Download early astronomers - St. Bridget Parish School

EARLY
ASTRONOMERS
Aristotle (~384-322 BC)
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Define the five Elements: Water, Aether (the
Heavens, and of course, Earth, Wind & Fire
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Geocentric Model – Earth is at the center of
the solar system
Order: Earth, moon, Venus, sun, Mars,
Jupiter, Saturn
Didn’t explain retrograde motion
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Change in a planet’s direction caused by the
change in position we see the planet as Earth
passes it
PTOLEMY
Ptolemy (~150 AD)
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Said planets move in small circles called
epicycles
Epicycles moved on a larger circle
I.E. Frisbee’s spinning on the rim of a bicycle
rim
Theory survived until 1500’s
RENAISSANCE:
COPERNICUS
COPERNICUS (1473-1543)
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Polish lawyer
Began the take down of geocentric model
Heliocentric Model – Sun is at the center of the s.s.
Model was proposed 2000 yrs earlier by Aristarchus
– but it was rejected
Explained how planets closer to sun have smaller
orbits and farther planets have larger orbits
Retrograde motion then is just the closer planets
passing the further out planets.
TYCHO BRAHE
TYCHO BRAHE (1546-1601)
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Danish
Designed & built accurate instruments
Measured planetary positions – very meticulous
Data became crucial in supporting heliocentric
theory and reveal true shape of planetary orbits
Saw 1st (known) supernova in 1572
Saw comet in 1577 & showed it was beyond the
moon.
JOHANNES KEPLER
KEPLER (1571-1630)
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Assistant to Brahe
When Brahe died, took all his data
With data, able to draw a detailed picture of
the orbit of Mars
Showed orbit is elliptical in shape
Developed 3 laws of planetary motion (We’ll
talk about these at a later time!)
GALILEO GALILEI
GALILEO (1564-1642)
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First to use the telescope to look at the sky
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Studied the moon and sun
Discovered Jupiter’s four largest moons
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Invented by Johannes Lippershey a Dutch
spectacle maker
Named the Galiean Satellites
Found the phases of Venus
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Similar to the phases that our moon goes through
Convicted of heresy in his 70”s and sentenced to
house arrest for rest of life.
Psalm 93:1, Psalm 96:10, and 1
Chronicles 16:30 include text
stating that "the world is firmly
established, it cannot be moved."
MODERN:
SIR ISAAC NEWTON
NEWTON (1642-1727)
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Some consider to be greatest scientist of all time
Worked/discoveries in mathematics, physics, and
astronomy
Pioneered modern study of motion, optics, and
gravity
Deduced the Law of Gravity
Invented Calculus
Developed 3 Laws of Motion
Newton in part gave birth to Astrophysics
Died of kidney infection, but more likely due to
mercury poisoning.
OTHER NOTABLES:
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Sir William Herschel
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Islamic Civilization
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English
1781 discovered Uranus
Named bright stars: Betelgeuse, Aldebaran
Revolutionized math – Algebra
Asian Civilization
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Recorded unusual celestial events: eclipses, comets,
exploding stars
Predicted eclipses