This page gathers the 88 dictionary entries belonging to the domain “Astrophysics”, as labelled by Wiktionary. Each word leads to its full entry: definitions, etymology, pronunciation, examples.
- absolute horizon noun A boundary in spacetime, defined with respect to the external universe, inside which events cannot affect an external observer.
- accelerating universe noun A theory that describes and seeks to explain the seemingly increasing rate of the expansion of the universe.
- accretion noun The formation of planets, stars, and other celestial bodies by the aggregating of matter drawn together by gravity; also, the growth of a…
- accretion disk noun A structure formed by matter falling into a gravitational source such as a galaxy, black hole, or protostar.
- antisun noun A hypothetical sun composed of antimatter.
- antiuniverse noun A conjectured universe formed from antimatter.
- antiverse noun Synonym of antiuniverse (“a conjectured universe formed from antimatter”).
- apparent horizon noun A surface that is the boundary between lightrays that are directed outwards and moving outwards and those directed outward but moving…
- apsidally adv With regard to or in relation to an apsis, the point at which an orbiting object is at its minimum or maximum distance from the orbited…
- argument of periapsis noun The angular distance between the ascending node of an object orbiting a primary body and its periapsis measured from that body.
- axis of evil noun An anomaly in the temperature of the cosmic microwave background as the result of a preferential axis which may have shaped the development…
- banana orbit noun A specific shape or particle orbit that resembles a banana when viewed from the side or above, occurring because the particle moves back…
- big bang noun a physical theory that describes how the universe expanded from an infinitely small, hot, and dense point.
- boson star noun A theoretical type of heavenly body composed of a form of boson that is self-repelling, what should be highly dense and bend spacetime in a…
- BZ black hole noun A rotating black hole that extracts energy from its rotation and magnetic fields to emit a jet of particles and radiation.
- Clarke orbit noun geostationary orbit
- coronal hole noun A region in the corona of a star where magnetic field lines extend out into space, allowing solar wind to escape.
- cosmographer noun A scientist specializing in understanding and describing the nature of the universe.
- dark energy noun A hypothetical form of energy thought to be spread uniformly throughout space (and time) and to have anti-gravitational properties: it…
- dark flow noun A possible non-random component of the peculiar velocity of galaxy clusters.
- dark light noun A hypothetical force of nature that acts on dark matter to allow dark matter to interact with itself.
- dark matter noun Matter which cannot be detected by its radiation but whose presence is inferred from gravitational effects.
- dark sector noun The unknown portion of the Universe outside standard physics, including dark matter and dark energy.
- dex noun An order or factor of ten.
- domain wall noun A two-dimensional singularity hypothesized in string theory.
- dredge up noun A temporary episode of deep convection in an evolved star, which brings fusion products to the surface of the star and allows them to be…
- dynamo noun The mechanism by which a celestial body, such as the Earth or a star, generates a magnetic field.
- escape velocity noun The minimum speed needed to escape the gravitational field of a planet or other body.
- eternal black hole noun A theoretical idealization of a usually stationary black hole that has existed forever, rather than being formed from the collapse of some…
- eternally collapsing object noun A proposed alternative to a black hole whose collapse continually slows down, and that does not form an event horizon.
- event horizon noun The gravitational sphere of a black hole within which the escape velocity is greater than the speed of light.
- extrasolar adj of or originating in a system other than Earth's, the solar system.
- extremal black hole noun A black hole with the minimum possible mass that is compatible with its charge and angular momentum.
- frost line noun In a solar system, the distance from the protosun beyond which hydrogen-containing gas compounds freeze.
- frozar noun Synonym of frozen star (“black hole alternative”) An astrophysical star stilled to a stop by gravitational relativistic time dilation…
- frozen star noun Synonym of stellar black hole.
- gravitate verb To move under the force of gravity.
- gravitational mirage noun A distorted or false image of a distant galaxy (e.g. an image of a distant galaxy as a ring, or as multiple copies of itself) caused by a…
- gravity assist noun The favorable alteration of the speed and trajectory of a spacecraft as a result of its passing near to a celestial body.
- Hayashi limit noun A theoretical maximum radius of a star of given mass; the radius at which the inward force of gravity exactly balances the outward pressure…
- Hayashi track noun A luminosity–temperature relationship obeyed by infant stars of less than 3 M☉ in the pre-main-sequence phase (PMS phase) of stellar…
- helmet streamer noun A bright loop-like discharge of stellar matter in the corona of a star, connecting coronal holes of opposite magnetic polarity.
- Henyey track noun A path taken by pre-main-sequence stars with masses greater than 0.5 solar masses in the Hertzsprung–Russell diagram after the end of the…
- infant star noun A newly formed star; a star that has just begun to sustain a fusion reaction.
