1. Universe Recap / Objects in the Universe

2. Universe / Gravity Recap
Which planet has the lowest gravity?
Pluto (Dwarf Planet)
Which planet has the highest gravity?
Jupiter
On which planet were you the “lightest”?
Pluto
On which object were you the “heaviest”?
Neutron Star
Why do you think you were the heaviest on that object?
It has the most gravity

3. Universe / Gravity Recap
Define mass
How much matter an object contains
Define Weight
Force of attraction between you and the Earth
What does the force of gravity depend on?
Your mass
Mass of the Planet you’re on
Distance from the center of the planet
What equation can we use to determine the force due to gravity?
F = Mm r2

4. Universe / Gravity Recap
Between mass and weight which one changes depending on which planet you’re on?
Weight. Mass stays constant but weight depends on gravity
Why did you have to jump 5 times?
To eliminate any experimental errors

5. Universe / Gravity Recap
On which moon/planet could you jump the furthest?
Moon
On which planet would you jump the shortest?
Jupiter
Why would you jump the shortest on that planet?
It has more gravity so you would be “weighed” down.

6. Objects in the Universe
Planets
Moons
Small Bodies in solar system with weak gravity and no atmosphere
Dwarf Planets
Comets
Asteroids
Meteoroids

7. What is a planet? A planet is a celestial body that
(a) has sufficient mass for its self-gravity assumes a nearly round shape, and
(b) is in orbit around a star, and is neither a star nor a satellite of a planet
But with this, Pluto should be a planet.

8. Theory changed
A planet is a celestial body that
(a) has sufficient mass for its self-gravity assumes a nearly round shape, and
(b) is in orbit around a star, and is neither a star nor a satellite of a planet, and
(c) has cleared the neighborhood around its orbit
Is pluto a planet then?

9. Objects in the Universe
Planets
Moons
Small Bodies in solar system with weak gravity and no atmosphere
Dwarf Planets
Comets
Asteroids
Meteoroids

10. Dwarf Planets Orbits sun Not enough mass to clear items out of orbit
Has own gravity
Not enough mass to clear items out of orbit
5 Dwarf planets

11. Comets Small body of ice, rocks and dust “Dirty Snowballs”
Gives off dust and gas in form of a tail when it gets close to the sun
Tail always points away from the sun

12. Asteroids Asteroid Belt Hundreds of thousands of asteroids
Small, irregularly shaped, rocky object
Most are located between Mars and Jupiter
Asteroid Belt
Hundreds of thousands of asteroids
570km to 4 m in diameter

13. Meteroid Rocky Body that varies in size. Smaller than asteroid
Enters Earths atmosphere and can become either a meteor or meteorite
Meteor: Bright streak of light. Meteroid burns up as it enters atmosphere
Meteorite: Meteroid that reaches Earths surface and doesn’t burn up