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 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: Why do things move in a common pattern? Why are there two types of planets? Why do asteroids and comets exist? 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 Pierre-Simon 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 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 4 The result is a spinning, flattened disk, with mass concentrated near the center and the temperature highest near the center 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   Metals Rock Hydrogen Compounds Hydrogen and Helium Gas Examples Iron, Nickel, Aluminum Various Minerals Water (H2O), Methane (CH4), Ammonia (NH3) Hydrogen, Helium Typical Condensation Temperature 1,900 ºF –2,400 ºF 440 ºF –1,900 ºF -190 ºF do not condense in nebula Relative Abundance (by mass) 0.20% 0.40% 1.40% 98%