n
(astronomy) The conjunction of two celestial objects.
n
(astronomy, archaic or historical) A small circle on the celestial sphere, parallel to the horizon, that is used in astronomy and navigation to show altitude of a star or any other heavenly body.
n
(astronomy) The most protruding part of planetary rings as seen from a distance, perceived to project like handles on either side of the disc of the planet.
n
(astronomy) The point opposite the solar apex
n
A faint, white halo rarely seen in the sky opposite the sun on the parhelic circle
n
(astronomy) The point in the sky opposite to that of the centre of the galaxy (when viewed from Earth)
n
The hypothetical analog of moon, revolving around the antiearth.
n
Alternative form of apoapsis [(astronomy) The point of a body's elliptical orbit about the system's centre of mass where the distance between the body and the centre of mass is at its maximum.]
n
(astronomy) The point of greatest separation between a celestial object and the star which it orbits.
n
(astronomy) The point on the celestial sphere toward which the Sun appears to move relative to nearby stars.
adj
(astronomy) Relating to aphelion
n
(astronomy) The point in the elliptical orbit of a planet, comet, etc., where it is farthest from the Sun.
n
(astronomy) The point of a body's elliptical orbit about the system's centre of mass where the distance between the body and the centre of mass is at its maximum.
n
(astronomy) Apoapsis around Mars.
n
(planetology) Alternative form of apoareion [(astronomy) Apoapsis around Mars.]
n
(astronomy) Alternative form of apastron [(astronomy) The point of greatest separation between a celestial object and the star which it orbits.]
n
(astronomy) The furthest point of an astronomical object in an elliptical orbit to the center of mass of the system
n
(astronomy) Return to the same apparent position, as after a revolution.
n
(astronomy) The furthest point of an astronomical object in an elliptical orbit to its center of attraction (the principal focus of the ellipse)
n
Alternative form of apocenter [(astronomy) The furthest point of an astronomical object in an elliptical orbit to its center of attraction (the principal focus of the ellipse)]
adj
(astrophysics) Of or pertaining to the apocenter, the point in an orbit which is furthest from the orbited body
n
(astronomy) The point in an orbit around the Moon that is most distant from that body.
n
(astronomy) apocenter, apobaryon
n
(astronomy) The point in the orbit of a star at which it is furthest from the centre of its local galaxy
n
(astronomy, more generally) The point, in an orbit about any planet, that is farthest from the planet: the apoapsis of any satellite.
n
Ellipsis of Apohele asteroid. [(astronomy) An asteroid whose orbit lies completely within the orbit of the Earth.]
n
(astronomy) An asteroid whose orbit lies completely within the orbit of the Earth.
n
(astronomy) In an orbit around the planet Mercury, the point that is most distant from Mercury.
n
(rare) Alternative form of apokrone [Apoapsis around the planet Saturn.]
n
(astronomy) The point of an elliptical lunar orbit where the distance between the satellite and the Moon is at its maximum.
n
(astronomy) Apoapsis around Saturn
n
(astronomy) A close approach of two heavenly bodies; a conjunction or occultation.
n
(astronomy, obsolete) The nearest and furthest points to the centre of gravitational attraction for a body in orbit. More usually called an apsis.
n
(astronomy) An imaginary line defined by an orbit's eccentricity vector. For such orbits the apse line is found: for elliptical orbits – between the orbit's periapsis and apoapsis (also known as the major axis) for parabolic and hyperbolic orbits – between the orbit's periapsis and focus.
adj
(astronomy) Of or pertaining to the apsides.
adv
(astrophysics) 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 object
n
(astronomy) Either of the points in the elliptical orbit of a planet or comet where it is closest or furthest from the sun; perihelion or aphelion; an apside
n
(astrology) The horoscope, or that degree of the ecliptic which rises above the horizon at the moment of one's birth; supposed to have a commanding influence on a person's life and fortune.
