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7. Star and Planet Formation
Primary goals
- Describe how the solar system formed
- Explain how the characteristics of the solar
system today can be linked to the formation of the solar system
Section 7.1 [p. 191-204] is a
good introduction to the planets. Read it like a magazine article.
Read Section 8.1 [p. 215-216]
Solar System Characteristics [section
7.2 p. 205-206]
- What general observations can we make about the
solar system?
- List the planets in order outward from the sun
Gravity and Thermal Pressure [p.
516]
Explanation D2L
- Describe thermal pressure. When does it increase?
Decrease?
- What happens when thermal pressure > gravity?
Gravity > thermal pressure? Gravity = thermal
pressure?
Star Formation
Molecular Clouds
[p. 513]
- Why do we look at one region to see various
stages of star formation?
Collapse of Molecular Cloud
[p. 518-519]
- Why is it important that a cloud collapse to form
a star?
- What do we think caused the collapse that led to
the formation of our solar system?
Heating of Molecular Cloud Cores
[p. 217, 520, 521, 523]
- Describe the process of gravitational heating.
Protostar [p.
521-522]
- When in the star-forming process do we say that a
protostar has formed?
- How do we detect protostars? [Evidence!]
Star
- How do we define when a protostar
becomes a star? [p. 523]
Materials for Planets
Formation of Solar System Orderly
Motions and Solar System Disk
- Solar nebula
--What evidence do we have that disks form around stars? [p. 218]
-- What is the solar nebula? [p. 219-220]
Composition of the Solar Nebula
[p. 219-220]
- What groups of materials made up the solar
nebula?
Condensation
[p. 219]
- Describe the general process of condensation. Be
sure to talk about temperature.
Condensation Sequence
[p. 220]
Explanation D2L
- Describe the condensation sequence in the solar
nebula.
- Describe how the same material condensed out at
different times depending on the distance from the protosun/sun.
- Describe why different material condensed out
depending on the distance from the protosun/sun.
- freeze scene
from The day After Tomorrow--1/2 min
Solar Wind Pushes Solar Nebula Out of
Solar System [p. 222]
- What was different about the solar system before
and after the solar nebula was pushed out?
- What evidence do we have that this might have
occurred?
- What solid materials existed (were available for
accretion) after the solar nebula was gone? How was that different for
different parts of the solar system?
Research
video of
solar nebula 4 min
-
YouTube why inner planets and outer planets are different
Building the
Planets/Asteroids/Comets
Collection of dust into large objects [p.
220-221]
- Dust to planetesimal
-- How do meteorites provide evidence for the collection of dust into
planetsimals?
- Planetesimal to embryo
--Describe runaway growth. Describe how runaway growth can result in one
large embryo in an area of space (rather than many embryos).
--What is the Heavy Bombardment?
- Explain why the composition of planetesimals in
the inner solar system is different from the planetesimals in the outer
solar system.
Formation of Inner Planets and
Asteroids [p. 220-221]
- What is the composition of the inner planets?
- Describe the formation of asteroids.
Formation of Outer
Planets and Comets [p. 221-223]
Explanation D2L
- What was different about the formation of embryos
in the outer solar system that allowed them to collect H?
- Describe runaway growth of Jupiter and Saturn.
- Describe the relative different gas amounts in the outer
planets and describe why they are different. Include the role of the
solar wind.
- Speculation: What would have had to happen for
the inner planets to have gases like the
outer planets?
- Comets
-- Describe the formation of comets.
--What happened to the comets that were among the outer planets?
--Describe the Oort cloud. How did comets get there?
--Describe the Kuiper belt. How did comets get there?
How Good is the Theory?
- --research video
1 min
Difficulties in modeling
exoplanets
How Old is the Solar System? [section
8.5 p. 225-228]
- Briefly describe how we determine the age of the
solar system.
--Be able to use the term radioactive decay.
--Why do we analyze meteorites?
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