Duane's right Ziggy,

There's so little mass in the asteroid belt that it wasn't even taken into account when the Pioneer and Voyager crafts flew right through without a scratch..

But you raise a very good point and you might be pointing to the wrong source.
Comets might be the culprit that foils Jupiter's plot.

Once thought to be dirty snowballs, it appears they are far more complex with the
latest info from Stardust. Towering pinnacles, plunging craters, steep cliffs and dozens of jets spewing violently..Stardust will land in 2006 with some interesting data.

Comets might be what keeps feeding the interior planets with enough mass which they sweep out from the Kuiper Belt..This plus what they throw at Jupiter themselves, keeping it fed. Their num,bers may have been quite large in the solar systam's early infancy.

I suspect it is they who bring in the iron and drop it in the Sun's corona which
professor Manuel mistakens for being solar in origin. The high ionization of iron
that exists in the corona cannot take place in high density environments. This is why scientists called the highly ionized iron "coronium" when they first observed it.
We could not reproduce it in a lab because the density of Earth's atmosphere is
too high. The Sun's interior is also too high. The only logical explanation I can come up with ( other than incoming stardust itself ) is that comets drag both water
and heavy matter inbound...or they make an exchange of some sort..

Anyway, that's my 2 cents...Take it with a grain of salt. Someone might pitch in a better explanation.

blueshift