Re: What would happen to a person if placed within Jupiters atmosphere?

Many questions! I will try to answer them in the order presented. However,
much of the answer is anticipated by the questions that you are asking.

It would, indeed, have to be a special space suit that is capable of 
providing air and temperature control, resistance to the turbulence in the
atmosphere, and also prevent the pressure from crushing the occupant. And
it would need to have some form of thrusters - although they may actually
be required to push the astronaut down instead of up! Presuming that matter 
behaves the same way on Jupiter that it does on Earth, the density of the 
atmosphere above Jupiter would quickly get sufficient that neutral bouyancy 
could be reached and the astronaut would "float". The overall density of
Jupiter is 1.3 g/cm3 (compared to 5.5 g/cm3 for Earth) but this is 
primarily a result of the fact that it is a "gas giant". The atmosphere
gets much more dense the further down one goes.

Would the astronaut ever reach a solid surface? According to my sources,
yes, the core of Jupiter is a rocky planet of some description - or 
something that bears a resemblance to a rocky planet. The idea is that
in the upper atmosphere, Jupiter has a wild collage of gases. But as one
decends, it sorts itself out into a layer of molecular hydrogen, which
eventually gives ways to a layer of liquid metallic hydrogen (a result of
both pressure and temperature), and finally, an interior solid core - which
might be rock but could also be solidified gases do to the tremendous 
pressures.

If so, would this be the core of the planet? Sure - although by "core" do
you mean "the centre of the planet" or the interior sphere that formes
the planet's centre? Earth's core is a molten iron/nickel/lots of other 
stuff region that defines the deepest layer of distinguishable material 
below the surface. It is not a solid mass. Within Jupiter, there must be
some "core region" - but whether or not that would constitute a "solid
surface" is questionable. Presumably, if Jupiter has a rocky planet inside
of its atmosphere, then that rocky planet might, itself, have structure and 
a "core".

I suppose the best way to think about Jupiter is a cloud of gas that gets
more and more dense, the closer to the centre that you get. At some point,
pressure and temperature may balance out to allow some inner region to 
maintain a solid structure and a "surface".

If so would it be as hot or hotter than the core of our planet? Likely 
hotter. Jupiter is a very dim (VERY dim) star in the sense that it radiates
more heat than it receives from the Sun. It glows but with a very feeble
light. It would have needed to be somewhere between 75 and 90 times its
present size to have become a "thermonuclear" star like the Sun.

Is the gaseous atmosphere similar to the aquatic atmosphere of our planet, 
in the sense that the pressure increases the greater the depth? If it does, 
would the pressure crush the suit at a certain point? Yes and yes - unless
the suit was built to withstand the pressure!

Would the astronaut ever be able reach a point on Jupiter, where he/she 
could stand on a solid surface, and be able to walk around and see what's 
what? So, overall, the answer is that "yes, at some point they would hit
a surface". However, the gas pressure and gravity would make it unlikely
that they would be able to go for a stroll. And they would likely need 
some form of weights or reverse thrusters to keep themselves down there.
The density at the "surface" would likely be sufficient to pop them back
out of the atmosphere much like a cork in water!

But if all of the technical challenges could be met, wow, what an 
interesting ride it would be!