1. The Inner Planets Notes

2. 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

3. 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

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

5. 1st Rock - Mercury Dead planet, shrinking Extreme temperatures
Thin atmosphere
Fast orbit, slow rotation, year shorter than day!
No moons
Smallest planet

6. 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

7. 3rd Rock - Earth One moon Only planet with life
Ocean’s cover 75% of surface
Study of Earth: Geology (3rd & 4th Quarter)

8. 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

9. 5th Rock - Ceres Dwarf planet Largest object in Asteroid Belt
1st a planet, then asteroid, now dwarf

10. 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!!!