The Solar System contains 1 star, 8 planets, and 63 major moons. It is divided into inner and outer planets, with the inner planets being smaller, rocky, and closer to the Sun, and the outer planets being larger, gaseous, and further from the Sun. In addition to planets and moons, the Solar System contains asteroids, comets, and meteoroids. Comets are dirty snowballs composed of dust, rock and frozen gases like methane and ammonia that reflect light from the Sun as they orbit.

1. The Solar System
• 1 star
• 9 8 planets
• 63 (major) moons
• asteroids, comets, meteoroids

3. Inner Planets
•Mercury, Venus, Earth
and Mars
•Close to Sun
•Smaller
•Rocky, solid surfaces
•High densities
•Slow rotation
•No rings
•Few moons
Outer Planets
•Jupiter, Saturn,
Uranus, and Neptune
•Far from Sun
•Larger
•Gaseous surface
•Low densities
•Fast rotation
•Many rings
•Many moons

4. Terrestrial planets

5. Jovian planets (and earth)

6. Asteroids - rocks with sizes greater than 100m across
Three asteroids
hit the Earth
every 1 million
years!

7. Known asteroid impact sites

8. Meteors –– interplanetary
rocky material smaller than
100m (down to grain size).
•called a meteor as it burns
in the Earth’’s atmosphere
•if it makes it to the ground,
it is a meteorite

9. Comets
Dirty snowballs - dust and rock in methane, ammonia and ice
All light is reflected from the Sun - the comet makes no light of its own
Halley’s Comet in 1986
The nucleus is a few km in diameter

10. Comets
Dirty snowballs - dust and rock in methane, ammonia and ice
All light is reflected from the Sun - the comet makes no light of its own
Halley’s Comet in 1986
The nucleus is a few km in diameter