Transcript solar system formation notes

Formation of the Solar System
Demonstration
There are four bowls with pepper around
the room. Get in a place where you can
observe it.
 When given the instruction, mix the water
and the pepper
 Record your observations

1
2
3
Observations
1.
2.
3.
Sketch and describe how the pepper is
distributed in the bowl
Sketch and describe what happens when
you first start mixing the water and the
pepper
Sketch and describe what happens after
you stop mixing the water and pepper.
Be sure to mention how fast the pepper
is moving near the outside of the bowl
vs. the center
Formation of the Solar System
A hypothesis for the formation of the Solar
System must answers four questions:
1. Why do things move in a common pattern?
2. Why are there two types of planets?
3. Why do asteroids and comets exist?
4. Why do exceptions to the general patterns
happen?
Take notes on video
The Nebular Theory
States that the formation of the Solar
System came from the collapse of a
nebula
 Pioneered by Immanuel Kant and PierreSimon Laplace
 Accurately answers the four questions

Review: What’s in a Nebula

Dust
Metals
 Minerals
 Rocks


Gas
Hydrogen
 Helium
 Methane
 Water
 Ammonia

Patterns of Motion
Simply stated, this means everything moves
around the Sun in the same way.
The Patterns of Motion
Gravity draws all the gas and dust
together and the nebula collapses
 As it collapses, it begins to spin and heat
up
 Particles hit each other, flattening the
cloud to a disk
 Mass accumulates in the center of disk,
resulting in a protostar

The Patterns of Motion
1
2
The original cloud is large and spread out and its rotation is
very slow. The cloud begins to collapse
4
The result is a spinning, flattened disk, with mass
concentrated near the center and the temperature
highest near the center
Because of the conservation of energy, the cloud heats
up as it collapses. Because of angular momentum, the
cloud spins faster as it contracts.
3
Collisions between particles flatten the cloud into a
disk.
The Two Types of Planets
The disk consolidates to form the Sun and
the planets
 The two types of planets come from
differences in temperature across the disk
 The particles that make the rocky planets
solidify at a higher temperature than the
gas planets
 The point where this the gas turns to liquid
or ice is called the frost line

The Frost Line
Within the frost line, rocks and
metals are solid but hydrogen
compounds stay gaseous
Beyond the frost line, hydrogen
compounds, rocks, and metals
turn to solids
Within the solar nebula, 98% of the material is
hydrogen and helium gas that doesn’t condense
anywhere.
Planet Formation
Planets gradually form through a process
called accretion
 In accretion, particles of rock or ice collide
with each other and stick together
 Eventually accretion creates seeds of
planets called planetesimals
 Planetesimals join together to make the
planets

Accretion
Planet Formation

Inside the frost line, the planetesimals do
not create enough gravitational pull to
attract gas


This is because the gas has too much energy
Outside the frost line, the planetesimals do
attract gas

This is because the gas no longer has as
much energy and turned into a liquid or solid
Planet Formation
Comets and Asteroids
Comets and asteroids come from the
leftovers of planetesimals that did not join
planets
 Asteroids come from the leftover rocky
planetesimals
 Comets come from the leftover icy
planetesimals

Exceptions to the Pattern
Planets create enough gravitational pull to
capture moons
 The gas that wasn’t taken in by planets
was pushed out of the solar system by
solar wind
 Planetesimals hitting planets could knock
planets onto their sides

Check Your Understanding
What did the pepper represent in the
activity?
 What part of the formation of the Solar
System did observation 3 represent?
 How would you describe the formation of
the Solar System using the activity?
 How does this activity and the formation of
the Solar System differ?

When Materials Solidify
Examples
Typical
Condensation
Temperature
Relative
Abundance
(by mass)
Metals
Rock
Hydrogen Compounds
Hydrogen and Helium Gas
Iron, Nickel,
Aluminum
Various Minerals
Water (H2O), Methane
(CH4), Ammonia (NH3)
Hydrogen, Helium
1,900 ºF –2,400 ºF
440 ºF –1,900 ºF
-190 ºF
do not condense in nebula
0.20%
0.40%
1.40%
98%