A full explanation of the motion of trapped particles would be too abstract and mathematical for this level, but some basic ideas may be described on an intuitive level. The magnetic force on a moving particle is always perpendicular to the motion, as well as to the magnetic field lines. That is why the basic pattern is motion in a circle, around a magnetic field line. ... The best-known periodic motion is the back-and-forth swing of a pendulum, say of a weight suspended by a string (drawing). ...

... This lesson plan supplements the material on the web page . Stargazers and Skywatchers," on disk Ssky.htm , on the web . ... Recognize the daily motion of the Sun across the sky, defining the main directions of east, west, south and north . ... Terms learned: East, west, south, north, horizon, equinox, winter solstice, summer solstice, elevation of the Sun )above the horizon). ... You watch the shadow of a flagpole on a sunny day. ... The noon sun is in the south, so the shadow points north. ...

Hubble Observations Shed New Light on Jupiter Collision . Was it a comet or an asteroid? ... Their initial findings, combined with results from other space-borne and ground-based telescopes, shed new light on Jupiter's atmospheric winds, its immense magnetic field, the mysterious dark debris from the impacts, and the composition of the doomed comet itself. ... Hubble's ultraviolet observations show the motion of very fine impact debris particles now suspended high in Jupiter's atmosphere. ...

Cosmic Research, Vol. 42, No. 5, 2004, pp. 435­488. Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 5, 2004, pp. 453­508. Original Russian Text Copyright © 2004 by Veselovsky, Panasyuk, Avdyushin, Bazilevskaya, Belov, Bogachev, Bogod, Bogomolov, Bothmer, Boyarchuk, Vashenyuk, Vlasov, Gnezdilov, Gorgutsa, Grechnev, Denisov, Dmitriev, Dryer, Yermolaev, Eroshenko, Zherebtsov, Zhitnik, Zhukov, Zastenker, Zelenyi, Zeldovich, Ivanov-Kholodnyi, Ignat'ev, Ishkov, Kolomiytsev, Krasheninnikov, Kudela,