Re: The antics of thermodynamics, the depravity of relativity, the bunkum of quantum

On Tue, 11 Mar 2025 0:29:28 +0000, Peter Moylan wrote:

On 11/03/25 06:54, jerryfriedman wrote:

On Sun, 9 Mar 2025 9:50:06 +0000, Peter Moylan wrote:
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On 09/03/25 09:58, Phil wrote:

On 08/03/2025 22:46, Bertietaylor wrote:

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It's just as implausible as the suggestion (easily
disproved) that the pressure is zero at the centre of the
earth.

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The pressure is most certainly zero at the centre of the
stars and planets. Read a first year book on physics.

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Which will say that within an enclosed surface with mass the
net gravitational force or pressure is zero.

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Read that first year book yourself. Did you find the words "or
pressure"? No, I didn't think so. You've tried to conclude
something about the pressure from the gravitational force. That
doesn't work, because they are different quantities.
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Gravitational force, like all forces, is a vector quantity. It has
a magnitude and a direction. That makes it possible that a number
of nonzero vectors can sum to zero; and, indeed, that is what
happens inside a spherical shell.
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Pressure is a scalar. If you add two pressures, you get a higher
pressure. There's no such thing as a negative pressure to cancel
out the first pressure.

Pressure is not a scalar. It is a vector with the same dimension as
force. Yes there is such a thing as negative pressure, if we are talking
about force directions.. Heard of decompression? There the force pulls
the surface inwards, as pressure inside is negative with respect to
outside.

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Think of a cone, or similar shape, whose point is at the centre of
the earth. You can separate out a section with thickness dr, and
write down the force balance equation for that slab. (This, too, is
first year physics.) From that you get a differential equation for
the pressure as a function of radius. No matter what
simplifications you make, you will get the same conclusion: the
deeper you go, the higher the pressure. Which is something that
ocean divers can confirm from their own experience.

Handwaving above, typically pedantic, which needs to be fixed by the
great good sense of Arindam, as he provided many years ago. To repeat,
thus, as he had to do many times.
Yes pressure increases with depth. But this is not continuously so. At
some stage it peaks when there is enough mass below as there is enough
mass above. There is crushing with mass above and mass below enough heat
generated thus for rocks to melt. Then there is less crushing with less
mass below and too much mass above pulling the molten matter up. At some
depth there is thus less compression. The rocks cool. They become solid
and act as thousands of kilometers of insulation from the lava heat.
Till when the core is reached there is veryblittle pressure, very low
temperature but a lot of current in the core. Remaining heat or pressure
by the piezoelectric effect converts to continuously circulating direct
steady current responsible for the magnetic field which is undeniable in
presence. Without extreme coldness in the core the magnetic fields of
Earth, Sun, dark matter, etc. could not exist.
Thus there is nonlinearity involved. Small pedantic minds do not
understand nonlinearity. They just don't get it, especially when they
are puffed up academics. Arindam the greatest genius of all time made
his living from all sorts of nonlinearities - and that too in hostile
environments where he was always persecuted for his background and
independent outlook. He has changed the world with his brilliant works,
ranging from phased array antenna design to complex queuing systems for
teletraffic.Now as he works fir himself he is enjoying himself
thoroughly.

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Even swimming pool divers.

Did they swim in a pool at the centre of the Earth?
Woof-woof, what fools these pedantic apes be!
Bertietaylor (Arindam's celestial cyberdogs, educating academics)

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At the centre of the earth, the gravitational force is zero but
the pressure is at a maximum.
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Presumably, by an analogous argument, the pressure at the centre
of a balloon is also zero?

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Actually, the gravitational force at the centre of a balloon is
zero, if you count only the force due to the balloon itself. But of
course, you do have to count the attraction from the earth as
well.
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Either way, what you conclude about the gravitational force says
nothing about the pressure. They're different quantities.

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They're different, but they are connected.  Since the gravitational
force at the center of the Earth is 0, you can conclude that the
pressure /gradient/ there is 0.  Hint to Arindam.

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Re-reading this thread, I have suddenly realised what has misled
Arindam. He keeps using "force" and "gravitational force" as if they
were interchangeable. Not all forces are gravitational forces; and to
calculate pressure you have to add up all the forces, not just the
gravitational component. At the centre of the earth, you also have to
taken into account the radially directed non-gravitational  force that
comes from the weight of all the rocks (and so on) above your head.