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Manhattan Project

(Encyclopedia)Manhattan Project, the wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materi...

solar energy

(Encyclopedia)solar energy, any form of energy radiated by the sun, including light, radio waves, and X rays, although the term usually refers to the visible light of the sun. Solar energy is needed by green plants...

nuclear reactor

(Encyclopedia)CE5 Power reactor system nuclear reactor, device for producing controlled release of nuclear energy. Reactors can be used for research or for power production. A research reactor is designed to pr...

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...

cancer, in medicine

(Encyclopedia)cancer, in medicine, common term for neoplasms, or tumors, that are malignant. Like benign tumors, malignant tumors do not respond to body mechanisms that limit cell growth. Unlike benign tumors, mali...

brown dwarf

(Encyclopedia)brown dwarf, in astronomy, celestial body that is larger than a planet but does not have sufficient mass to convert hydrogen into helium via nuclear fusion as stars do. Also called “failed stars,”...

radar

(Encyclopedia)radar, system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, ...

cosmic rays

(Encyclopedia)cosmic rays, charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (...

colon cancer

(Encyclopedia)colon cancer, cancer of any part of the colon (often called the large intestine). Colon cancer is the second most common cancer diagnosed in the United States. Epidemiological evidence has shown that ...

Neptune, in astronomy

(Encyclopedia)Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...