Download Formation of the Solar System

Formation of the Solar System
Week 5
(Welcome back from Spring Break)
Quick overview of the Solar System
• Space School:
http://www.youtube.co
m/watch?v=mtKNH2Y2
OJM&feature=related
Theories of How the Solar System Formed
Target 1:
• Summarize the major features that a theory of solar system
origins has to explain.
All theory's of how the solar system formed must explain
observations of composition, motion, and organization of
the objects in the solar system.
YouTube Video:
Astropedia
http://www.youtube.com/watch?v=l82OYfeDWqY&feature=bf
_prev&list=PLA021BE54103940FE&lf=plpp_video
TERRESTRIAL vs GIANT PLANETS
The inner planets are smaller and denser than
the outer planets, and are made of silicates
and metals. In contrast, the outer planets
are dominated by hydrogen and have many
satellites that are rich in water ice and other
volatiles.
DIFFERENTIATION!!!!
PROGRADE ROTATION
All planets move around
the Sun in the same
direction that the Sun
rotates and close to
the equatorial plane of
the Sun.
Visit this animation to
observe the motions
of the objects in the
solar system.
http://janus.astro.umd.edu/javadir/orbit
s/ssv.html
Angular Momentum
Mass and Angular Momentum
• Although the Sun has
99.98% of the mass in the
solar system, the planets
have 99.7% of the system’s
angular momentum.
This means that most of the
“spin” in the solar system
comes from the planets!
Definition
• Angular Momentum:
is a vector quantity that can
be used to describe the
overall state of a physical
system.
• Linear Momentum:
p = mv
Angular Momentum:
Try this at home!
Angular Momentum, L
L = mvr
L = angular momentum
m = mass
v = velocity
r = radius
Which one of these variable changed in your
spinning seat experiment?
Angular Momentum of a system
is Conserved in the Universe!
One of Brian Boitano’s crowdpleasing skating moves
involves initiating a spin
with his arms extended and
then moving his arms closer
to his body. As he does so,
he spins at a faster and
faster rate. Which of the
following laws best explains
this phenomenon?
(A) Conservation of Mechanical Energy
(B) Conservation of Angular Momentum
(C) Conservation of Linear Momentum
(D) Newton’s First Law
(E) Newton’s Second Law
Angular Momentum is Conserved
Professor Brian Cox
provides a preview of
the winning theory of
the formation of the
solar systems and how
angular momentum
plays an important role:
http://www.youtube.com/
watch?v=zzGxbFVOX1A
&feature=related
RETROGRADE PLANETS
Despite the general
regularity of planetary
orbital spin motion,
Venus, Uranus and
Pluto all spin in a
retrograde direction.
Read Handout:
Retrograde Rotation
Tilt of Planets on their Axes
Why do the planets have tilts?
• The asteroids have compositions intermediate
between the rock & metal rich inner planets
and the volatile-rich outer solar system, and
are located between the orbits of Mars and
Jupiter.
• The oldest and most primitive meteorites
contain grains of compounds that are
expected to have formed in a cooling cloud of
cosmic abundance at temperatures of a few
hundred degrees.
• The oldest rock age recorded in the solar
system is 4.5 billion years old.
COMETS
Comets, like the surface of some outer planet
satellites, appear to be composed primarily of
water ice, with significant quantities of
trapped or frozen gases like carbon dioxide,
plus silicate dust.
Volatiles
Volatile compounds (such as water) must have
reached the inner planets in spite of the fact
that he bulk composition of these bodies
suggests formation at temperatures too high
for volatiles to form solid grains
Irregular Satellites
All the giant planets have
systems of regular
satellites orbiting in
their equatorial planes,
rather like miniature
versions of the solar
system.
Regular Satellites: Uranus
Except Uranus, the giant planets have one or more irregular
satellite that have an orbit that is either retrograde or have
high inclinations or eccentricities.
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What is the solar system made of?
Where did that material come from?
Why is the solar system rotating?
How did the planets form?
Why are there some terrestrial planets and some
gaseous or icy? And why are they where they
are?
• Why do some planets have moons?
• How old is the solar system?
The Condensation Theory
• The most widely accepted theory of the
formation of our own solar system and other
planetary systems.
Reading:
The Condensation Theory - Nebular
Contraction
http://lifeng.lamost.org/courses/astrotoday/CH
AISSON/AT315/HTML/AT31502.HTM
Overview
Collapse of a nebula
(a) Conservation of angular
momentum demands that a
contracting, rotating cloud
(a) must spin faster as its size
decreases.
(b) Eventually, the primitive
solar system came to resemble a
giant pancake. The large blob at
the center would ultimately
become the Sun.
Condensation and Accretion
Reading: Differentiation in the Solar System –
The Role of Heat
http://lifeng.lamost.org/courses/astrotoday/CHAISSON/AT315/HTML/AT31503.HTM
Age of the Solar System
• http://www.youtube.com/watch?v=UcaZfWa
NR64&feature=fvsr
Fun Friday
The History Channel - The Universe:
How the Solar System was Made
http://www.youtube.com/watch?v=WjOWGHYxLg&feature=related
Learning Targets
• Summarize the major features that a theory of solar system origins
has to explain.
• Outline the process by which planets form as natural by-products of
star formation.
• Explain the role played by dust in the currently accepted model of
solar system formation.
• Account for the differences between the terrestrial and the jovian
planets.
• Discuss the role of collisions in determining specific characteristics
of the solar system.
• Explain the angular momentum problem and discuss some
proposed solutions.
• Discuss the role of meteorites and radioactive dating to determine
the current age of the solar system.
Review with Questions
• http://lifeng.lamost.org/courses/astrotoday/C
HAISSON/AT315/HTML/AT315EOC.HTM
• Reference:
http://lifeng.lamost.org/courses/astrotoday/CH
AISSON/AT315/HTML/AT31500.HTM