QUESTION: Would Jupiter ever blow up from the probe?

ANSWER:
 No, Jupiter would never blow up from the probe impact. The mass 
 of the probe is 340 kg and the mass of Jupiter is 318 times the mass of the
Earth. So the probe impacting Jupiter at worst would be about the same as a
1.06 kg mass -- something about like a brick -- impacting the Earth. Since the
mass of the  Earth is about 6 x 10**24 kg clearly the impact is infinitesimal.
       
Of course, the speed of impact would increase the explosive potential, but the
lack of a solid surface on Jupiter would decrease the explosive potential.
       
The probe enters the Jupiter atmosphere at very high speed which in effect
multiples the impact of the small impacting mass and the impact energy
increases as the square of the speed. The probe entry speed of 47 km/s would
be about 1000 time that of the brick being dropped from a 5-story building and
the impact energy would be multipled a million times.  This energy is not
removed suddenly but was dissipated over a period of a few seconds for the
most part but totally over a period of several minutes. But even if there were
a sudden impact, the mulitplying factor of a million is still small compared
to the mass of the Earth -- a billion billion to one.
       
Another thought might be that there are certain chemical elements in the
atmosphere of Jupiter which if heated to high enough temperature by the
entrance of the probe could cause a chain reaction explosion. No evidence do
date based on remote measurements of Jupiter's composition has given rise to
any such expectation. Furthermore, the impacts of comet 
Shoemaker-Levy last year -- 18 massive impacts from this disintegrating body
-- created fireballs seen around world from Hubble telescope images.  These
were many times larger than anything the probe could create. No one has reported
any visual indication of the probe entering the Jovian atmosphere.