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” Believed in geocentric system

geo - means of Earth; related to Earth -centric means Earth in the center What does the word ‘ geocentric ’ mean? Well, if… and… then… geocentric means in the center

Copernicus Polish Astronomer 1500s Believed in heliocentric system For images of this astronomer, go to: Source of photo, which is in public domain: Wikipedia

helios - means of the sun; related to the sun -centric means sun in the center What does the word ‘ heliocentric ’ mean? Well, if… and… then… heliocentric means in the center View an interesting phenomenon in an animation of our heliocentric system: centric.html centric.html

helios - means of the sun; related to the sun -centric means sun in the center What does the word ‘ heliocentric ’ mean? Well, if… and… then… heliocentric means in the center View an interesting phenomenon in an animation of our heliocentric system: centric.html centric.html

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 Image of Galileo, which is in public domain: Wikipedia

What did Galileo see in the sky to make him believe in heliocentrism? 2. The moon has mountains, valleys. It isn ’ t smooth and perfect. 3. Jupiter has moons, so everything does not orbit around Earth. 1. Venus has phases (like the moon), so it must orbit the sun.

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. ”

Newton, English Scientist Recognized that two factors keep planets in orbit: – Inertia (1 st law of motion) – Gravity Fabulous pictures on this site: Source: Wikipedia/pulic domain

6. Which kind of solar system do we live in: geocentric or heliocentric? 7. What did Copernicus believe? 8. 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?