Geo 101N 1st Edition Lecture 1Outline of Last Lecture I. Syllabus reviewOutline of Current Lecture II. Why Earth is SpecialIII.Modern UniverseIV. Wavelengths of lightV. Edwin Hubble/Universe expansionVI. When was the universe born?VII. Big BangVIII.Stars and GalaxiesCurrent LectureII. Why Earth is Speciala. Earth has a quartz rich crustb. Hot interior; evidence-active tectonics-evolving landscapes-volcanic activity/creation of new land massc. Earth orbits in the “just right” zone in the solar system -enough radiation from the sun; not too muchIII.Modern Universea.Consists of 300 billion sunsIV. Wavelengths of lighta. The color of light fromstars is stretched (shifted)toward wavelengths @ thered end of the spectrum(red = longer wavelengths)b. Color from a moving objectwill appear to be a differentcolor c. An object moving away will have longer wavelengths (red); coming towards = These 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.shorter wavelengths (blue/purple)V. Edwin Hubble/Universe expansiona. Created the classification for galaxies still used today; Hubble Sequenceb. discovered a constant relationship between a galaxies' “redshift” and distance, which helped to eventually prove that the universe is expandingc. proved that other galaxies exist outside of our own (Milky Way)VI. When was the universe born?a. Approx. 13.8 Ga (billions of years ago)VII. Big Banga. Theory according to Western cosmology; states that all matter in the universe originated @ a single point @ the instant of formationVIII.Stars and Galaxiesa. Stars are balls of super-heated gasb. Gravity binds stars together to form galaxiesc. More than 100 billion galaxies exist in the visible
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