History of Astronomy: Part Duex

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-History of Astronomy Part Duex

• Objectives
• Define heliocentric, geoheliocentrism, parallax
• Identify progress of astronomical beliefs, key
  people, and events
• Define and identify implications of Keplers Laws
  of Planetary Motion

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Astronomy

• Copernicus onward

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So where did we leave off?

• Belief in the geocentric theory
• Earth is at the center of the universe
• Earth is stationary
• In Europe, this was during the Dark Ages and
  knowledge was only held by the Catholic Church
  they strongly supported this theory
• Big changes would have to be made to change the
  system

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Nicolaus Copernicus

• Polish Astronomer
• 1514 proposed theory of heliocentrism
• Heliocentrism
• Sun is at the center of the universe/solar system

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Heliocentrism
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Heliocentrism
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Tycho Brahe

• Famous for his astronomical measurements
• Made many redundant observations but did not have
  the mathematical tools to analyze them
• November 11, 1572 Tycho Supernova

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Tycho Brahe

• Geoheliocentrism 1587 Earth is at the center
  of the universe, sun revolves around the Earth,
  planets revolve around the sun

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Parallax
Method of viewing an object from two different
locations, and viewing the relative change in
position as seen by the observer allows you to
determine the distance to an object Tycho
used parallax in an attempt to support his
geoheliocentric model.
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Galileo

• Developed first telescope used for astronomy in
  1609
• First to observe the phases of Venus

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Johannes Kepler

• Used Tycho Brahes Data
• 1617-1621 - proposed his Three Laws of Planetary
  Motion

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Keplers First Law

• The path of the planets about the sun are
  elliptical in shape, with the center of the sun
  being located at one focus. (The Law of Ellipses)
  

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Perihelion closest point of an orbit to the
sun Aphelion farthest point of the orbit to the
sun
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Keplers Second Law

• An imaginary line drawn from the center of the
  sun to the center of the planet will sweep out
  equal areas in equal intervals of time. (The Law
  of Equal Areas)

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Planets move quicker nearer to the sun than they
do farther from the sun.
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Keplers Third Law

• The ratio of the squares of the periods of any
  two planets is equal to the ratio of the cubes of
  their average distances from the sun. (The Law of
  Harmonies)
• Period (T) time to go around once

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What the heck does that mean?

• Stuff thats further away from the Sun takes
  longer to orbit it!
• Stuff thats closer to the Sun takes _________ to
  orbit it

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