Dwarf Planets and Other Objects

Asteroids and moons might form by which of the following processes?

• Condensation of gas and dust in space

• Direct fusion of stars

• Evaporation of planetary atmospheres

• Melting of comets

A dwarf planet is characterized by which of the following?

• It orbits the Sun, has enough mass for a nearly round shape, but has not cleared its orbital path.

• It is the largest planet in the solar system.

• It has a ring system and many moons.

• It is made entirely of gas and has no solid surface.

A dwarf planet is:

• a type of star

• a small celestial body that orbits the sun and has not cleared its orbit of other debris

• a moon of a planet

• a comet

The characteristics of comets and asteroids are:

• Comets are icy and have tails when near the Sun; asteroids are rocky and do not have tails.

• Comets are rocky and found in the asteroid belt; asteroids are icy and found in the Kuiper belt.

• Both comets and asteroids are made of gas and have visible tails.

• Comets and asteroids are both only found near Earth.

Define: meteoroid

• A meteoroid is a small rocky or metallic body in outer space.

• A meteoroid is a type of comet found in the Earth's atmosphere.

• A meteoroid is a large planet in our solar system.

• A meteoroid is a star that emits light.

Define: meteorite

• A meteorite is a meteoroid that survives its passage through Earth's atmosphere and lands on Earth's surface.

• A meteorite is a type of cloud that forms during thunderstorms.

• A meteorite is a star that explodes in space.

• A meteorite is a planet that orbits the Sun beyond Neptune.

Reading Check: The largest dwarf planet is ________ and the smallest dwarf planet is ________.

• Pluto and Haumea

• Eris and Ceres

• Ceres and Haumea

• Eris and Haumea

Are you more likely to see a meteor or a meteoroid?

• Meteor

• Meteoroid

Copy the table below and list the major characteristics of a dwarf planet. Object: Dwarf Planet Defining Characteristic: ____________

• A dwarf planet is a celestial body that orbits the Sun and is spherical in shape but has not cleared its orbit of other debris.

• A dwarf planet is a star that emits its own light and heat.

• A dwarf planet is a planet that has cleared its orbit of all other objects.

• A dwarf planet is a comet that has a visible tail when close to the Sun.

Based on your results, explain why impact craters on moons and planets differ. (MiniLab)

• Because moons and planets have different atmospheres and surface conditions.

• Because all craters are formed in the same way regardless of location.

• Because craters only form on planets, not moons.

• Because moons and planets are the same and have identical craters.