The Inner Planets of the Solar System

Vocabulary practice flashcards covering the characteristics, compositions, atmospheres, and features of the inner planets (Mercury, Venus, Earth, and Mars).

Inner Planets

The planets Mercury, Venus, Earth, and Mars, which orbit closest to the Sun and are smaller and denser than the outer planets, having few to no moons or rings.

Outer planets

Planets in the solar system that often have dozens of satellites and rings composed of particles of ice and rock.

Silicates

Minerals that largely compose the crusts of the inner planets.

Iron and nickel

Metals that form the cores of the inner planets and comprise Mercury.

Inner planet terrain features

Craters, valleys, and volcanoes, which are found across all four inner planets.

Weather-generating inner planets

The three inner planets—Venus, Earth, and Mars—that have atmospheres sufficient to generate weather.

Mercury

The closest planet to the Sun and the smallest of the planets, which looks much like Earth's Moon, has no moons, and is one of the densest planets.

Mercury's magnetic field

A planetary magnetic field measuring only about $1\%$ of Earth's.

Mercury's daytime temperature

High temperature reaching up to $430^\circ\text{C}$ because its very thin atmosphere cannot keep heat out.

Mercury's nighttime temperature

Freezing temperature dropping as low as $-187^\circ\text{C}$ because its very thin atmosphere cannot keep heat in.

Venus

An inner planet about the same size as Earth that has no moon of its own and is the hottest planet due to a heat-trapping atmosphere.

Venus' atmosphere

A thick toxic atmosphere that traps heat and is composed of $96\%$ carbon dioxide, and nitrogen.

Sulphuric acid

A corrosive compound that, along with other corrosive compounds and very little water, makes up dense clouds in Venus' atmosphere.

"Morning star"

A name given to Venus because it is the brightest object seen in the sky, with the exception of Earth's moon.

Earth

The third inner planet and the largest of the four inner planets, notable as the only one with liquid water necessary for life.

Earth's atmosphere

An atmospheric layer that protects the planet from radiation and helps keep sunlight and warmth in to support life.

Mars

The fourth planet from the Sun, characterized by a solid core, a surface filled with craters, a smaller magnetic field, and lower density than Earth.

"Red Planet"

A name used for Mars due to the rust of iron on its surface.

Olympus Mons

The largest mountain in the Solar System, situated on the terrain of Mars.

Phobos and Deimos

The two small moons that orbit Mars.