Download The Planets Notes - Sardis Secondary

Chapter 23
Earth Science 11
• Inner planets:
• Closest planets to the sun
• A.k.a. terrestrial planets
• All have a rocky crust, dense mantle
layer, and a very dense core
• Mercury, Venus, Earth, and Mars
• Outer planets:
• Furthest away from the sun
• A.k.a. Jovian planets (Jupiterlike)
• Larger than terrestrial planets
• Gaseous and less dense
• Jupiter, Saturn, Uranus,
and Neptune
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Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
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My
Very
Excellent
Mother
Just
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Us
Nachos
• Orbits the sun in 88 days
• Smallest of the terrestrial planets
• Has impact craters on the surface from
huge rocks smashing into it
• Daytime temperature of more than
400⁰C
• Nighttime temperature as low as -200⁰C
• Due to heat radiating away quickly
• Almost no atmosphere
• Weak gravity
• Known as Earth's twin (similar diameter,
mass, gravity)
• Very weak magnetic field
• Rotates from east to west (not like other
planets)
• Impossible to see surface from earth due to thick pale yellow clouds
• Made of droplets of concentrated sulfuric acid
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Most of our knowledge comes from radar-mapping (1991)
Landscape has volcanic features, faulting, and impact craters
Lava covers about 80% of the surface of Venus
Atmosphere is mostly carbon dioxide and 3% nitrogen
• High pressure atmosphere
• Surface temperature of about 482⁰C
• Strong winds of over 300 km/hr
Takes 687 days to orbit the sun
Weaker gravity than Earth
Weak magnetic field
Tilt of Mars’ axis gives Mars four seasons
Each season is twice as long as Earth’s
Daily temperature of 27⁰C
Nightly temperature of -125⁰C
Atmosphere is about 95% carbon dioxide and 5% nitrogen and
argon
• Has polar ice caps
• Mostly frozen carbon dioxide and some frozen water
• Has many extinct volcanoes
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Takes 11.9 Earth years to complete one orbit
Rotates once every ten hours
Largest planet in the solar system
Twice the total mass of all other planets combined
Gaseous surface
Consists of alternating light and dark-colored bands that run parallel to its
equator
Dark bands are areas of sinking gases
Light bands are areas of rising gases
Wind blows between the bands
The Great Red Spot:
• Rises about 8km above the cloud tops
• Photographs indicate that the spots may be relatively calm areas that rotate slowly
within the turbulent atmosphere
• Strongest known magnetic field
• Takes nearly 30 Earth years to
complete one orbit
• Turns on its axis once every 10.7
hours
• Surface has colored bands (areas of
rising and sinking gases) parallel to
the equator
• Has fewer bands than Jupiter
• Wind speed is faster – 1800km/hr
• Takes 84 Earth years to complete one
orbit
• Not easily visible to the unaided eye
• Not discovered until 1781
• Average surface temperature is about -200⁰C
• Unusual features:
• Turns on its axis once every 17.2 hours
• Orbits the sun on its side (even though the magnetic field is upright)
• The side of the planet facing away from the sun was no cooler than the
side facing the sun
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Discovered in 1846
Takes 165 Earth years to orbit the sun
Rotates every 16.1 hours
Wind speeds up to 2200 km/hr
Surface temperature of -214⁰C
• Now known as a dwarf planet
(August 24, 2006)
• Composed of rock and ice
• International Astronomical Union (IAU) defines a planet as a
celestial body which:
• 1. is in orbit around the Sun
• 2. has sufficient mass to be a nearly round shape
• 3. has “cleared the neighborhood” around its orbit
• Why is Pluto no longer a planet?
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Relatively low mass
Not dense enough to be terrestrial (inner planet)
Not large enough to be Jovian (outer planet)
Orbit is on a different plane than the rest of the planets
• Glowing head and long, bright tail
• Head glows by reflected sunlight
• Most of the time, a comet is barely
visible even through a telescope
• Spend much of the time beyond the orbit of Pluto
• When a comet comes near the sun, solar wind drives particles
and gases away - this forms the tail
• Halley’s Comet:
• Most famous
• Returns every 76 years (last in 1986)
• Asteroids:
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Solid, rocklike masses
Most have irregular shape
Brightness changes as they rotate
Revolve around the sun in the same direction as the planets
• Most asteroids lie between Mars and Jupiter (asteroid belt)
• Ex. Ceres and Pallas – largest asteroids
• Meteoroid:
• Rock or icy fragment travelling in space
• May be as large as boulders or as small as sand grains
• Meteor:
• The light made by a meteoroid as it passes through Earth’s atmosphere
• Light is caused by friction between the rapidly moving meteoroid and the
atmosphere
• Meteorite:
• Part of a large meteoroid that survives its trip through the atmosphere
and strikes Earth’s surface
• 93% are stones (look like dark igneous rocks)
• Largest known stone weighs about a metric ton (Norton county, Kansas, in
1948)
• Other types of meteorites are irons or stony-irons.
• Shooting Star:
• Visible path of a meteoroid as it enters the atmosphere, becoming a
meteor
• As it enters the atmosphere the meteor burns and vaporizes
• If the meteor survives the entry and lands on the surface of Earth, it is
classified as a meteorite