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

Also sulphur, a nonmetallic chemical element; symbol S. Atomic number 16; atomic weight 32.06; melting point 112.8°C (rhombic), 119.0°C (monoclinic), about 120°C (amorphous); boiling point 444.674°C; specific gravity at 20°C, 2.07.

M.E. sulphur, from L. sulpur, sulphur, sulfur "brimstone;" maybe from Skt. sulveri "eneny of copper," as copper loses all its properties when heated with sulfur. It was known from prehistoric times. In 1809, the French chemists, Louis-Joseph Gay-Lussac and Louis-Jacques Thenard proved the elemental nature of sulfur.

Gugerd, from Mid.Pers. gôgird "sulfur," gôgirdômand "sulfurous."

1a) Math.: The number or quantity that is the result of adding two or more numbers or quantities.
1b) A particular amount or total, especially of money.
2a) To combine into an aggregate or total (often followed by up).
2b) To ascertain the sum of, as by addition (Dictionary.com).

M.E. summe, from O.Fr. summe, from L. summa "total number, whole, essence, gist," noun use of feminine of summus "highest," superlative of superus, → super-.

Bazâv, from Mid.Pers. abzây-, abzudan (Mod.Pers. afzâ-, afzudan) "to increase;" Parthian abigâw- "to increase;" Sogd. β(ə)žāw "to grow, increase;" O.Pers. abiyajāv- "to increase, add to, promote," from abi-, aiby- "in addition to; to; against" + root jav- "press forward;" Av. gu- "to increase;" Khotanese gvāna- "growth;" Skt. jav- "to press forward, impel quickly, excite," javate "hastens").

To make a summary of; state or express in a concise form.

→ summary + → -ize.

1) A brief account giving the main points of something.
2) Covering the main points; comprehensive.

From L. summarium "an epitome, abstract, summary," from summa "totality, gist," → sum, + → -ary.

Bazâvak, from bazâv, present stem of bazâvidan, → sum, + -ak relation suffix.

The season that starts when the Sun, during its apparent yearly motion, attains the celestial longitude 90 degrees in the Northern Hemisphere and 270 degrees in the Southern Hemisphere. The current length of the summer season, around the epoch 2000, is 93.65 days.

M.E. sumer, from O.E. sumor (cf. O.S., O.N., O.H.G. sumar, O.Fris. sumur, M.Du. somer, Du. zomer, Ger. Sommer), from PIE base *sem- "summer;" cf. Av. ham- "summer;" Mid.Pers. hāin "summer;" Skt. sámā- "half-year, season;" Arm. am "year," amarn "summer;" O.Ir. sam "summer;" O.Welsh ham "summer."

From Mid.Pers. tâpistân, ultimately from Proto-Iranain *tap-stā- "hot, heat season, time, place." The first component *tap- "to shine, radiate;" cf. Mod.Pers. tâbidan, variants tâftban "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."
The second component *stā- "to stand; to set; to place;" a suffix of "place, land, country" and in rare cases "time;" examples: لرستان "Lorestân;" کردستان "Kurdestân;" افغانستان "Afghanistan;" ترکستان "Turkistan;" پاکستان "Pakistan;" انگلستان "England;" لهستان "Poland;" کوهستان "kuhestân = mountaneous region, highland;" تابستان "summer;" زمستان "winter." From Mid.Pers. -stân, -istân. Examples: gôstân (گاوستان) "cowshed;" šapistân (شبستان) "dormitory;" tâpistân "summer;" zamistân "winter." From O.Pers. stāna- "place;" Av. stāna-, as in gaostāna- (Mid.Pers. gôstân, as above) "cowshed;" from Proto-Iranian *stāna-. This suffix is related to O.Pers./Av. base sta- "to stand;" Mod.Pers. istâdan (ایستادن) "to stand;" cf. Skt. sthā- "to stand," sthāna- "standing;" Gk. histemi "to put, place," stasis "standing still;" L. stare "to stand;" Goth. standan; O.H.G. stantan; O.E. standan; E. stand; PIE base *sta- "to stand."

The moment in the northern hemisphere when the → Sun attains its highest → declination of 23°26' (or 23°.44) with respect the → equator plane. It happens when the Earth's axis is orientated directly toward the Sun, on 21 or 22 June. During the northern solstice the Sun appears to be directly overhead at noon for places situated at → latitude 23.44 degrees north, known as the → tropic of Cancer. The summer solstice can occur at any moment during the day. Two successive summer solstices are shifted in time by about 6 h. The summer solstice in the northern hemisphere is the → winter solstice in the southern hemisphere.

→ summer; → solstice.

The triangular shape formed by the three bright stars → Altair, → Deneb, and → Vega on the northern hemisphere's → celestial sphere, particularly visible during the summer months.

→ summer; → triangle.

