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

The → heat capacity of a → mole of a substance, expresses as: C_a = C.A , where C is the → specific heat and A the → atomic weight .

→ atomic; → heat.

A physical process whereby heat is imparted to (e.g. → interstellar dust grains or → molecular hydrogen) through collisions (with hot electrons, ions, etc.).

→ collisional; → heating.

Same as → Einstein model.

→ Einstein; → theory; → specific heat.

Energy possessed by a substance in the form of kinetic energy of atomic or molecular translation, rotation, or vibration.

Heat, from O.E. hætu, hæto, from P.Gmc. *khaitin- "heat," from *khaitaz "hot" (cf. O.N. hiti, Ger. hitze "heat," Goth. heito "fever").

Garmâ "heat, warmth," from Mid.Pers. garmâg; O.Pers./Av. garəma- "hot, warm;" cf. Skt. gharmah "heat;" Gk. thermos "warm;" L. formus "warm," fornax "oven;" P.Gmc. *warmaz; O.E. wearm; E. warm; O.H.G., Ger. warm; PIE *ghworm-/*ghwerm- "warm."

The ratio of an amount of heat, dQ, transferred to a body in some process to the corresponding change in the temperature of the body: C = dQ/dT. The heat capacity depends upon the mass of the body, its chemical composition, thermodynamic state, and the kind of process employed to transfer the heat. The word "capacity" may be misleading because it suggests the essentially meaningless statement "the amount of heat a body can hold," whereas what is meant is the heat added per unit temperature rise. → specific heat.

→ heat; → capacity.

A type of → heat transfer by means of molecular agitation within a material without any motion of the material as a whole.

→ heat; → conduction.

A type of → heat transfer involving mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it.

→ heat; → convection.

Assuming that the Universe is a thermodynamically → isolated system, a state of absolute uniformity in the Universe in which all temperature differences would reduce to zero and no energy will be available for use, according to the → second law of thermodynamics. In that condition of maximum → entropy, the Universe would be in a state of unchanging death. First introduced by the German physicist Hermann von Helmholtz (1821-1894) in 1854, on the basis of William Thomson's (1824-1907) idea.

→ heat; → death; → Universe.

The amount of heat energy required to transform an amount of a substance from the liquid phase to the gas phase. → molar heat of vaporization.

→ heat; → vaporization.

A structure that protects against excessive heat, especially that which covers the vulnerable surfaces of a → spacecraft and protects it when re-entering the Earth's atmosphere.

→ heat; → shield.

The spontaneous transportation of heat through matter, from a region of higher temperature to a region of lower temperature.

→ heat; → transfer.

Meteorology: A period of several successive days of abnormally hot and usually humid weather occurring in summer.

→ heat; → wave.

Celle-ye tâbestân literally "the fortieth of summer," i.e. "midsummer," from cellé pertaining to "forty (days)," from cel, cehel, → forty, + tâbestân, → summer.

1) The process whereby a system's temperature increases. → warming.
2) A device or system for supplying heat, especially central heating, to a building; the heat supplied.

→ heat; → -ing.

The region located between the → termination shock and the → heliopause where the turbulent and hot → solar wind is compressed as it passes outward against the interstellar wind.

Heliosheath, from → helio- + sheath, from O.E. sceað, scæð; cf. M.Du. schede, Du. schede, O.H.G. skaida, Ger. Scheide "scabbard."

Hurniyâm, from hur- "sun," → helio-, + niyâm "sheath," from Proto-Iranian *nigāma-, from ni- "down; into," → ni- (PIE), + gāma- "to go, to come" (Av. gam- "to come; to go," jamaiti "goes;" O.Pers. gam- "to come; to go;" Mod./Mid.Pers. gâm "step, pace," âmadan "to come;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come"); cf. Skt. nigamá- "insertion, incorporation."

The amount of → thermal energy that is absorbed or released by a unit amount of a substance in the process of a phase change under conditions of constant pressure and temperature.

→ latent; → heat.

The region between a planet's magnetopause and the bow shock caused by the solar wind.

From → magneto- + sheath, from O.E. sceað, scæð, from P.Gmc. *skaithiz (cf. M.Du. schede, Du. schede, O.H.G. skaida, Ger. Scheide "scabbard").

From meqnât-, → magnet, + niyâm "sheath," from Proto-Iranian *nigāma-, from ni- "down; into," → ni-, + gāma- "to go, to come" (Av. gam- "to come; to go," jamaiti "goes;" O.Pers. gam- "to come; to go;" Mod./Mid.Pers. gâm "step, pace," âmadan "to come;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come"); cf. Skt. nigamá- "insertion, incorporation."

Same as → Joule's constant.

→ mechanical; → equivalent; → heat.

The → heat capacity of one → mole of substance: C_μ = μ C, where μ is the → molecular weight and C the → specific heat capacity. The molar heat capacity of water is practically 18 cal/mole.C°.

Molar, adj. of → mole; → heat; → capacity.

The amount of heat energy required to vaporize 1 mole of a liquid at its → boiling point, usually expressed in kJ/mol.

→ molar; → heat; → vaporization.

The entropy change for chemical reactions involving crystalline solid is zero at the absolute zero of temperature. Also known as the third law of thermodynamics.

→ Nernst effect; → heat; → theorem.