Glossary

A

ASTRONAUT
A person who travels in space.

ASTRONOMER
Scientist who observes and studies planets, stars, and galaxies.

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 spins.

ATOM
The tiny building block that makes up everything.

B

BLACK HOLE
An invisible object in outer space formed when a massive star collapses from its own gravity. A black hole has such a strong pull of gravity that not even light can escape from it.

BLUR
To make less clear, to run together.

BIG BANG THEORY
A theory that says the universe began with a super-powerful explosion.

BOLT
A flash of lightning.

BOULDER
A very large piece of rock.

BRITTLE
Easy to break or crack.

BULGE
To swell or stick out; the part that swells or sticks out.

C

COLLAPSE
To fall down or fall to pieces.

COLLISION
A crash or forceful joining together.

COMET
A big ball of dirty ice and snow in outer space.

COSMONAUT
An astronaut from the former Soviet Union or present day Russia.

CRATER
A hole caused by an object hitting the surface of a planet or moon.

D

DETECT
To discover something which is hidden or unknown.

E

ENERGY
The power to do work.

ENVIRONMENT
Everything that surrounds anything.

EXPAND
To make larger.

F

FUEL
Anything that is burned to give heat or power.

G

GAMMA-RAY
An invisible form of energy that is given off by atoms.

GAP
An empty space.

GAS
A form of matter which is not a liquid or a solid. A gas will spread out to fill up all of the space that is open to it.

GRAVITY
The invisible force between objects that makes objects attract each other.

GRAVITATIONAL PULL
The attraction that one object has for another object due to the invisible force of gravity.

H

I

J

K

L

LUNAR MODULE
The section of the Apollo spacecraft designed to land on the Moon.

LUNAR ROVER
The car-like vehicle used by Apollo astronauts while exploring the Moon's surface.

M

MATTER
What all things are made of.

METEOR
An object from space that becomes glowing hot when it passes into Earth's atmosphere.

METEORITE
A piece of stone or metal from space that falls to Earth's surface.

METEOROID
A piece of stone or metal that travels in outer space.

MODULE
A part of a set that can be arranged together in different ways.

MYTHOLOGY
Old stories that usually explain how something came to be.

N

NUCLEAR FUSION
A process where atoms are joined and tremendous amounts of energy are released.

O

P

PAYLOAD
Cargo which is carried on the Space Shuttle.

PHYSICIST
A person who studies physics.

PHYSICS
The study of how objects (from the very tiny to the very big) behave.

PLAINS
Large pieces of flat land.

POLE
The point at either end of the invisible line known as the axis. Planets have a south pole and a north pole.

Q

R

RE-ENTRY
The return of a spacecraft into Earth's atmosphere.

REFLECT
To throw back light, heat, or sound.

REUSABLE
Can be used again.

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

SCATTERED
Going in many different directions.

SOLAR
Having to do with the Sun.

SOLAR FLARE
A storm or eruption of hot gases on the Sun.

SOLAR WIND
Streams of gas particles flowing out from the Sun.

SPACE PROBE
An unmanned research craft sent into space.

SPECTROGRAPH
The picture produced by a spectroscope.

SPECTROSCOPE
An instrument that breaks up the white light from a star into its different colors.

SUNSPOT
A dark area on the Sun's surface that is cooler than the area around it. Sunspots are caused by magnetic storms on the Sun.

SUPERNOVA
An explosion of a star that causes the star to shine millions of times brighter than usual.

T

U

UNIVERSE
The huge space which contains all of the matter and energy in existence.

V

VEHICLE
Something used to carry people and things over land or in space.

VISIBLE
Able to be seen.

VOLCANO
An opening in a planet's surface through which hot liquid rock is thrown up.

W

WEIGHTLESS
Having little or no weight; not feeling the effects of gravity.

X

Y

Z