Transcript History of Astronomy - Grafton School District

History of Astronomy
Early Astronomy
Astronomy
• Is science that the universe
Greeks
• 600 B.C. – A.D. 150
• Measured distances to the Sun and Moon
Eratosthenes
Eratosthenes
Successfully Measured
the circumference of
the Earth
1.7% Error 2400 Years
Ago
Geocentric View
Geocentric View
Pre 300 B.C.
Earth is the center of
the Univerese
The orbs (Sun, Moon,
Mercury, Venus, Mars
and Jupiter) orbit the
Earth each day
Surrounded by a Hollow
Sphere
Heliocentric
Aristarchus (312-230 B.C.)
• Earth and the other
planets orbit the sun
• Dominated Western
Thought for over 2000
Years
Ptolemaic System
Ptolemy (A.D. 141)
• Believed in Geocentric
Model
• Observed Retrograde
Motion
– Planets Move to the
East, but periodically
they stop and reverse
direction
• Social Bias in Science
Modern Astronomy
Renaissance of Science
• Broke Away from Religious and Philosophical
Views
• Used Natural Laws to explain the motions of
the Heavens
Modern Astronomy
Nicolas Copernicus
• 1473-1543
• Earth is a Planet
• Sun Centered
• Planets Orbited the Sun
in Complete Circles
Modern Astronomy
Tycho Brahe
• 1546 -1601
• Spent 20 yrs. Measuring
the Locations of the
Heavenly Bodies
Johannes Kepler
• 1571-1630
• Assistant to Brahe
• Discovered 3 Laws of
Planetary Motion
– Ellipse
• Determined the
Distance from the Sun
to Earth is 1AU = 150
Million km
Modern Astronomy
Galileo Galilei
• 1564 – 1642
• Major Contribution was
the behavior of the
Moving Objects
• Ground Lenses to make
telescopes
• Made Discoveries that
supported Heliocentric
View
Sir Isaac Newton
• 1642-1727
• Expanded on Galileo
Force
• Formulated and tested
the Law of Universal
Gravitation at the age of
23
• This is the force that
makes planets revolve in
a circle