Tour
of the Solar System
I. Types
of planets
A. Terrestrial planets -- Earth-like
1. Planets: Mercury,
Venus, Earth, and Mars
2. Composition: rocky
3. Size:
smaller
4. Position:
closer to the Sun
5. Density:
high (as high as 5.5 gms/cm3)
6. Moons: few
(0-2)
7. Rings: none
B. Jovian planets -- Jupiter-like
1. Planets:
Jupiter, Saturn, Uranus, Neptune
2.
Composition: gaseous
3. Size: larger
4. Position:
farther from the Sun
5. Density:
low (as low as .9 gms/cm3)
6. Moons: many
(8+)
7. Rings: all have
them
C. Pluto does not easily fall into
either category
1. Could be
terrestrial planet because of size, composition (not gassy), and its
one moon
2. Could be jovian
planet because of its extreme distance from Sun and its low density
3. Some astronomers
actually choose not to consider Pluto a planet. Tradition will
probably keep Pluto as a planet for many years.
II. Planet descriptions, in order of distance from Sun. You
can remember the order of the planets with the sentence, "My very
educated mother just showed us nine
planets" for Mercury, Venus,
Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
A. Mercury: "Blasted and dead"
1. No atmosphere
2. Extremes of
temperature
3. Heavily cratered
from impacts of rock fragments
B. Venus: Earth-like with Greenhouse Effect
1. Atmosphere of
carbon dioxide (much higher concentration than is found on Earth) and
nitrogen
2. Surface is
extremely hot and atmospheric pressure is extremely high
3. Venus rotates
backward (clockwise as viewed from N. Pole) compared to the rest of the
planets
4. Continually
covered with thick clouds
C. Mars: Water and maybe life
1. Mars is about
half the diameter of Earth
2. Largest volcanoes
in the solar system are found on Mars
3. Mars has two
moons, Phobos and Deimos, which were probably asteroids that were
captured by Mars' gravitation
4. There is abundant
evidence that water was present on the Martian surface
D. Jupiter: Weather and amazing moons
1. Has atmosphere
made up mostly of hydrogen and helium. This is similar, of
course, to what is found in stars.
2. The four largest
moons are known as the Galilean moons in honor of Galileo who first
discovered them
3. Gaseous clouds
move in response to very strong winds.
4. The Great Red
Spot is the most prominent feature seen on the planet.
a. Likely a massive (bigger than the size of
Earth), swirling storm.
b. It has been present on Jupiter ever since
it has been viewed w/ higher powered telescopes (early to mid-1900's).
5. Two and a half
times more massive than all the other planets put together.
E. Saturn: Rings and Titan
F. Uranus: Gas giant and Herschel family
G. Neptune: Gas giant and blue
III. Other features of solar system
A. Asteroids
B. Comets