Cassini division

noun

Cas·​si·​ni division

ka-ˈsē-nē-

variants or less commonly Cassini Division

astronomy

: the dark region between the two brightest rings of Saturn

A sequence of smoothly undulating brightness fluctuations is observed in the outer Cassini division within a band located between Cassini division120,000 and 121,900 km from the centre of Saturn.

—Jeffrey N. Cuzzi et al., Nature, 20 Aug. 1981

This consensus lasted until 1675, when astronomer Jean Dominique Cassini reported a dark line (now known as the Cassini Division) within the rings, dividing them into two segments—an inner ring and an outer ring.

—Alan Rubin, Astronomy, December 2002

Word History

Etymology

after Giovanni Domenico Cassini †1712 Italian engineer & astronomer

First Known Use

1870, in the meaning defined above

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