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

The point in the → southern hemisphere where the → rotation axis of the Earth touches the → celestial sphere. In contrast to the → north celestial pole, no bright star is visible in that direction.

→ north; → celestial; → pole.

The point on → horizon in direction of → geographic south pole.

→ south; → point.

A large area of the south polar region of → Mars which is covered with layers of → water ice and → dust. The SPLD, like the NPLD, has a maximum relief relative to the surrounding terrain of ~ 3.5 km and ~ 1,000 km across. Above the SPLD lies a very thin temporary (1-10 m) cap of → carbon dioxide ice/frost that snows out in the winter and sublimates over the spring and summer seasons. It is believed that the rhythmic nature of the deposits is related to oscillations in Mars' → orbital parameters (J. J. Plaut et al., 2007, Science 316, 92).

→ south; → polar; → layer; → deposit.

1) An → imaginary point in the → southern hemisphere representing the intersection of the → Earth's → rotation axis with the → globe with the → celestial sphere.
2) For a → magnet, the pole which points toward the geographic south.
3) In a → magnetic field, the point which receives a → line of force coming from the → north pole.

→ south; → pole.

A star that would mark the south → celestial pole. Presently no bright visible star is situated along the → rotation axis of the Earth in the southern hemisphere. But, because of the Earth's → axial precession, about 7,000 years from now the star → Delta Velorum in the constellation → Vela, the Sail, will come to within 0.2 degrees of the South Celestial Pole (around the year 9250 B.C.). That is closer to marking the celestial pole than → Polaris or → Sirius ever do during their reigns as pole stars! Sirius will become the South Pole Star some 60 thousand years from now (around the year 66270 B.C.). In that time, Sirius will come to within 1.6 degrees of the South Celestial Pole.

→ south; → celestial; → pole.

Of or pertaining to the south.

M.E., O.E. suðerne, from suð, → south, + -erne, suffix denoting direction.

Daštari, relating to daštar, → south.

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.