T.Planets

T.Planets - - 1) Creation of the Universe o Sumerian...

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- 1) Creation of the Universe o Sumerian Mythology: Epic of Gilgamesh = oldest story of man o Archbishop Usher in 17 th century dated earth to 4004 BCE. o Scientific Big Bang theory (George LeMaitre) then Inflationary Big Bang Theory (Alan Guth) and now Concordance Model allowing for fast expansion due to Dark Energy. - 2) A Scientific Narrative o Society often uses Radio-Carbon Dating but this is too short for terrestrial planets. Only goes to post-ice age ~ 5730 years as Carbon half-life. Atoms decay into daughters Ratio of half-lives: 1:1 for first half-life, 1:3 for 2 nd , 1:7 for 3 rd o Other options: 40K decays to 40Ar (10.9%) and 40Ca (89.1%) with half- life of 1.3 Ga. 87RB decays to 87 Sr with a 47 Ga half-life. Really slow! 238U decays to 206Pb with a half-life of 4.47 Ga and 235U decays to 207Pb with a half-life of 704 Ma. Urnaium-lead dating on zircons crystals is the most trusted model. 146Sm decays by rlease of partice to 142 Nd with a half- life of 103 million years. Pretty much no Sm left on earth. o Oldest materials: Oldest mineral: Zicrons in Australia to 4.4x10^9.
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Oldest rocks: Acasta Gneiss 3.96x10^9 and 4.03x10^9 - metamorphic rock. Faux-amphibolites found in Porpoise Cove Quebec dated by 146Sm to 4.28x10^9 years. Oldest meteorite: 4.567 GA found in Tagish Lake Britich Columbia (most primitive material in solar nebula) - 2.2) Nucleosynthesis and the Sun’s Fire o Burbidge, Burbidge, Fowler and Hoyle propose Big Bang theory where all the most basic/rudimentary elements were formed ~ 13.5-13.9x10^9 (actually closer to 13.72) o Big Bang: Incredibly hot 10^27 K, massive explosion and cools (adiabatic expansion). At 1 second leptons and quarks begin to condense (these forms atoms). At 3-4 seconds all baryonic mater of the universe has largely been formed from quarks into protons. Hydrogen is formed. Leptons become electrions. Neutrons begin to attach to protons: H 2 deuterium hydrogen isotope. After 500 seconds: exploding universe is too cool with too low particle density and hydrogen fusion stops. Left with plasma with 95% hydrogen, 5% helium. - 2.2.2) Nucleosynthesis o Gravity compresses material together, enough heat + density leads to protostars. About ~200 million years post Big Bang. o Hydrogen to Helium stage in stars begin. Sun Facts: 1.99x10 30 kg, 92% hydrogen 7% helium by atom cunt, 75-25 by mass. Metals make less than 2%. Power of the Sun: 3.86x10 26
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o Small stars produce and burn up till Li and Be stage. They burn slowest and live longest. Larger stars go Hydrogen to Helium in the CNO process.
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This note was uploaded on 04/28/2011 for the course EPSC 180 taught by Professor Oliviajensen during the Spring '10 term at McGill.

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T.Planets - - 1) Creation of the Universe o Sumerian...

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