The Moon: Glossary

A

accumulated

to gather or pile together

astronaut

a person who travels beyond the earth's atmosphere

astronomer

an expert in the study of the Sun, Moon, stars, planets, and other space bodies

atmosphere

all the gases which surround a star, like our Sun, or a planet, like our Earth

axis

an imaginary straight line around which an object rotates

C

comet

body of ice, gas, and dust that orbits the sun

crater

a hole caused by an object hitting the surface of a planet or moon or a depression around the opening of a volcano

D

debris

the remains of anything broken down or destroyed

diameter

the distance through a circle or sphere from one side to the other

E

eclipse

the hiding or dimming of one celestial object by another object

erosion

the movement of weathered rocks and soil

G

gibbous

what the moon is called when the majority of the nearside is illuminated and only a diminishing crescent remains in darkness, culminating in the "full moon" when the Moon and the Sun are on opposite sides of the Earth

gravity

a mutual physical force attracting two bodies, influenced by the mass of the two objects and the distance between the two objects

L

lunar

of, involving, caused by or affecting the moon; from the Latin word "luna", which means moon

lunar eclipse

occurs when the Earth passes between the Moon and the Sun

lunar module

the section of the Apollo spacecraft designed to land on the Moon

M

mass

the measure of the amount of matter in an object

meteor

A shooting star or actually space debris that enters and burns up in earth's atmosphere

moon

a small natural body which orbits a larger one. A natural satellite

moonrise

the moon coming up over the horizon

N

NASA

the National Aeronautics and Space Administration which is in charge of all space programs for the United States

new moon

the phase of the Moon when the Moon is lined up between the Earth and the Sun. We see the side of the Moon that is not being lit by the Sun

O

orbit

the path followed by an object in space as it goes around another object; to travel around another object in a single path

P

phase

the particular appearance of a body's state of illumination, such as the new, full or crescent phases of the Moon

phenomena

Something impressive or extraordinary

R

revolve

to move in an orbit or circle around something

rotate

to turn around a center point, or axis, like a wheel turns on a bicycle

S

satellite

a smaller body which revolves around a larger body; a natural or an artificial moon. Earth-orbiting spacecraft are called satellites

solar eclipse

a shadow which falls on an area of Earth when the Moon moves between the Sun and Earth

T

telescope

a device which makes a larger image of a faraway object

U

universe

the huge space which contains all matter and energy

W

wane

to decrease in size

wax

to increase in size