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angstrom

(Encyclopedia)angstrom ăngˈstrəm [key], abbr. Å, unit of length equal to 10−10 meter (0.0000000001 meter); it is used to measure the wavelengths of visible light and of other forms of electromagnetic radiatio...

polonium

(Encyclopedia)polonium pəlōˈnēəm [key], radioactive chemical element; symbol Po; at. no. 84; mass no. of most stable isotope 209; m.p. 254℃; b.p. 962℃; sp. gr. about 9.4; valence +2 or +4. Polonium is an e...

Ashkin, Arthur

(Encyclopedia)Ashkin, Arthur, 1922–2020, American physicist, b. Brooklyn, N.Y., Ph.D. Cornell, 1952. Ashkin worked for four decades at Bell Laboratories, retiring in 1992. Ashkin researched microwaves, nonlinear ...

fog

(Encyclopedia)fog, aggregation of water droplets or ice crystals immediately above the surface of the earth (i.e., a cloud near the ground). A light or thin fog is usually called a mist. Fog may occur when the mois...

Mössbauer, Rudolf Ludwig

(Encyclopedia)Mössbauer, Rudolf Ludwig, 1929–2011, German physicist, Ph.D. Max Planck Institute for Medical Research, Heidelberg, Germany, 1957. Mössbauer was a professor at the California Institute of Technolo...

cloud chamber

(Encyclopedia)cloud chamber, device used to detect elementary particles and other ionizing radiation. A cloud chamber consists essentially of a closed container filled with a supersaturated vapor, e.g., water in ai...

Jupiter, in astronomy

(Encyclopedia)Jupiter jo͞oˈpətər [key], in astronomy, 5th planet from the sun and largest planet of the solar system. Astronomers have discovered 79 satellites orbiting Jupiter, but five of those, small sate...

radiological weapon

(Encyclopedia)radiological weapon: see radiation weapon. ...

black light

(Encyclopedia)black light: see ultraviolet radiation. ...

fluoroscope

(Encyclopedia)fluoroscope flo͝orˈəskōp [key], instrument consisting of an X-ray machine (see X ray) and a fluorescent screen that may be used by physicians to view the internal organs of the body. During medica...