Lecture 12:
The Solar
System…Briefly
• Formation of the Moonhttp://www.youtube.com/watch?v=WpOKztEiMqo&feature
=related
• Formation of our Solar System
• Conservation of Angular Momentum
• Why are the larger, gaseous planets farther away and the
smaller, rocky planets that are closer?
• How do we have an estimate of our solar system’s age?
• What makes something a dwarf planet?
The IAU says it is a celestial body orbiting the Sun
a) massive enough to be rounded by its own gravity
b) has not cleared its orbit of planetesimals.
Collisions dominated the early solar system
(What is the key force here?)
• dust collects together into planetesimals
• planetesimals collect together into
protoplanets
• Protoplanets gather up left over debris and
became planets
The solar system formed from a giant cloud of
rotating, cold gas and dust called the solar
nebula about 4.6 billion years ago
The planets formed by the accretion of
planetesimals and the accumulation of gases
in the solar nebula
Which planet formed
at the furthest location
from the Sun where it
was hot enough to boil
water ?
A. Mercury
B. Mars
C. Jupiter
D. Neptune
E. None of the above
How should we categorize the objects in
the Solar System?
Discuss size of Earth, Venus, Mars, Mercury & Moon
Venus
Earth
_______
is nearly same diameter as _______
Mars is
________
nearly half the Earth’s diameter
Moon is about ¼ Earth’s diameter
_____
Mercury is smaller than Mars, about size of Saturn’s
itan and Jupiter’s moon G_______
anymede
moon T___
The Sun is the Largest Object in
the Solar System
• The Sun contains more than 99.85% of the
total mass of the solar system
• If you put all the planets in the solar system
together, they would not fill up the volume
of the Sun
• 110 Earths or 10 Jupiters fit across the
diameter of the Sun
How big is the Sun?
The Sun has a diameter of approximately
1.4 million kilometers. Roughly how many
Earths would fit across the diameter of the
80%
Sun?
10
100
1000
10,000
1 million
on
1
m
ill
i
0
00
10
00
10
10
8%
6%
3%
0
3%
10
A.
B.
C.
D.
E.
Where are the asteroid belts and what are their names?
What is the name of the largest asteroid in the Main Asteroid belt?
Discuss the VUP’s.
What is the name of the largest asteroid in the Kuiper belt?
Main
Asteroid
Belt
How should we divide the Solar System?
How should we divide the Solar System?
How should we divide the Solar System?
How should we divide the Solar System?
Mercury
Jupiter
Mercury
Jupiter
Brilliant blue
Neptune has
a giant storm
too
• Which of these is Earth-like?
• Which of these is Jupiter-like?
• Or are they the same (both Earth-like
or Jupiter-like)?
How should we divide the Solar System?
By Density?
The Inner Planets
(Family Portrait)
Inner (Terrestrial) Planets
•
•
•
•
•
Mercury
Venus
Earth
Mars
Characteristics
–
–
–
–
–
–
Small
Rocky
Very close to the Sun
Have few moons
Have no rings
a central metallic core, mostly iron, the Moon is similar, but lacks
an iron core
The Outer Planets
(Family Portrait)
Outer (Jovian) Planets
•
•
•
•
•
Jupiter
Saturn
Uranaus
Neptune
Characteristics
–
–
–
–
–
–
–
Large
Gaseous
Far from the Sun
Have many moons
Have rings
Have magnetic fields
thick atmosphere and a
dense molten core
The surface of
Venus is
completely
hidden beneath
permanent cloud
cover
The Venusian Surface
Venus is covered with gently rolling hills and
numerous volcanoes
EARTH
• The Privileged Planet
Mars, as seen from the Hubble Space Telescope
Enormous
shield
volcanoes
Valles Marineris is as big as the entire United States of America
Ice caps dominate the poles during
different times of the year
Olympus Mons - the largest volcano in the solar
system has a base larger than the state of Arizona
Early space probes to Mars found no
canals but did find some
controversial features
Surface features indicate that
water once flowed on Mars
Ohio
River
valley
on Earth
River
channels
on Mars
Viking I Lander Picture from 1976
1999 Picture
from the Mars
Pathfinder
Lander
Note the remotecontrol rover,
Sojourner, next to
a Martian rock
Mars Water/Ice Discovered
North Pole only
None found on South Pole – only CO2 – dry ice
Activities Manual
Prather • Offerdahl • Slater
The Martian meteorite found
in Antarctica has not
provided conclusive evidence
about life on Mars
Most asteroids orbit the Sun
between Mars and Jupiter
In general, asteroids are small
Asteroid Ida and its
tiny moon, Dactyl
Outer
Outer
(Jovian)
Planets
Planets
•
•
•
•
•
Jupiter
Saturn
Uranus
Neptune
Pluto
•
•
•
•
Enormous
Gaseous
Far from Sun
Separated by large
distances
• Have ring systems
• Have many moons
Inner planets are vastly different than outer
planets in terms of orbital distances
The Outer Planets
(Family Portrait)
Jupiter is the Largest of the Gas Giant Planets
Besides being the
largest planet,
Jupiter is probably
best known for its
Great Red Spot - a
hurricane-like storm
that has been
observed ever since
the invention of the
telescope.
Jupiter has four large moons and
tens of small ones
Saturn has the most extensive ring
system in the solar system
Saturn’s spectacular rings are composed of
fragments of ice and ice-coated rock
Titan is Saturn’s largest moon
Saturn and Jupiter
share the same
basic structure
A system of rings and
satellites revolves
around Uranus
Uranus has a hazy
atmosphere with
few clouds
Uranus’ tilt gives it very
exaggerated seasons
Brilliant blue
Neptune has
a giant storm
too
Neptune’s
Rings
Uranus and Neptune have similar
interiors
Main Asteroid Belt & Kuiper Belt
Dinosaurs…
Vagabonds of the Solar System
Comet Kohoutek and Comet West
Comets have two tails
The anatomy of a comet
ion tail
coma
dust tail
Anatomy of a comet
Comets often have two tails:
a thin ION tail (in a line) and
a curving DUST tail (dust deviates)
NOTICE the colors are off, they
should be:
• The blue tail should always be
the ion (gas) tail as it fluoresces and
it should be straight in a line away
from the Sun.
• Thus the dust tail is (dang)
curved and should be whitish to
whitish-yellow.
Comets lack tails until they enter the inner solar system. A
comet’s tails always point away from the Sun, no matter which
way the comet is moving!
15 km long by 8 km wide
Comet Halley nucleus
Meteor showers occurs when Earth passes through the dusty tail debris
left by a passing comet. Dust particles burn up as they enter Earth’s
atmosphere, like bright light shooting from a single point in the sky.
Taken by an amateur astronomer, this picture shows the comet
taken on October 1 as a bright green glow in the sky.
The Deep Impact spacecraft will pass a mere 435 miles (702
kilometers) from Comet Hartley 2 on November 4th, 2010 about
6:50 am PT.
Meteoroids, Meteors, Meteorites
& Tektites