rhertz <hertz778@gmail.com> wrote:

That there was a relationship between energy and mass was suspected
since the last years of XIX century.

By 1899, Poincaré derived such a relationship by using a thought
experiment with a "light cannon" and its recoil, once it shot a pulse of light. By equating the energy of the light pulse and the recoil of such
a cannon, it lead him to attribute to electromagnetic radiation a mass
equal to E/c? where E is the total energy of the radiation.

https://www.bjp-bg.com/papers/bjp2019_2_081-093.pdf

But Thomson, Lorentz, Heaviside and many others were closing the
approach to this concept by using measurements of the recently
discovered electron.

This was known by 1900 (values in c.g.s. system):

1. (Lorentz and others): Energy of an electron at rest E = e?/R

2. Charge e (Planck 1900): e = 4.69E-10 esu (g^1/2 cm^3/2 s^-1)

3. Ratio e/m (Thomson 1900): e/m = 6.32766E+17 esu/g

OR m/e = 1.58036E-18 g/esu

4. Mass of electron (1900): m = (m/e) e = 7.4119E-28 g

5. Radius of an electron (1907, Rutherford, others): R = 1.11E-14 cm

6. Energy stored in an electron (1907): E = 1.976E-05 erg or g.cm?/s?

[snip nonsense about relativity based on your misconceptions]

Your complete cluelessness wrt physics and the history of it
is coming through again.
In 1900, Lorentz, Thomson, and friends didn't have an idea
of what the electron mass or charge might be.
All they had, from Thomson's measurements of 1897,
was the e/m ratio.
The electron mass was completey unknown until Millikan, (in 1909)
measured the electron charge.
The smallness of the electron mass came as a complete surprise.

Lorentz' 'electrons' like in his 'Theory of electrons'
have nothing to do with actual electrons.
That's why Lorentz and Einstein couldn't and didn't discuss
the electron mass at all.
They were not predicting the mass,
they were predicting (correctly of course)
how the mass should vary with velocity,
(in the terms of 1900)

Jan

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rhertz <hertz778@gmail.com> wrote:

That there was a relationship between energy and mass was suspected
since the last years of XIX century.

By 1899, Poincaré derived such a relationship by using a thought
experiment with a "light cannon" and its recoil, once it shot a pulse of light. By equating the energy of the light pulse and the recoil of such
a cannon, it lead him to attribute to electromagnetic radiation a mass
equal to E/c? where E is the total energy of the radiation.

https://www.bjp-bg.com/papers/bjp2019_2_081-093.pdf

There you go again, clueless as usual.
Maxwell himself already predicted radiation pressure,
and he knew that EM fields must have energy.
Again, 'everyone' knew that in the late 19th century.
It was used extensively to extend thermodynamics
to include EM fields.
Maxwell was hardly original in this.
Kepler already postullated radiation pressure,
from the observation of comet tails being blown away from the sun,
but he could not quantify it.
Lebedev confirmed Maxwell's prediction quantitatively in 1900.
Poincare's thought experiment is merely a demonstration,

Jan

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Ross Finlayson <ross.a.finlayson@gmail.com> wrote:

On 11/13/2024 02:26 PM, J. J. Lodder wrote:

rhertz <hertz778@gmail.com> wrote:

That there was a relationship between energy and mass was suspected
since the last years of XIX century.

By 1899, Poincaré derived such a relationship by using a thought
experiment with a "light cannon" and its recoil, once it shot a pulse of >> light. By equating the energy of the light pulse and the recoil of such
a cannon, it lead him to attribute to electromagnetic radiation a mass
equal to E/c? where E is the total energy of the radiation.

https://www.bjp-bg.com/papers/bjp2019_2_081-093.pdf

There you go again, clueless as usual.
Maxwell himself already predicted radiation pressure,
and he knew that EM fields must have energy.
Again, 'everyone' knew that in the late 19th century.
It was used extensively to extend thermodynamics
to include EM fields.
Maxwell was hardly original in this.
Kepler already postullated radiation pressure,
from the observation of comet tails being blown away from the sun,
but he could not quantify it.
Lebedev confirmed Maxwell's prediction quantitatively in 1900.
Poincare's thought experiment is merely a demonstration,

Jan

Yeah, according to SR, the latest in the line of "solar sail"
experiments should be doing perfectly fine.

??? Why latest? Radiation pressure (and radiation recoil)
is routinely observed and accounted for
in the observation and calculation of satellite orbits.
It may cost real money, in fuel for station keeping,
so it must be real,

Jan

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