Climate change spells disaster for termite-loving numbats

Australia is known for its wonderous and unique wildlife. But, just like the rest of the world, Australia is expected to get even hotter due to climate change. This could spell disaster for many of the marsupials that call ...

Using smart materials to deploy a Dark Age explorer

One of the most significant constraints on the size of objects placed into orbit is the size of the fairing used to put them there. Large telescopes must be stuffed into a relatively small fairing housing and deployed to ...

A sun protection mechanism helps plants to survive

Just as people can get sunburned, plants can also suffer from too much sunlight. To stay healthy, they use an internal "sun protection mechanism." Pierrick Bru, a Ph.D. student working with Alizée Malnoë at Umeå Plant ...

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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