Jupiter's Ring Halo
Why do small particles hover around Jupiter's rings?
These particles form a previously unknown
ring halo,
recently discovered by the
robot spacecraft Galileo
currently orbiting
Jupiter.
Galileo obtained this image when on the far side of Jupiter - from this
orientation
scattered sunlight makes the
halo ring visible.
The amount of scattering indicates that halo particles are very small -
perhaps 100 times smaller than the width of a human hair.
Particles this small are believed to survive only for years, and so must somehow be replenished to
Jupiter's ancient ring system.
One possible explanation for this unusual halo is that
electromagnetic fields around
Jupiter gently push small
charged particles out of the ring plane.
This
false color image has been artificially stretched in the
vertical direction to highlight the ring halo.