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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 ...
A zeitgeber (/ ˈ (t) s aɪ t ɡ eɪ b ər, ˈ z aɪ t-/ (T)SYTE-gay-bər, ZYTE-, German: [ˈtsaɪtˌɡeːbɐ]) is any external or environmental cue that entrains or synchronizes an organism's biological rhythms, usually naturally occurring and serving to entrain to the Earth's 24-hour light/dark and 12-month cycles.
Bioluminescence differs from biofluorescence in that it is the natural production of light by chemical reactions within an organism, whereas biofluorescence and biophosphorescence are the absorption and reemission of light from the natural environment.
Some drugs have a photosensitizing effect. Properties of natural or artificial light that may abnormally affect people include: Timing of light (upset of normal circadian rhythms, seasonal affective disorder, sleep disorders) Intensity of light (photophobia, sunburn, skin cancer) [1] [2] [3] Wavelength of light (in lupus, urticaria)
Most people in the world depend on the sun to get vitamin D, [31] and elderly populations in low UVB countries experience higher rates of cancer. [32] There are not many foods that naturally have vitamin D. [33] Examples are cod liver oil and oily fish. If people cannot get sunlight, then they will need 1,000 IU of vitamin D per day to stay ...
Photosensitizers utilize light to enact a chemical change in a substrate; after the chemical change, the photosensitizer returns to its initial state, remaining chemically unchanged from the process. Photoinitiators absorb light to become a reactive species, commonly a radical or an ion, where it then reacts with another chemical species. These ...
Artificial light at night refers to any light source other than a natural light source. Sources of artificial light include LEDS and fluorescents. This particular light source has effect on the reproduction, immune function, metabolism, thermoregulation and body temperature of organisms that need light for their daily activity.
Bioluminescence is the production of light by living organisms. This list of bioluminescent organisms is organized by the environment, covering terrestrial, marine, and microorganisms. Terrestrial animals