National 5 Physics - Space

Planet

orbits a star, made round by its own gravity and has cleared its orbit of other material

Star

something that produces light and heat through nuclear fusion

Moon

orbits a planet

Dwarf planet

orbits a star, made nearly round by its own gravity but has not cleared its orbit of other material

Exoplanet

planet outside our solar system

Sun

closest star to Earth, we orbit it

Solar system

star plus everything that orbits that star (planets, comets etc)

Asteroid

small rocky objects orbiting the Sun that do not have the characteristics of planets or comets

Galaxy

large collection of stars, gas dust etc

Universe

everything that exists/all of space

GPS

Global Positioning System, a satellite system used for navigation

ISS

International Space Station

Geostationary satellite

a satellite with a period of 24 hours and an altitude of 36000 km which always remains above the same point on the Earth's surface.

Altitude

height above the Earth's surface that a satellite orbits at.

Period (of a satellite)

time it takes to complete one orbit.

Ion drive

a device that uses the acceleration of charged particles by an electric field to propel a spacecraft

Slingshot manoeuvre

the use of the movement and gravity of a planet to alter the direction and speed of a spacecraft

Re-entry

the return of a spacecraft into the Earth's atmosphere

Rocket

a device that is accelerated forwards by the reaction force of a gas being propelled out of the back.

Lightyear

the distance that light travels in one Earth year (365 days)

Big Bang

the theory which describes the formation and evolution of the early Universe from an infinitely dense, hot point to its current state.

Continuous spectra

a spectrum of light which consists of all wavelengths and has no gaps

Line emission spectra

a spectrum of light which consists of discrete wavelengths, producing lines of separate colours. Each element has a unique line spectrum.

Line absorption spectra

a spectrum of light produced by shining a continuous spectrum through a gas, resulting in dark lines being observed which correspond to the emission lines that would be produced by the gas.