Flat, from O.N. flatr, from P.Gmc. *flataz (cf. O.H.G. flaz "flat, level," O.E. flet, O.H.G. flezzi "floor"), perhaps from PIE *pla- (cf. Gk. platys "broad, flat;" Av. pərətu- "broad, wide;" Skt. prthu- "broad, wide, large").
Taxt "flat;" Mid.Pers. taxtag "tablet, plank, (chess)board."
Fr.: variété plate
flat rotation curve
xam-e carxeš-e taxt
Fr.: courbe de rotation plate
A galactic → rotation curve in which the → rotation velocity is constant in the outer parts. The flat component is preceded by a rising curve that shows solid body rotation in the very center of the → galaxy. A flat rotation curve implies that the mass is still increasing linearly with radius. See also → dark matter.
Fr.: univers plat
A Universe where the → geometry is → Euclidean, i.e. parallel lines remain parallel when extended into the distance and the sum of the interior angles of a triangle is 180°. The → space-time in a flat Universe has a null → curvature constant, k = 0. See also → closed Universe, → open Universe.
Fr.: champ plat
Exposure of a diffuse and uniform source in order to calibrate the non-uniformity of an imaging detector such as a CCD.
Fr.: problème de la platitude
The observed fact that the → geometry of the → Universe is very nearly flat, in other words its density is very close to the → critical density. This would be an extreme coincidence because a → flat Universe is a special case. Many attempts have been made to explain the flatness problem, and modern theories now include the idea of → inflation.
Inflate, from L. inflatus p.p. of inflare "to blow into, puff up," from → in- "into" + flare "to blow."
Pandâmidan "to swell," from pandâm [Mo'in] "swelling;" Borujerdi panâm, panam "swellig;" Malâyeri panomidan "to swell;" Laki penamiyen "to swell;" Hamadâni pandumidan "swelling of the eye or other parts of the body;" Kermâni padum kerdan "to swell," padum "swelled; fat, corpulent;" Tâleši pandâm, pandom "swelling;" Gilaki pandâm kudan "rising of river water caused by flood;" cf. Gk. pneuma "wind; breath," from pnein "to blow; to breathe;" PIE base *pneu- "to breathe." Related terms in other Indo-European languages: O.E. fnaeran "to breathe heavily," fneosan "to snort, sneeze;" M.H.G. pfnusen, pfnehen "to breathe, pant, sniff, snort, sneeze;" Norw. fnysa "to breeze;" M.Du. fniesen, Du. fniezen "to sneeze;" O.H.G. niosan, Ger. niesen "to sneeze."
1) General: The act of inflating; the state of being inflated.
Verbal noun of → inflate.
Fr.: modèle d'inflation
A class of → Big Bang models of the Universe that include a finite period of accelerated expansion in their early histories. Such an event would have released enormous energy, stored until then in the vacuum of space-time. The horizon of the Universe expanded, temporarily, much faster than the speed of light. → inflaton field.
Fr.: champ inflaton
A hypothetical → scalar field that provides a theoretical basis for → inflation in the early → Big Bang history of the → Universe. The inflaton field would fill space with the same energy at every point. In general, the scalar field can vary with time and space, though to a first approximation everywhere in the Universe will have the same value at any time. The field has a particle associated with it, called → inflaton, just as the → electromagnetic field is associated with the → photon. The inflaton field is characterized also by a → negative pressure that would yield a tremendous → repulsive gravity during a brief lapse of time. In the earliest moments of the Universe, space is uniformly filled with an inflaton field, whose value places it higher up on its → potential energy curve. The inflaton's → potential energy would drop in a tiny fraction of a second, on the order of 10-35 seconds. And yet, during that brief instant, space would expand by a colossal factor, of at least 1030.