fluorescence piranha swimming in water

uorescence is a luminescence which is mostly found as an optical phenomenon in cold bodies, in which a molecule absorbs a high-energy photon, and re-emits it as a lower-energy (longer-wavelength) photon. The energy difference between the absorbed and emitted photons ends up as molecular vibrations (heat). Usually the absorbed photon is in the ultraviolet, and the emitted light (luminescence) is in the visible range, but this depends on the absorbance curve and Stokes shift of the particular fluorophore. Fluorescence is named after the mineral fluorite (calcium fluoride), which exhibits this phenomenon. See more at Wikipedia.org...

>For the armoured vehicle, see Mowag Piranha Catoprion Citharinus Pristobrycon Pygocentrus Serrasalmus The piranhas or pirañas are a group of carnivorous freshwater fish living in South American rivers. They belong to five genera of the subfamily of Serrasalminae (which also includes closely related herbivorous fish including pacus and silver dollars). They are normally about 15 to 25 cm long (6 to 10 inches) long, although reportedly individuals have been found up to 40 cm in length. They are known for their sharp teeth (able to bite through a steel fishing hook) and an aggressive appetite for meat and flesh. They are normally only found in the Amazonian, Guyanas' and Paraguayan river systems. However, piranha (most likely former aquarium-dwellers) are also occasionally found in the Potomac River, but they typically do not survive the cold winters of that region[1]. See more at Wikipedia.org...