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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 ...
Rare-earth elements occur in nature in combination with phosphate ( monazite ), carbonate - fluoride ( bastnäsite ), and oxygen anions. In their oxides, most rare-earth elements only have a valence of 3 and form sesquioxides (cerium forms CeO2 ). Five different crystal structures are known, depending on the element and the temperature.
The smallest known near-Earth asteroid is 2022 WJ 1 with an absolute magnitude of 33.58, [112] corresponding to an estimated diameter of about 0.7 m (2.3 ft). [135] The largest such object is 1036 Ganymed, [112] with an absolute magnitude of 9.26 and directly measured irregular dimensions which are equivalent to a diameter of about 38 km (24 mi ...
Phosphorus. Phosphorus is a chemical element; it has symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram (compare ...
NASA says they were able to detect between 100 and 412 parts per million in an area spanning a cubic meter of soil, which is around the equivalent of a standard 12-ounce bottle of water — to put ...
The total volume of water on Earth is estimated at 1.386 billion km 3 (333 million cubic miles), with 97.5% being salt water and 2.5% being freshwater. Of the freshwater, only 0.3% is in liquid form on the surface. [ 2][ 3][ 4] Because the oceans that cover roughly 70.8% of the area of Earth reflect blue light, Earth appears blue from space ...
The study of light, known as optics, is an important research area in modern physics. 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.
Magma (sometimes colloquially but incorrectly referred to as lava) is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. [ 3] Besides molten rock, magma may also contain suspended crystals and gas bubbles.