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The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is by far the most important source of energy for ...
The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.
Sunlight is a key factor in photosynthesis, the process used by plants and other autotrophic organisms to convert light energy, normally from the Sun, into chemical energy that can be used to synthesize carbohydrates and fuel the organisms' activities. Daylighting is the natural lighting of interior spaces by admitting sunlight.
This is a list of sources of light, the visible part of the electromagnetic spectrum.Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that ...
This integrated solar irradiance is called solar irradiation, solar radiation, solar exposure, solar insolation, or insolation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Irradiance in space is a function of distance from the Sun, the solar cycle, and cross-cycle changes. [2]
The emission spectrum of a light source varies depending on the light generating mechanism. Thermal sources such as incandescent bulbs produce electromagnetic radiation over a broad and continuous range of wavelengths, including infrared and ultraviolet. A black body radiator is the idealized version of a thermal source. As the temperature of a ...
The data for the study was obtained last year by one of the three telescopes on an instrument called the Extreme Ultraviolet Imager aboard the Solar Orbiter, a sun-observing probe built by the ...
Extremely hot stars (such as O- and B-type) emit proportionally more UV radiation than the Sun. Sunlight in space at the top of Earth's atmosphere (see solar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m 2 in vacuum.