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The Solar System
Section I
The Solar System
Modern View

solar system includes Sun, eight planets,
many small objects, and a HUGE
VOLUME OF SPACE!!!!!!!!!!
Solar Nebula Theory
How solar system/planets began
 Started with a nebula of gas, ice, and dust
slowly formed in space
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Nebula – cloud of dust, hydrogen gas, plasma
– partially ionized gas, free electrons with
out an atom/nucleus
 Plasma
The cloud began to
rotate in space
 Formed a thin disk of
gas and dust around
forming sun (protosun)
 Planets (protoplanet)
grow from gas and
dust in disk
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Ideas about the night sky have
changed over time
Earth-centered model – early Greeks
thought planets, Sun, Moon, and stars
rotated around Earth
 Geocentric
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Sun-Centered model
Nicholas Copernicus and Galileo Galilei
observed that the moon revolved around
Earth and that Earth and other planets
revolved around the Sun
 Heliocentric
 Copernicus came up
with this model
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Sun is the center of the solar system,
everything revolves around it
The Planets
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First four inner planets – small and rocky with
iron cores.
Last four outer planets – large and gaseous
Why?
The only elements left after the sun was created
were those with high melting points (metals)
Johannes Kepler
Discovered elliptical pattern of planet
orbits
 Planets travel at different speeds in their
orbits around the sun
 Planets closer to sun travel faster, farther
travels slower
 Orbital velocity is the speed of a planet
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- Observing the Solar System
Planet Speed Versus
Distance
Johannes
Kepler
discovered a
relationship between
the speed of a planet
and its distance from
the sun. Use the graph
to discover what
Kepler learned.
Planet Speed Versus Distance
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Reading Graphs:
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According to the
graph, what is Earth’s
average speed?
About
30 km/s
Planet Speed Versus Distance
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Drawing
Conclusions:
What is the general
relationship between a
planet’s speed and its
average distance from
the sun?
Planets that are closer
to the sun move faster.
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Planet Speed Versus Distance
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Predicting:
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The planet Uranus is
about 2,900 million km
from the sun. Predict
whether its speed is
greater or less than
Jupiter's speed.
Explain your answer.
Uranus’s
speed is less
than that of Jupiter
because Uranus is
farther from the sun than
Jupiter.
Section II

The Inner
Planets
Planet/Dwarf Planet
Qualifications
Planet
 a celestial body that:
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Is in orbit around sun
has sufficient mass for its
self-gravity to overcome
rigid body forces so that it
assumes a hydrostatic
equilibrium (nearly round)
shape
has cleared the
neighborhood around its
orbit
Dwarf Planet
 A celestial body that:
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is in orbit around the Sun
has sufficient mass for its
self-gravity to overcome
rigid body forces so that it
assumes a hydrostatic
equilibrium (nearly round)
shape
has not cleared the
neighborhood around its
orbit
is not a satellite
The Inner Planets

Terrestrial planets are made of rock and
metals
Mercury
Distance: .387 AU
 Moon/Rings: none
 Atm: none
 Avg. temp: 127˚C (261F)
 Composition: Rock and metal
 Water: ice trapped in shaded areas
 Oddities: has lobate scarps caused by
shrinking of planet when cooled, smallest
planet; rev. 88 days, rot. 59 days

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
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Venus
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Distance: .723 AU
Moons/Rings: none
Atm: very thick, 96% carbon dioxide, pressure
90x Earth’s
Avg. Temp: 482˚C (900F)
Composition: rock and metal
Water: none
Oddities: thick atm. causes increased
greenhouse effect, retrograde rotation, Earth’s
twin, sulfuric acid in atmosphere; rev. 225 days,
rot. 243 days
Retrograde vs. Direct Rotation
Retrograde: (clockwise) Spinning in the
opposite direction of the other planets
 Direct rotation: (counter-clockwise) most
planets spin in this direction
 Venus
 Uranus
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causes an intense greenhouse effect
 Results in surface temperatures between
450°C and 475°C
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Earth
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Distance: 1 AU (150 million km)
Moons/Rings: 1 - Luna
Atm: mostly Nitrogen
Avg. Temp: 15˚C (59F)
Composition: rock and metals (silicates)
Water: large amounts of liquid water
Oddities: liquid water
___________________
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AU = astronomical unit
1 AU = the distance from
the Sun to the Earth
More than 70% of surface covered with
water
 Water is solid, liquid, gas b/c of position in
solar system
 Atmosphere protects surface from most
meteors and Sun’s radiation

Mars
Distance: 1.52 AU
 Moons/Rings: 2 moons, Deimos, Phobos
 Atm: thin, 95% carbon dioxide
 Avg. Temp: - 63˚C (-81F)
 Composition: Rock and metal
 Water: frozen water at poles/underground
 Oddities: outflow channels, dust storms,
has largest volcano – Olympus Mons, red
in color; rev. 687 days, rot. 24 h 37 min

Has largest volcano in the solar system
 Olympus Mons
 3x taller than
Mt. Everest
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Soil shows NO evidence of life………..
perhaps……………
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Has gullies and deposits of soil and rocks,
which may indicate the presence of liquid
groundwater
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Strong winds caused
by differences in
temperature between
day and night
Causing strong dust
storms
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Is tilted on its axis, which causes seasons
Two small moons, Phobos and
Deimos
Believed to have been pulled from the
asteroid belt when they passed too close to
Mars and was pulled in by Mars’
gravitational pull
Asteroid Belt
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A piece of rock similar to planet material
Divides inner planets (Mars) from outer planets
(Jupiter)
Asteroids can be a few feet to several hundred
miles wide.
contains at least 40,000 asteroids that are more
than 0.5 mile across.
Collide with each other to make more/smaller
951 Gaspra
Scientists believe that the
gravitational pull of Jupiter keeps
the inner planets from
bombardment by asteroids
Section III

