Earth And Space Science Gt, Chapter 29 "the Planets"

Front 1

Asteroid

Back 1

Fragment of Rock that orbits the sun.

Front 2

Asteroid Belt

Back 2

The regions between the orbit of Mars and Jupiter in which most asteroids are found.

Front 3

Astronomical Unit

Back 3

Average distance betwen the earth and the sun, approximately 149.5 million km.

Front 4

Coma

Back 4

Spherical cloud of gas and dust that surronds the nucleus of a comet.

Front 5

Comet

Back 5

body of rock, dust, methane, ammonia, and ice that revolves around the sun in a long, eliptical orbit.

Front 6

Earth-grazer

Back 6

Asteroid that orbits the sun in an elongated ellipse that may pass close to the earth and sun.

Front 7

Ellipse

Back 7

oval whose shape is determined by two points within the figure.

Front 8

Epicycle

Back 8

small circular motion of the planets within thier orbits proposed as an explination for retrograde motion.

Front 9

Fireball

Back 9

brilliant flash of light produced by a meteor that vaporized quickly.

Front 10

Focus

Back 10

one of two points within an ellipse that determines the shape of the figure.

Front 11

Geocentric

Back 11

earth-centered

Front 12

Heliocentric

Back 12

sun-centered

Front 13

Inertia

Back 13

tendency of a moving body to remain in motion or a stationary body to remain at rest until an outside force acts on it.

Front 14

Iron Meteorite

Back 14

type of meteorite made of iron, with a characteristic metallic apperance.

Front 15

Jovian Planet

Back 15

any one of the first four outer planets---Jupiter, Saturn, Uranus, or Neptune---with properties similar to those of Jupiter.

Front 16

long-period comet

Back 16

comet with a period of several thousand or million years.

Front 17

meteor

Back 17

meteoroid that enters the earth's atmosphere.

Front 18

meteor shower

Back 18

phenomenon caused by the burning up of large numbers of meteors as they enter the earth's atmosphere.

Front 19

meteroite

Back 19

meteor or part of a meteor left after it hits the earth's surface.

Front 20

meteroid

Back 20

small bit of rock or metal moving through the solar system left by a comet or produced by a collision between asteroids.

Front 21

Oort cloud

Back 21

spherical cloud of dust and ice surronding the solar system that may contain as many as a trillion comets.

Front 22

Orbit Period

Back 22

time required for a planet to make one revolution around the sun.

Front 23

Retrograde Motion

Back 23

apparent periodic reversal in the motion of some planets as viewed from the earth.

Front 24

Short Period Comet

Back 24

comet with a period of up to 100 years.

Front 25

Stony meteorite

Back 25

most common type of meteroite simialr in compostion to rocks found on the surface of the earth.

Front 26

Stony-iron meteorite

Back 26

rare type of meteroite that contains both iron and stone.

Front 27

terrestrial planet

Back 27

anyone of the four planets closest to the sun---Mercury, Venus, Earth, and Mars---with properties similar to those on Earth.

Front 28

Trojan asteroid

Back 28

asteroid that orbits the sun just ahead of or behind the planet Jupiter.