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Planet Earth

Planet Earth. Jim Wright 732-445-3445 jdwright@rci.rutgers.edu 3 exams 90 points Pop quizzes make up remaining 30 pts. Planet Earth. From now on: Communication through Sakai I will monitor Chat the night before the exam to answer questions. Cosmology: The Birth of the Earth.

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Planet Earth

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  1. Planet Earth • Jim Wright • 732-445-3445 • jdwright@rci.rutgers.edu • 3 exams 90 points • Pop quizzes make up remaining 30 pts

  2. Planet Earth From now on: Communication through Sakai I will monitor Chat the night before the exam to answer questions

  3. Cosmology: The Birth of the Earth R. Williams (ST Scl)-NASA

  4. The Flat Earth Society http://theflatearthsociety.org/ History of Concepts ~1000 BC ~ days of Homer - Earth is a flat disk with water at edges + land in middle. Stars overhead in Celestial Sphere + Hades below my, how far we have progressed!

  5. Heraclides (330 B.C.) formalized Plato's first Solar System model, called the Geocentric model. Proposed that earth rotates on its axis, from east to west, once every 24 hours. Frequently hailed as the originator of the heliocentric theory, although this is doubted http://zebu.uoregon.edu/~js/ast121/lectures/lec01.html

  6. Earth Sun Moon Aristarchus (270 B.C.) developed the heliocentric theory His astronomical ideas were often rejected in favor of the geocentric theories of Aristotle and Ptolemy until they were successfully revived nearly 1800 years later by Copernicus and extensively developed and built upon by Johannes Kepler and Isaac Newton http://zebu.uoregon.edu/~js/ast121/lectures/lec01.html

  7. W. W. Norton Greek Eratosthenes calculated circumference of earth ~200 BC World map according to Eratosthenes (194 B.C.) http://www.henry-davis.com/MAPS/Ancient%20Web%20Pages/112.html

  8. Alexandria Syene (~Aswan) Eratosthenes (276-194 B.C.) measured the size of the Earth He knew Sun cast different noon-time shadows at different places

  9. 7.2° Observation: When the Sun is overhead in Syene, it’s 7.2° south of overhead in Alexandria 786 km to the north 786 km 7.2° Calculation: 786 km 7.2° = ? km 360° The Size of the Earth Assumption: • Sun's rays are parallel • the Earth is round Result: ? = 39,300 km This is within 2% of the actual circumference of the Earth!

  10. Greek Eratosthenes calculated circumference of earth ~200 BC W. W. Norton World map according to Eratosthenes (194 B.C.) http://www.henry-davis.com/MAPS/Ancient%20Web%20Pages/112.html

  11. Digitally stacked images showing location of Mars on successive nights in August 2004 showing Retrograde Motion http://antwrp.gsfc.nasa.gov/apod/ap031216.html Claudius Ptolemy, (87 -150 AD), astronomer, mathematician and geographer from Alexandria, Egypt, believed geocentric universe and circular orbits but had to explain retrogrademotion http://campus.pc.edu/faculty/rarts/courses/physics/105/notes/Topic_2_The_Motions_of_the_Planets/Ptolemys_geocentric_universe.jpg

  12. Digitally stacked images showing location of Mars on successive nights in August 2004 showing Retrograde Motion http://antwrp.gsfc.nasa.gov/apod/ap031216.html Claudius Ptolemy, (87 -150 AD), astronomer, mathematician and geographer from Alexandria, Egypt, believed geocentric universe and circularorbits but had to explain retrogrademotion http://campus.pc.edu/faculty/rarts/courses/physics/105/notes/Topic_2_The_Motions_of_the_Planets/Ptolemys_geocentric_universe.jpg Note circular orbits

  13. circa 1500’s…Copernicus’s revolution… the Heliocentric view of the Universe…

  14. W. W. Norton. Modified from Snow, 1987 Retrograde motion Digitally stacked images showing location of Mars on successive nights in August 2004 http://cygnus.colorado.edu/ http://antwrp.gsfc.nasa.gov/apod/ap031216.html

  15. Tychonic System – a hybrid of geo and heliocentric models Proposed by Tycho Brahe (1546-1601) – the man with the golden nose Famous for astronomical calculations The unmoving Earth is the center. Both the Moon & Sun orbit the Earth. But, the planets orbit the Sun! http://www.astronomy.ohio-state.edu/~pogge/Ast161/Unit3/watershed.html

  16. 1600’s Kepler showed planets had elliptical orbit …the hallmark of Ptolemy’s calculations for the geocentric hypothesis was wrong

  17. circa1600…Galileo uses the newly invented telescope to establish conclusively that the planets revolve around the sun

  18. Solar system - our planets that surround the sun W. W. Norton

  19. Spiral Galaxy ngc4414 Galaxy - immense system of hundreds of billions of stars pulled together by gravity

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