The Outer Planets
Outer Planets
Gaseous planets or made of gases
 Also known as the “gas giants”
 Tend to be oblate
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Jupiter
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Distance: 5.2 AU
Moons/Rings: 60+ largest are Ganymede
(largest in solar system), Io, Callisto, Europa /
yes rings of smoke-sized particles
Atmosphere: mostly hydrogen and helium gas
Avg. Temp: -108˚C surface (-162F)
Composition: mostly gas, possible liquid helium/
hydrogen interior, possible rocky core
Water: droplets in lower cloud layers
Oddities: Great Red Spot – continuous storm;
rev. 12 years, rot. 9h 50 min, wind speeds 540
km/h
The Great Red Spot is the most
spectacular of Jupiter’s many
constant high-pressure gas storms
Three Earth’s would fit inside of this “hurricane”
Has at least 61 moons – four are
large and have atmospheres
Io
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is very volcanically active; the closest
large moon to Jupiter
Europa
composed mostly of rock; may have an
ocean of water under a thick layer of ice
 Only other place water may exist
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Ganymede
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largest moon in solar system, even larger
than planet Mercury
Callisto
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cratered rock and ice crust
Saturn
Distance: 9.54 AU
 Moons/Rings: 60+ moons, largest is Titan /
rings made of ice particles (aggregate size to
snow)
 Atm: mostly hydrogen and helium gas
 Avg. Temp: -139˚C (-218F)
 Composition: mostly gas, possible liquid
helium/hydrogen interior, possible rocky core
 Water: ice only
 Oddities: floats, less dense than water
rev. 29.5 year, rot. 10 h 30 min
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Saturn’s Auroras
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Each large ring composed of thousands of
ringlets of ice and rock particles
Uranus
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Distance: 19.19 AU
Moons/Rings: 20+ moons largest Titania/ rings
of dark boulders discovered during occulation
Atm: mostly hydrogen and helium gas
Avg. Temp: -197˚C (-323F)
Composition: mostly gas, methane ice interior
Water: water ice in mantle
Oddities: retrograde rotation, rotates on its side
where its axis of rotation in parallel to its orbit;
rev 84 years, rot. 17 h
Axis of rotation nearly parallel to
plane of orbit
Neptune
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Distance: 30.06 AU
Moons/Rings: 10+ largest Triton / lightweight,
dark particle (see through occulation)
Atm: mostly hydrogen, helium, methane
Avg. Temp: -200˚C (-328F)
Composition: mostly gas, methane ice interior,
possible rocky core
Water: slushy ice in mantle
Oddities: methane makes blue color, storms –
The Great Dark Spot, “Scooter”, sometimes
further from the sun than Pluto; rev. 164 years,
rot. 16 h; winds 1,000 km/h
bluish-green colored atmosphere similar to
that of Uranus (methane)
 Storms on Neptune reveal an active and
rapidly changing atmosphere
 has at least 11 moons, of which pinkish
Triton is largest
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Kuiper Belt
A belt of icy objects past Neptune’s orbit
 Some astronomers believe Pluto and
Charon are part of that belt
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Dwarf Planets
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Why isn’t Pluto a planet anymore?
25 facts
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Pluto
Distance: 39.53 AU
Moons/Rings: 3 moons – Charon, Hydra, Nix /
no rings
Atm: thin – Nitrogen, carbon monoxide,
methane
Avg. Temp: -215˚C (-355F)
Composition: Frozen nitrogen and rock
Water: none
Oddities: only has atmosphere when closer to
the sun than Neptune, inside of Neptune’s orbit
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During part of Pluto’s
248 year orbit it is
closer than Neptune
Unknown composition
appears solid
Double planet
Other Dwarf Planets
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Ceres: distance - 2.76 AU
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Sedna: distance – 526.6 AU
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Eris: distance – 67.7 AU largest
Order
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Mercury
Venus
Earth
Mars
(Ceres)
Asteroid belt
Jupiter
Saturn
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Uranus
Neptune
Kuiper Belt
Pluto
(Eris)
Oort Cloud
(Sedna)
Why is it not feasible for an
astronaut to visit any planets?
Takes to long to get there
Weak bones and muscles
Section III
Other objects
Comet
Dust and rock particles combined with
frozen water, methane, and ammonia
 Dirty snowball
 Nucleus – mass of frozen ice and rock
 Coma – gases and released dust
vaporized from the heat of the sun
 Dust/Gas tail – forms from solar wind
pushing gases and dusts in coma
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Comet structure
Comets
Ice and dust vaporize as comet nears Sun.
 Vaporized material forms bright cloud
called coma around comet nucleus.
 Solar wind pushes tail away from sun.
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Oort Cloud
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large group of comets surrounding solar
system beyond Pluto.
Amateur astronomers discovered
Hale-Bopp in 1995.
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Meteoroid – piece of broken up comet
moving through space
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Meteor – meteoroid that burns in the
Earth’s atmosphere
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Meteorite – meteoroid that strikes Earth
B. (3.) Meteor Showers: occur when Earth’s
orbit passes through a group of meteoroids
that enter the atmosphere.
What is a shooting star?
It
is NOT a star!!
Look Familiar??????
Shooting Star:
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A meteor that is burning up
in the Earth's atmosphere.
Weight Chart
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Mercury
Venus
Earth
Moon
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Sun
0.4
0.9
1
0.17
0.4
2.5
1.1
0.8
1.2
0.01
28
Age Chart
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Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
88 Earth days
225 Earth days
365 Earth days
687 Earth days
12 Earth years
29.5 Earth years
84 Earth years
165 Earth years
248 Earth years