Cassini confirms a dynamic atmosphere at Saturn’s moon Enceladus 29 July 2005 The 500 km diameter moon Enceladus is a very bright icy moon at a distance of 4 Saturn radii away from Saturn. It has long been associated with the formation of the E ring, Saturn’s outermost ring. The first two more distant flybys of Enceladus on February 17th at an altitude of 1,167 kilometres (725 miles), and on March 9th, 500 kilometres (310 miles) above Enceladus’ surface had shown draping or bending of the magnetic field around the moon, revealing that Enceladus was acting as a large obstacle to the flow of plasma and magnetic field from Saturn by its extended asymmetric atmosphere. The recent close flyby confirms and extends the The latest close flyby of Saturn’s icy moon observations from the two more distant flybys which Enceladus by NASA’s Cassini spacecraft confirms took place earlier this year. Although no other that the moon has a significant, extended and instruments on the Cassini spacecraft had detected dynamic atmosphere. The flyby, which took place evidence of this atmosphere on the first two flybys, on 14th July 2005, was Cassini’s lowest altitude on the basis of the magnetometer [MAG] flyby of any object to date, a mere 173 kilometres instrument observations alone a decision was (108 miles) above the surface of Enceladus. made to modify the spacecraft trajectory for the 14th July encounter to fly much closer to the Image: This artist concept shows the detection of surface of Enceladus. an dynamic atmosphere on Saturn's icy moon Enceladus. The Cassini magnetometer instrument Professor Michele Dougherty from Imperial College is designed to measure the magnitude and London, who is Principal Investigator on the direction of the magnetic fields of Saturn and its Magnetometer instrument on Cassini, says “These moons. During Cassini's three close flybys of latest observations are very exciting, they confirm Enceladus- Feb. 17, March 9 and July 14-the the existence of an atmosphere which we predicted instrument detected a bending of the magnetic from the distant earlier flybys and they will also field around Enceladus due to electric currents allow us to gain a much better understanding of the generated by the interaction of atmospheric processes taking place which are producing this particles and the magnetosphere of Saturn. very exotic atmosphere.” The graphic shows the magnetic field observed by Observations from numerous instruments now Cassini as well as the predicted neutral cloud confirm what MAG was able to see from a great being vented from the south pole. Cassini's distance. Not only is the magnetic field even more magnetometer observed bending of the magnetic strongly bent around the atmospheric obstacle field consistent with its draping around a connected to the moon but the other instruments conducting object, which indicates that the also detected the presence of the atmosphere. The Saturnian plasma is being diverted away from an magnetic data also suggests that the atmosphere is extended atmosphere. not symmetric and may be arising from a comet-like Credit: NASA/JPL jet from the southern hemisphere. Also the 1 / 2 spacecraft passed right through the electric current carrying region associated with the atmospheric interaction. APA citation: Cassini confirms a dynamic atmosphere at Saturn’s moon Enceladus (2005, July 29) retrieved 24 September 2021 from https://phys.org/news/2005-07-cassini-dynamic-atmosphere-saturns- moon.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. 2 / 2 Powered by TCPDF (www.tcpdf.org).