Earth and Beyond Glossary

  • lunar calendar: a calendar based on lunar cycles (phases of the Moon)

  • solar calendar: a calendar whose dates indicate the position of the Earth in its orbit around the Sun

  • constellation: a group of stars that when viewed from Earth form a pattern in the sky

  • star lore: mythical stories about the stars, planets and constellations

  • telescope: an instrument designed to make distant objects appear nearer and magnified

  • prograde: direct or forward motion (proceeding from west to east across the sky)

  • retrograde: reversed motion (proceeding from east to west across the sky)

  • moon: a body that orbits around a planet or small body such as an asteroid (not a star)

  • lunar: related to the Moon, e.g. lunar surface (Moon's surface), lunar day (the Moon's day)

  • eclipse: the blocking of light coming from a celestial object, for example, a solar eclipse or a lunar eclipse

  • gravity: the force that attracts a body towards the centre of the Earth or towards any other celestial body having mass

  • mass: the quantity of matter an object contains

  • weight: the force exerted on a mass due to gravity

  • acceleration due to gravity: the acceleration given to an object by the attractive gravitational force of the Earth or other celestial body

  • gravitational force: the force that attracts an object with mass towards another object with mass

  • ecosystem: a community of living organisms and their interaction with the environment

  • intertidal zone: an area that is above water at low tide and under water at high tide (i.e. lies between low and high tide levels)

  • tides: the regular rise and fall of the oceans (and some rivers and lakes) twice per day caused by the gravitational attraction of the Moon and to a lesser extent the Sun

  • tidal bulge: a swell in the sea level in line with the Moon on either side of the Earth (along the Earth-Moon line)

  • spring tides: extreme tides with the maximum difference between low and high tides which occur when the Earth, Moon and Sun are in alignment

  • neap tides: tides with the minimum difference between low and high tides which occur when the Moon and Sun are at right angles to each other

  • sphere: any round object that has a surface that is the same distance from its centre at all points, for example, a ball or globe

  • axis: a real or imaginary straight line about which something turns; the imaginary axis of the Earth passes through the North and South Pole

  • rotation: the spinning of the Earth (or other object or planet) on its axis

  • revolution: the orbit of Earth (or other object or planet) around the Sun

  • day: the length of time it takes for a planet to spin once on its axis

  • orbit: the path followed by a planet , moon, or other object in space as it travels around another object; the path of the Earth around the Sun is an orbit

  • solar energy: energy from the Sun's light and heat

  • intensity: the concentration or amount of something

  • oblique: at an angle other than 90 degrees, slanting inward

  • direct: the shortest way

  • indirect: not direct, by a longer way

  • equator: an imaginary horizontal line around the middle of the Earth, at an equal distance from the North Pole and the South Pole

  • equinox: occurs twice a year (around 20 March and 22 September) when the Sun's rays fall directly on the Earth's equator

  • hemisphere: one half of a sphere or globe; the Earth is divided at the equator into the Northern and Southern hemispheres

  • tilt: to slant or tip

  • season: each of the four divisions of the year (spring, summer, autumn, winter) which have different weather patterns and daylight hours

  • solstice: occurs twice in a year (around 21 June and 21 December), when the Sun's rays strike the Tropic of Capricorn (southern summer solstice) or the Tropic of Cancer (northern summer solstice) directly

  • fossil fuels: a natural fuel such as coal, oil or natural gas, formed in the geological past from the remains of living organisms

  • decompose: to break down or decay

  • coal: brown or black rock that can be ignited and burned, and which consists of carbonised plant matter

  • crude oil: a dark oil found in rock formations deep underground, used as fuel

  • natural gas: a flammable gas, consisting largely of methane, occurring naturally underground and used as fuel

  • renewable: something of which there is an unlimited supply found in nature, or which can be reused

  • non-renewable: something of which there is a limited supply, or which can only be used once

  • vegetation: the general word used for plant growing in an area or region

  • photosynthesis: the process whereby green plants use sunlight (energy), water and carbon dioxide to produce glucose, which is food for the plant; oxygen is released during this process

  • cellulose: a carbohydrate which plants use to form leaves and stems

  • glucose: a carbohydrate produce by most plants, which is energy rich

  • starch: a carbohydrate consisting of a large number of glucose units

  • observatory: a room or building housing a telescope or other scientific equipment for observations and research, especially of objects in space.