Geo 101 1st Edition Lecture 2Outline of Last Lecture I. Why Earth is specialII.Modern UniverseIII. Wavelengths of lightIV. Edwin Hubble/Universe expansionV. When was the universe born?VI. Big BangVII. Stars and GalaxiesOutline of Current Lecture VIII. Earth in Contexta. ElementsIX. Solar System X. Planets/Planet formationCurrent LectureII. Elements & Atoms: Building blocksa. atom: smallest particle that retains the characteristic id an elementb. prontons(+ charge; found in nucleus), neutrons (neutral; found in nucleus) and electrons (- charge; charged cloud around the nucleus) c. atomic number: the # of protons in the nucleus. The atomic number is the definition of the atom, anything with 6 protons is Carbon etc.III.Element Formationa.At the moment of the big bang there was no matter, the first instant after matterwas formed; protons, neutrons and electrons formed (w/in 3 minute Hydrogen and Helium formed)b.Started a rapid cascade of event; the new born universe expanded, cooled and became less denseIV. After the Big Banga. The expansion & cooling of the universe allowed atoms to begin bondingi. H forms and begins fueling starsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Atoms & molecules group together in nebulae due to gravityb. Gravity caused nebulae to collapse, increase in temperatures, density and rate of rotationc. Condensed nebulae formed flattened accretion discsd. Heat and mass from collapse “ignites” nuclear fusion (combination of 2+ atoms to form heavier atoms)V. Elements form in starsa. Mass of a star dictates the elements produced (ie, smaller mass stars such as our sun “burn” slowly, live longer and create lighter elements ie carbon)b. Stellar nucleosynthesis:i. When a star runs out of fuel they heat due to an inward collaps/implosionii. Becomes a cataclysmic explosion (supernova: this is when/how heavier elements are formed)c. Big bang nucleosynthesis formed lighter elements (H, He, Li, Be and B)d. Heavier elements born of stars (atomic #’s 6-26)e. Supernova create elements heavier than 26, that is, with atomic numbers higher than 26VI. Our modern solar systemVII. Where are wea. Earth is 1 of 8 planets orbiting our sun, 3rd in line from the sunb. Our solar system is located on an arm of the galaxy called the Milky WayVIII.How did the solar system form?a. Nebular Theory: nebulae formed ~4.56 Gai. Nebula: a cloud of gas containing H & Heii. Heavier elements produced from stellar nucleosynthesis presentb. These materials collect into a disc shape with a ball formed at the center (called aprotoplanetary disc)i. The ball at the center grows hot & denseii. A fusion reaction begins giving birth to a suniii. Dust rings condense into particles; particles form planetesimals(beginning of a planet)iv. Planetesimals start colliding (evidence can be seen on Mercury and the Moon in the form of craters), this is planetary accretionIX. Accretion of Eartha. Not entirely ceased yet today but it is much slowedb. The meteor that is thought to have caused the end of the dinosaurs was accretionc. Small meteors and dust particles continue to add ~100,000 kg to earth each day (relatively a negligible amount) X. Nature of Our Solar Systema. Our sun = medium sized star orbited by 8 planets; diameter is 109 times larger than the diameter of Earth)i. 99.85% of the mass of our solar system is in the sunb. Planet: set of criteria established by the IAU (International Astronomical Union)i. Is a large solid body orbiting a star ii. Has nearly spherical shapeiii. Has cleared it’s neighborhood of other objects iv. Pluto cannot meet the 3rd criteria and so became the founding member ofthe order of dwarf planets XI. Planetsa. Terrestrial: Mercury, Mars, Earth and Venusi. Small, dense, composed of rockii. Have compositional layers (crust, mantle, core)iii. Relatively think atmosphereb. Jovian (Jupiter-like/Giant): Jupiter, Saturn, Uranus and Neptunei. Large, gas giantsii. Much of the volume is a thick atmosphere overlaying oceans of liquid gasesiii. Characterized by many moons or ring systemsc. Variation in composition:i. Proximity to the forming sun was a key factor in what formed where in the early solar systemii. Denser matter (metals, minerals) condensed close in while carbonaceous matter and various ices condensed farther outXII. Asteroids and cometsa. Asteroids: rocky planetessimals that form an orbiting belt between Mars and Jupiteri. some asteroids get knocked off course by Jupiter and assume new orbits. They become meteors as they streak through the atmosphere and meteorites when they land of a planet’s surfaceb. Comets: mixtures of ice and rock that originates beyond the Kuiper belt, some cross into the inner solar system where they occasionally collide with