n
(astronomy) The point in an orbit at which a body passes the ecliptic plane going north.
n
(astrology) The relative position of heavenly bodies as they appear to an observer on earth; the angular relationship between points in a horoscope.
n
An atmospheric phenomenon visible shortly before sunrise or after sunset, when a pinkish glow extending roughly 10–20° above the horizon surrounds the observer.
n
(astronautics) A type of movement of a spacecraft from one orbit to another, in which the spacecraft first raises its apoapsis to an extremely high altitude, then, at the new, higher, apoapsis, performs an engine burn to change its periapsis to that of the desired orbit, and, finally, upon reaching the new periapsis, performs a third burn to lower the eccentricity of its orbit and circularize in the desired orbit, or performs these steps in reverse to move from a higher to a lower orbit.
n
(astrology) The position of the center of the sun in the sky.
n
(astrophysics) geostationary Earth orbit
n
(astronomy) The complement of an altitude
n
(astronomy) The alignment of two bodies in the solar system such that they have the same longitude when seen from Earth.
adj
(astronomy) Describing bodies that share the same orbit.
n
(astronomy, of multiple planets or other orbiting bodies) The state or characteristic of orbiting a central celestial object within the same orbital plane.
adj
(astronomy) said of the distance of a planet from the sun or earth, as measured in the plane of the ecliptic, or the distance from the sun or earth to that point where a perpendicular, let fall from the planet upon the plane of the ecliptic, meets the ecliptic
n
(astronomy) The interval of a planet's orbit in which its curtate or shortened distance is less than the true distance.
n
(astronomy) A measure of the chaos on the surface of a star
n
(astronomy) The side of a planet that faces towards the sun around which it orbits
n
(astrology) An aspect or position of two planets when they are distant from each other a tenth part of the zodiac.
n
(astronomy) The point in an orbit at which a body passes the ecliptic plane going south.
n
(astronomy, celestial mechanics) The angle PCR formed by P = the periapsis of a celestial body's elliptical orbit, C = the center of that elliptical orbit, and R = the corresponding point to that celestial body (the projection of the celestial body along a direction parallel to the minor axis of its orbit onto the auxiliary circle (a circle which shares a diameter with the major axis of the celestial body's orbit)).
n
(astronomy, nautical) A table giving the apparent position of celestial bodies throughout the year; normally given as right ascension and declination.
n
The barrier crossed by astronauts at which the gravitational attraction of the Moon is the same as that of the Earth
n
(astrology) That placement of a planet in the zodiac in which it is deemed to exert its strongest influence.
n
(astronomy) exozodiacal cloud (of dust etc)
n
(astronomy) A bright spot or patch between sunspots.
n
(astronomy) A point on the celestial sphere where the sun crosses the celestial equator on March equinox.
n
(astronomy) A point on the celestial sphere where the sun reaches the northernmost point on June solstice.
n
(astronomy) A point on the celestial sphere where the sun reaches the southernmost point on December solstice.
adj
Refers to the orbit of a satellite whose rate of revolution is matched to the rotation period of the Earth. A special case is the geostationary orbit which is circular and equatorial, so that the satellite appears to be fixed over a particular point on Earth's sky.
n
(astronomy) A conjunction of the planets Jupiter and Saturn.
n
(astrodynamics) A sun-synchronous orbit.
n
(astronomy) The region in which a given astronomical body dominates the attraction of satellites.
n
(aerospace) An elliptical orbit used to transfer between two circular orbits of different radii in the same plane.
adj
(astronomy) Between Mercury and the Sun.
n
(astronomy) The orbital plane passing through a planetary system's barycenter (center of mass) perpendicular to its angular momentum vector.
n
(astronomy, celestial mechanics) the mathematical relationship between the mean anomaly (M) and the eccentric anomaly (E) of a planet in an elliptical orbit with eccentricity (𝜀). M=E-𝜀· sin (E).
