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

The period during which the Sun is close enough to one of the → lunar orbit nodes so that an eclipse can take place. This time window lasts for 37 days for → solar eclipses and almost 24 days for → lunar eclipses. These seasons occur every 173.31 days. Two eclipse seasons make up an → eclipse year.

→ eclipse; → season.

A large aggregate of single-state → fermions of lowest energy. When the temperature is lowered to absolute zero, all electrons in solids attempt to get into the lowest available energy level. However, electrons cannot all occupy the lowest energy, or ground state, in virtue of the → Pauli exclusion principle. They stack up in the lowest energy states, with two fermions in each state, one spin up and one spin down. Such assemblage of filled states is called the Fermi "sea," and this state of matter is called → degenerate. All states with energy less than the Fermi energy are filled, and all states above the Fermi energy are empty.

→ fermi; → sea.

A high-precision echelle spectrograph built for exoplanet findings and installed on the ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003. HARPS has discovered dozens of exoplanets, making it the most successful planet finder behind the Kepler space observatory. HARPS can detect movements as small as 0.97 m s^-1 (3.5 km h^-1), with an effective precision of the order of 30 cm s^-1, and a → resolving power of 120,000 (Mayor et al., 2003, ESO Messengar 114, 20).

→ high; → accuracy; → radial; → velocity; → planet; → search; → -er.

1) (n.) A systematic inquiry or investigation into a subject in order to discover or establish or revise facts, theories, applications, etc.
2) (v.) To carry out research into a subject.

From M.Fr. recerche, from O.Fr. recercher "to seek out, search closely," from → re-, intensive prefix, + cercher "to seek for," from L. circare "to go about, wander, traverse," from circus→ circle.

Pažuheš, verbal noun of pažuhidan "to search;" Mid.Pers. wizôy- "to examine, investigate;" ultimately from Proto-Iranian *pati-iud-, from *pati- "agaist, back, opposite to, toward, face to face, in front of (cf. O.Pers. paity; Av. paiti; Skt. práti; Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE base *proti) + *iud- "to struggle for something, to fight (Av. yūδ- "to fight, struggle;" Mod.Pers. justan, juy- "to search, seek, ask for"); cf. Mid.Pers. vijuyihitan "to search, seek."

Systematic activity combining both basic and applied research, and aimed at discovering solutions to problems or creating new goods and knowledge. (BusinessDictionary.com).

→ research; → development.

A person who has the quality of guiding, regulating, or controlling the work of other researchers.

→ research; → director.

A nuclear reactor designed for radionuclide production, materials testing, and training.

→ research; → reactor.

A scientist who devotes himself to doing research.

Agent noun, from → research + → -or.

A grid of fine lines photographed onto or cut into a glass plate and used as a reference for astronomical observations.

From Fr. réseau, O.Fr. reseuil "little net," from raiz "net," from L. rete "net."

Rezo, loan from Fr., as above.

1) A large lake or landlocked body of water.
2) A large area or great number of something. → Fermi sea.

O.E. sæ "sheet of water, sea, lake;" cf. Du. zee, Ger. See, O.N. sær "sea," Goth saiws "marsh."

Daryâ "sea;" Mid.Pers. daryâp variant zrah; O.Pers. drayah-; Av. zrayah- "sea;" cf. Skt. jráyas- "expanse, space, flat surface."

The → apparent horizon formed by the sea.

→ sea; → horizon.

To explore or examine in order to find something.

M.E. serchen, cerchen, from O.Fr. cerchier "to search," from L. circare "to go about, wander, traverse," from circus "circle."

Jost-o-ju interfixed jost and juy past and present stem of jostan/juyidan "to seek, strive for;" Proto-Iranian *iud- "to struggle for something, to fight" (Av. yūδ- "to fight, struggle;" Mod.Pers. justan, juy- "to search, seek, ask for"); cf. Mid.Pers. vijuyihitan "to search, seek."

The scientific attempt to detect → intelligent extraterrestrial → life by surveying the sky to find the existence of → transmissions, especially → radio waves or → light, from a → civilization on a distant → planet. The SETI Institute, that carries out the project, is a private non-profit center founded in 1984. There are many methods that SETI scientific teams use to search for extraterrestrial intelligence. Many of these search billions of radio frequencies that reach Earth from all over the → Universe, looking for an intelligent → radio signal. Other SETI teams search by looking for signals in pulses of light emanating from the stars.

→ search; → extraterrestrial; → intelligence.

The hard shell of a marine mollusk.

→ sea; → shell.

Sadaf, loan from Ar. Kelâcak from Tabari, variant kelâcin, cf. Gilaki guš kuli. The component kel-, kul might be related to PIE *qarq- "to be hard," → crab.

One of the four periods of the year astronomically defined by the position of the Sun with respect to the equator. As a result of the obliquity of the ecliptic, the angular distance between the Sun and the equator varies in the course of the year. This circumstance gives rise to seasons. The current lengths of the astronomical seasons, around the year 2000, are about: spring 92.76 days, summer 93.65 days, autumn 89.84 days, and winter 88.99 days. The seasons are unequal because the Earth's orbit is slightly elliptical and the Sun is not exactly at the center of the orbit. Moreover, the Earth moves faster when it is close to the Sun than when it is farther away, so the seasons that occur when the Earth is close to the Sun pass more quickly.

M.E. sesoun, seson, from O.Fr. seison "a sowing, planting," from L. sationem (nominative satio) "a sowing," from p.p. stem of serere "to scatter seed over land."

Fasl, from Ar. faSl "cutting, dividing; section."

An international collaboration, more accurately named SuperWASP, led by the United Kingdom, that aims at detecting → extrasolar planets by means of the → transit method. SuperWASP consists of two robotic observatories that operate continuously all year around, providing coverage of the sky in both hemispheres. The first, SuperWASP-North, is located on the island of La Palma. The second, SuperWASP-South, is located at the site of the South African Astronomical Observatory (SAAO). The observatories each consist of eight wide-angle cameras that simultaneously monitor the sky for → planetary transit events. Using the array of cameras makes it possible to monitor millions of stars simultaneously at an → apparent visual magnitude from about 7 to 13.

→ wide; → angle; → search; → planet.