Re: Want to prove E=mc²? University labs should try this!

On Thu, 21 Nov 2024 5:03:41 +0000, rhertz wrote:

On Thu, 21 Nov 2024 4:12:04 +0000, ProkaryoticCaspaseHomolog wrote:

The important thing is that despite silly computational errors
on _both_ our parts, we can agree that your statement of
Wed, 20 Nov 2024 08:46 is false, where you wrote:
>
| "The stored energy increases constantly until the temperature of the
| cavity walls (not cancelled by any means) destroy the material that
| form the cavity (either coatings or places on the cavity surface,
| making holes)."
>
Since once it reaches steady state, the ball radiates as much power as
is being pumped in, there is no danger of the ball being destroyed, as
you claimed in earlier posts.
>
I have absolutely no idea what this scaling crap is to which you
refer. The Stefan-Boltzmann law is applicable to small surfaces
as well as large. It _DOES_ need to be modified for bodies that
are not black, by application of an empirical emmisivity term.

>
You are right on the surface issue. I used πr² instead of 4πr².
>
>
Regarding the subject of constantly increasing stored energy, I repeat
that the internal energy density increases until the cavity breaks down.

That can't happen, because, among other things, ultra-high
reflectivity dielectric mirrors are only so from a single direction
(usually normal to the surface). At any angle other than the one for
which they have been designed, constructive interference doesn't work
as well. And there is absolutely no way to design a matte surface to
support such constructive interference.
In practical terms, the reflectivity of a matte surface would be
around 0.9 or so.
Let's FANTASIZE, however, the internal power levels that you could
achieve if you were an alien species living in a different universe
with different physical laws allowing ultra-high reflectivity from all
angles. If x is the reflectivity of the walls, then the ultimate power
multiplication in the cavity would be given by P = 1/(1-x). So a
reflectivity of 0.99999 would allow internal power levels 100000 times
the incoming power. Would this break down the walls? No, because the
total power leaking into the walls would be (1-0.99999)*100000 times
the incoming power. At steady state, EXACTLY as much power is absorbed
by the walls from the cavity as is being pumped into the cavity.
5 W pumped into this fantasy cavity results in half a million watts
internal power levels, resulting in 5 W absorbed by the cavity walls
and 5 W emitted by the sphere after its temperature rises to its
steady-state level.

This is not the case of Planck's BB cavity, where the BBC was heated
from outside and left to rest until it reached thermal equilibrium.
Then, through a small orifice, experimental physicists at the Berlin
University lab (Physikalisch-Technische Reichsanstalt) measured
externally the irradiated power using a very sensitive heat sensor.
>
Here are some names that worked at the PTR in the 1890s. Ruben, a friend
of Planck, perfected the measurements reaching infrared radiation down
to 40 micrometers. He provided the charts and data to Planck, who
adjusted the 1986 Wien theory.
>
Otto R. Lummer, E. Gehrcke, R. Wien, Pringsheim, Kurlbaum.
>
Planck used the findings of Lummer-Pringsheim (1900) and Rubens-Kurlbaum
(1899-1900), performed at the Berlin PTR (Physical-Technical
Reichsanstalt) laboratory, provided to him by Rubens in Sept. 1900.
Planck had only 3 months to present his theory to the German Physics
Society in Dec. 1900, where he introduced his famous quantum of action.
>
I repeat the link with the history between 1850 and 1900:
>
Thermal Radiation, Black Body Theory and the Birth of Quantum Physics
>
https://physictheories.blogspot.com/2019/
>
http://users.df.uba.ar/dmitnik/fisica4/articulos/cuantica/Lummer.pdf
>
************************************************
>
I expect that you may understand the differences between the PTR Black
Body Cavity (externally heated) and my idea of pumping direct energy
into an almost perfectly reflecting cavity.

Rather than pursuing this topic, which I consider dead, there are
other aspects of LIGO's optical system that I would rather consider.
Let's look again at the description here:
https://www.ligo.caltech.edu/page/ligos-ifo
How does LIGO (1) prevent light from being reflected back into the
laser, and how does it (2) prevent light from being directed directly
from the laser into the detector?
Look at the image, "Layout of a basic Michelson interferometer". This
image leaves out some important optical elements. Note how, besides
light from the two paths combining into an single beam at the
detector, a great deal of light is reflected back directly into the
laser?
Such light would destabilize the laser.
A typical solution is to place a polarizer and a quarter-wave plate
in front of the laser. This converts the laser light into circularly
polarized light (CP). On the way back to the laser, the CP light
is converted back into linearly polarized light, but at 90 degrees
orientation relative to the outgoing light. Because of that, it is
blocked from re-entering the laser.
Now let's look at the illustration, "Basic Michelson interferometer
with Fabry Perot cavities." The polarizer plus quarter-wave plate
arrangement would work to block light from re-entering the laser, but
look at the light being reflected directly from the two partially-
transmitting mirrors on the near side of the Fabry Perot cavities!
This light would go directly into the detector and ruin the ability to
null out the signal!
I think that I've figured out a solution. Does anybody here know how
it is actually done in LIGO from reading the documentation?