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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...

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, ...

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...

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...

Conon

(Encyclopedia)Conon kōˈnŏn, –nən [key], 3d cent. b.c., Greek astronomer and mathematician of Samos. He traveled in the western part of the Greek world making astronomical observations, then settled at Alexand...

satellite, natural

(Encyclopedia)satellite, natural, celestial body orbiting a planet, dwarf planet, asteroid, or star of a larger size. The most familiar natural satellite is the earth's moon; thus, satellites of other planets are o...

Secchi, Pietro Angelo

(Encyclopedia)Secchi, Pietro Angelo pyĕˈtrō änˈjālō sĕkˈkē [key], 1818–78, Italian astronomer, a Jesuit priest. He was director of the observatory of the Gregorian Univ., Rome, from 1849. He is known es...
 

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