Planets

Front 1

astronomy

Back 1

the study of the moon, stars, and otherobjects in space

Front 2

axis

Back 2

imaginary line that passes throughEarth's center and the North and Southpoles, about which Earth rotates.

Front 3

rotation

Back 3

spinning on an axis

Front 4

revolution

Back 4

movement of an object around anotherobject

Front 5

orbit

Back 5

path of an object as it revolves aroundanother object in space

Front 6

solstice

Back 6

the two days of the year on which the sunreaches its greatest distance north or south ofthe equator

Front 7

equinox

Back 7

equinoxthe two days of the year on which neitherhemisphere is tilted toward or away from thesun

Front 8

phases

Back 8

one of the different apparent shapes of the moonas seen from Earth

Front 9

full moon

Back 9

the moon's illuminated side faces earth andappears as a fully-lighted disk

Front 10

new moon

Back 10

moon phase in which the moon's unilluminated side is facing Earth

Front 11

tide

Back 11

tide periodic rise and fall of the water level inthe oceans and other large bodies of water

Front 12

Mars

Back 12

fourth planet from the Sun; has polar ice caps, athin atmosphere, and a reddish appearancecaused by iron oxide in weathered rocks and soil

Front 13

Earth

Back 13

Earththird planet from the Sun; has an atmospherethat protects life and surface temperatures thatallow water to exist as a solid, liquid, and gas

Front 14

Venus

Back 14

second planet from the Sun; similar to Earth inmass and size

Front 15

Mercury

Back 15

smallest planet, closest to the Sun; does not havea true atmosphere; has a surface with manycraters and high cliffs

Front 16

Milky Way

Back 16

name of the galaxy to which our solar systembelongs

Front 17

universe

Back 17

huge group of single stars, star systems, starclusters, dust, and gas bound together by gravity

Front 18

galaxy

Back 18

a huge group of single stars, star systems, starclusters, dust, and gas bound together by gravity

Front 19

outer planets

Back 19

Jupiter, Saturn, Uranus, and Neptune; sometimes called gas giants

Front 20

Pluto

Back 20

a dwarf planet in our solar system

Front 21

Neptune

Back 21

distant planet of the solar system, eighth inorder from the sun; appears blue

Front 22

Uranus

Back 22

distant planet of the solar system, seventh inorder from the sun; spins almost entirely on its side

Front 23

Saturn

Back 23

Saturnsixth planet from the sun in the solarsystem, circled by a system of broad, flat rings

Front 24

Jupiter

Back 24

the largest planet in the solar system, a gas giantthat is the fifth in order from the sun and one ofthe brightest objects in the night sky

Front 25

meteorite

Back 25

a meteoroid that passes through the atmosphereand hits Earth's surface

Front 26

asteroid

Back 26

rocky objects revolving around the sun that aretoo small and numerous to be considered planets

Front 27

rocket

Back 27

device that expels gas in one direction to movein the opposite direction

Front 28

satellite

Back 28

an object that revolves around another object inspace

Front 29

probe

Back 29

spacecraft that has various scientific instrumentsthat can collect data, including visual images, buthas no human crew