Re: What is a photon

On Sun, 15 Jun 2025 18:33:24 +0000, Paul.B.Andersen wrote:

>
"The Structure of Heavenly Bodies":
https://groups.google.com/d/msg/sci.physics/8jH-SQIFFDo/O1jn3HpiBQAJ
>
Quote about the pressure within the Earth:
  "F = G*m*D*pi*4*R/3
   Now when R or the radius of the Earth is zero, which is the case
   when the m is at the centre of the Earth, then F = 0. Now pressure
   is force per unit area, so pressure at the centre of the Earth is
   also zero."
>
Do you, Bertitaylor, like Arindam, claim that the pressure at
the centre of the Earth is zero?

Den 17.06.2025 01:35, skrev Bertitaylor:

Yes

On Tue, 17 Jun 2025 20:41:41 +0000, Paul.B.Andersen wrote:

>
Thanks for a clear answer.
You, like Arindam believe that the pressure within the Earth
is highest right below the surface and is diminishing with depth.
>
The equation F = G*m*D*pi*4*R/3 is the gravitational force
on a mass m when it is a distance R from the centre of the Earth.

Den 18.06.2025 03:29, skrev Bertitaylor:

 Wrong. See if you can find where you are wrong.
 As your knowledge of basic physics is far lower than that of any Indian
kid in middle school in the 1960s no point in continuing.

You are making a fool of yourself again.
This equation is taken from Arindam's paper quoted above.
Arindam:
" F = G*m*D*pi*4*R/3
   Now when R or the radius of the Earth is zero, which is the case
   when the m is at the centre of the Earth, then F = 0."
This is correct!
F is the gravitational force on a body with mass m a distance
R from the centre of the Earth.
A more common variant of the equation is:
  g = dF/dm = G*D*pi*4*R/3
The force on a mass m is F = g*m
Arindam's knowledge of basic physics is far lower than that
of any Indian kid in middle school in the 1960s so he believes
that when the gravitational force on a small mass is zero, then
the pressure must be zero, which is absolutely ridiculous!

On Tue, 17 Jun 2025 20:41:41 +0000, Paul.B.Andersen wrote:

>
The gravitational force on the mass m at the surface is:
  F = m⋅9.91953 N (we ignore the rotation of the Earth)
>
Let's consider the following scenario:
We have a 1000 m deep cylindrical hole in the surface of the Earth.
>
The gravitational force on you standing at the bottom of the hole is:
  F = m⋅9.91790 N
>
If your mass is 80 kg, your weight will be 0.1244 N less at
the bottom of the hole than on the surface.
>
So the gravitational force diminish with depth.
>
Now we fill the hole with water.
The pressure at the surface is 1 atm = 1013.25 hPa
The pressure on you is now 10020 kPa or ca 100 atm.
>
The pressure increases with depth, as any scuba diver would tell you.
>
How can you, like Arindam, fail to know this?
>
If we fill the hole with stone with density 5563 kg/m³
(the average density of the Earth),
the pressure at the bottom of the hole becomes:
  55275 kPa or 556 atm

Consider this scenario:
There is a cylindrical tunnel right through the Earth.
The cross area of the tunnel is 10 m².
You jump into the tunnel, and end up weightless at
the centre of the Earth. No gravitational forces are
acting on you, as correctly claimed by Arindam.
Now we fill the tunnel with 710e9 kg (710 Tg) of stone.
So on each side of you there is a 335 Tg pile of rock,
and every gram of the rock is gravitationally pulled towards you.
Sure, you are still weightless, but the piles of rock on ether side
of you are not.
The pressure at the centre of the Earth is 360 GPa = 3.5 million atm.

>
Do you still not understand how idiotic Arindam is when he
claim that the pressure at the centre of the Earth is zero?
>

--
Paul
https://paulba.no/