Transcript The Solar System

The Solar System
What is our little corner of the
Milky Way Galaxy like?
Composition of the Solar
System
The sun = 99.85% of all the matter in the
solar system.
Jupiter contains more than twice the
matter of all the other planets combined.
Star/Sun = 1
Planets = 8
Dwarf Planets = 5
Size Comparisons
Solar System Structure
All planets orbit the sun in a counterclockwise fashion. Orbits are contained
within a very narrow disk or plane.
Most orbits are very nearly circular with
the exception of Mercury and Pluto.
Solar System Structure
The spin axes of most
planets and moons are
perpendicular to the
orbital plane (Venus and
Uranus are notable
counter examples).
Thus, solar system is
basically disk shaped with
the Sun near the center.
Small Rocky Worlds
Terrestrial/Rocky Planets – Small, dense,
rocky worlds with less atmosphere than
the other type of planet. Craters, no
rings, very few moons.
Mercury
Venus
Earth
Mars
Jovian/Gaseous Planets
Jovian Planets – Large, gaseous, low
density worlds. Thick gaseous mostly
hydrogen atmospheres, rings, lots of
moons, and very large in comparison to
terrestrial planets.
Jupiter
Saturn
Neptune
Uranus
Pluto
Pluto – Does not fit the current definition
of a “planet”.
Pluto is a small icy world clearly different
from either the Jovian and Terrestrial
worlds.
Since its discovery by Clyde Tombaugh
in 1930, it has been a unique mystery
mostly because of its great distance from
the Earth and is peculiar orbit.
Pluto’s Orbit
Space Debris
Asteroids  (minor
planets) are small
rocky worlds. Most
(not all) orbit between
Mars and Jupiter—
Asteroid Belt . Most
are irregular in shape,
crated, and dense.
Comets
An impressive
glowing object
that is illuminated
by the Sun as it
sweeps through
the inner solar
system. Dirty
snowball theory.
(Water and CO2
ices)
Meteor  falling “shooting star” – bits
of rock and metal falling into the Earth’s
atmosphere and bursting into vibrant
light as they drastically heat because of
the friction created between them and the
Earth’s atmosphere. These bits are, on
average, tiny – specks of dust, sand grain
size, small pebbles – NOT large.
Meteoroid  in space before its fiery
collision with the Earth’s atmosphere.
Meteorite  fallen piece that survived
the fall. Most “shooting stars” are less
than 1 gram of material.
Age of the Solar System
Oldest rocks dated on Earth ~ 3.9 billion
years; however, the Earth’s own volcanism
and plate-tectonics erase most of the
evidence!!
Lunar rocks are dated to 4.48 billion years.
Meteorites ~ 4.6 billion years
Sun estimated age is based on all the
circumstantial evidence ~ 4.5 - 5 billion
years. It has about a 10 billion-year life.
Solar Nebula Theory
A large massive slowly rotating
cloud of interstellar material begins
to collapse under the influence of
gravity. A star forming nebula
begins to grow warm and grow
denser.
The warming center is becoming a
“protostar” of mostly hot hydrogen
gas. Further out in the nebula other
clumps of dust and debris are
gathering into asteroid sized objects
and “planetesimals”.
Solar Nebula Theory
When nuclear fusion begins we
have a new star! The star will
vaporize the inner regions of the
cloud and begin to drive off the
gaseous and dusty material
As the star continues to
shine and produce energy
the nebula is driven off
revealing the surviving
material; planets, comets,
and asteroids.