The star that governs the solar system. It is a yellow main-sequence star of spectral type G2, shines with apparent magnitude -26.74, and has an absolute magnitude of +4.83. The Sun is 4.6 billion years old and lies 27,000 light-years from the Galactic center.

O.E. sunne; cf. O.N., O.S., O.H.G. sunna, M.Du. sonne, Du. zon, Ger. Sonne, Goth. sunno; cognate with Pers. xor, hur, as below.

Xoršid "sun," originally "sunlight," from xor "sun," variant hur; Mid.Pers. xwar "sun;" Av. hū-, hvar- "sun;" cf. Skt. surya-, Gk. helios, L. sol, cognate with E. sun, as above; PIE base *sawel- "sun" + šid "light, sunlight;" from Mid.Pers. šêt "shining, radiant, bright;" Av. xšaēta- "shining, brilliant, splendid, excellent."

→ light pillar.

→ sun; → pillar.

A comet that passes extremely close to the Sun's → surface, in some cases within a few thousand kilometres of the Sun's surface. The Great Comet of 1965, Ikeya-Seki, was a member of the sun-grazer family, coming within about 650,000 km of the Sun's surface. Passing so close to the Sun, sun-grazers are subjected to destructive → tidal forces along with intense solar heat which can completely evaporate them during such a → close approach.

→ Sun; → grazer.

An instrument for showing apparent solar time by the position of the shadow cast by an indicator. → gnomon.

From → Sun + -dial M.E. instrument for telling time by the Sun's shadow, presumably from M.L. dialis "daily," from L. dies "day;" → diurnal.

Sâ'at-e âftâbi, from sâ'at, → clock, + âftâb, → Sun.

The light of the Sun.

→ sun; → light.

Âftâb, "sun(shine);" Mid.Pers. âftâp; Proto-Iranian *abi-tap-, from *abi- "to, upon, against" (O.Pers./Av. abiy-/aiwi- "to, upon, against;" Skt. abhi-, Gk. amphi-) + *tap- "to shine" (Mod.Pers. tâbidan, variants tâftban "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm").

The time at which the apparent upper limb of the rising Sun is on the astronomical horizon, that is when the true zenith distance, referred to the center of the Earth, of the central point of the disk is 90°50', based on adopted values of 34' for horizontal refraction and 16' for the Sun semidiameter.

→ Sun; → rise.

The time at which the apparent upper limb of the setting Sun is on the astronomical horizon, that is when the true zenith distance, referred to the center of the Earth, of the central point of the disk is 90°50', based on adopted values of 34' for horizontal refraction and 16' for the Sun semidiameter.

→ Sun; → set.

An area seen as a dark patch on the Sun's surface. Sunspots appear dark because they are cooler (of about 4000 °C) than the surrounding → photosphere (about 6000 °C). They range in size from a few hundred kilometers to several times the Earth's diameter and last from a few hours to a few months. Very small sunspots are called → pores. The number of sunspots varies from maximum to minimum in about 11 years, the → sunspot cycle. Their appearance during a cycle follows the → Sporer law. A typical spot has a central → umbra surrounded by a → penumbra, although either features can exist without the other. Sunspots are associated with strong magnetic fields of 0.2 to 0.4 → tesla. A given sunspot has a single magnetic → polarity. The opposite polarity may be found in other sunspots or in the bright and diffuse → facular region adjacent to the sunspot. The first recorded naked-eye sightings of sunspots were by Chinese astronomers in the first century B.C. Johannes Fabricius (1587-1617) was the first to argue that sunspots are areas on the solar surface.

→ Sun; → spot.

→ solar cycle.

→ sunspot; → cycle.

Periods of time when the → relative sunspot number is low. These periods of time occur approximately every 11 years and represent the minimum in the → sunspot cycle.

→ sunspot; → minimum.

A quantity which gives the number of sunspots at a given time. It is defined by the relationship R = k(10g + f), where R is the sunspot number, k is a constant depending on the observation conditions and the instrument used, g is the number of the groups and f is the number of individual spots that can be counted. Also called the → Wolf number and → relative sunspot number.

→ sunspot; → number.

The loss of energy by high-energy electrons in a → galaxy cluster, which distorts the → cosmic microwave background (CMB) radiation through → inverse Compton effect. When photons from the CMB radiation travel through a hot plasma (with a temperature of around 10⁸ K), in which bathe a galaxy cluster, they collide with energetic electrons and some of the energy of the electrons is transferred to the low energy CMB photons. If we look at the CMB radiation through such a plasma cloud, we therefore see fewer microwave photons than we would if the cloud were not there.

Named after Rashid Sunyaev (1943-) and Yakov Borisovich Zel'dovich (1914-1987), Russian astrophysicists; → effect.

Same as → perigee full Moon.

→ super-; → Moon.