The Inner Planets

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The Inner Planets

• How are the inner planets similar to one another?
• The terrestrial planets are relatively small and
  have solid, rocky surfaces.
• terrestrial planet one of the highly dense
  planets nearest to the sun Mercury, Venus,
  Earth, and Mars.

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The Inner Planets
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The Inner Planets, continued

• Mercury has extreme temperatures.
• Mercury is the closest planet to the sun.
• One year there is only 88 days on Earth.
• The side of Mercury facing the sun can reach 720
  K. The side facing away from the sun is only 103
  K.
• Mercury is covered by craters.

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The Inner Planets, continued

• Thick clouds on Venus cause a greenhouse effect.
• Venus has a thick atmosphere containing large
  amounts of sulfuric acid.
• The atmospheric pressure on Venus is 90 times
  that of Earth.
• A runaway greenhouse effect keeps the surface
  temperature above 700 K.

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The Inner Planets, continued

• Earth has ideal conditions for living creatures.
• Earth is the only planet known to harbor life.
• hydrosphere the portion of Earth that is water
• The atmosphere protects Earth from radiation.
• Earths atmosphere is 78 nitrogen, 21 oxygen,
  and 1 carbon dioxide and other gases.
• The atmosphere protects Earth from harmful
  radiation and high-energy particles emitted by
  the sun.

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The Inner Planets, continued

• Many missions have explored the planet Mars. Mars
  has many extreme landforms.
• The Martian volcano Olympus Mons is the largest
  mountain in the solar system.
• The surface of Mars is red from large amounts of
  iron oxide in the soil.

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The Inner Planets, continued

• An asteroid belt lies beyond the orbit of Mars.
• The dwarf planet Ceres is in the asteroid belt.
• asteroid a small, rocky object that orbits the
  sun most asteroids are located in a band between
  the orbits of Mars and Jupiter
• dwarf planet a celestial body that orbits the
  sun, is round because of its own gravity, but has
  not cleared its orbital path

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The Gas Giants

• What are gas giants?
• The outer planets are much larger than the inner
  planets and have thick, gaseous atmospheres, many
  satellites, and rings.
• A gas giant is a planet that has a deep, massive
  atmosphere Jupiter, Saturn, Uranus, and Neptune.
  All the gas giants have rings and satellites.

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The Gas Giants
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The Gas Giants, continued

• Jupiter is the largest planet in the solar
  system.
• Jupiter is big enough to hold 1300 Earths.
• Jupiter rotates once around its axis in less than
  10 hours.
• Jupiters atmosphere has swirling clouds of
  hydrogen, helium, methane, and ammonia.
• Jupiter has more than 60 satellites.

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The Gas Giants, continued

• Saturn has the most extensive ring system.
• Saturn is 95 times the mass of the Earth and
  takes over 29 y to orbit the sun. It rotates in
  10.7 h.
• Saturns rings are narrow bands of tiny particles
  of dust, rock, and ice.
• Saturn has more than 40 satellites.
• Saturn may still be forming.
• Saturn radiates three times more energy than it
  receives from the sun.

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The Gas Giants, continued

• Uranus and Neptune are blue gas giants.
• They hold thick, gaseous atmospheres composed of
  hydrogen, helium, and methane.
• The methane gives both planets a bluish color.
• Uranus is 14 Earth masses, and it takes about 84
  y to orbit the sun at its distance of 19 AU.
• Neptune is 17 Earth masses, and takes
  approximately 164 y to orbit the sun at a
  distance of 30 AU.

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Beyond the Gas Giants

• What type of bodies lie beyond the gas giants?
• Beyond the gas giants are numerous small bodies
  composed of ice and rock.
• Not all large objects in the solar system are
  planets.
• The scientific definition of planet was decided
  upon in 2006 by the International Astronomical
  Union.
• Pluto, formerly considered a planet, was
  reclassified as a dwarf planet.

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Beyond the Gas Giants, continued

• There are many objects beyond Neptune.
• Beyond Neptune lies the Kuiper Belt.
• The Kuiper Belt contains many small bodies of ice
  and rock.
• Scientists think that these bodies are the
  remnants of the material that formed the solar
  system.
• At least two dwarf planets, Pluto and Eris, can
  be found in the Kuiper Belt.