The Inner Planets Notes

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 Types Terrestrial Planets Dwarf 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 Too small to fully clear orbits, often found in Asteroid Belt or Kuiper Belt

Order of the Solar System Sun Inner Planets Mercury Venus Earth Mars Asteroid Belt Asteroids Ceres Outer Planets Kuiper Belt Oort Cloud

1st Rock - Mercury Dead planet, shrinking Extreme temperatures Thin atmosphere Fast orbit, slow rotation, year shorter than day! No moons Smallest planet

2nd Rock - Venus 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

3rd Rock - Earth One moon Only planet with life Ocean’s cover 75% of surface Study of Earth: Geology (3rd & 4th Quarter)

4th Rock - Mars 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

5th Rock - Ceres Dwarf planet Largest object in Asteroid Belt 1st a planet, then asteroid, now dwarf

Asteroid 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!!!