, it always existed and always will although its form may change. |
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