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astronomical unit

(Encyclopedia)astronomical unit (AU), mean distance between the earth and sun; one AU is c.92,960,000 mi (149,604,970 km). The astronomical unit is the principal unit of measurement within the solar system, e.g., M...

Young, Charles Augustus

(Encyclopedia)Young, Charles Augustus, 1834–1908, American astronomer, b. Hanover, N.H., grad. Dartmouth, 1853. He discovered the reversing layer of the solar atmosphere and proved the gaseous nature of the sun's...

ring, in astronomy

(Encyclopedia)ring, in astronomy, relatively thin band of rocks and dust and ice particles that orbit around a planet in the planet's equatorial plane. All four of the giant planets in the solar system—Jupiter, S...

Pleiades, in astronomy

(Encyclopedia)Pleiades plēˈədēz, plīˈ– [key], in astronomy, famous open star cluster in the constellation Taurus; cataloged as M45. The cluster consists of some 500 stars, has a diameter of 35 light-years, ...

Puck, in astronomy

(Encyclopedia)Puck, in astronomy, one of the natural satellites, or moons, of Uranus. ...

Rhea, in astronomy

(Encyclopedia)Rhea, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn V (or S5), Rhea is 950 mi (1530 km) in diameter, orbits Saturn at a mean distance of 327,487 mi (527,...

Regulus, in astronomy

(Encyclopedia)Regulus rĕgˈyələs [key], brightest star in the constellation Leo; Bayer designation Alpha Leonis; 1992 position R.A. 10h08m, Dec. +12°00′. A bluish-white main-sequence star of spectral class B7...

Pollux, in astronomy

(Encyclopedia)Pollux, brightest star in the constellation Gemini; Bayer designation Beta Geminorum; 1992 position R.A. 7h44.8m, Dec. +28°03′. An orange giant of spectral class K0 III, it is the nearest giant sta...

Saturn, in astronomy

(Encyclopedia) CE5 Saturn and its ring system as seen from Earth Saturn, in astronomy, 6th planet from the sun. Saturn has 82 confirmed natural satellites, many of which have not been named. Five of the discov...

Prometheus, in astronomy

(Encyclopedia)Prometheus prōmēˈthēəs [key], in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XVI (or S16), Prometheus is an irregularly shaped (nonspherical) body me...
 

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