Download Unit 3: The Solar System Historical Models of the Solar System

Unit 3: The Solar System
Historical Models of the Solar System: Lesson 1
GEOCENTRIC – EARTH Centered
HELIOCENTRIC – SUN Centered
Aristotle (6th Century BCE )
- 1st to propose geocentric model
- Couldn’t observe PARALAX, so he
thought Earth wasn’t moving
Aristarchus (310-230 BCE)
-1st to propose heliocentric model
- He was ridiculed and his model
was not accepted
Ptolemy (100-170 CE)
- His geocentric model was used
for 1400 years.
- All orbits of all bodies in space
traveled in a perfect circle at a
constant speed
- “Wheels on wheels” model –
planets move in small circles that
moved in larger circles
Copernicus (1473-1543)
-1st detailed and accepted
heliocentric model
- planetary orbits were circular
Kepler (1571-1630)
- Founded 3 Laws of planetary
motion
- Discovered the elliptical
movement of planets
Parallax - the effect where the position or direction of an object
appears to change when viewed from different positions, especially
that of a star viewed from different points in the earth's orbit.
Gravity and the Solar System: Lesson 2
Gravity and the forces that change it
______________: a force of
___________________ between 2 objects due to
their ___________ and the ___________
between them. Gravity is the
______________ force in ___________,
yet it accounts for the ______________ of
planets, stars, and galaxies.
Sir Isaac Newton was the first to ______________
describe how ______________ works. He is
known for Newton’s Law of Universal Gravitation:
1. ______________ affects the force of
_________________. The strength of the
__________ of gravity depends on the
______________ of the MASSES of two
objects. Therefore, as the MASSES of the 2
Formation of the Solar System
Step 1
Solar Nebula
Because of gravity, a cloud of
dust and gas collapse, it forms a
rotating protostellar disk
Step 2
The Sun Forms
Temperatures in the
protostellar disk become so hot
that fusion begins and stops the
collapse of matter. This forms
the sun
Step 3
Planetesimals Form
objects ______________, the force that the
objects exert on one another
_________________.
2. ______________________ affects the
force of gravity. As the distance between
2 objects ___________________, the
_________ of _____________ between
them ___________________.
3. __________________ affects Planetary
Motion. The __________ exerts a
_______________ on a planet which keeps it in
_________________.
Dust granules form and slowly
increase in size. They collide to
form Planetesimals.
Step 4
Planets Form
Planetesimals collide and form
planets. The rocky, metallic
planets form in the high
temperature inner disk. Planets
with small, rocky cores and
deep gaseous atmospheres
form in the cold outer disk.