PLANETS

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39.7-39.9
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PLANETS
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PLANETS
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PLANETS
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INNER PLANETS-MERCURY

• Planet nearest to the sun
• Completely circles sun in 88 Earth days
• Daytime is long and hot-can get up to 430C
• Nighttime is cold-can get up to -170C
• Atmosphere is about a trillionth as dense as the
  Earths atmosphere
• There are no winds to carry heat from one region
  to another

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INNER PLANETS-VENUS

• Second planet from the sun
• Average temperature is 460C which is too hot for
  oceans
• Takes 243 Earth days to make one full spin
• 225 days to make one revolution around the
  sun-this means a day on Venus lasts longer than a
  year.
• Spins counterclockwise.

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INNER PLANETS-EARTH

• Bluest planet- has more water surface than land
• Atmosphere is just dense enough to keep the
  oceans liquid
• Insulating atmosphere/relatively high daily spin
  which makes only a small lowering of temperature
  on the nighttime side of Earth

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INNER PLANETS-MARS

• A little more than half the Earths size
• Has a core, mantle, crust, and a thin, nearly
  cloudless atmosphere
• Seasons are nearly twice as long as Earth seasons
  because Mars takes nearly 2 Earth years to orbit
  the sun
• Atmosphere is 95 carbon dioxide and only 0.15
  oxygen
• Temperature at equator is 30C in the daytime to
  a chilly -130C at night.
• A Martian day lasts 24 hours and 37.4 minutes
• Since atmosphere has a low density and unequal
  heating, Martian winds are about ten times
  stronger then winds on Earth

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MARS-TWO MOONS

• Phobos-inner
• Phobos orbits at a distance of almost 6000
  kilometers in 7.5 hours
• Deimos orbits at a distance of 20,000 kilometers
  in 30.3 hours
• Deimos is about half the size of Phobos

DEIMOS
PHOBOS
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OUTER PLANETS-JUPITER

• Largest of all the planets
• Thought of as a failed star-composition is closer
  to the sun rather than the terrestrial planets
• more liquid than gaseous or solid
• Atmosphere is 82 hydrogen, 17 helium, and 1
  methane, ammonia, and other molecules
• Inner heat comes from gravitational contraction
• 28 moons
• Four largest moons are Io, Europa, Ganymede, and
  Callisto

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OUTER PLANETS-SATURN

• Composed of hydrogen and helium
• Lowest density of any planet
• rings are made of are made of chunks of frozen
  water and rocks
• All rings travel in independent orbits
• Outer rings travel slower than inner rings
• 23 moons beyond its rings

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SATURN'S MOONS

• Titan is the largest moon
• Titan has a methane atmosphere with atmospheric
  pressure greater than the Earths
• Titan surface temperature is -170C
• One side of Iapetus is very bright and the other
  is very dark

IAPETUS
TITAN
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OUTER PLANETS-URANUS

• Density is slightly greater than water
• Axis is tilted 98to the perpendicular of its
  orbital plane, in other words, it lies on its
  side
• No internal source of heat
• Its a cold place
• Has at least 21 moons
• Complicated faint ring system

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OUTER PLANETS-NEPTUNE

• Atmosphere is mainly hydrogen and helium, with
  some methane and ammonia
• Emits 2.5 times as much heat energy as it
  receives from the sun
• Has 8 moons in addition to its ring system

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NEPTUNE'S MOONS

• Triton orbits Neptune in 5.9 days in the
  direction opposite to the planets eastward spin
• Triton has twice as much mass as our moon
• Tritons has bright polar caps and geysers of
  liquid nitrogen
• Nereid takes nearly a year to orbit Neptune in a
  highly elongated elliptical path

NEREID
TRITON
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OUTER PLANETS-PLUTO

• Takes 438 years to make a single revolution
  around the sun
• Smaller than our moon
• Is among thousands of bodies beyond Neptune that
  orbit the sun in the Disk-shaped region known as
  the Kuiper-belt
• Pluto is no longer considered a planet, instead,
  it is the largest of the objects in the
  Kuiper-belt
• Has a moon named Charon
• Charon appears motionless in Plutos sky

PLUTO AND CHARON