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

Current "state of the art" weighting technology (expensive) can measure
about 1 nanogram of MASS.
I asked ChatGPT this question:
"If I use a high precision laser having 5 Watts steady power for 72
hours, injecting the light into an almost perfect reflective cavity
(more than 99% of reflectivity), can I prove that the internal MASS
increased as
m=E/c² states?
ChatGPT answered this:
Conclusion
If the laser operates for 72 hours, the theoretical mass increase inside
the cavity is approximately 14.4 picograms, but in practice, the
steady-state energy inside the cavity will be significantly lower due to
losses. Proving this mass increase experimentally would require an
exceptionally controlled setup and cutting-edge measurement tools. While
it is a challenging experiment, its successful execution would provide a
novel confirmation of m=E/c² in an optical context!
I simplify calculations here:
5 Watts x 72 Hr =    1,296,000 Joules (Kg.m²/s²)
MASS increase in 72 Hr =   1.0368 μgrams of MASS
WEIGHT INCREASE =    1.007 μgrams of WEIGHT ≈ 1.007E-09 Newtons
ChatGPT WARNINGS:
Challenges in Proving the Mass Increase
While the mass increase is theoretically calculable, there are practical
hurdles:
1. Energy Retention in the Cavity
Steady-State Limit: A laser does not continuously add energy to a cavity
indefinitely. After a certain time, the energy inside the cavity
stabilizes at a steady state determined by:
E(stored) = P(laser)/P(loss) x τ
τ is the cavity’s photon lifetime.
Real cavities lose energy through mirror transmission, scattering, and
absorption. Even with highly reflective mirrors (99.999%), steady-state
energy may be orders of magnitude smaller than the total energy
delivered by the laser.
2. Balance Sensitivity
Mass Changes: To measure a steady increase up to 1.0368 μgrams of MASS,
you would need an extremely sensitive device like an electromagnetic
balance or other precision mass measurement tools with sub-μgram
sensitivity.
Current state-of-the-art balances can detect mass changes at this scale,
but such measurements are delicate and require isolation from
vibrations, air currents, and thermal effects.
3. Environmental Interference
Thermal Effects: Energy absorption by mirrors or cavity components can
cause thermal expansion or convection currents that might mimic a weight
change.
Radiation Pressure: The laser light exerts a tiny force on the mirrors,
which might introduce additional complications.
4. Loss Compensation
Not all the laser energy is stored. The difference between the laser's
energy input and the cavity’s steady-state energy is lost as heat,
scattered light, or transmitted light. This loss must be carefully
accounted for to isolate the contribution of stored energy to the mass
increase.
Experimental Considerations to maximize your chances of success:
High-Q Cavity: Use ultra-high-reflectivity mirrors to maximize energy
retention and reduce losses.
Sensitive Instrumentation: Employ a precision electromagnetic balance
capable of detecting picogram-scale changes.
Environmental Isolation: Perform the experiment in a vacuum chamber and
on an isolated platform to reduce noise.
Calibration: Account for all sources of error, including thermal effects
and laser power fluctuations.
***********************************************
BUT WHAT REALLY MATTERS HERE IS THAT THE AI ENGINE CONFIRMED THAT NOBODY
IN THE ENTIRE SCIENTIFIC COMMUNITY HAS EVEN TRIED EXPERIMENTS OF THIS
SORT, WHICH ARE CONCEPTUALLY SIMPLE!
WHY, I ASK? MAYBE THE RESULTS COULD BE SHOCKING!
With a little of ingenuity, you could try this at home, using a
DIFFERENTIAL ELECTROMAGNETIC BALANCE. Here is a guide:
Homemade Microgram Electrobalance
https://www.erowid.org/archive/rhodium/chemistry/equipment/scale.html
You should add a DIFFERENTIAL BALANCE, with two cavities (one with the
laser turned off).
Here is a company that sells microgram balances ($10,000 and up), mainly
for Big Pharma companies.
https://www.mt.com/us/en/home/products/Laboratory_Weighing_Solutions/microbalances/ultra-micro-balance.html
HEY!, THERE IS A CHANCE THAT YOU CAN CONFIRM OR DISPROVE E=mc².
AND BY DISPROVING IT, RELATIVITY GOES TO THE TRASH BIN. ALL OF IT, AND
DERIVATIONS APPLIED ALL OVER THE REALM OF PHYSICS!