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| artificial satellite | A mechanical object launched by a rocket from Earth, which orbits a planet or a moon |
| asteroid | One of thousands of small bodies that orbit the Sun, mostly between the orbits of Mars and Jupiter. |
| astrobiology | The study of life on other planets |
| astronaut | A person who travels beyond the Earth & into space. |
| astronomer |
A scientist who studies the stars, planets and the universe |
| astronomical
unit (AU) |
The mean distance between Earth and the Sun (150 000 000 km). |
| astronomy | The scientific study of all objects in the universe. |
| astrophysics | A branch of astronomy concerned with the physical nature of heavenly bodies. |
| atmosphere | The 'blanket' of different gases that surrounds a planet or moon. |
| aurora | Atmospheric event seen in the polar regions - colourful light displays occur when solar winds meet the edge of Earth's magnetic field. Known as: Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) |
| black hole | Theoretical region of space with such intense gravity that light cannot escape; caused by the collapse of a star |
| chromosphere | The layer of crimson gas around the Sun. |
comet![]() |
A heavenly body consisting of a head and a tail. At the centre of the head is a nucleus of ice and rock. Find out more about comets here |
| constellation | An apparent group of stars in a definite region of the sky. There are 88 recognised & designated constellations |
| corona | The Sun's pearly white outer layer of gas, which extends more than a million kilometres; it is visible only during an eclipse. |
| cosmos | The universe |
| docking | The joining of one spacecraft to another in space |
eclipse![]() |
The blocking of light as one heavenly body passes between the Sun & another body, casting a shadow. Solar eclipse - when the Moon passes between Sun & Earth, casting a shadow on the Earth. Lunar eclipse - when Earth passes between Sun & Moon, casting a shadow on the Moon. Eclipses can be partial or total. |
| equinox | On about 21 March & 23 September each year, the Sun is directly over the Equator causing equal hours of day & night. |
| galaxy | A vast system of stars (thousands of millions) held together by gravity.There are millions of galaxies in the universe, in three main shapes: spiral, elliptical or irregular. Our galaxy is called the Milky Way & is spiral. |
| evening star | A planet seen in western sky after sunset, especially Venus |
| halo |
(1) A luminous ring seen around the Moon or Sun, caused by the refraction of light through high clouds. (2) A ring of old stars which surround the Milky Way in halo fashion |
| interstellar space | The regions of space beyond the solar system, among the stars |
| Iight-year | The distance travelled by a beam of light in 1 year; equal to 9.46 million million kilometres |
| meteor | A brief flash of light in the sky caused by a small body from space (a meteoroid) burning up in the Earth's atmosphere; often called a 'shooting star'. An estimated 100 million meteors occur each day |
| meteorite | A meteoroid that reaches Earth before burning up. Meteorites are typically lumps of stone (aerolites) or iron (siderites). One found near Grootfontein in Namibia weighed some 50 tonnes. |
| meteoroid | A small solid object moving through space |
| Milky Way | Our galaxy; it contains an estimated 200 000 million stars and is of the spiral type |
| moon | Any natural satellite of a planet. The Moon is Earth's only natural satellite |
| morning star | A planet seen in the eastern sky before sunrise, especially Venus |
| nebula | A hazy mass of gases and particles in space |
| nova | The apparent sudden brightening of a star in the night sky, thought to be caused when material drawn from a companion star ignites |
| orbit | The elliptical path of one celestial body around another |
| photosphere | The visible surface of the Sun |
| planetarium | A kind of projector that demonstrates the motions of heavenly bodies on a hemispherical ceiling |
planet![]() |
A major celestial body that does not give out its own light; usually orbiting a star. Find out more about planets here |
| quasar | Short for 'quasi-stellar object'; mysterious distant objects in the universe, which are powerful sources of radio waves and light |
| radiation | Electromagnetic waves or particles which travel through space carrying energy. Some forms are dangerous |
| radio astronomy | The study of radio energy emitted by celestial bodies |
| radio telescope | A telescope that collects radio waves from space |
| red shift | A shift in the light emitted by galaxies towards the red end of the spectrum, indicating that the galaxies are moving away from each other, which suggests the universe is expanding |
| satellite | A natural or artificial body that orbits a planet or moon |
| shooting star | A common type of meteor, caused by objects as small as 1 mm in diameter |
solar
flare ![]() |
An eruption of radiation on the Sun |
| solar system | The Sun and its satellites |
| solar wind | The constant stream of atomic particles flowing outwards from the Sun |
| solstice | On about 21 June & 22 December every year the Sun is at its furthest from the Equator, causing the longest or shortest day. |
| speed of light | Approximately 300 million metres per second; the fastest speed of any object in the universe |
| star | A heavenly body that generates its own heat and light. Our nearest star after the Sun is Proxima Centauri, 4.28 light-years away. Some 5000 stars are visible to the naked eye |
| Sun | Our star; a glowing ball of gases, mainly hydrogen and helium, 109 times wider than Earth, with an average surface temperature of 6000°C.Find out more about the sun here |
| sunspots | Dark patches on the Sun, 1500°C cooler than its average surface temperature. Cause is unknown |
| supernova | The explosive 'death' of a massive star which happens after it has consumed all its nuclear fuel. |
| universe | Everything that exists: matter, space & energy. Generally accepted that it's 15 billion years old, it seems to be expanding, like an inflating balloon |
If you use any part of this in your own work, acknowledge this source in your bibliography like this: Thomas, R. & Sydenham, S. Glossary of Astronomy
[Online] www.kidcyber.com.au (2000) updated March 2009 ©www.kidcyber.com.au Back to Space