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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 ...
Ulexite (/ juː ˈ l ɛ k s aɪ t /) sometimes called TV rock or TV stone due to its unusual optical properties, is a hydrous borate hydroxide of sodium and calcium with the chemical formula NaCaB 5 O 6 (OH) 6 ·5H 2 O. The mineral occurs as silky white rounded crystalline masses or in parallel fibers.
Anthropic rock is rock that is made, modified and moved by humans. Concrete is the most widely known example of this. [ 1 ] The new category has been proposed to recognise that human-made rocks are likely to last for long periods of Earth's future geological time , and will be important in humanity's long-term future.
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.
Optical radiation is the part of the electromagnetic spectrum with wavelengths between 100 nm and 1 mm. [1] [2] This range includes visible light, infrared light, and part of the ultraviolet spectrum. [3] Optical radiation is non-ionizing, [4] and can be focused with lenses and manipulated by other optical elements.
The change from supercooled liquid to glass occurs at a temperature called the glass transition temperature, which depends on both cooling rate and the amount of water dissolved in the magma. Magma rich in silica and poor in dissolved water is most easily cooled rapidly enough to form volcanic glass.
Earthshine – Light reflected from the Earth; Zodiacal light – Faint solar glow caused by interplanetary dust at sunset and sunrise; Gegenschein – Optical effect of interplanetary dust reflections; Reflection nebula – Clouds of interstellar dust which reflect the light of nearby stars
This list contains natural objects up to apparent magnitude 3.5. All objects are listed by their visual magnitudes, and objects too close together to be distinguished are listed jointly. Objects are listed by their proper names or their most commonly used stellar designation.