An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Popular name for the constellation → Crux. Its four brightest stars form a distinctive cross shape.

→ southern; → Crux.

The half of the → Earth or another → north pole between the → south pole and the → equator.

→ southern; → hemisphere.

The transit of a celestial object, especially the Sun, across the meridian due south of the observer.

Verbal noun from → south (v.).

Gozar-e daštar-su, literally "passage southward," from gozar, → passage; daštar→ south; su, → direction.

1) Physics: That part of the boundless four dimensional continuum in which matter can be physically extended.
2) Astro.: That part of the Universe which lies beyond the Earth's atmosphere and in which the density of matter is low. Also known as outer space.

M.E., from O.Fr. espace, from L. spatium "room, area, distance, stretch of time," of unknown origin.

Fazâ, loan from Ar.

Electricity: An electric charge belonging to a cloud of electrons lying between a cathode and plate within an electric tube.
Geophysics: An excess of either negatively or positively charged ions in a layer of the atmosphere, giving that layer either a negative or positive charge.

→ space; → charge.

Man-made objects in orbit around the Earth that no longer serve any useful purpose. The estimated number of debris include about 22,000 tractable objects larger than 10 cm in all orbits, of which 2,200 are dead satellites and last stages of the rocket that put them in orbit. There are also left-overs from spacecraft and mission operations, such as bolts, lens caps, clamp bands, auxiliary motors, etc. The debris presents a threat because of their high speeds, which ranges between 15 and 20 km/sec. Also called space junk, space waste, orbital debris.

→ space; → debris.

A travel outside the Earth by manned or unmanned vehicle requiring space technology.

→ space; → flight.

Set of operations (rotation about an axis, reflection across a plane, translation, or combination of these) which when carried out on a periodic arrangement of points in space brings the system of points to self-coincidence.

The word group comes from the mathematical notion of a group.

A manned or unmanned space flight outside the Earth's atmosphere.

→ space; mission, from L. missionem (nominative missio) "act of sending," from mittere "to send," of unknown origin.

Gosilân, from gosil, variant gosi "sending away, dismission;" Mid.Pers. wisé "to despatch" (Parthian Mid.Pers. wsys- "to despatch;" Buddhist Mid.Pers. wsydy "to despatch;" Sogdian 'ns'yd- "to exhort"), from Proto-Iranian *vi-sid- "to despatch, send off," from prefix vi- "apart, away, out," + *sid- "to call" + -ân nuance suffix; fazâyi adj. of fazâ, → space.

The velocity and direction of motion of a star or celestial object with respect to the Local Standard of Rest. Same as → peculiar velocity.

→ space; → motion.

A spacecraft carrying instruments intended for use in exploration of the physical properties of outer space or celestial bodies other than Earth.

→ space; → probe.

A reusable space vehicle designed to travel between the Earth and an orbiting space station for specific missions (carrying a crew and a cargo deploying and retrieving satellites) and then to return.

→ space; M.E. shotil (n.); O.E. scytel "a dart, arrow;" cf. O.N. skutill "harpoon;" akin to shut, shoot.

Nâvak "small ship; ship like," from nâv "ship" (O.Pers./Av. *nāv-, O.Pers. nāviyā- "fleet;" cf. Skt. nau-, nava- "ship, boat;" Gk. naus "ship;" L. nauticus "pertaining to ships or sailors") + -ak diminutive/similarity suffix. Nâvak also means "a small arrow, an arrow flying swift," which may have a different origin.

A program aimed at monitoring the near-Earth environment for recognizing and preventing space hazards by means of radar and optical observations from either space or the ground. The objective of the → European Space Agency initiative is to support the European independent utilization of, and access to, space for research or services, through the provision of timely and quality data, information, services and knowledge regarding the space environment, the threats and the sustainable exploitation of the outer space surrounding our planet Earth. The SSA Program was authorized at the November 2008 Ministerial Council and formally launched on 1 January 2009. The mandate was extended at the 2012 and 2016 Ministerial Councils, and the program is funded through to 2020. The program comprises three segments: 1) Space Surveillance and Tracking (SST), which is the monitoring and tracking of every object orbiting the Earth, such as satellites, space stations and debris. The objective is the prediction and warning of collisions and re-entry events. 2) → Space Weather (SWE), which aims at detection and forecasting of space weather and its effects through monitoring of the Sun, solar wind, magnetosphere, radiation belts, ionosphere and disturbances in the geomagnetic field. 3) → Near-Earth Objects (NEOs), which provides warning services against potential asteroid impact risks, including discovery, identification, orbit prediction and civil alert capabilities.

→ space; → situation; → -al; → awareness.

A large satellite equipped to support a human crew and designed to remain in orbit around Earth for an extended period and be used for a variety of purposes (conducting research, repairing satellites, performing other space-related activities).

→ space; → station.

The systematic application of science, technology, and engineering to the exploration and utilization of outer space.

→ space; → technology.

A telescope which is placed in an orbit around the → Earth and operates through commands from sent from the control center on Earth, such as → Hubble space telescope, → Herschel satellite, → Infrared Astronomical Satellite (IRAS), → Infrared Space Observatory (ISO), → International Ultraviolet Explorer (IUE), → Planck Satellaite , → Spitzer Space Telescope.

→ space; → telescope.

The velocity of a star relative to the Sun.

→ space; → velocity.

The varying conditions in space and specifically in the near-Earth environment. Space weather is chiefly solar driven, resulting from solar activities such as → solar flares, → solar wind, and → coronal mass ejections that affect → magnetosphere, → ionosphere, and → thermosphere. Non-solar sources such as Galactic → cosmic rays, → meteoroids, and → space debris can all be considered as altering space weather conditions at the Earth. Space weather may affect the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health. The research in this field aims at monitoring and diagnosis of space weather conditions and constructing reliable numerical prediction models. See also → Space Situational Awareness.

→ space; → weather; → meteorology.

The slight erosion of Solar System bodies (planets, moons, asteroids) caused by the → solar wind, → cosmic rays, and → micrometeorite bombardments. Space weathering affects the physical and optical properties of the surfaces of these bodies. Understanding this process is therefore important for the interpretation of remotely obtained spectral data, such as space probe photographs of outer Solar System moons.

→ space; → weathering.

A physical entity resulting from the union of space and time concepts. In its most simple version space-time is the four-dimensional continuum, having three spatial coordinates and one temporal coordinate, in which any → event or physical object is located. In → special relativity it is Minkowski's flat space-time. In → general relativity, it is described by a curved entity characterized by a → metric. Free-fall motion describes the → geodesic of this curved space-time. It may have additional dimensions in the context of speculative theories, such as → string theory.

→ space; → time.