Inner Planets Notes - Brian...

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The Inner Planets NotesThe Inner Planets Notes

How Many Planets?How Many Planets?

• How many planets are there in our Solar

System? 9? 8?

• 13 Planets!!!

– 4 terrestrial planets

– 4 gas planets

– 5 dwarf planets

Planet TypesPlanet Types

• Terrestrial Planets– “rocky planets”

– Mercury, Venus, Earth, Mars

– Orbit the Sun

– Clear their own orbits of other objects

• Dwarf Planets– Made of rock and ice

– Ceres, Pluto, Haumea, Makemake, Eris

– Orbit the Sun

– Too small to fully clear orbits, often found in Asteroid Belt or Kuiper Belt

Order of the Solar SystemOrder of the Solar System

• Sun

• Inner Planets– Mercury

– Venus

– Earth

– Mars

• Asteroid Belt– Asteroids

– Ceres

• Outer Planets

• Kuiper Belt

• Oort Cloud

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11stst Rock Rock -- MercuryMercury

• Dead planet, shrinking

• Extreme temperatures

• Thin atmosphere

• Fast orbit, slow rotation, year shorter than day!

• No moons

• Smallest planet

22ndnd Rock Rock -- VenusVenus

• Bright in night sky

• Earth’s “evil twin”, same size, same materials

• Thick, deadly atmosphere, massive lightning

• Heavily volcanic

• Hottest planet, runaway greenhouse effect

• No moons

33rdrd Rock Rock -- EarthEarth• One moon

• Only planet with life

• Ocean’s cover 75% of surface

• Study of Earth: Geology (3rd & 4th Quarter)

44thth Rock Rock -- MarsMars

• The Red Planet

• Half the size of Earth

• Thin CO2 atmosphere

• Used to have thicker atmosphere, liquid water on surface, maybe life

• Most studied and visited planet

• 2 moons, Phobos & Deimos

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55thth Rock Rock -- CeresCeres

• Dwarf planet

• Largest object in

Asteroid Belt

• 1st a planet,

then asteroid,

now dwarf

Asteroid BeltAsteroid Belt

• Asteroid Belt between Mars & Jupiter

• Asteroids: small, rocky objects, most under 1 km in diameter

• Over 100,000 asteroids in the belt

• “leftover” pieces from solar system creation

• Some have large elliptical orbits that bring them closer to the Sun than the Earth, and could smash into Earth!!!