# Universe Recap / Objects in the Universe

## Presentation on theme: "Universe Recap / Objects in the Universe"— Presentation transcript:

Universe Recap / Objects in the Universe

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

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

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

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.

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

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.

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?

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

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

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

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

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