chapter 24
TRANSCRIPT
The Solar SystemThe Solar System
Section ISection I
The Solar SystemThe Solar System
Ideas about the night sky have Ideas about the night sky have changed over timechanged over time
Earth-centered model – early Greeks Earth-centered model – early Greeks thought planets, Sun, Moon, and stars thought planets, Sun, Moon, and stars revolved around Earthrevolved around Earth
Sun-Centered modelSun-Centered modelNicholas Copernicus and Galileo Galilei Nicholas Copernicus and Galileo Galilei
observed that the moon revolved around observed that the moon revolved around Earth and that Earth and other planets Earth and that Earth and other planets revolved around the Sunrevolved around the Sun
Modern ViewModern View
solar system includes Sun, eight planets, solar system includes Sun, eight planets, many small objects.many small objects.
NEBULA THEORY (origin of NEBULA THEORY (origin of solar system)solar system)
a nebula of gas, ice, and dust slowly a nebula of gas, ice, and dust slowly formed in spaceformed in space
A cloud of material in the nebula A cloud of material in the nebula slowly rotated in spaceslowly rotated in space
As the cloud contracted, it grew As the cloud contracted, it grew warmer, triggering a nuclear fusion warmer, triggering a nuclear fusion
reaction that created the Sunreaction that created the Sun
The leftover matter became the The leftover matter became the planets and asteroidsplanets and asteroids
First four inner planets – small and rocky First four inner planets – small and rocky with iron cores.with iron cores.
last four outer planets – large and last four outer planets – large and lightweight …lightweight …
Planet orbits are elliptical and the Sun is Planet orbits are elliptical and the Sun is not directly in the center of the orbits.not directly in the center of the orbits.
Section IISection II
The Inner PlanetsThe Inner Planets
MercuryMercuryClosest to the Sun, smallest planetClosest to the Sun, smallest planet
Weak magnetic field suggests an iron coreWeak magnetic field suggests an iron coreHas many craters and high cliffsHas many craters and high cliffsno true atmosphere, so surface no true atmosphere, so surface
temperatures range from very hot to very temperatures range from very hot to very coldcold
VenusVenussecond from the Sun and similar to Earth second from the Sun and similar to Earth
in size and massin size and mass
extremely dense atmosphere of cloudsextremely dense atmosphere of cloudsCarbon dioxide traps solar energyCarbon dioxide traps solar energy
causes an intense greenhouse effectcauses an intense greenhouse effectResults in surface temperatures between Results in surface temperatures between
450450°C and 475°C°C and 475°C
EarthEarth
average distance between Earth and the average distance between Earth and the Sun is 150 million kmSun is 150 million km
Water exists on surface as solid, liquid, Water exists on surface as solid, liquid, and gasand gas
More than 70% of surface covered with More than 70% of surface covered with waterwater
Atmosphere protects surface from most Atmosphere protects surface from most meteors and Sun’s radiationmeteors and Sun’s radiation
MarsMarsCalled red planet because iron oxide in Called red planet because iron oxide in
rocks makes them reddish-yellowrocks makes them reddish-yellowPolar ice caps made mostly of frozen Polar ice caps made mostly of frozen
carbon dioxide and frozen watercarbon dioxide and frozen water
Has largest volcano in the solar systemHas largest volcano in the solar system
Soil shows NO evidence of life………..Soil shows NO evidence of life………..
perhaps……………perhaps……………
Has gullies and deposits of soil and rocks, Has gullies and deposits of soil and rocks, which may indicate the presence of liquid which may indicate the presence of liquid groundwatergroundwater
Thin atmosphere of mostly carbon dioxideThin atmosphere of mostly carbon dioxideStrong winds caused by differences in Strong winds caused by differences in
temperature between day and nighttemperature between day and night
Is tilted on its axis, which causes seasonsIs tilted on its axis, which causes seasons
Two small moons, Phobos and Two small moons, Phobos and DeimosDeimos
Section IIISection III
The Outer PlanetsThe Outer Planets
JupiterJupiter
fifth planet from the Sun, largest planet in fifth planet from the Sun, largest planet in the solar systemthe solar system
Below atmosphere, liquid hydrogen and Below atmosphere, liquid hydrogen and helium are suspectedhelium are suspected
Solid rocky core may exist below liquid Solid rocky core may exist below liquid levellevel
The Great Red Spot is the most The Great Red Spot is the most spectacular of Jupiter’s many spectacular of Jupiter’s many
constant high-pressure gas stormsconstant high-pressure gas storms
Has ringsHas rings
Has at least 61 moons – four are Has at least 61 moons – four are large and have atmosphereslarge and have atmospheres
IoIo is very volcanically active; the closest is very volcanically active; the closest
large moon to Jupiterlarge moon to Jupiter
EuropaEuropacomposed mostly of rock; may have an composed mostly of rock; may have an
ocean of water under a thick layer of iceocean of water under a thick layer of ice
GanymedeGanymede largest moon in solar system, even larger largest moon in solar system, even larger
than planet Mercurythan planet Mercury
CallistoCallistocratered rock and ice crust may surround cratered rock and ice crust may surround
a salty ocean and rock corea salty ocean and rock core
SaturnSaturnSixth planet from the sun, second largest Sixth planet from the sun, second largest
in the solar system, largest densityin the solar system, largest density
Thick outer atmosphere of hydrogen, Thick outer atmosphere of hydrogen, helium, ammonia, methane, and water helium, ammonia, methane, and water vaporvapor
Might have a small, rocky coreMight have a small, rocky core
Each large ring composed of thousands of Each large ring composed of thousands of ringlets of ice and rock particlesringlets of ice and rock particles
Has at least 31 moonsHas at least 31 moons
Largest moon, Titan, is larger than Largest moon, Titan, is larger than the planet Mercurythe planet Mercury
Thick clouds on Titan prevent scientists Thick clouds on Titan prevent scientists from seeing surface…….from seeing surface…….
