Visibility

thumb|Twilight is the period between dawn and [[sunrise, and between sunset and dusk.]] thumb|Morning twilight: astronomical, nautical, and civil stages at dawn. The apparent disk of the Sun is shown to scale. thumb|Evening twilight: civil, nautical, and astronomical stages at dusk. The solar disk is shown to scale.

anthropogenic light in the night environment, caused by excess or misdirected lighting

elastic scattering of light, or other electromagnetic radiation, by particles of size much smaller than the wavelength of the radiation

thumb|upright=1.2|World map showing the areas of Earth receiving daylight around 1:00 pm UTC in April

thumb|Harmattan Haze in [[Abuja]] thumb|right|Haze over the Mojave Desert from a [[brush fire in Santa Barbara, California, seen as the Sun descends on the 2016 June solstice, allows the Sun to be photographed without a filter.]] thumb|Haze as smoke pollution over the Mojave from fires in the Inland Empire, June 2016, demonstrates the loss of contrast to the [[Sun, and the landscape in general.]]

period of twilight in the morning or evening

physical law describing absorption of light

microscopic solid or liquid matter suspended in the Earth's atmosphere

In meteorology, visibility is the measure of the distance at which an object or light can be clearly discerned. It depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time of day. It is reported within surface weather observations and METAR code either in meters or statute miles, depending upon the country. Visibility affects all forms of traffic: roads, railways, sailing and aviation.

thumb|Turbidity standards of 5, 50, and 500 NTU

natural logarithm of the ratio of incident to transmitted radiant power through a material; the absorbance × ln(10)

scattering of an electromagnetic plane wave by a homogeneous sphere, producing an infinite series of spherical multipole partial waves

Solar radiation scattered and absorbed in Earth's atmosphere

markings used on emergency vehicles

distance over which a pilot of an aircraft on the centreline of the runway can see the runway surface markings

visual phenomenon caused by a satellite reflecting sunlight onto the Earth

Air pollution in the Arctic caused by sources further South

name of the exponent in the formula that is usually used to describe the dependency of the aerosol optical thickness, or aerosol extinction coefficient on wavelength

Wikimedia list article

upright|thumb|Gloomy mudflats at Bo'ness in Scotland Gloom is a low level of light which is so dim that there are physiological and psychological effects. Human vision at this level becomes monochrome and has lessened clarity.

black (or other) and white chequered pattern, associated with policing