Glossary

[ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ]

A

ASTEROID
A rocky space object that can be a few feet wide to several hundred miles wide. Most asteroids in our solar system orbit in a belt between Mars and Jupiter.

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

BACTERIA
Living things that have only one cell and are so small they can only be seen with a microscope.

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

CELSIUS
A metric temperature scale in which water freezes at 0 degrees and boils at 100 degrees.

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

DEBRIS
Broken, scattered remains; rubble; pieces of rubbish or litter.

DETECT
To discover something which is hidden or unknown.

E

ELLIPTICAL
Shaped like an egg that has ends which are equal.

ENERGY
The power to do work.

ENVIRONMENT
Everything that surrounds anything.

EXPAND
To make larger.

F

FRAGMENT
A broken piece of something.

FUEL
Anything that is burned to give heat or power.

G

GALAXY
A giant collection of gas, dust, and millions or billions of stars.

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

HURRICANE
A very, very strong windstorm where the wind blows in circles at more than 46 kilometers per hour. Heavy rains often come with the winds.

I

J

K

KILOMETER
1,000 meters. A kilometer equals 0.6214 miles.

L

LIGHT YEAR
The distance light can travel in one year, which is 9,500,000,000,000 kilometers.

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

MASS
The amount of matter in an object.

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

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

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

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

PARTICLE
A very, very tiny piece of matter such as an electron, proton, or neutron found inside of an atom.

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

RADIO WAVE
A type of energy that is made by charged particles such as electrons moving back and forth.

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

SATELLITE
An object that moves around a larger object. There are natural satellites such as moons and there are man-made satellites such as the Hubble Space Telescope.

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

TELESCOPE
A device which creates a larger image of a far away object.

U

ULTRAVIOLET RAY
An invisible form of energy which is given off by the Sun. Ultraviolet rays cause people to get sunburned.

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

V

VALLEY
A piece of low land lying between hills or mountains.

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

WATER VAPOR
Water which is in the form of a gas.

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

X

X-RAY
An invisible form of energy which can go through most solid objects.

Y

Z

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