Mar 30 2006
From The Space Library
Scientists with NASA’s ESA-Huygens Mission reported in Nature the detection of a new class of small moonlets within Saturn’s rings. The ESA spacecraft’s camera had detected four faint, propeller-shaped moonlets, measuring 100 meters (300 feet) across, in a small fraction of the mid A-ring, a bright section in Saturn’s main rings. Based on this observation, scientists speculated that the total number of Saturn’s moonlets could be approximately 10 million. Previous measurements, including those that NASA’s Voyager spacecraft had made in the early 1980s, had shown that Saturn’s main rings are composed predominantly of water-ice particles, ranging from approximately 1 centimeter (0.39 inch) to approximately 10 meters (32.8 feet) in radius. Two previously identified embedded ring moons, known as Pan and Daphnis, have a radius measuring several kilometers. Based on the discovery of the smaller moonlets, scientists concluded that Pan and Daphnis were likely the largest members of the ring population. The verification of the moonlets’ existence would also help answer the question of whether Saturn’s rings had formed when a larger moon exploded, or were remnants of the swirling discs of gas, dust, and debris from which Saturn and its moons had formed.
NASA, “ESA Finds ‘Missing Link’ Moonlet Evidence in Saturn’s Rings,” news release 06-130, 29 March 2006, http://www.nasa.gov/home/hqnews/2006/mar/HQ_06130_cassini_moonlets.html (accessed 14 September 2009); Ker Than, “Saturn’s Rings Created by Collision,” Space.com, 29 March 2006, http://www.space.com/scienceastronomy/060329_saturn_moonlets.html (accessed 25 August 2010); see also Matthew S. Tiscareno et al., “100-Metre- Diameter Moonlets in Saturn’s A Ring From Observations of ‘Propeller’ Structure,” Nature 440, no. 7084 (30 March 2006): 648-650.
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