Fr.: solution de Larson-Penston
The analytical solution to the → hydrodynamic equations describing the → collapse of an → isothermal sphere. The Larson-Penston solution is → self-similar for a purely dynamical isothermal collapse with spherical symmetry. It corresponds to the collapse prior to the formation of a → protostar, and thus is suitable for the study of → pre-stellar cores. The Larson-Penston solution was extended by Shu (1977) to obtain a whole family of solutions for this problem.
Named after R. B. Larson (1969, MNRAS 145, 271) and M. V. Penston (1969, MNRAS 144, 425), who simultaneously, but independently, did this study.
Fr.: faible résolution
The quality of an instrument that lacks sufficient resolution for a specific observation. This is a relative quality, but presently a resolution below about 1 arcsecond.
Fr.: calendrier luni-solaire
A calendar in which the → solar year consists of 12 or 13 lunar → synodic months. Lunisolar calendars are → solar calendars, but use the lunar month as the basic unit rather than the → solar day. The 13th → embolismic month is to keep lunar and solar cycles in pace with each other. The reason is that the solar year has about 365 days, but 12 lunar months amount to 354 days, which is about 11 days short of a year. The most well-known lunisolar calendars are the Babylonian, Hebrew, and Chinese.
Fr.: précession lunisolaire
mean solar day
ruz-e xoršidi-ye miyângin (#)
Fr.: jour solaire moyen
The average length of the apparent solar day. In other words, the interval between successive transits of the mean Sun for a given observer.
mean solar time
zamân-e xoršidi-ye miyângin (#)
Fr.: temps solaire moyen
The time since the mean Sun crossed the meridian with 12 hours added to make the day begin at midnight.
The state, process, or condition of being or becoming obsolete or outdated and no longer used.
Becoming obsolete; passing out of use.
1) pitâr; 2) pitârdan
Fr.: 1) obsolète, désuet; 2) rendre obsolète
1a) No longer in general use; fallen into disuse.
From L. obsoletus "grown old, worn-out," p.p. of obsolescere "fall into disuse, be forgotten about, become tarnished," which probably is from ob "away" + an expanded form of solere "to be used to, be accustomed."
Pitâr, from Tabari pitâr "worn out," specifically "rotten tree," pitə-pât "anything worn out or useless," from pit, variant of Pers. pud "worn out, decayed," pusidan/pus- "to rot," cf. Pashto puda, Wakhi pitk "rotten, foul," Kurd. (Kurm.) puc "rotten, useless;" Av. pu- "to stink, rot," akin to Gk. puos, L. pus "pus."
Parker Solar Probe
gomâne-ye xoršidi-ye Parker
Fr.: Parker Solar Probe
A NASA space mission launched on August 12, 2018 to study the outer corona of the Sun at very close distances. Parker Solar Probe is the first space mission to penetrate into solar corona as close as about 10 solar radii. It will approach the Sun to this distance 25 times. Approaching the Sun to such distances is a big technological challenge. The main goals of the mission are to answer these questions: Why is the solar corona so hotter than the solar surface? How is the solar wind accelerated? How are the energetic particles produced and transported?
Named after the physicist Eugene Newman Parker (1927-), who proposed the existence of the solar wind and did pioneering work for its interpretation.
partial solar eclipse
Fr.: éclipse partielle de soleil
Fr.: solution particulière
Fr.: obsolescence programmée
The business strategy of deliberately designing products so they have a limited effective lifespan. Its objective is to incite the consumer to abandon the currently owned item and buy another one.
Of or relating to an epoch earlier than the formation of the Sun.
Fr.: grain pré-solaire
Fr.: abondance protosolaire
1) The degree to which an → optical system renders visible
separate parts of an object. Also known as → angular resolution and
→ spatial resolution. See also
→ spectral resolution.
Verbal noun of → resolve.
resolution of a force
Fr.: résolution de force
Vâgošudan, from prefix vâ-, → re-, + gošudan, gošâdan "to loose, open up, let free;" gošâd "opened; ample, broad;" Mid.Pers. wišâdan "to let free;" Khotanese hīyā "bound;" O.Pers. višta "untied, loosened," vištāspa- "with loosened horses" (personal name); Av. višta "untied," ā-hišāiiā "holds fettered," hita- "fastened, tied on, put to;" cf. Skt. sā- "to bind, fasten, fetter," sitá- "bound," ví-sita- "untied."