Download Scientists` Contributions to Our Understanding of

Scientists’ Contributions to
Our Understanding of the
Solar System
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)
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
What does the word ‘geocentric’ mean? Well, if…
geoand…
means of Earth;
related to Earth
-centric means in the center
then…
geocentric meansEarth in the center
1. “geocentric”
Copernicus
Polish Astronomer

Source of photo, which is in public domain: Wikipedia
http://www.bun.kyoto-u.ac.jp/phisci/Gallery/copernicus.html
For images of this astronomer, go to:
1500s
 Copernicus
believed in
heliocentric
system
http://www.aip.org/history/esva/catalog/esva/Copernicus_Nicolaus.html
What does the word ‘heliocentric’ mean? Well, if…
heliosand…
means of the sun;
related to the sun
-centric means in the center
then…
View an interesting phenomenon in an
animation of our heliocentric system:
http://www.astro.utoronto.ca/~zhu/ast210/heli
centric.html
heliocentric means sun in the center
heliocentric model
Galileo,
Italian Astronomer

1500s and 1600s
 Believed in
heliocentric system
& supported
Copernicus
 Improved the
telescope to view
objects in sky
Image of Galileo, which is in public domain: Wikipedia
For images of this astronomer and his telescope, go to
Galileo’s proof of
heliocentrism:
1. Venus has phases (like the moon), so it must
orbit the sun.
2. The moon has mountains, valleys. It isn’t
smooth and perfect.
3. Jupiter has moons, so everything does not
orbit around Earth.
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.”
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.
The planets orbit the sun in
an elliptical path.
Newton,
English Scientist

Recognized
that two
factors keep
planets in
orbit:
– Inertia
(1st law of
motion)
– Gravity
Fabulous pictures on this site:
http://www-gap.dcs.st-and.ac.uk/~history/PictDisplay/Newton.html
Source: Wikipedia/pulic domain
What does “geocentric” mean? Draw and
label a diagram of this model of the solar
system.
2. What does ‘heliocentric’ mean? Draw and
label a diagram of this model.
3. What type of model did the Greeks believe in?
1.
4. Which kind of solar system do we live in:
geocentric or heliocentric?
5. What did Copernicus believe?
6. Copernicus was correct, but people didn’t
agree with him until someone else found
more evidence. Who was this person? What
did he discover?
1. What does “geocentric” mean? Draw and label a
diagram of this model of the solar system.
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
4.
Which kind of solar system do we
live in: geocentric or heliocentric?
5.
What did Copernicus believe?
Heliocentric model
6. Copernicus was correct, but people
didn’t agree with him until someone
else found more evidence. Who was
this person? What did he discover?
Galileo saw moons orbiting Jupiter, phases of
Venus, and the moon was not perfect.