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force

(Encyclopedia)force, commonly, a “push” or “pull,” more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and dir...

antiparticle

(Encyclopedia)antiparticle, elementary particle corresponding to an ordinary particle such as the proton, neutron, or electron, but having the opposite electrical charge and magnetic moment. Every elementary partic...

supernova

(Encyclopedia)supernova, a massive star in the latter stages of stellar evolution that suddenly contracts and then explodes, increasing its energy output as much as a billionfold. Supernovas are the principal distr...

metric system

(Encyclopedia)CE5 metric system, system of weights and measures planned in France and adopted there in 1799; it has since been adopted by most of the technologically developed countries of the world. It is based...

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 ...

Tito, Josip Broz

(Encyclopedia)Tito, Josip Broz yôˈsĭp brôz tēˈtō [key], 1892–1980, Yugoslav Communist leader, marshal of Yugoslavia. He was originally Josip Broz. As premier and minister of defense from 1945, Marshal T...

space exploration

(Encyclopedia)CE5 Moon mission assembly CE5 Stages in a moon mission shown counterclockwise from launching on the first day to splashdown on the ninth day. space exploration, the investigation of physical co...

Pleistocene epoch

(Encyclopedia)Pleistocene epoch plīˈstəsēn [key], 6th epoch of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table). According to a classification that considered its depos...

electricity

(Encyclopedia)CE5 Electrical and radio symbols electricity, class of phenomena arising from the existence of charge. The basic unit of charge is that on the proton or electron—the proton's charge is designate...

observatory

(Encyclopedia)observatory, scientific facility especially equipped to detect and record naturally occurring scientific phenomena. Although geological and meteorological observatories exist, the term is generally ap...