Gr. 5 Solar System and Galaxy Review

comet

A ball of frozen dust and rock that orbits the sun and has a tail that glows

asteroid

Rocky objects revolving around the sun that are too small and numerous to be considered planets

outer planets

The four large planets known as gas planets (Jupiter, Saturn, Uranus, and Neptune) that orbit beyond the asteroid belt and are farthest away from the sun.

inner planets

The four solid, rocky planets planets closest to the sun; Mercury, Venus, Earth, and Mars also known as the terrestrial planets.

Milky Way Galaxy

a gigantic cluster of billions of stars that is home to our solar system

Solar System

a system made up of the eight unique planets, including Earth, and many smaller bodies such as asteroids, meteoroids, and comets, that orbit the sun

planet

an object that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit

Neptune

eighth planet from the Sun; is large and gaseous, has rings that vary in thickness, and is bluish-green in color

Mars

fourth planet from the Sun; appears reddish because of iron oxide in weathered rocks; has polar ice caps, a thin atmosphere, and two moons

galaxy

large group of stars including any objects orbiting the stars , dust, and gas held together by gravity;

Jupiter

largest planet and fifth planet from the Sun; has faint rings, many moons, an atmosphere formed mostly of hydrogen and helium, and its surface has continuous storms

Mercury

planet closest to the Sun; has a thin atmosphere with temperature extremes, an iron core, and many craters

Venus

second planet from the Sun; similar to Earth in mass and size; has a thick atmosphere and a surface with craters and volcanoes

Saturn

second-largest and sixth planet from the Sun; has a complex ring system, at least 31 moons, and a thick atmosphere made mostly of hydrogen and helium

Uranus

seventh planet from the Sun; is large and gaseous, has a distinct bluish-green color, and rotates on an axis nearly parallel to the plane of its orbit

asteroid belt

the region of the solar system between the orbits of Mars and Jupiter, where many asteroids are found

Earth

third planet from the sun; has an atmosphere that protects life and surface temperatures that allow water to exist as a solid, liquid, and gas