Health

How much sun is good for health?

Spanish researchers have estimated the duration of solar radiation exposure required in order to obtain the recommended doses of vitamin D. While in spring and summer, 10 to 20 minutes in the sun are enough, in the winter ...

Health

Secret to health benefits of sunshine is more than vitamin D

Summer sunshine makes most of us feel better, but there may be more to the benefits than just feeling good. A growing body of evidence suggests sunlight itself – with adequate protection, of course – may actually be good ...

Oncology & Cancer

Outdoor workers face increased cancer risk

(Medical Xpress)—Perth researchers have completed a comprehensive study into Australian workers and their exposure to ultraviolet radiation - a known human carcinogen.

Health

IID: Sleep quality impacts skin function, aging in women

(HealthDay)—For premenopausal women, sleep quality is associated with skin function and aging, according to a study presented at the International Investigative Dermatology meeting, held from May 8 to 11 in Edinburgh, U.K.

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Sunlight

Sunlight, in the broad sense, is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon. Near the poles in summer, the days are longer and the nights are shorter or non-existent. In the winter at the poles the nights are longer and for some periods of time, sunlight may not occur at all. When the direct radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and heat. Radiant heat directly produced by the radiation of the sun is different from the increase in atmospheric temperature due to the radiative heating of the atmosphere by the sun's radiation. Sunlight may be recorded using a sunshine recorder, pyranometer or pyrheliometer. Sunlight takes about 8.3 minutes to reach the Earth. The World Meteorological Organization defines sunshine as direct irradiance from the Sun measured on the ground of at least 120 watts per square metre.

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared, visible, and ultra-violet light. Bright sunlight provides luminance of approximately 100,000 candela per square meter at the Earth's surface.

Sunlight is a key factor in photosynthesis, a process crucially important for life on Earth.

This text uses material from Wikipedia, licensed under CC BY-SA