Circling around magnetic field lines. ... The ring current . Because positive ions and negative electrons drift in opposite directions (see drawing), that motion will create an electric current that circulates clockwise around the Earth when viewed from north. ... How then can the radiation belt and ring current arise? ... Electric fields are able to push trapped particles earthward, and unlike the purely magnetic motion described earlier, an electric field can also energize them. ...

... Auroral Currents . ... 25b. Io Dynamo . ... Aurora from Space . ... The giant planet Jupiter has four large moons, discovered by Galileo and visible through good binoculars. ... A dynamo is created in a magnetic field by an electric circuit, part of which is moving relative to the rest (additional conditions must also be met). ... Furthermore, the plasma between them conducts electricity very well along its magnetic field lines, which act as if they were wires connecting Io and the planet (drawing)....

... NASA's Hubble Space Telescope has detected a long-sought population of comets dwelling at the icy fringe of the solar system . The observation, which is the astronomical equivalent to finding the proverbial needle-in-a-haystack, bolsters proof for a primordial comet reservoir just beyond Neptune , currently the farthest planet from the Sun . ... The comet-disk lies just beyond Neptune and might stretch 500 times farther from the Sun than Earth . ... Comet Introduction Kuiper Belt Objects . ...