- intermediate-velocity adj Usually of an interstellar cloud, of a mid-range of velocity relevant to a particular physical context.
- isolated horizon noun In the context of black holes, a null hypersurface (a surface where light rays travel) that is in equilibrium with its surrounding…
- Jeans escape noun A type of atmospheric escape in which a light gas atom or molecule (typically a helium atom or hydrogen molecule) gains sufficient momentum…
- Lagrange point noun A point in an orbital configuration of a two-body system where a small object affected only by gravity can theoretically be stationary…
- Lagrangian adj Of or relating to a Lagrange point.
- light sector noun The known universe; the part of the universe that is not part of the dark sector; the segment of the universe that is explained by the…
- longitude of periapsis noun The longitude of an orbiting body at which the periapsis would occur if the body had no orbiting inclination.
- micro black hole noun A hypothetical tiny black hole, of less than one solar mass, for which quantum mechanical effects play an important role.
- naked singularity noun An as yet theoretical gravitational singularity with no event horizon, making it observable, unlike a black hole whose event horizon…
- nongalactic adj Far from galaxies; not interacting with galaxies.
- nuclear pasta noun A type of degenerate matter found within the crusts of neutron stars, where the competition between nuclear attraction and Coulomb…
- one-way light time noun The amount of time required for light or a radio signal to travel between the Earth and a celestial body.
- periapsis noun The point of a body's (elliptical) orbit in a 2-body gravitational system such that the distance between the two bodies (measured from…
- PeVatron noun An astrophysical particle accelerator capable of energizing cosmic rays to PeV (“peta-electron-volt”) power levels.
- phantom energy noun A category of dark energy, where dark energy is not fixed in amount nor in density, and continuously increases over time.
- Planck relic noun A black hole with an event horizon on the order of a Planck length (~ 10⁻³⁵ metres), and a mass on the order of a Planck mass (~ 20…
- pseudostreamer noun A bright loop-like structure in the corona of a star, similar to a helmet streamer, but connecting coronal holes of the same magnetic…
- quark matter noun A hypothetical phase of matter made up of quarks that are so tightly packed (due to high surrounding pressure) that they do not chunk into…
- r-process noun The relatively rapid nucleosynthesis process, in supernovae, in which a large neutron flux allows rapid neutron capture and synthesis of…
- radiopanspermia noun The propagation of life through space by way of scattering via radiation pressure of stars, or being launched into space from the source…
- recombination noun The process by which the plasma of electrons and protons produced after the Big Bang condensed into hydrogen, or the epoch in which this…
- reionization noun The process by which the plasma of electrons and protons is produced after the Big Bang, when stars and galaxies ionized neutral hydrogen…
- rotation curve noun for a galaxy, a plot of the orbital velocity of objects with respect to the center of the galaxy, as a function of the distance between the…
- s-process noun the relatively slow nucleosynthesis process, in giant stars, in which neutron capture synthesizes elements up to atomic mass number 210 (at…
- sane noun Ellipsis of SANE disc, a type of black hole accretion disc.
- Schwarzschild's method noun A method to develop triaxial equilibrium kinematic models of actual galaxies (without knowledge of the motions of the component elements of…
- secular adj Relating to long-term non-periodic irregularities, especially in planetary motion or magnetic field.
- siren noun An astrophysical event that can be used for calculating cosmic distances.
- snow line noun The inner limit where volatile molecules can remain frozen in the zone around a star.
- space reddening noun The reddening of the light from distant stars because of selective absorption and scattering by interstellar dust
- spacetime metric noun Any method used to measure the geometry of the universe.
- spaghettification noun The gravitational stretching of objects into long, thin shapes, usually near a black hole.
- spaghettify verb To stretch an object into a long thin shape under the influence of a very strong gravitational field gradient, such as found near a black…
- strangeon star noun An extreme form of exotic degenerate star. An evolution of neutron stars. A star primarily composed of strangeons. Conceptually a giant…
- synestia noun A donut-shaped body of vaporized and molten rock formed from the collision of two planet-sized objects.
- technetium star noun A star in which technetium has been detected. Technetium is too short-lived to occur primordially in the star, if the star is about 4.5…
- trojan noun A Trojan asteroid.
- Trojan asteroid noun an asteroid occupying the Trojan points of the Sun-Jupiter system
- Trojan point noun the L4 and L5 Lagrange points of the Sun-Jupiter orbital configuration
- twilight zone noun A moving line that divides the daylit side and the dark night side of a planetary body.
- warp bubble noun A detached region of spacetime which is theoretically capable of moving faster than the speed of light.
- X factor noun The proportionality constant which converts CO emission line brightness to molecular hydrogen mass.
- Yarkovsky effect noun A force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum.
- YORP effect noun The effect of solar radiation on an asymmetric asteroid or other small body whereby its rate of rotation increases, potentially leading to…