Download Chapter 29 – The Solar System

Section 1 – Wrote notes on board
CHAPTER 29 – THE SOLAR
SYSTEM
SECTION 2 – THE INNER
PLANETS
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The inner planets are also referred to as
Terrestrial planets (Earth-like)
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Mercury, Venus, Earth, Mars
Small, dense, rocky
Metal core
No rings
Mercury
 Closest to the sun
 Smallest planet now that
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Pluto is not a planet
Orbit period = 88 days
Planetary day = 59 days
Almost no atmosphere
Cold nights (-280 F)
Hot days (800 F)
Very dense, thought to have
large iron core
No moons
Venus
 Second planet from the sun
 Orbit period = 225 days
 Planetary day = 243 days
 Rotates opposite on its axis
 Second to the Moon in brilliance
 Similar to Earth in
 Size, Density, and Location
 Shrouded in thick clouds of sulfuric acid
 Atmosphere is 97% carbon dioxide
 Surface atmospheric pressure is 100 times that of Earth’s
Venus
 The clouds of Venus do not allow visible light
through
 The Magellan orbiter produced radar images
of the surface of Venus from 1990 to 1994
Earth
 Third planet from the sun
 Fifth largest planet
 One moon
 Life is possible because of distance from sun
 Venus to close…to hot for liquid water
 Mars to far…to cold for liquid water
Planets – A Brief Tour
 Mars
 The “Red Planet”
 Orbit period = 687 days
 Planetary day = 24 hours 37 minutes
 Cold polar temps (-193 F)
 Polar caps of water ice, covered by
thick layer of frozen carbon dioxide
Mars
 Numerous large
volcanoes
 Largest is Olympus Mons
Mars
 Several canyons
 Some larger than Earth’s Grand Canyon
 Calles Marineras – The largest canyon
 Almost 5000 km long
 That’s as long as the U.S.
Mars
 “Stream drainage”
patterns
 Found in some valleys
 No bodies of surface
water on the planet
 Possible origins
 Past rainfall
 Surface material
collapses as the
subsurface ice melts
Planets – A Brief Tour
 Moons of Mars
 Two moons
 Phobos
 Deimos
 Captured asteroids
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The fourth planet out from the Sun, Mars, has two moons. The are named Phobos (meaning "fear") and Deimos
(meaning "panic"); appropriate companions for Mars, the God of War.
SECTION 3 – THE OUTER
PLANETS
The outer planets are also referred to as the Jovian
planets (Jupiter-like)
 Jupiter, Saturn, Uranus, Neptune
 Large, low-density, gaseous
 Massive
 Referred to as “Gas Giants”
 All have rings, but Saturn's are the most prevalent
Jupiter
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5th planet from sun
Largest planet
Orbit period = 12 years
Very massive
 2.5 times more massive
than combined mass of all
the planets, satellites, and
asteroids
 If it had been ten times
larger, it would have been a
small star
Jupiter
 Rapid rotation
 Slightly less than 10 hours
 Slightly bulged equatorial regions
 Banded appearance
Jupiter
 Great Red Spot
 In planet’s southern hemisphere
 Like a giant hurricane, has been going for hundreds
of years
 600 km/hr winds
Jupiter
 Structure
 Liquid hydrogen ocean
 Halfway into the interior,
pressure causes liquid
hydrogen to turn into metallic
hydrogen
 Core of rock and metallic
minerals
Jupiter
 At least 28 moons
 Four largest moons
 Discovered by Galileo
 Called Galilean satellites
Saturn
 Sixth planet from sun
 Second largest planet
 At least 20 moons
 Orbit period = 29.5 years
 Planetary day = 10 hours 40 minutes
 Also has banded appearance
Saturn
 Saturn has such a low density (0.7 g/cm3) it
would actually float in water!
Uranus
 7th planet from sun
 3rd largest
 Orbit period = 84 years
 Planetary day = 17 hours
 Uranus and Neptune are nearly twins
 Rotates “on its side”
 At least 15 moons
Neptune
 8th planet from sun
 Orbit period = 165 years
 Planetary day = 16 hours
 Dynamic atmosphere
 1,000 km/hr winds!
 Great Dark Spot
 Storm the size of Earth
 White cirrus-like clouds
above the main cloud deck
 Eight moons
Pluto
 Now a “minor planet” or “planetoid”
 Not visible with the unaided eye
 Orbit period = 250 years
 Planetary day = 6 days
 Highly elongated orbit cases it to occasionally
travel inside the orbit of Neptune, where it resided
from 1979-1999
 1 Moon (Charon)
 The moon is half the size of Pluto
 Average temp is -210 C
Planets – A Brief Tour
29.4 – ASTEROIDS, COMETS,
AND METEOROIDS
 There are millions of smaller bodies of matter
flying all around the solar system
 Some are just bits of dust or ice, others are as
large as small moons
 They are leftover material from the nebula
that formed our solar system
Asteroids
 Asteroids are the largest
of the smaller bodies in
the solar system
 Fragments of rock that
orbit the sun
 More than 50,000
asteroids for sure,
possible millions
 Asteroids have impacted the Earth, causing
mass extinctions in the past
Asteroids
 Most lie between Mars and Jupiter in what is
known as the Asteroid Belt
Asteroids
 Three main types of asteroids
 1.) Made of carbon materials
 Dark in appearance
 2.) Made of iron and nickel
 Metallic appearance
 3.) Made of silicate minerals
 Looks like ordinary earth rocks
Asteroids
 Some asteroids are not in the asteroid belt
 Trojan Asteroids are in groups just ahead of
and just behind Jupiter
 Earth-grazers have very elongated orbits
which brings them close to Earth at times
 They can, and have, collide with Earth
Planets – A Brief Tour
 Comets
 Often compared to large “dirty
snowballs”
 Composition
 Frozen Gases (water, methane, ammonia)
 Rocky and metallic materials
 Frozen gases vaporize when near the
sun
 Produces a glowing head called the coma
 Some develop a tail that points away from
the Sun due to radiation pressure and solar
wind
Comets
 Three main parts
 1.) Nucleus
 2.) Coma
 3.) Tail
Comets
 Scientists think that
comets come from a
very distant cloud of
dust and ice called the
Oort Cloud
 They are so far away
from the sun that many
take millions of years to
orbit
Comets
 Long-period Comets –
Periods of several
thousands or even
millions of years
 Short-period Comets –
Periods of around 100
years
 Halley’s Comet appears
every 76 years
Meteoroids
 Meteoroids are smaller bits of rock or metal
 Called meteors when they enter Earth’s
atmosphere
 A meteor shower is when Earth encounters a
swarm of meteoroids
 Meteoroids are referred to as meteorites when
they are found on Earth
Meteoroids
 Most are less than 1 mm in diameter
 A large one would be greater than 1 cm in
diameter
 Can be produced by collisions between
asteroids
Meteoroids
 Most meteoroids burn up when entering
Earth’s atmosphere
 This is what you are seeing when you see a
“shooting star”
Meteoroids
 Three basic types of meteorites
 1.) Stony Meteorites
 Similar to Earth rocks
 2.) Iron Meteorites
 Metallic appearance
 3.) Stony-iron Meteorites
 Contain both iron and stone (very rare)
Meteorites from Mars?
 Meteorite found in Antarctica in 1984
 Thought to have come from Mars!
 In 1996 scientists discovered fossil
evidence of microorganisms
 How could it have reached Earth? Why is
this significant?