Tuesday, 6 October 2015

Fissure eruptions from the southern polar region of Saturn's moon Enceladus.

Observations of Saturn's moon Enceladus by the Cassini space probe have revealed a number of sulci (linear structures) in the southern polar region. These have been named the Alexandria, Baghdad, Cairo and Damascus Sulci, or informally the 'Tiger Stripes'. A number of jets of water vapour and ice particles have been seen emerging from these sulci, and infrared images suggest that they are warmer than the surrounding terrain.

In a paper published in the journal Nature on 7 May 2015, Joseph Spitale of the PlanetaryScience Institute, Terry Hurford of NASA's Goddard Space Flight Center, Alyson Rhoden of the Applied Physics Laboratory at Johns Hopkins University, Emily Berkson of the Rochester Institute ofTechnology and Symeon Platts of the Film and Television Department at the University of Arizona discuss the results of a re-examination of a series of images of Enceladus taken by the Cassini Space Probe in 2010.

Spitale et al. found that rather than discrete and isolated jets issuing from particular points on the sulci, there were in fact curtains of material being expelled all along the length of these feature, strongly supporting the idea that these are fissures from which material from the interior of the moon is escaping.

 Curtain eruptions issuing from fissures in the southern polar region of Saturn's moon Enceladus. Cassini/JPL/NASA.

The 'jets' could be observed as discrete brighter features within these curtains, however attemps to calculate the precise position of these features by triangulation from different images failed, and proved more inaccurate when more widely spaced observations were used. Such widely spaced observations would be expected to give a more precise estimate of the position of an object, which suggests that these features are in fact illusionary; their position appears to vary depending on the position of the observer (like a rainbow). It is therefore concluded that the jets do not represent areas where material is being expelled at a higher rate than elsewhere on these fissures.

See also...

http://sciencythoughts.blogspot.co.uk/2015/04/methane-storms-as-possible-cause-of.htmlMethane storms as a possible cause of Titan’s equatorial dune fields.                        Observations by the Cassini Space Probe have revealed vast dune fields, similar to those observed...
http://sciencythoughts.blogspot.co.uk/2013/09/the-origin-of-mini-jets-in-saturns-f.htmlThe origin of mini-jets in Saturn's F Ring.     The F Ring is the outermost and thinest of Saturn's rings. It was discovered by the Pioneer 11 Spacecraft in 1979, and has been studied by NASA's Cassini...
http://sciencythoughts.blogspot.co.uk/2012/12/cassini-probe-finds-400-km-river-on.htmlCassini Probe finds 400 km river on Titan. NASA scientists have released an image of a 400 km long river on Saturn's moon Titan, imaged by the Cassini Space Probe during a flyby on 26 September 2012. The river meanders for some distance across...
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