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solar wind

(Encyclopedia)solar wind, stream of ionized hydrogen—protons and electrons—with an 8% component of helium ions and trace amounts of heavier ions that radiates outward from the sun at high speeds. The continuous...

spectrum

(Encyclopedia)CE5 Dispersion of white light by a triangular prism spectrum, arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other propert...

nebula

(Encyclopedia)nebula nĕbˈyo͝olə [key] [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to b...

nuclear weapons

(Encyclopedia)nuclear weapons, weapons of mass destruction powered by atomic, rather than chemical, processes. Nuclear weapons produce large explosions and hazardous radioactive byproducts by means of either nuclea...

Titan , in astronomy

(Encyclopedia)Titan tīˈtən [key], in astronomy, the largest of the named moons, or natural satellites, of Saturn. Also known as Saturn VI (or S6), Titan is 3,200 mi (5,150 km) in diameter, orbits Saturn at a mea...

chromium

(Encyclopedia)chromium krōˈmēəm [key] [Gr.,=color], metallic chemical element; symbol Cr; at. no. 24; at. wt. 51.9961; m.p. about 1,857℃; b.p. 2,672℃; sp. gr. about 7.2 at 20℃; valence +2, +3, +6. Chromiu...

isotope

(Encyclopedia)CE5 Isotopes of hydrogen isotope īˈsətōp [key], in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of ...

sodium

(Encyclopedia)sodium, a metallic chemical element; symbol Na [Lat. natrium]; at. no. 11; at. wt. 22.98977; m.p. 97.81℃; b.p. 892.9℃; sp. gr. 0.971 at 20℃; valence +1. Sodium is a soft, silver-white metal. Ext...

bromine

(Encyclopedia)bromine brōˈmēn, –mĭn [key] [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2℃; b.p. 58.78℃; sp. gr. of liquid 3.12 at 20℃; density of va...

boron

(Encyclopedia)boron bōrˈŏn [key] [New Gr. from borax], chemical element; symbol B; at. no. 5; interval in which at. wt. ranges 10.806–10.821; m.p. about 2,300℃; sublimation point about 2,550℃; sp. gr. 2.3 ...