Long ago, it was commonly
believed that the world was flat…
It was also believed that the
Sun was not in the center of the Solar System.
Geocentric Model
Geocentric Model: stated that the Earth was the center of the Solar System
“Geo” means “Earth”
Has anyone ever had a Geode?
When you look at the sky, it feels like the Earth is still and that the sun, moon, and
stars are moving around it.
Before there were space shuttles or
advanced telescopes, it was
difficult to discover how
space was oriented.
Astronomers used their observations
and the knowledge they had to develop
Scientific Theories for how the Solar System
was set up
Scientific Theory: an attempt to explain a pattern observed repeatedly in the natural worldex. We notice that the Sun “rises” and “sets,” so we try to make an educated guess as to WHY that is happening
Example of a Scientific TheoryExample: Ancient astronomers believed that the planets revolved around the Earth because they did not have evidence yet to prove that theory wrong
They thought that they had evidence that the Earth was in the center of the solar system. Their “evidence” was that they:
Noticed that the Earth felt still or stationary
Noticed that the position of the Sun and planets kept changing in relation to Earth
Scientific Theory
The Earth-Centered Model or “Geocentric Theory” is an example of a Scientific Theory that was incorrect, but seemed true or valid based on the information that was available to astronomers at the time
Remember that a Scientific Theory is a POSSIBLE EXPLANATION for repeatedly observed patterns in nature.
The Geocentric System
In the Geocentric System, the Earth is at the center of the revolving planets and stars.
Aristotle Lived in 384 BC – 322 BC
Ancient Greek philosopher, scientist, and was an important figure in politics and theatre
mrsvesseymathematicians.wikispaces.com
AristotleOften known as the “grandfather of science” because he believed in using observations and experiments to discover scientific information.
Aristotle’s view on how our Solar
System workedHe and other ancient Greek astronomers realized that the planets moved
The name “planet” means “wanderer” in Greek
Noticed that stars moved, but stayed in the same position to one another
Believed in the Geocentric model and thought that the other planets revolved around the Earth
PtolemyEgyptian astronomer and mathematician
Lived between AD 90- AD 168
Was able to predict the movements of the planets through geometry
Believed in the Geocentric model –that the Earth was the center of the our Solar System
en.wikipedia.org
“Helios” means Sun in Greek
Heliocentric Model: a model where the Sun is considered to be the center of the Solar System and the planets orbit around it
CopernicusLived from 1473-1543
Polish astronomer
Developed the Heliocentric Model
Copernicus discovered that the planets revolve around the Sun and believed they did this in a circular motion
In the 1500s and early 1600s, most people didn’t believe him and still believed in the Geocentric model
ircamera.as.arizona.edu
Copernicus discovered the
Heliocentric model by
studying the movements of the
planets. He realized all of the planets had the
same annual movement except
for the Sun.
GalileoOriginally believed in the Earth centered model
Used the newly invented telescope to make discoveries that support the Heliocentric Model
Saw 4 of Jupiter’s moons revolving around Jupiter, which proved that not everything revolved around the Earth
en.wikipedia.org
Kepler Lived from 1571-1630
Believed in the Heliocentric Model
He discovered that the orbits of the planets were in the shape of an ellipse, NOT a perfect circle
Discovered that orbits are ellipses by studying the orbit of Mars
Satellite
Satellite: any object that revolves around another object in an orbit
Orbit: the movement of an object traveling forward in space while at the same time being pulled toward Earth in a curved path as a result of gravity
Manmade satellites can be used for a
number of things: Communication: satellites transmit radio and television programs to locations around the world
Scientific Data: satellites gather spring growth, sea-surface temperature, reflected sunlight, carbon monoxide concentrations
Weather: satellites constantly monitor the Earth’s global weather patterns
Back to Sputnik
Launched by the Soviet Union in 1957
Orbited the Earth for 57 days before gravity pulled it back into the atmosphere, where it burned up
Scared Americans
Americans thought that the Soviet Union was using Sputnik to spy on different parts of the world.
This launched a “Space Race” between the United States and the Soviet Union
Soviet Union1961 – Yuri A. Gagarin became the first person in space and he orbited the Earth and returned safely
President John F. Kennedy called for the United States to send humans to the moon and return them safely to
Earth His goal was to was to achieve this by the end of the 1960s.
Yes! First men on the moon on July 20, 1969 from the United States
Apollo 11
Neil Armstrong, Buzz Aldrin, and Michael Collins