Understanding the technical jargon that makes up the science behind understanding the origins of the universe is made a little simpler with this helpful glossary.
Anisotropy: The variation of a physical property, depending on the direction in which it’s measured. For example, the temperature of the cosmic microwave background radiation is anisotropic.
Antimatter: Material composed entirely of antiparticles.
Antiparticle: A counterpart to every particle having the same mass but opposite properties at a quantum level (electrical charge, for example). The positively charged positron is the antiparticle of the negatively charged electron, for example.
Baryon: The family of heavy subatomic particles, which includes protons and neutrons, that interact through the strong nuclear force.
Big Bang: The widely accepted theory that says the universe started expanding roughly 14 billion years ago from an extremely dense and hot state.
Black hole: An object with such a strong gravitational field that nothing inside it can escape, including light.
Boson: Force-carrying fundamental particles, such as the photon (electromagnetic force) or the W and Z bosons (weak force).
Cosmic microwave background (CMB): The cooled remnant of the Big Bang, this microwave radiation fills the entire universe and can be observed today with an average temperature of about 2.725 kelvin.
Dark energy: A mysterious energy, thought to make up 70 per cent of the universe, which causes the universe to expand more and more quickly.
Dark matter: Unknown substances that are detectable in space by their gravitational effects, but which don’t shine like normal matter.
Doppler effect: The process by which the frequency or wavelength of light or sound seems to be altered by the motion of its source relative to the observer.
Electron: A light fundamental particle with a negative charge.
Fundamental particle: A particle, such as the quark or electron, which scientists believe cannot be subdivided further.
Galaxy: An enormous system containing billions of stars, plus vast amounts of dust and gas; the Milky Way, for example.
Hubble constant: The ratio of the speed with which galaxies are moving away (receding) from an observer to their distance from us, due to the expansion of the universe.
Nebula: A cloud of gas and dust in space that may emit, reflect, and/or absorb light.
Neutrino: A fundamental particle that has no electric charge and very little mass. It can pass through whole planets or stars without interacting with other particles.
Neutron: One of the baryons that make up atoms. Neutrons have no electrical charge and are made of one up quark and two down quarks.
Neutron star: The collapsed core of a massive star that remains after a supernova explosion. The remaining matter is compressed so tightly that negatively charged electrons and positively charged protons are forced together.
Photon: A small packet of electromagnetic radiation.
Planet: A large, near-spherical object that orbits a star.
Proton: A baryon found in the nucleus of every atom. Made of two up quarks and one down quark, a proton has a positive charge.
Pulsar: A fast-spinning, dense neutron star that emits light, radio waves, and/or X-rays in beams like the light from a lighthouse.
Quantum: The smallest possible unit of something that can exist.
Quark: The family of fundamental particles that combine to make baryons. Quarks come in six flavours: up, down, charm, strange, top, bottom.
Quasar: The bright centre of an active galaxy, probably fuelled by an enormous black hole that swallows matter.
Red giant: A large, bright star with a low surface temperature.
Red-shift: An increase in the wavelength of light or sound. In the case of distant galaxies, this increase is caused by the expansion of the universe.
SETI: The search for extraterrestrial intelligence.
Solar system: The Sun and all the celestial bodies that orbit it, including the planets and their moons, asteroids, comets and so on.
Star: A large mass of hot gas held together by its own gravity and fueled by nuclear reactions.
String theory: Theory of the universe, which says that the fundamental ingredients of nature are but tiny one-dimensional filaments called strings.
White dwarf: The remnant core of a star that has exhausted its nuclear fuel and settled into a solid ball of matter.
