Sunlight

Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun, particularly infrared, visible, and ultraviolet light. On Earth, sunlight is filtered through the Earth's atmosphere, and is obvious as daylight when the Sun is above the horizon.

When the direct solar radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and radiant heat. When it is blocked by the clouds or reflects off other objects, it is experienced as diffused light.

The World Meteorological Organization uses the term "sunshine duration" to mean the cumulative time during which an area receives direct irradiance from the Sun of at least 120 watts per square meter.

Sunlight may be recorded using a sunshine recorder, pyranometer or pyrheliometer.

Sunlight takes about 8.3 minutes to reach the Earth. On average, it takes energy between 10,000 and 170,000 years to leave the sun's interior and then be emitted from the surface as light.

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux. Bright sunlight provides illuminance of approximately 100,000 lux or lumens per square meter at the Earth's surface. Sunlight's composition at ground level, per square meter, with the sun at the zenith, is about 527 watts of infrared radiation, 445 watts of visible light, and 32 watts of ultraviolet radiation. At the top of the atmosphere sunlight is about 30% more intense with more than three times the fraction of ultraviolet (UV), with most of the extra UV consisting of biologically-damaging shortwave ultraviolet.

Sunlight is a key factor in photosynthesis, a process vital for many living beings on Earth.

Read more about SunlightComposition and Power, Calculation, Solar Constant, Total (TSI) and Spectral Solar Irradiance (SSI) Upon Earth, Intensity in The Solar System, Surface Illumination, Climate Effects, Past Variations in Solar Irradiance, Life On Earth, Cultural Aspects, Effects On Human Health

Other articles related to "sunlight":

Sunbreak
... A sunbreak is a natural phenomenon in which sunlight obscured over a relatively large area penetrates the obscuring material in a localized space ... The typical example is of sunlight shining through a hole in cloud cover ... Another form of sunbreak occurs when sunlight passes into an area otherwise shadowed by surrounding large buildings through a gap temporarily aligned with the position of the sun ...
Sunshiny
... Sunlight is a portion of the electromagnetic radiation given off by the Sun, particularly infrared, visible, and ultraviolet light ... On Earth, sunlight is filtered through the Earth's atmosphere, and is obvious as daylight when the Sun is above the horizon ... Sunlight may be recorded using a sunshine recorder, pyranometer or pyrheliometer ...
Sunshiny - Cultural Aspects
... The effect of sunlight is relevant to painting, evidenced for instance in works of Claude Monet on outdoor scenes and landscapes ... Many people find direct sunlight to be too bright for comfort, especially when reading from white paper upon which the sun is directly shining ... To compensate for the brightness of sunlight, many people wear sunglasses ...
Sunshiny - Effects On Human Health
... The body produces vitamin D from sunlight (specifically from the UVB band of ultraviolet light), and excessive seclusion from the sun can lead to deficiency unless adequate amounts are ... A lack of sunlight, on the other hand, is considered one of the primary causes of seasonal affective disorder (SAD), a serious form of the "winter blues" ... most of the treatments (other than prescription drugs) involve light therapy, replicating sunlight via lamps tuned to specific wavelengths of visible light, or full-spectrum bulbs ...
Sunlight - Effects On Human Health
... The body produces vitamin D from sunlight (specifically from the UVB band of ultraviolet light), and excessive seclusion from the sun can lead to deficiency unless adequate amounts are ... A lack of sunlight, on the other hand, is considered one of the primary causes of seasonal affective disorder (SAD), a serious form of the "winter blues" ... drugs) involve light therapy, replicating sunlight via lamps tuned to specific wavelengths of visible light, or full-spectrum bulbs ...

Famous quotes containing the word sunlight:

    Weave, weave the sunlight in your hair—
    —T.S. (Thomas Stearns)

    Calm as that second summer which precedes
    The first fall of the snow,
    In the broad sunlight of heroic deeds,
    The City bides the foe.
    Henry Timrod (1828–1867)

    Semi-Saracenic architecture, sustaining itself as if by miracle in mid air; glittering in the red sunlight with a hundred oriels, minarets, and pinnacles; and seeming the phantom handiwork, conjointly, of the Sylphs,... the Fairies,... the Genii, and ... the Gnomes.
    Edgar Allan Poe (1809–1849)