n
(astronomy) The three laws of planetary motion discovered by Kepler in the early 17th century, stating that (i) the orbit of a planet is an ellipse with the Sun at one of the two foci, (ii) a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time, and (iii) the square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.
n
(astrophysics) first Lagrange point, located further in towards the primary of a system where a smaller object orbits a larger one, in front of the smaller object, inline with a line drawn through the centres of the larger and smaller objects
n
(astrophysics) third Lagrange point, located 180-degrees behind or ahead on the orbit of the smaller object in orbit around a larger one, diametrically opposed to the smaller object
n
(astrology) In Vedic astrology, the degree of the sign that is rising on the eastern horizon at the time of a person's birth.
n
(astrophysics) Alternative form of Lagrange point [(astrophysics, orbital mechanics) A point in an orbital configuration of a two-body system where a small object affected only by gravity can theoretically be stationary relative to the two larger objects.]
n
(geometry, astronomy) Synonym of apse line
adv
(astronomy) In a path near the equator, so that the declination is small, or near the horizon, so that the altitude is small; said of the heavenly bodies with reference to the diurnal revolution.
n
Alternative form of McDowell line [(aerospace) The altitude of periapsis at which atmospheric drag will prevent an object from successfully orbiting.]
n
(climatology) Any of the three cyclic variations in the Earth's orbit around the Sun, respectively the obliquity of its axis, the precession of the equinoxes, and the eccentricity of its orbit.
n
Ellipsis of Molniya orbit. [A highly elliptical orbit with an eccentricity of 0.74, inclination of 63.4 degrees, an argument of perigee of −90 degrees, and an orbital period of half a sidereal day, around the Earth.]
n
By analogy, the equivalent orbit for the southern hemisphere, with the argument of perigee changed to +90 degrees.
n
(astronomy) The axis of a projected conical shadow; the direction of the force of gravity at a location; down.
n
(astrology) The subjective vibration of a planet.
n
One complete circuit round an orbited body.
n
The orbit that an astronomical body such as a planet, asteroid, comet or satellite would follow if suddenly all perturbing forces other than the gravitational attraction of the Sun or (for a satellite) its planet were to disappear.
n
The minimum distance between the two bodies in such a system.
n
The point in an elliptical orbit around Mars that is closest to Mars.
n
(astronomy) That point of the orbit of a celestial body which is closest to the star around which the body is orbiting.
n
(astronomy) The pericenter, the point of closest approach of an astronomical object in an elliptical orbit to the center of mass of the system.
n
(astronomy) The point in an elliptical orbit around a black hole where the orbiting body is closest to the black hole.
n
(astronomy) The peribaryon, the point of closest approach of an astronomical object in an elliptical orbit to its center of attraction.
n
The point in an elliptical orbit around the moon that passes closest to the moon.
n
(astronomy) pericenter, peribaryon
n
(astronomy) The closest point in a star's orbit around the centre of a galaxy (the galactic periapsis).
n
(astronomy) The point, in an orbit about the Earth, that is closest to the Earth: the periapsis of an Earth orbiter.
n
(astronomy) The point in the elliptical orbit of a comet, planet, etc., where it is nearest to the Sun.
n
(astronomy, obsolete) Synonym of perihelion
n
(astronomy) The point of an elliptical lunar orbit where the distance between the satellite and the Moon is at its minimum.
n
Synonym of peribothron (“periapsis of a black hole”)
adj
(astronomy) Relating to the light from a star partially obscured by a planet with an eccentric orbit
n
(astrology) The zodiacal region of the sky in which the sun, moon, or a planet appears at the time and place of a person's birth.
n
(astronomy) The surface (plane) that contains the orbit of a planet in a solar system.
n
(astronomy) Any of several charts of the celestial sphere having an overlay or window that may be adjusted to show the stars visible at a particular time, or from a particular place
n
Alternative form of pole star [(astronomy) The star nearest a celestial pole of a planet.]
