From: jimp@gonzo.specsol.net
Ruben Safir wrote:
> Jim Pennino wrote:
>> Popping Mad wrote:
>>> If the center of the earth would have 0 force do to gravity (all the
>>> Gravity cancels out) then why is it that the deeper you go into a plant,
>>> like Jupiter for example, the pressure increases and the center of a
>>> star, when it forms, ignites into nuclear fusion?
>>
>> Pressure and gravity are not the same force.
>>
>> Pressure is the result of mass that is above you.
>>
>> Gravity is the result of mass that is around you.
>>
>> On the surface of the Earth all the mass above you is air and the
>> pressure because of the weight of that air is about 14 psi. As you
>> descend into the Earth there is more and more massive stuff above you
>> pushing you down and the pressure goes up.
>>
>> As you descend into the Earth the vector sum of gravity changes. You
>> now have mass above you pulling you up. The gravity thus decreases.
>>
>> The simplist way to put it is that as you go down, the gravity of the
>> stuff above you cancels the gravity of the stuff below you but the
>> weight of stuff above you is always increasing.
>>
>
>
> Yeah that is the part that is hard to reconcile. It might not be
> pulling on YOU but it is pulling on the mass above (and in the center)
> around you.
The gravity felt is the vector sum of the total of all the Earth around
you, which is zero.
The pressure felt is the simple sum of all the Earth that is above you,
which is a big number.
I'm assuming you know the difference between a vector and simple sum.
>
> To clarify this a little bit, lets assume you enter a black hole in a
> vacume. You might not feel any presure on your body.
--
penninojim@yahoo.com
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