Astro Cards

Front 1

crater

Back 1

bowl shaped feature on the moon,formed by impact of meteoroid hitting the moon

Front 2

Plains

Back 2

called maria (latin for "seas") by Galileo,made of black volcanic lava

Front 3

Rays

Back 3

pulverized rock thrown out oon crater formation

Front 4

rills

Back 4

long, narrow trenches on the moon, formed by noonquakes

Front 5

Mountain ranges

Back 5

in circular patterns bordering the moon's great plains

Front 6

Fault

Back 6

a break or fracture along surface which movement has occurred

Front 7

Age of lunar rocks

Back 7

3.1 to 4.4 billion years

Front 8

Waxing phase

Back 8

illuminated portion of moon getting larger

Front 9

Waning phase

Back 9

illuminated portion of moon getting smaller

Front 10

Crescent moon

Back 10

less than one half of moon's observed surface illuminated

Front 11

Gibous moon

Back 11

more than one half of moon's surface illuminated

Front 12

new moon

Back 12

phase where one half of moon's surface is illuminated fro a observer on earth ocurs at 12 noon local solar time

Front 13

first quarter noon

Back 13

phase where one half of moon's surface is illuminated for an observer on earth occurs at 6 p.m. local solar time

Front 14

full moon

Back 14

phase where all of moon's surface is lluminated for an observer on earth, occurs at 12 midnight local solar time

Front 15

last-quarter moon

Back 15

phase where one half of moon's surface is illuminated for an observer on earth, occurs at 6 a.m. local solar time

Front 16

period for phases of moon

Back 16

29.5 days

Front 17

eclipse

Back 17

darkening of one celestial body by another

Front 18

umbra

Back 18

darkest,smallest region of the shadow during an eclipse

Front 19

penumbra

Back 19

semi-dark region of the shadow during an eclipse

Front 20

solar eclipse

Back 20

event when moon's position is between the sun and moon and casts a shadow onto the moon

Front 21

total solar eclipse

Back 21

when the sun's surface is totally obscured by the moon

Front 22

patial solar eclipse

Back 22

when only a portion of sun's surface is obscurred by the moon

Front 23

annular eclipse

Back 23

solar eclipse with bright ring

Front 24

lunar eclipse

Back 24

event when earth's position is between the sun and moon and casts a shadow onto the moon

Front 25

total lunar eclipse

Back 25

entire face of moon obscured

Front 26

tides

Back 26

rise and fall of the ocean's surface due to gravitational forces of sun and moon

Front 27

spring tide

Back 27

maximum variation in tides, occurs at new and full moons when sun and moon's gravitational forces combine

Front 28

Neap tide

Back 28

minimum variation in tides, occurs at first-quarter and last-quarter phases of the moon when sun and moon's gravitational forces cancel

Front 29

Asteroids

Back 29

millions of planetary bodies predominantly found between mars and Jupiter, sizes range from 100's of kilometers to a few kilometers in diameter, believed to be early solar system material that never collected into a planet

Front 30

Meteroroid

Back 30

interplanetary metallic and stony objects that range in size from millimeters to few hundreds of meters

Front 31

Meteor

Back 31

a meteoroid that enters earth's atmosphere and gives off light due to friction of air

Front 32

Meteorite

Back 32

a meteor that strikes the earth's surface and is not burned up in earth's atmosphere

Front 33

Comet

Back 33

small object composed of dust and ice that revolves around the sun in highly elliptical orbit, characterized by luminous "tails" when orbit is close to the sun

Front 34

Oort cloud

Back 34

vast reservoir of long-term comets, far beyond orbit of Pluto

Front 35

Kuiper belt

Back 35

source region of short-term comets, between orbits of Neptune and Pluto

Front 36

Interplanetary dust

Back 36

also known as micrometeoroids, observed from earth by two phenomena called zodiacal light and Gegenshein

Front 37

Moons of Mars

Back 37

called Phobos and Deimos, very small size and thought to be captured asteroids

Front 38

Galilean moons of Jupiter

Back 38

called lo, Europa, Ganymede, and Callisto, discovered by Galileo in 1610, Ganymede is the largest moon in the solar system

Front 39

Titan

Back 39

largest moon of Saturn, the second largest moon in the solar system

Front 40

Triton

Back 40

largest moon of Neptune

Front 41

Charon

Back 41

moon of Pluto

Front 42

Calestial Sphere

Back 42

the huge imaginary dome with earth at tis center, on which the stars appear to be mounted

Front 43

Declination

Back 43

celestial latitude on the celestial sphere, angular measure in degreess north and south of celestial equator, 0 degrees at celestial equator, +90 degrees at north cleestial pole, -90 degrees at south celestial pole

Front 44

Right ascension

Back 44

celestial longitude on the celestial sphere, measured in units of hours form the clestial prime meridian (ohr) eastward to a maxium of 24 hours

Front 45

Celestial prime meridian

Back 45

half-circle that passes through the vernal equinox, the north celestial pole, and the south celestial pole

Front 46

Ecliptic

Back 46

the apparent path of the sun trace annually on the celestial sphere

Front 47

Celestial equator

Back 47

extension of earth's equator on the celestial sphere

Front 48

light year

Back 48

the distance light travels in a time of one year

Front 49

Parsec

Back 49

the distance to a star that exhibits a parallax of 1 second of arc

Front 50

Absolute magnitude

Back 50

the brightness a star would have at a distance of 10 pc

Front 51

apparent magnitude

Back 51

the brightness of a celestial object as observed from the earth, from original scale defined by Greek astronomer, Hipparchus

Front 52

H-R Diagram

Back 52

the chart obtained when absoulute magnitude of stars is plotted against their temperature

Front 53

Red giants

Back 53

large, cool stars to the upper right on the H-R diagram

Front 54

Main sequence

Back 54

the narrow band of sttars going from upper left to lower right on a H-R diagram