n
(astronomy) The star nearest to Earth's axis when extended above the North Pole: currently Polaris, formerly Thuban.
n
(astronomy, historical) The outermost celestial sphere of the heavens in Ptolemaic astronomy, which was believed to cause all the inner spheres to rotate.
n
A reduction to bring the apparent place of a moving point or planet to the mean place.
n
(astronomy) An unusually close perigee resulting from evection.
adj
Used other than figuratively or idiomatically: see quasi, stellar.
n
A theoretical type of orbit which goes in a straight-line, up and down; with 100% orbital eccentricity (eccentricity=1.0); the orbital path passing through the center-of-mass of the primary mass being orbited; having an periapsis at 0, and two apoapsides, as both arms going out from the periastron are equidistant; where the orbital ellipse has zero width semi-minor axis/minor axis, and the path of the ellipse is the same as the major axis.
n
(astronomy) The nearest a satellite can approach its parent body without being pulled apart by tidal forces.
n
(philosophy) A china teapot which hypothetically orbits the Sun between Earth and Mars, which is too small to be detected by telescopes but cannot be proven not to exist.
n
(astrology) A grouping of several planets in a sign.
n
(astronomy) A secondary circle.
n
(astronomy) The sidereal year of a planet. (I.e., in the definition for "sidereal year", replace "Earth" by the given planet.)
n
(astronomy) sidereal rotation period
n
(astronomy) The point to which the Sun appears to be moving with respect to the local stars
adj
(geometry) Convex; having the property that any line segment joining any mapped point to a specified point in the domain lies entirely in the domain.
adj
(astronomy) Centered on or measured from a star
adj
Not reaching orbit; having a trajectory that does not reach orbital velocity and so must return to ground eventually.
n
(astrodynamics) A nearly polar orbit in which a satellite passes over the surface of a planet maintaining the same local mean solar time.
adj
(astronomy) Whose path or orbit passes very close to the sun
n
(astronomy) A conjunction of two or more of the heavenly bodies.
n
(astronomy, astrology) An alignment of three celestial bodies (for example, the Sun, Earth, and Moon) such that one body is directly between the other two, such as occurs at an eclipse.
n
(sports) A soccer ball pattern with 32 panels of 20 hexagons and 12 pentagons, a rounded truncated icosahedron ball. The classic stereotypical black pentagon and white hexagon design.
n
(astrology) An essential dignity in which unequal segments of every astrological sign have internal rulerships which affect the power and integrity of each planet in a natal chart.
n
(astronomy) The line between the day side and the night side of a moon, planet or other celestial body.
n
(astronomy, obsolete) A libration of the starry sphere in the Ptolemaic system; a motion ascribed to the firmament, to account for certain small changes in the position of the ecliptic and of the stars.
n
(astronomy, celestial mechanics) The angle PFC formed by P = the periapsis of a celestial body's elliptical orbit, F = the focus of that orbit, and C = the current position of the celestial body.
n
(astronomy) The ecliptic: the belt-like region of the celestial sphere corresponding to the apparent path of the sun over the course of a year.
n
(astronomy) A soft glow of white light seen in the sky along the ecliptic in an elongated triangular form with its base being on the horizon, particularly in the tropics.
n
Obsolete form of zodiac. [(astrology) The belt-like region of the celestial sphere approximately eight degrees north and south of the ecliptic which include the apparent path of the sun, moon, and visible planets.]
Note: Concept clusters like the one above are an experimental OneLook
feature. We've grouped words and phrases into thousands of clusters
based on a statistical analysis of how they are used in writing. Some
of the words and concepts may be vulgar or offensive. The names of the
clusters were written automatically and may not precisely describe
every word within the cluster; furthermore, the clusters may be
missing some entries that you'd normally associate with their
names. Click on a word to look it up on OneLook.
Our daily word games Threepeat and Compound Your Joy are going strong. Bookmark and enjoy!
Today's secret word is 8 letters and means "Believable and worthy of trust." Can you find it?