Chapter 21: The Solar System

What is Pluto’s current classification?

Streak of light made by a glowing rocky particle moving through Earth’s atmosphere

The outer planets have atmospheres composed mostly of

chunks of rock and ice that orbit the Sun between Mars and Jupiter

Because Mercury’s mass is so small, it

How is Venus unlike other planets?

Why do scientists think that liquid water might have once existed on Mars?

Source of short-period comets in the outer part of the solar system

Which shape describes a planet’s orbit?

Earth is the only planet with a wide variety of life because of its

Which planet is the solar system’s largest?

Depression formed when a meteorite hits Earth

The planets in the solar system are so far apart that the distances b/w them in are measured in

Small, rocky particle that strikes a planet or moon

Why is Venus’s average surface temperature greater than Mercury’s?

Why is Venus the hottest inner planet?

small, rocky particle that moves through space

All the inner planets

Which planet has a moon larger than the planet Mercury?

Which inner planet has the longest period of revolution and why?

Which statement is true of every outer planet?

All the outer planets are made mostly of

What keeps planets in orbit around the Sun?

Comets form a glowing tail when

An object that orbits the Sun, and has a mass greater than the mass of other objects near it is