Asteroid Belt
The region between the orbits of Mars and Jupiter where the most asteroids are found.

Astrophysics
The branch of astronomy and physics that deals with physical aspects of space objects.

Atmosphere
The layer of gas surrounding the earth or other planets. The upper atmosphere is the region of Earth’s atmosphere above the troposphere (which extends to about 20 km). Regions of the upper atmosphere are the stratosphere, mesosphere and thermosphere.

Aurora (or Southern/Northern Lights)
A luminous electrical atmospheric phenomenon usually of streamers of light in the sky above the northern or southern magnetic poles.
The release of atoms and molecules in the polar upper atmosphere that appears as permanent, ring shaped belts called Auroral Oval. They are caused by global electrical discharges.

Big Bang Theory
The theory that the universe was once clustered and at the ‘beginning’ it exploded out, as shown by the fact that objects are still moving out from the centre.

Black hole
An object whose gravity is so strong that its speed of movement exceeds the speed of light.

Comet
A small body of ice and dust which orbits the Sun.

Constellation
A group of stars that make a shape, often named after mythological characters, people, animals, and things.

Corona
The very hot outer layer of the Sun’s atmosphere, composed of superheated gases and extending into space.

Cosmic Rays
Nuclear and atomic particles moving through space at speeds close to the speed of light. They are thought to come from stars in the Milky Way galaxy.

Crater
A round ‘dent’ left in a planet or satellite from a meteoroid has hit.

Crust
The outer layer of Earth and other planets.

Galaxy
A large group of stars.

Gravity
A physical force attracting two bodies.

Gamma Rays
High energy radiation which can be generated by nuclear reactions

Heliosphere
The region starting at the Sun’s surface and extending to the limits of the solar system, well beyond the orbits of the most distant planets.

Hydrosphere
The water on or around the surface of a planet.

Ionosphere
The region of Earth’s atmosphere that extends from about 50 to 300 miles above the surface of the planet.

Jet Propulsion
Thrust generated by the rapid movement of gas which is forced out of the back of the engine.

Light year
The distance light travels in a vacuum in one year.

Lunar
Referring to the moon.

Lithosphere
The crust of a planet.

Magnetic Field
A field of magnetic force around the Sun and the planets, generated by electrical currents.

Meteor
A luminous occurrence caused when a meteoroid enters the atmosphere - this is more commonly known as a shooting star.

Meteorite
A part of a meteoroid that survives through the Earth’s atmosphere.

Meteoroid
A small rock in space.

Radiation
Energy transmitted through space as waves or particles.

Solar Flare
An explosive release of energy marked by a sudden brightening near a sunspot or on the solar surface.

Solar Wind
A hot, fast, deadly gas released from the Sun’s Surface . A solar wind can blow at 400 km/second and has temperatures in excess of 27,000 degress celsius.

Satellite
A body that revolves around a larger body.

STS
Originally, Space Transportation System, but now commonly stands for Shuttle Transportation System.

Sunspot
A dark, fringed blemish on the solar surface that is caused by a concentration of the Sun’s magnetic field.