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coronagraph

(Encyclopedia)coronagraph kərōˈnəgrăfˌ [key], device invented by the French astronomer B. Lyot (1931) for the purpose of observing the corona of the sun and solar prominences occurring in the chromosphere. Be...

Davidson, George

(Encyclopedia)Davidson, George, 1825–1911, American geographer and astronomer, b. England. From 1845 to 1895 he was on the staff of the U.S. Coast and Geodetic Survey. He charted (1850–60) the U.S. Pacific coas...

Julian Day calendar

(Encyclopedia)Julian Day calendar, system of astronomical dating that allows the difference between two dates to be calculated more easily than conventional civil calendars with their uneven months. It was devised ...

‘Oumuamua

(Encyclopedia)‘Oumuamua ōmo͞oˈəmo͞oˈə [key], officially 1I/2017 U1 (‘Oumuamua), interstellar object, the first to be discovered in the solar system. Highly variable in brightness, it also is highly and u...

fission

(Encyclopedia)fission, in physics: see nuclear energy and nucleus; see also atomic bomb. ...

photoelectric cell

(Encyclopedia)CE5 Photoelectric cell: Light causes a photosensitive surface to emit electrons, which flow as current to the positive terminal. A galvanometer measures the current and thus indicates light intensi...

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...

Rankine temperature scale

(Encyclopedia)Rankine temperature scale, temperature scale having an absolute zero, below which temperatures do not exist, and using a degree of the same size as that used by the Fahrenheit temperature scale. Absol...

particle accelerator

(Encyclopedia)CE5 Linear accelerator (LINAC) CE5 Cyclotron: As the charged particles move faster, they spiral out to the edge of the Ds. particle accelerator, apparatus used in nuclear physics to produce bea...

Calypso, in astronomy

(Encyclopedia)Calypso, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XIV (or S14), Calypso is a small, irregularly shaped (nonspherical) body measuring about 21 mi (34...