Robotics

The first walking robot that moves without GPS

Desert ants are extraordinary solitary navigators. Researchers at CNRS and Aix-Marseille University, in the Institut des Sciences du Mouvement—Étienne Jules Marey (ISM), were inspired by ants as they designed AntBot, the ...

Energy & Green Tech

A new way to provide cooling without power

MIT researchers have devised a new way of providing cooling on a hot sunny day, using inexpensive materials and requiring no fossil fuel-generated power. The passive system, which could be used to supplement other cooling ...

Energy & Green Tech

Stacking solar cells method could be electricity gain

Is there a way to stack solar cells and convert more of the energy in sunlight into electricity? Not only has a company developed a method, but, as a headline said Wednesday in MIT Technology Review, the approach could make ...

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