1. WARM UP
What two things determine the strength of an object’s gravitational force?

2. Planetary Formation and Moons!
How do scientists theorize the formation of planets? What are moons?
Planetary Formation and Moons!

3. Review Gravity is the force that pulls objects toward each other.
The strength of gravitational force depends on the
MASS of the object
DISTANCE between the objects

4. MASS
100,000 kg
100kg

5. DISTANCE
STRONG GRAVITATIONAL FORCE
WEAK GRAVITATIONAL FORCE

6. The Formation of a Planet
A star supernovas (explodes) and sends off HUGE amounts of dust and rock.
The gravitational force of a large rock pulls in smaller rocks and dust.
The new planet continues to “grow” until no more rocks and dust are left around it.

7. What is a solar system and what are the characteristics of ours?
Solar Systems

8. Review
Outer space contains planets, stars, natural satellites (moons) asteroids, meteoroids, and comets.

9. Solar Systems
A solar system is a collection of celestial bodies (planets, moons, asteroids, etc) orbiting a star.

10. Our Solar System Our solar system contains 1 star (the Sun) 8 planets
240 known moons
Comets (giant balls of ice)
Asteroids (flying space rocks)
Meteoroids (small asteroids)

11. The Formation of a Planet
Gravity holds a planet together in a spherical (round) shape.

12. Types of Planets

13. Types of Planets The two types of planets are
Terrestrial Planets – Rocky planets with a solid surface (examples: Earth, Mars, Mercury)
Gas Giants – Giant planets made mostly of gas (examples: Jupiter, Saturn, Uranus)

14. Terrestrial Planets
The 4 planets closest to the Sun are terrestrial planets (aka: rocky planets or inner planets).
Mercury
Venus
Earth
Mars

15. Asteroid Belt
The asteroid belt is a huge area containing asteroids and meteoroids located between the inner and outer planets.

16. Gas Giants
The 4 planets furthest from the Sun are Gas Giants (aka: Jovian/outer planets).
Jupiter
Saturn
Uranus
Neptune

17. The Kuiper Belt
The area surrounding our solar system composed almost entirely of comets.

18. Planetary Satellites
A planetary satellite is a natural object that orbits (revolves around) a planet due to gravity.
Also known as a MOON.
Planets don’t always have moons.
Some planets have many moons.

19. Phases of the Moon
The phases of the moon occur because of the moon’s revolution around Earth.
The lit portion of the moon that we see changes depending on the position of the moon around Earth.

20. Planets
Memory tip: “My Very Excellent Mother Just Served Us Nachos.”

21. EXIT SLIP What are the two different types of planets?
What is the major difference between the inner and outer planets in our solar system.