Gas Giant gravity

I just have a couple of minor points of contention in Roger's informative
posting...

Roger Sanger ([email removed]) writes:
>The gravity on the surface of a gas giant would be sufficient to
>literal crush a human, or even a starship.  They are typically
>MANY thousands of times greater mass than the earth.

I think you mean the *pressure* is immense on the surface of a gas giant,
rather than the gravity.  Though gas giants may bethousands of times more
massive than earth, they are typically also much larger.  Surface gravity
increases linearly with mass, but decreases with the square of the radius.
So, a planet 1000 times more massive and 20 times larger would have a
surface gravity only 2.5 times that of Earth.  This a high gravity
situation, but not beyond all help from technology.

>In extreme gravity situations, providing oxygen would be a moot
>issue, because the various mechanisms of cellular metabolism
>would be hampered too greatly by the force of gravity to function
>properly.  Just as you wouldn't be able to move due to your own
>incredible weight, neither would your mitochondria.

Gravity becomes practically insignificant at such small scales.  The
square-cube law comes into play (gravitational force is proportional to the
cube of the length, while strength is proportional to the square).  For a
cell-sized structure the strength/weight ratio is about 1 000 000 times
greater than for a complete human body.

>Free radicals are atoms or molecules which have an
>unpaired electron in orbit, making them highly reactive and prone
>to pulling an electron off of an adjacent atom or molecule
>inorder to re-establish an even number of electrons.  The
>molecule which just lost its paired electron has thus become a
>free-radical, and the cycle of electron stealing repeats itself
>in a harmful chain reaction.

Where does the energy come from in this chain reaction?  I would expect
that only molecules with lower binding energies would be susceptible to
free radical damage, and hence less able to remove electrons from further
molecules.
Certainly free radicals damage biological molecules, but is it really a
chain reaction?

- --
Tim Little