Radiation belts and mega-planets

[squeegee]

Okay, so 11 more extra-solar planets have been discovered:
http://www.cnn.com/2001/TECH/space/04/05/new.planets/index.html

One of the planets in the above story is described as a Jupiter-sized planet in the 'habitable zone', and there's some speculation it's possible that a satellite of this mega-planet would be hospitable to life.

I recall from one of the Pioneer or other probes that fierce radiation bands were found around Jupiter. I've poked around some of the Nasa/space sites, but haven't found more information.

Questions:

- What does the radiation around Jupiter consist of? Focused solar wind? Intense magnetism from the big guy? Something else?

- Do all Jupiter-size (or bigger) planets have radiation belts? If not, is Jupiter unusual in this regard?

- Most importantly, does this radiation preclude satellites orbiting super-large planets from harboring life?

[bibliophage]

Jupiter has radiation belts similar to the Earth's Van Allen belts. The Earth's Van Allen belts are composed of both protons and electorons, but in Jupiter's magnetosphere the electrons are more important.

The inner magnetosphere extends to about 6 Jupiter radii from the planet, about the same as the orbital distance of the closest major moon, Io. In this region, the magnetic field is associated with currents inside Jupiter's liquid metallic hydrogen core.

The middle magnetosphere extends to about 50 Jupiter radii and the outer magnetosphere extends to about 100 radii or more. All four major moons are in or near the middle magnetosphere, protected from the solar wind by the outer magnetosphere.

Io might be a dangerous place to visit. There are bursts of radiation associated with Io's movement through Jupiter's magnetosphere. I don't know if the exact cause of the bursts is well understood.

Saturn also has a magnetosphere, but the magnetic fields are much weaker than Jupiter's, perhaps weaker than the Earth's.

[kniz]

There was a TV show recently about how the moon's of the different planets may be where we go to explore the solar system. They talked about the danger of radiation on the moons around Jupiter (but none of the other planets). They said that the radiation the moons were receiving is 4000 times the letal dose for humans. Didn't make me want to spend my next vacation there.