- a person who travels in space. The word 'astronaut' comes from the Greek words meaning "space sailor."
astronomer
- a scientist who makes observations and studies planets, stars, galaxies any anything else in space
atmosphere
- the gases that surround a planet
axis
- An imaginary pole that runs through the earth from the north pole to the south pole - earth orbits around it
C
comet
- a small frozen mass of gas, dust, and ice. Comets revolve around the Sun or pass through the Solar System in elliptical orbit
crater
- a hole formed by a meteorite hitting the surface of a planet or a moon dark matter
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
