1. THE SOLAR SYSTEM

2. Measuring Distances in the Solar System
1 AU is the average distance between the Sun and the Earth ( km)
1 AU = km
Jupiter is 780 million km from the Sun, therefore, Jupiter is 5.2 AU from the Sun

3. Planets Planets must: Be in orbit around a star (such as the Sun)
Have enough mass to be pulled into a stable sphere shape by gravity
Dominate its orbit (mass must be greater than anything else that crosses its orbit)

4. INNER PLANETS (Terrestrial plants): Mercury, Venus, Earth, and Mars
located closest to the sun
composed primarily of rock and metals; have solid surfaces
have high density
slow rotations
no rings and few satellites (moons)

5. OUTER PLANETS (Gas Giant planets): Jupiter, Saturn, Uranus, and Neptune
located further from the sun
composed mostly of gases (“gas giants”)
low densities
have rapid rotation
have rings and many satellites (moons)

8. Dwarf planets: orbit the Sun and have spherical shape but do not dominate their orbits. For example, in 2006 it was determined that Pluto was NOT a true planet because it does not dominate its orbit.

9. Other Objects in our
Solar System

10. Asteroids
small celestial objects in the Solar System composed of rocks, minerals and metals
smaller than planets, range in size, have no definite shape
lots located in the asteroid belt between the orbits of Mars and Jupiter (this asteroid belt also separates the inner and outer planets)

11. Satellites
small celestial bodies that orbit a larger one (planet) in a fixed path (example – moons)

12. Meteoroids
celestial objects even smaller than asteroids composed of rock and iron or dust – many are asteroid fragments
can vary in size, from the size of dust particles to the size of buildings
When they are caught in the Earth’s atmosphere, friction causes them to burn up, creating a streak of light across the sky. They are then referred to as Meteors or A SHOOTING STAR!!! (Which occur once every 15 minutes on average).
If the meteor does not burn up completely, small pieces may land on the surface of the Earth, which is referred to as a Meteorite

14. Comets
large chunks of ice, dust and rock that orbit the Sun (the orbit can take a few years to a hundred thousand years) (nicknamed “Dirty Snowballs”)
can be 100m to 40 km in diameter
Short-period comets: originate from just beyond Neptune and orbit the Sun in less than 200 years (for example, Halley’s Comet which takes years to orbit)
Long-period comets: originate from a spherical cloud of debris further than Pluto and orbit the Sun in more than 200 years (for example, Hale-Bopp Comet which takes 2380 years to orbit)
When comets come close to the Sun, the surface sublimates (changes from solid to gas) and the icy nucleus heats up; therefore, gases and dust escape in cloud called a “coma”. Radiation and solar wind from the Sun exert a force on the coma causing a gaseous tail.