Whiteout (weather) moving. Local, short-duration whiteout conditions can be created artificially in the vicinity of airports and helipads due to aircraft operations. Snow on the ground can be stirred up by helicopter rotor down-wash or airplane jet blast, presenting hazards to both aircraft and bystanders on the ground. Whiteout (weather) Whiteout is a weather condition in which visibility and contrast are severely reduced by snow or sand. The horizon disappears from view while the sky and landscape appear featureless, leaving no points of visual reference by which to navigate. Whiteout has been defined as: "A condition of diffuse light when no shadows
Irrational rotation Irrational rotation In the mathematical theory of dynamical systems, an irrational rotation is a map where "θ" is an irrational number. Under the identification of a circle with R/Z, or with the interval [0, 1] with the boundary points glued together, this map becomes a rotation of a circle by a proportion "θ" of a full revolution (i.e., an angle of 2"πθ" radians). Since "θ" is irrational, the rotation has infinite order in the circle group and the map "T" has no periodic orbits. Alternatively, we can use multiplicative notation for an irrational rotation by introducing the map The relationship