1. Formation of the Solar System

2. MODELS OF THE SOLAR SYSTEM
There are two main models that have existed in history
________________________________________________________
Also called the Ptolemy Model
Also called the Copernican Model

3. Model with Earth in the ______________________________
GEOCENTRIC MODEL
Model with Earth in the ______________________________
Everything in space revolved around the ________________
Proposed by many including the famous Greek philosopher, Aristotle, around 350 BC
In 140 AD, ________________________ expanded Geocentric Model
Could _____________________________________ motion of the sun and planets
Used mathematics and little observation
Very complicated
Used for over 1000 years

4. Think! What did Aristotle propose about the Solar System?
Define ‘geocentric’:

5. HELIOCENTRIC MODEL
Model with ______________ in the center of the Solar System
In 1543, Nicolaus Copernicus moved the sun to the center.
Was ___________________________by scientific community

6. DEVELOPMENT OF THE HELIOCENTRIC MODEL
In 1605, Johannes Kepler improved the model by proposing
that the orbits around the sun are ______________________, or ovals, rather than circles.
In 1609, Galileo Galilei made a ________________________
Key ___________________________________ that allowed important
__________________________________ to be made in support of the Heliocentric Model
In 1687, Sir Isaac Newton ties it all together
Explained that ___________________________________ keeps the planets in orbit around the sun, and satellites in orbit around planets.

7. Think!
What did each of these scientists do or say to build on our knowledge of the Solar System:
Copernicus?
Kepler?
Newton?

8. STEPS THAT LEAD TO THE CHANGE FROM GEOCENTRIC
TO HELIOCENTRIC
Ptolemy & Aristotle didn’t have the
_____________________________________to make good
_____________________________________
Ptolemy could _________________________, but the model was very complicated and he didn’t make many observations
Copernicus, Kepler, Galileo, & Newton each
_________________________________________________ to the development of the Heliocentric Model

9. FORMATION OF THE SOLAR SYSTEM
According to dating of rocks, scientists believe the solar
system is approximately _____________________________
______________________________________: model for the formation of the solar system in which the sun and planets condense from a cloud (or nebula) of gas and dust.
NEBULAR MODEL PROCESS
Nebula began to collapse due to gravity
Nebula then formed a _______________________________
Supporting evidence for the disk:
Planets lie in the _____________________________________
Planets have almost circular orbits (they are ellipses though)
Planets orbit in the same direction as the material in the center.

10. NEBULAR MODEL PROCESS, CONTINUED
Center becomes hottest part with most material =
___________________
___________________________ formed around the Sun by the accretion of matter in the disk.
PLANETESIMAL = ________________ that become ___________
4a) Planetesimals become larger as gravity attracts more material to them
4b) They then ______________________________________________ to become even larger = the Planets

11. Nebular Model

12. Think!
What are 2 pieces of evidence that support the Nebular Model?

13. SOLAR SYSTEM BODIES SMALLER THAN MOONS
ASTEROID: fragments of rock that orbit the sun
___________________________ of the “smaller” bodies
Asteroid Belt = Between ___________________________________
COMET: small body of
_________________________________________________ loosely packed together that follows an elliptical orbit (“dirty snowballs”)
Some comets have two tails:
___________________________________: made of gases; blown by solar wind so it always is pointed away from the sun
___________________________________: made of dust; less affected by solar wind so often curved by the comet’s orbital motion

14. Halley’s Comet Orbits the sun every _____________________
Next time it passes the Earth is in 2061
Notice two tails

15. SOLAR SYSTEM BODIES SMALLER THAN MOONS
METEOROID = small pieces of rock that
_________________________________________________.
METEOR = meteoroid that
_________________________________________________(most burn up before reaching the ground).
“Shooting Stars” = meteors
METEORITE = meteor that ___________________________

16. Think!
How are “smaller bodies” (asteroids, comets, and meteoroids) the same?
How are they different?