Planets Surfaces of planets have a…. Terrestrial or Rocky Surface (Inner Planets) 2. Gaseous Surface (Outer Planets) Mercury, Venus, Earth, and Mars Jupiter, Saturn, Uranus, Neptune

Gaseous Planets are considerably LARGER! Question 1: Which celestial object has a similar composition to Saturn? SATURN’S Diameter= 120,200 kilometers Made of Helium and Hydrogen. ( Has a small, rocky core) EARTH’S Diameter= 12,756 kilometers Saturn has a diameter 9.4 times larger than Earth’s.

Planets may have… RINGS!! Tidal Forces, breaking up debris, form them. Sometimes even their own satellites. Size of particles: 1mm-10 m in diameter. Made of rock and/or ice. Such as: Jupiter, Saturn, Uranus, and Neptune.

Movement of Planets is based on revolution around the … Question 3: What is this? SUN All on the same plane. Pluto is 17° off the plane.

And….rotation on the planet’s AXIS Also, while Earth has a tilt of 23.5º, Venus is tilted by 177º and Uranus is tilted by 98º! Mercury has no tilt!

Moons ORBIT Moons are studied in relation to the planet they… Question 4: Besides the moon, what else orbits the Earth? Moons are studied in relation to the planet they… Not all planets have moons, such as… ORBIT MERCURY AND VENUS

Asteroids: They were found in between Mars and Jupiter. Astronomers thought at one time… There were 13 planets. The 9 we are aware of (includes Pluto) and Ceres, Vesta, Juno, and Pallas. They were found in between Mars and Jupiter. One by one, they found many more objects like the 4 “new planets”. So, they changed them from “planets” to “dwarf planets” and identified their location as the asteroid belt.

Asteroids cont. What do asteroids revolve? ASTEROID BELT :Located between the inner planets and the outer planets. Def: Rocks greater than 100 m in diameter.

COMETS Question 5: Why does the tail emerge? The main body or head is composed ice and rock particles mixed with gas, methane and ammonia. (Similar to dirty snowballs) And a TAIL that emerges as the comet gets CLOSER to the sun during its orbit Tail Head

The tail always points _________ from the Sun. AWAY Question 6: Why would this be true? Comets have a unique long, narrow ________________ orbit. ELLIPTICAL Located at the very edge of the Solar System. Past Neptune’s orbit.

METEOROIDS Chunks of rock that move about the Solar System. Less than 100 m in diameter. Smaller than asteroids. Could be part of old comets so they are also… smaller than comets. http://video.foxnews.com/v/2166556494001/massive-meteor-rocks-russia-injuring-hundreds?intcmp=related?playlist_id=1821663211001

Can be called… A meteor : A meteoroid that burns up in the Earth’s atmosphere. OR A meteorite: A meteoroid that strikes a planet or moon.

Pluto debate: http://www.youtube.com/watch?v=FqX2YdnwtRc Pluto is located in the “Kuiper Belt” (Outside Neptune’s orbit). It is similar to the asteroid belt, but all material is made of ice/rocks (too far from the Sun). Astronomers found many “objects” in the same location, recently. Made them think back to Ceres, Vesta, Pallas, and Juno. So, the International Astronomical Union (IAU) met in 2006 to settle the matter. Decided Pluto would be considered a “Dwarf Planet”. The “dwarf planets” are round like planets, but do not clear out their orbits of debris.

Take a moment to answer the “Follow-Up Questions” on your own Take a moment to answer the “Follow-Up Questions” on your own. Try not to use your notes…

Add the following terms to your “SUPER CONCEPT MAP” list on the bottom of p. 23: Ceres Asteroids IAU 8 Pluto Comets Kuiper Belt Rings Orbit Rock Meteors Moons Meteoroids Sun Asteroid Belt 9