An unstable elementary particles, belonging to the class called → baryons, which have greater mass than the neutron but very short lives (10-8 to 10-10 seconds).
hypervelocity star (HVS)
Fr.: étoile hypervéloce
A star whose velocity is so great that it will escape the
→ gravitational potential of our
→ Galaxy. Depending on the location and direction of
motion, this criterion typically corresponds to a stellar velocity in
the Galactic → rest frame larger than
400 km s-1, and up to about 1200 km s-1.
The nature of the HVSs spans a wide range of types from
→ OB stars, to metal-poor
→ F-type stars and G/K dwarfs. While there is evidence from many
late-type B HVSs in the → halo
to originate from the Galactic
→ supermassive black hole (SMBH),
other HVSs seem to originate from the → galactic disk.
HVSs can obtain their large velocities from a number of different processes:
A Gk. prefix denoting "under."
Gk. hypo "under" (prep.), "below" (adv.); cognate with L. sub- and O.Pers./Av. upā, as below.
Upâ-, from O.Pers. upā (prep.) "under, with;" Av. upā, upa (prep.; prevb) "toward, with, on, in" (upā.gam- "to arrive at," upāpa- "living in the water," upa.naxturušu "bordering on the night"); Mod.Pers. bâ "with," from abâ; cf. Skt. úpa (adv., prevb., prep.) "toward, with, under, on;" cognate with Gk. hypo, as above.
A curve generated by the trace of a fixed point on a small circle that rolls within a larger circle.
In a → right triangle, the side opposite to the right angle.
Vatar loan from Ar.
The failure of the body to maintain adequate production of heat under conditions of extreme cold.
Hypothermia, from → hypo- + therm, from Gk. therme "heat," from PIE *ghwerm-/*ghworm- "warm;" cf. Pers. garm "warm;" L. fornax "an oven;" O.E. wearm "warm" + -ia a noun suffix.
Upâgarmâyi, from upâ-, → hypo-, + 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" + -yi noun suffix.
engâre (#), upâdâyan
A statement which is based on previous observations and which serves as a starting point for further investigation by which it may be proved or disproved. See also → theory, → model, → ad hoc hypothesis, → Kant-Laplace hypothesis, → arge number hypothesis, → nebular hypothesis, → null hypothesis, → statistical hypothesis, → statistical hypothesis testing.
Hypothesis, from M.Fr. hypothèse, from L.L. hypothesis, from Gk. hypothesis "base, basis of an argument, supposition," literally "a placing under," from → hypo- "under" + thesis "a placing, proposition," from root of tithenai "to place, put, set," didomi "I give;" from PIE base *dhe- "to put, to do;" cf. Mod.Pers. dâdan "to give," Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do."
engâré sâxtan (#), upâdâyanidan
Fr.: faire une hypothèse
To form a → hypothesis.
Hypothesize, from hypothes(is), → hypothesis + -ize a verb-forming suffix, from M.E. -isen, from O.Fr. -iser, from L.L. -izare, from Gk. -izein.
Engâré sâxtan, from engâré, → hypothesis
+ sâxtan, sâzidan "to adapt, adjust, be fit; to build, make, fashion,"
Mid.Pers. sâxtan, sâz-,
Manichean Parthian s'c'dn "to prepare, to form," Av. sak- "to understand,
to mark," sâcaya- (causative) "to teach."
engâre-yi (#), upâdâyani
Of, pertaining to, or involving a → hypothesis; supposed.
The phenomenon exhibited by a body (especially a ferromagnetic or
imperfectly elastic material) in reacting to changes in the
forces, especially magnetic forces, affecting it.
Hysteresis, from Gk. hysteresis "being behind or late," from hystere-, stem of hysterein "to come late, lag behind" + -sis a suffix forming abstract nouns of action.
Pasmând "lagging behind," from pas "behind" (Mid.Pers. pas "behind, before, after;" O.Pers. pasā "after;" Av. pasca "behind (of space); then, afterward (of time);" cf. Skt. pazca "behind, after, later," L. post "behind, in the rear; after, afterward;" O.C.S. po "behind, after;" Lith. pas "at, by;" PIE *pos-, *posko-) + mând stem of mândan "to remain; to be fatigued," mân "house, family" (Mid.pers. mândan "to remain, stay;" O.Pers. mān- "to remain, dwell;" Av. man- "to remain, dwell; to wait;" cf. Gk. menein "to remain;" L. manere "to stay, remain, abide," mansio "a staying, a remaining, night quarters, station" (Fr. maison, ménage; E. manor, mansion, permanent); PIE *men- "to remain, wait for."
Fr.: cycle d'hystérésis
A closed curve showing the change in magnetic induction of a ferromagnetic body to which an external field is applied as the intensity of this field is varied from +Hs to -Hs and back again, where Hs is the magnetic field intensity corresponding to saturation.
Fr.: perte par hystérésis
Dissipation of energy which occurs, due to magnetic hysteresis, when the magnetic material is subject to changes of magnetization.