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Halley's comet

(Encyclopedia)Halley's comet or Comet Halley hălˈē, hāˈlē [key], periodic comet named for Edmond Halley, who observed it in 1682 and identified it as the one observed in 1531 and 1607. Halley did not live to ...

Halley, Edmond

(Encyclopedia)Halley, Edmond hălˈē, hôˈlē [key], 1656–1742, English astronomer and mathematician. He is particularly noted as the first astronomer to predict the return of a comet and the first to point out...

comet

(Encyclopedia)CE5 Comet: Whatever the direction of a comet's flight, its “tail” always points away from the sun. The tail disappears when the comet is far from the sun. comet [Gr.,=longhaired], a small cele...

meteor shower

(Encyclopedia)meteor shower, increase in the number of meteors observed in a particular part of the sky. The trails of the meteors of a meteor shower all appear to be traceable back to a single point in the sky, kn...

Kuiper belt

(Encyclopedia)Kuiper belt: see comet; Kuiper, Gerard Peter. ...

space probe

(Encyclopedia)space probe, space vehicle carrying sophisticated instrumentation but no crew, designed to explore various aspects of the solar system (see space exploration). Unlike an artificial satellite, which is...

Donati, Giovanni Battista

(Encyclopedia)Donati, Giovanni Battista jōvänˈnē bät-tēsˈtä dōnäˈtē [key], 1826–73, Italian astronomer, b. Pisa. Serving as director of the Florence Observatory from 1864, he was a pioneer in the spec...

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...

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