Informative Speech: the Sun, Is an Ordinary Star, Following Stellar Evolution

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Informative Speech Attention: Everything you have ever known, done, or accomplished; every single triumph or defeat of humanity (past, present, and future) is lost forever…it will be as if we never existed at all. Thesis: Our star, the Sun, is an ordinary star that will follow a predictable life-cycle known as stellar evolution. Credibility: I spent two years studying Astronomy at the University of Toledo from 2004-2006 Charles Liu, degrees from Harvard University and completed postdoctoral work at Kitt Peak National Observatory and Columbia University Alex Filippenko, Ph.D., Astrophysics, California Institute of Technology Sky and Telescope Magazine NASA Relevance: Survival of the human race Preview: Today I am going to take all of you on a journey through space and time to learn about the life-cycle of our star, the Sun. We will examine all the life stages of our Sun: from its beginning as a cloud of dust and gas, to its earliest form as a protostar, to its current stage in its main sequence, onward to its phase as a red giant, until its inevitable death as a white dwarf, finally ending as a black dwarf. I. Gas Cloud A. Our sun, like all other stars in the universe, began its life as a cloud of dust and gas B. Immense clouds, spanning light-years, but very sparse (several hundred atoms per cubic cm) 1) Earth’s surface = 1.0x1017 or 100 quadrillion atoms per cubic cm—NASA C. The cloud begins to swirl and coalesce inwardly under the relentless force of gravity D. With collapse now under gravity’s pull, the dust and gas particles begin to generate frictional heat II. Protostar (100,000-50million years)—NASA A. The kinetic energy generated by these particles rubbing together (friction) releases infrared energy B. Heat is approx. several hundred Kelvins (still cold) 1) 1 K=-457 F C. Dust and gas continue to collapse

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