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precession of the equinoxes

(Encyclopedia)CE5 Precession of the equinoxes (the points at which the earth's celestial equator intersects its ecliptic) is due to the slow rotation of the earth's axis around a perpendicular to the ecliptic. ...

power, electric

(Encyclopedia)power, electric, energy dissipated in an electrical or electronic circuit or device per unit of time. The electrical energy supplied by a current to an appliance enables it to do work or provide some ...

photovoltaic cell

(Encyclopedia)photovoltaic cell: see photoelectric cell; solar cell. ...

civil time

(Encyclopedia)civil time, local time based on universal time. Civil time may be formally defined as mean solar time plus 12 hr; the civil day begins at midnight, while the mean solar day begins at noon. Civil time ...

neptunium

(Encyclopedia)neptunium nĕpto͞oˈnēəm [key], radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640℃; b.p. 3,902℃ (estimated); sp. gr. 20.25 at 20℃; va...

geophysics

(Encyclopedia)geophysics, study of the structure, composition, and dynamic changes of the earth, its atmosphere, hydrosphere and magnetosphere, based on the principles of physics. The term was probably first used i...

second

(Encyclopedia)second, abbr. sec or s, fundamental unit of time in all systems of measurement. In practical terms, the second is 1/60 of a minute, 1/3,600 of an hour, or 1/86,400 of a day. Since the length of the da...

Tychyna, Pavlo

(Encyclopedia)Tychyna, Pavlo, 1891–1967, Ukrainian poet. Tychyna's first volume of verse (Solar Clarinets, 1919) revealed a strong symbolist influence. His later poetry, including The Party is our Guide (1934) an...

Hawthorne

(Encyclopedia)Hawthorne. 1 City (2020 pop. 88,083), Los Angeles co., S Calif., a suburb of Los Angeles; inc. 1922. Located in an oil- and gas-producing area, ...

Orbiting Geophysical Observatory

(Encyclopedia)Orbiting Geophysical Observatory (OGO), series of six orbiting observatories (see observatory, orbiting) launched between 1964 and 1969 by the National Aeronautics and Space Administration (NASA) to s...