- Accretion disk
- Hot, swirling matter spiralling into a compact object, heated to extreme temperatures and glowing brightly.
- Alter
- A distinct identity state within a person with dissociative identity disorder.
- Astronomical unit (AU)
- The average Earth–Sun distance — about 149.6 million km — used as a yardstick for distances inside the Solar System.
- Base pair
- A rung of the DNA ladder: two complementary bases (A–T or C–G) joined across the helix.
- Big Bang
- The hot, dense, expanding state from which the observable universe emerged some 13.8 billion years ago.
- Brown dwarf
- A 'failed star' massive enough to fuse deuterium briefly but not hydrogen — sitting in the grey zone between a giant planet and a small star.
- Capsid
- The protein shell of a virus, often built from many copies of one or two protein subunits arranged with symmetry.
- Corona
- The Sun's outer atmosphere of superheated plasma, visible during a total eclipse.
- Cosmic horizon
- The edge of the volume of space from which light has had time to reach us.
- Cosmic inflation
- A hypothesised brief period of exponential expansion in the first fraction of a second after the Big Bang. Explains the universe's large-scale smoothness and flatness, but the underlying mechanism is still debated.
- Cosmic microwave background
- The faint, almost-uniform microwave glow filling the sky — the oldest light we can see, released about 380,000 years after the Big Bang when atoms first formed.
- Cosmological constant
- A uniform energy density of empty space, the simplest possible form of dark energy.
- Dark matter halo
- The roughly spherical envelope of dark matter that surrounds and shapes every galaxy.
- Degenerate matter
- Matter so dense that quantum pressure, not heat, holds it up against gravity.
- Dissociation
- A disconnection between thoughts, identity, consciousness, and memory.
- Ecliptic
- The roughly flat plane in which the planets orbit the Sun.
- Electron
- A negatively-charged elementary particle that surrounds the atomic nucleus in a cloud-like probability distribution.
- Event horizon
- The one-way boundary around a black hole — once inside, nothing can return to the outside universe.
- Exomoon
- A moon orbiting an exoplanet rather than a planet in our Solar System. No exomoon has been definitively confirmed.
- Expansion
- The stretching of space itself, carrying distant galaxies away from each other.
- Fusion
- The merging of lighter atomic nuclei into heavier ones, releasing energy — what powers stars.
- Galactic core
- The dense central region of a galaxy, often hosting a supermassive black hole.
- Genome
- The complete set of genetic instructions for an organism.
- Gluon
- The carrier of the strong force, the glue that holds quarks together inside protons and neutrons.
- Grain of sand
- Quantumaire's reference unit: 0.5 mm — what Earth would be if we shrank the universe to fit on a table.
- Gravitational lensing
- The bending of light by gravity — used to detect mass we cannot see directly.
- Habitable zone
- The orbital range around a star where temperatures permit liquid water on a rocky planet's surface.
- Heliosphere
- The vast bubble of charged particles streaming out from the Sun — the region of space dominated by the solar wind, ending at the heliopause far past Pluto.
- Helix
- A spiral structure — DNA forms two intertwined helices.
- Horizon
- The boundary beyond which information cannot reach us — for example, the edge of the observable universe.
- Hypergiant
- An exceptionally massive, luminous star nearing the end of its life.
- Khufu
- The Fourth-Dynasty pharaoh traditionally credited as the pyramid's builder, c. 2560 BCE.
- Kuiper belt
- A doughnut-shaped region of icy bodies beyond Neptune's orbit, home of Pluto and many dwarf planets.
- Light-year
- The distance light travels in one year — about 9.46 trillion kilometres.
- Limestone casing
- The polished outer layer that once made the Great Pyramid a smooth, gleaming surface.
- Main sequence
- The long-lived hydrogen-fusing stage where most stars, including the Sun, spend their lives.
- Molecular cloud
- A cold, dense region of interstellar gas — mostly molecular hydrogen — where new stars condense out of collapsing pockets.
- Multiverse
- A speculative collection of many universes beyond our own, predicted by some models (eternal inflation, the string-theory landscape, many-worlds). None currently confirmable by observation.
- Nucleus
- The dense core of an atom, made of protons and neutrons.
- Oort cloud
- A vast, faint, spherical shell of icy bodies surrounding the Solar System out to roughly 100,000 AU.
- Orbital
- Not really an orbit — a mathematical region around a nucleus where an electron is likely to be found.
- Organelle
- A specialised structure within a cell, like a tiny organ — nuclei, mitochondria, and chloroplasts are organelles.
- Orion correlation
- A speculative claim that the three Giza pyramids mirror the belt stars of Orion.
- Parsec
- An astronomical unit of distance — about 3.26 light-years, defined by stellar parallax.
- Plate tectonics
- Earth's outer shell is broken into moving plates whose slow grinding drives earthquakes, mountain-building, and volcanism — recycling crust and helping stabilise the climate over geological time.
- Psychogenic
- A physical change driven by the mind rather than by external biology.
- Pulsar
- A rapidly rotating neutron star that emits beams of radiation along its magnetic poles.
- Quantum
- The smallest discrete amount of a physical property — energy, charge, spin — that something can have.
- Quark
- A fundamental particle of matter. Quarks combine in twos and threes to form hadrons such as protons and neutrons.
- Quasar
- The brilliantly luminous core of a galaxy whose supermassive black hole is rapidly accreting matter. Quasars can outshine their entire host galaxy and are seen across most of the observable universe.
- Redshift
- The stretching of light's wavelengths to redder colours as space itself expands between the source and us. The more distant a galaxy, the more redshifted its light.
- Reference scale
- A fixed object you compare everything else to so that wildly different sizes become intuitive.
- RNA
- Ribonucleic acid — a single-stranded molecule that carries genetic and regulatory information; many viruses use it as their genome.
- Schwarzschild radius
- The radius at which an object's mass would form an event horizon if it were compressed into a sphere. For Earth, about 9 mm; for the Sun, about 3 km.
- Singularity
- The point at the centre of a black hole where the known laws of physics break down — where our current theories run out.
- Spiral arm
- A bright lane of stars, gas, and star formation winding through a spiral galaxy.
- Standard candle
- An astronomical object whose intrinsic brightness is known, so its apparent brightness reveals its distance. Type Ia supernovae are the workhorse example.
- Stellar radius
- The distance from the centre of a star to its visible surface.
- Strong force
- The most powerful of the four fundamental forces, dominant at the scale of an atomic nucleus.
- Supercluster
- A loose, gravitationally bound assembly of galaxy clusters — among the largest organised structures in the universe.
- Supernova
- The explosive death of a massive star — bright enough, briefly, to outshine a galaxy.
- Tidal lock
- When a moon or planet's rotation period matches its orbit, so the same face always points toward its companion.
- Type Ia supernova
- A thermonuclear supernova produced when a white dwarf in a binary system gathers enough matter to ignite runaway carbon fusion. Their consistent peak brightness makes them cosmic distance rulers.
- WIMP
- Weakly Interacting Massive Particle — a leading dark matter candidate that has yet to be detected.
