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Michelson, Albert Abraham

(Encyclopedia)Michelson, Albert Abraham mīˈkəlsən [key], 1852–1931, American physicist, b. Strelno, Prussia, grad. Annapolis, 1873, and studied at Berlin, Heidelberg, and Paris. He was professor of physics at...

Sirius

(Encyclopedia)Sirius sĭrˈēəs [key], or Dog Star, brightest star in the sky. It is located in the constellation Canis Major (1992 position R.A. 6h44.8m, Dec. −16°42′); its Bayer designation is Alpha Canis M...

interference

(Encyclopedia)CE5 Constructive interference: Two crests or two troughs meet and combine (A, B, C). Destructive interference: A crest and a trough meet and cancel each other (D, E, F). interference, in physics, ...

infrared astronomy

(Encyclopedia)infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and building...

light

(Encyclopedia)light, visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range ...

iridium

(Encyclopedia)iridium ĭrĭdˈēəm [key], metallic chemical element; symbol Ir; at. no. 77; at. wt. 192.217; m.p. about 2,410℃; b.p. about 4,130℃; sp. gr. 22.55 at 20℃; valence +3 or +4. Iridium is a very ha...

indium

(Encyclopedia)indium ĭnˈdēəm [key], a metallic chemical element; symbol In; at. no. 49; at. wt. 114.818; m.p. 156.6℃; b.p. about 2,080℃; sp. gr. 7.31 at 20℃; valence +1, +2, or +3. Indium is a soft, malle...

sulfa drug

(Encyclopedia)sulfa drug, any of a class of synthetic chemical substances derived from sulfanilamide, or para-aminobenzenesulfonamide. Sulfa drugs are used to treat bacterial infections, although they have largely ...

red giant

(Encyclopedia)red giant, star that is relatively cool but very luminous because of its great size. All normal stars are expected to pass eventually through a red-giant phase as a consequence of stellar evolution. A...

gamma-ray astronomy

(Encyclopedia)gamma-ray astronomy, study of astronomical objects by analysis of the most energetic electromagnetic radiation they emit. Gamma rays are shorter in wavelength and hence more energetic than X rays (see...