Monday, June 15, 1998 Published at 02:31 GMT 03:31 UK
Galileo finds ghostly ring on Jupiter
The band of light that circles Jupiter's poles
The Galileo spacecraft, in orbit around the giant planet Jupiter, has detected a ghostly light ring that circles the planet's poles. Our science correspondent David Whitehouse reports:
The Galileo spacecraft is the most sophisticated satellite ever to orbit another planet.
Since December 1995 it has sent back many stunning images of Jupiter and its curious retinue of moons. But no image is as strange as the ribbon of light seen threading through the atmosphere on the dark side of the planet.
The stream of light is caused by the same effect that generates light on a television screen.
Electrons are funnelled by Jupiter's intense magnetic field towards its magnetic poles.
As these cascades of charged particles strike the planet's upper atmosphere they cause it to glow, just as a TV screen glows when struck by a beam of electrons from behind.
The region above Jupiter's cloud decks is a turbulent place full of intense radiation.
In some of the images of Jupiter's night side the footprint of a giant tube of electricity from a nearby moon can be seen striking the planet.