*The Shape of the Earth *Heliocentricity vs Geocentricity *Kepler's Laws of Planetary Motion

1. The Universe
and
Physics
Lesson 4
Physical Science
jgF

2. The Big BangThe Big Bang
• Happened 13.7 BYA
• Started out as
a singularity
• Planck Time: 10-43
seconds

3. How did the ancient
people thought
about the creation
and appearance of
our world and the
Universe?

5. Geocentricity
Heliocentricity
The Earth is at the center
The Sun is at the center
V
S

6. Geocentric ModelViews of the Earth
Thales
of Miletus
Anaximander
of Miletus
Asserted that the
Earth is flat like
a disk
Asserted that the
Earth is Shaped like
a cylinder.
Pythagoras
OF Samos
Alluded to a
Spherical earth,
though with
Some ambiguity.

7. Geocentric Model
Claudius Ptolemy Anaxagoras of Clazomenae
The most famous supporter
of the Geocentric Model
Determined the positions of The
Sun, Moon and Earth during
Solar and lunar eclipses.

8. Geocentric Model
Plato Eudoxus of Cnidus
“Saving the Appearances”—A
Challenge to explain the irregular
Motion of the heavenly bodies which
Are perfect.
The earth is surrounded by
27 Spheres of the firmament.

9. Geocentric Model
Aristotle Apollonius of Perga
Added the Sphere Of The
“Prime Mover”
Introduced the Epicycle and
The Deferent.

10. Geocentric Model
Hipparchus of Nicaea
Put the earth slightly
Off-centered in his model.
Claudius Ptolemy
(yes, again)
Ptolemaic Model
Equant—A Point Placed
directly opposite to Earth
from the deferent's center
…lasted for a very long time.

11. Heliocentric Model
Philolaus of Croton
Pyrocentricity—A great
“Central Fire” Is at the
middle of the Universe
Aristarchus of Samos
Considered to be the founder
Of heliocentricity.

12. Heliocentric Model
Nicolaus Copernicus
A Renaissance-era mathematician and philosopher who
formulated the heliocentric model 18 centuries after
Aristarchus.
“On the Revolution of Celestial Orbs” (1543)
Pioneered Heliocentricity
Despite possible religious
Objections.

13. Heliocentric Model
Tycho Brahe
Attempted to combine the Copernican Model with the
Benefits of the Ptolemaic System using his own: the
Tychonic Model.

14. Heliocentric Model
Galileo Galilei
• The first person to use the telescope for scientific
Observation
• Had many important discoveries in the field of astronomy
• A strong supporter of heliocentricity Despite persecution
by the Catholic Church

15. Heliocentric Model
Johannes KeplerAdopted Copernicus’ heliocentric approach and developed
Three laws which explain the motion of the planets around
The Sun.