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Bode's law

(Encyclopedia)Bode's law [for J. E. Bode], also known as Titius's law or the Titius-Bode law, empirical relationship between the mean distances of the planets from the sun. If each number in the series 0, 3, 6, 12,...

cycle

(Encyclopedia)cycle, in astronomy, period of time required for the recurrence of some celestial event. The length of a cycle may be measured relative to the sun or to the fixed stars (see sidereal time). A frequent...

sea level

(Encyclopedia)sea level, the level of the sea, which serves as the datum used for measurement of land elevations and ocean depths. Theoretically, one would expect sea level to be a fixed and permanent horizontal su...

ephemeris

(Encyclopedia)ephemeris ĭfĕmˈərĭs [key] (pl., ephemerides), table listing the position of one or more celestial bodies for each day of the year. The French publication Connaissance de Temps is the oldest of th...

Antipodes, islands, New Zealand

(Encyclopedia)Antipodes ăntĭpˈədēz [key], rocky uninhabited islands, 24 sq mi (62 sq km), South Pacific, c.550 mi (885 km) SE of New Zealand, to which they belong. Explored by British seamen in 1800, the Antip...

average

(Encyclopedia)average, number used to represent or characterize a group of numbers. The most common type of average is the arithmetic mean. See median; mode. ...

Wallace, Edgar

(Encyclopedia)Wallace, Edgar (Richard Horatio Edgar Wallace), 1875–1932, English novelist and playwright, b. Greenwich. He was the author of more than 150 detective and adventure novels, of which as many as 5 mil...

sundial

(Encyclopedia)sundial, instrument that indicates the time of day by the shadow, cast on a surface marked to show hours or fractions of hours, of an object on which the sun's rays fall. Although any object whose sha...

Graham, George

(Encyclopedia)Graham, George, 1674?–1751, English instrument maker. A clockmaker by trade, Graham designed clocks and watches that earned him membership in the Royal Society and were still manufactured into the p...

Tompion, Thomas

(Encyclopedia)Tompion, Thomas, 1639?–1713, English clockmaker. When the Royal Observatory at Greenwich was established in 1676, Tompion was chosen to make two clocks, to be wound only once a year, which proved to...