Scientists

1
Scientists Contributions to Our Understanding of
the Solar System
2
Greek Myths tell about

• A god named Helios, who was god of the Sun
• A goddess named Gaea (Gee-a), AKA Mother Earth,
  the protector of Earth and mother of the Titans
  and humans)

3
The Greeks

• Noticed that stars moved in fixed patterns as
  they seemed to move across sky except for 5
  that seemed to wander.

• Determined that these 5 were not stars
• Gave us the word planets which means wandering
  stars

• The Greeks believed in a geocentric system

4
geo- means
What does the word geocentric mean? Well, if
of Earth related to Earth
and
-centric means
in the center
then
geocentric means
Earth in the center
5
Geocentric model

• 1. geocentric

6
CopernicusPolish Astronomer

• 1500s
• Copernicus believed in heliocentric system

http//www.bun.kyoto-u.ac.jp/phisci/Gallery/copern
icus.html
7
helios- means
What does the word heliocentric mean? Well, if
of the sun related to the sun
and
-centric means
in the center
View an interesting phenomenon in an animation of
our heliocentric system http//www.astro.utoronto
.ca/zhu/ast210/helicentric.html
then
heliocentric means
sun in the center
8
heliocentric model
9
Galileo,Italian Astronomer

• 1500s and 1600s
• Believed in heliocentric system supported
  Copernicus
• Improved the telescope to view objects in sky

For images of this astronomer and his telescope,
go to http//www.aip.org/history/esva/catalog/esv
a/Galileo_Galilei).html
10
Galileos proof of heliocentrism
1. Venus has phases (like the moon), so it must
orbit the sun.
2. The moon has mountains, valleys. It isnt
smooth and perfect.
3. Jupiter has moons, so everything does not
orbit around Earth.
11
1633 at age 70, Galileo had to recant his
findings before the Church -

• must altogether abandon the false opinion that
  the sun is the center of the world and immovable,
  and that the earth is not the center of the
  world, and moves, and that I must not hold,
  defend, or teach in any way whatsoever, verbally
  or in writing, the said false doctrine, and after
  it had been notified to me that the said doctrine
  was contrary to Holy Scripture.

12
Another contributing scientist is Johannes Kepler
.
Around the same time as Galileo, Kepler
discovered that the planets revolve around the
sun in what shape?
elliptical
13
The planets orbit the sun in an elliptical path.
14
Newton,English Scientist

• Recognized that two factors keep planets in orbit

Gravity and Inertia
Fabulous pictures on this site
http//www-gap.dcs.st-and.ac.uk/history/PictDisp
lay/Newton.html
15

• What does geocentric mean? Draw and label a
  diagram of this model of the solar system.
• What does heliocentric mean? Draw and label a
  diagram of this model.
• 3. What type of model did the Greeks believe in?
• 4. Which kind of solar system do we live in
  geocentric or heliocentric?
• 5. What did Copernicus believe?
• 6. Copernicus was correct, but people didnt
  agree with him until someone else found more
  evidence. Who was this person? What did he
  discover?

16

• 1. What does geocentric mean? Draw and label a
  diagram of this model of the solar system.

17

• 2. What does heliocentric mean? Draw and label
  a diagram of this model of the solar system.
• 3. What did the Greeks believe?

Geocentric model
18

• Which kind of solar system do we live in
  geocentric or heliocentric?
• What did Copernicus believe?
• 6. Copernicus was correct, but people didnt
  agree with him until someone else found more
  evidence. Who was this person? What did he
  discover?

Heliocentric model
Galileo saw moons orbiting Jupiter, phases of
Venus, and the moon was not perfect.