UranusUranusSeventh planet from the Sun, large, and Seventh planet from the Sun, large, and
gaseousgaseous
Has thin, dark ringsHas thin, dark ringsAtmosphere of hydrogen, helium, and Atmosphere of hydrogen, helium, and
methanemethaneMethane makes the planet bluish-green in Methane makes the planet bluish-green in
colorcolor
Axis of rotation nearly parallel to Axis of rotation nearly parallel to plane of orbitplane of orbit
NeptuneNeptune
eighth planet from the sun, large and eighth planet from the sun, large and gaseousgaseous
bluish-green colored atmosphere similar to bluish-green colored atmosphere similar to that of Uranusthat of Uranus
Storms on Neptune reveal an active and Storms on Neptune reveal an active and rapidly changing atmosphererapidly changing atmosphere
has at least 11 moons, of which pinkish has at least 11 moons, of which pinkish Triton is largestTriton is largest
A. Comet: dust and rock particles A. Comet: dust and rock particles combined with frozen water, combined with frozen water,
methane, and ammonia.methane, and ammonia.
1. Halley’s comet: orbits Sun 1. Halley’s comet: orbits Sun every 76 years.every 76 years.
2. Oort Cloud: large group of 2. Oort Cloud: large group of comets surrounding solar system comets surrounding solar system
beyond Pluto.beyond Pluto.
3. Amateur astronomers 3. Amateur astronomers discovered Hale-Bopp in 1995.discovered Hale-Bopp in 1995.
4. Comet structure: large dirty 4. Comet structure: large dirty snowball of frozen rock and ice.snowball of frozen rock and ice.
CometsCometsa. Ice and dust vaporize as comet nears a. Ice and dust vaporize as comet nears
Sun.Sun.b. Vaporized material forms bright cloud b. Vaporized material forms bright cloud
called coma around comet nucleus.called coma around comet nucleus.c. Solar wind pushes on gas and dust in c. Solar wind pushes on gas and dust in
the coma, causing the particles to form a the coma, causing the particles to form a tail that always points away from the Sun.tail that always points away from the Sun.
d. Eventually, most of the ice in the d. Eventually, most of the ice in the comet’s nucleus vaporizes, leaving only comet’s nucleus vaporizes, leaving only small particles.small particles.
Comets vaporize and break up Comets vaporize and break up after passing close to the Sun after passing close to the Sun
several times. When the nucleus several times. When the nucleus breaks up, pieces spread out. The breaks up, pieces spread out. The dust and rock fragments are called dust and rock fragments are called
MeteoroidsMeteoroids..
B. (1.) B. (1.) MeteoroidMeteoroid: name given to : name given to small pieces of comet when they small pieces of comet when they
move through space.move through space.
B. (2.) B. (2.) MeteorMeteor: small meteoroid : small meteoroid that burns up in Earth’s that burns up in Earth’s
atmosphere.atmosphere.
B. (3.) Meteor ShowersB. (3.) Meteor Showers: occur when Earth’s : occur when Earth’s orbit passes through a group of meteoroids orbit passes through a group of meteoroids
that enter the atmosphere.that enter the atmosphere.
B. (4.) B. (4.) MeteoriteMeteorite: meteoroid that : meteoroid that strikes Earth.strikes Earth.
C. C. AsteroidAsteroid: rock similar to that : rock similar to that which formed planets.which formed planets.
C. (1.) Most asteroids lie in an C. (1.) Most asteroids lie in an asteroid belt located between Mars asteroid belt located between Mars
and Jupiter.and Jupiter.
Asteroid Info:Asteroid Info:
Jupiter’s gravity may have kept these Jupiter’s gravity may have kept these asteroids from forming a planet.asteroids from forming a planet.
some planets’ moons may be asteroids some planets’ moons may be asteroids pulled from the asteroid belt.pulled from the asteroid belt.
asteroid sizes range from very tiny to 940 asteroid sizes range from very tiny to 940 km in diameter.km in diameter.
Near: The Near Earth Asteroid Rendezvous Near: The Near Earth Asteroid Rendezvous probe indicates asteroid 433 Eros has been probe indicates asteroid 433 Eros has been
in many collisions over time.in many collisions over time.
SPACE STATION PHOTO SPACE STATION PHOTO