Zdenek Sekanina Zdenek Sekanina Zdenek Sekanina (born 12 June 1936, Mladá Boleslav, Czechoslovakia (now Czech Republic)) is a Czech-American astronomer and scientist. In 1959, Sekanina started to study astronomy at Charles University in Prague, where he was graduated in 1963. Since 1980, he has been working at the Jet Propulsion Laboratory. His main areas of professional study are meteors and interplanetary dust as well as the study of comets. In the course of his investigations, he dealt with Halley's comet, the Tunguska event, as well as the break-up and impact of Comet Shoemaker–Levy 9 on Jupiter. He was involved in the data
Rings of Saturn has been attributed to a perturbation caused by impact of material from Comet Shoemaker-Levy 9 in 1994. The C Ring is a wide but faint ring located inward of the B Ring. It was discovered in 1850 by William and George Bond, though William R. Dawes and Johann Galle also saw it independently. William Lassell termed it the "Crepe Ring" because it seemed to be composed of darker material than the brighter A and B Rings. Its vertical thickness is estimated at 5 m its mass at around 1.1 kg, and its optical depth varies from 0.05 to 0.12. That