In his 1852 paper on the "Refrangibility" ( wavelength change) of light, George Gabriel Stokes described the ability of fluorspar and uranium glass to change invisible light beyond the violet end of the visible spectrum into blue light. ĭescribed fluorescence in fluorites, Sir David Brewster described the phenomenon for chlorophyll in 1833 Īnd Sir John Herschel did the same for quinine in 1845. The chemical compound responsible for this fluorescence is matlaline, which is the oxidation product of one of the flavonoids found in this wood. It was derived from the wood of two tree species, Pterocarpus indicus and Eysenhardtia polystachya. Matlaline, the fluorescent substance in the wood of the tree Eysenhardtia polystachyaĪn early observation of fluorescence was described in 1560 by Bernardino de Sahagún and in 1565 by Nicolás Monardes in the infusion known as lignum nephriticum ( Latin for "kidney wood"). History A cup made from the wood of the narra tree ( Pterocarpus indicus) beside a flask containing its fluorescent solution Lignum nephriticum. But since fluorescence is due to a specific chemical, which can also be synthesized artificially in most cases, it is sufficient to describe the substance itself as fluorescent. The latter may be referred to as biofluorescence, indicating that the fluorophore is part of or is extracted from a living organism (rather than an inorganic dye or stain). Its most common everyday application is in ( gas-discharge) fluorescent lamps and LED lamps, in which fluorescent coatings convert UV or blue light into longer-wavelengths resulting in white light which can even appear indistinguishable from that of the traditional but energy- inefficient incandescent lamp.įluorescence also occurs frequently in nature in some minerals and in many biological forms across all kingdoms of life. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after.įluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors ( fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacuum fluorescent displays, and cathode-ray tubes. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. Fluorescent marine organisms Fluorescent clothes used in black light theater production, Pragueįluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. 651-655, 2010.For the album by Asobi Seksu, see Fluorescence (album).įluorescent minerals emit visible light when exposed to ultraviolet. *Citation: "G-band and Hard X-ray Emissions of the 2006 December 14 Flare Observed by Hinode/SOT and RHESSI," by Kyoko Watanabe, Säm Krucker, Hugh Hudson, Toshifumi Shimizu, Satoshi Masuda, Kiyoshi Ichimoto. It's possible that as the sun eases into a more active state over the next year, scientists will have more opportunities to study the flares.Ī paper on the new work, with Kyoko Watanabe of Japan Aerospace Exploration Agency as lead author, appeared May 20 in The Astrophysical Journal. "It's being done by electromagnetic effects that are not really understood," Hudson admitted.
"As opposed to the LHC where you accelerate a few particles, it would be like accelerating the whole building basically," said Hugh Hudson, also of Berkeley's Space Science Laboratories, who worked with Krucker.Īstronomers haven't figured out how exactly the sun works as a particle accelerator just yet.
It's not unlike what humans do at a much, much smaller scale in particle accelerators like the Large Hadron Collider. Now, it looks as if the extremely powerful electromagnetic fields somehow deliver enormous amounts of energy into particles in the sun's photosphere.
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