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location Greece
age 74
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Retired experimental particle physicist.

The picture is a fayum . It looks like aunts and cousins of mine :).


1d
comment How does ultrasonic horn produce a convection current in the water?
The word "horn" conveys directionality, i.e. a specific direction in which the energy is transferred. It would be amazing if there were no currents in the liquid considering also reflections from the beaker wall. Vibrations are bi directional by construction + is immediatley followe by - displacement.
1d
answered Send a signal from Earth to a planet billion light years away instantly
1d
comment Why do grapes in a microwave oven produce plasma?
since this came up again I watched the video(s). Is it possible that alcohol is formed by the radiation of the microwave? The "plasma" looks to me a lot like burning alcohol fumes ( I use alcohol to start the fire in my woodstove at my vacation cottage)
2d
comment Can a submerged capsized vessel be turned into a sort of diving bell and propelled forward like a submarine?
note that it could be done with a tin boat/large container as the buoyancy could be controlled by the thickness of the metal.
2d
comment Does the energy-time uncertainty principle require energy levels to have finite width?
Of course most atoms are stable if not disturbed, i.e. they will not spontaneously decay and that would make very very thin lines.
2d
comment Protons (as opposed to neutrons) to mediate nuclear fission?
Correct. The observation about charge in the question is also correct, that a proton has to overcome the coulomb force, but of course one wants the chain reaction to be self sustained in order to have a reactor.
2d
answered How do we know we've unified two interactions?
Apr
15
revised How does the frequency of a particle manifest itself?
added 179 characters in body
Apr
15
answered How does the frequency of a particle manifest itself?
Apr
15
answered Reason for the experiment
Apr
15
comment About light waves
read the last sentence of your link. In any case the luminiferous is dispoved by MM "Luminiferous"="carrier of light" :nothing carries light
Apr
15
comment About light waves
The failure of the MM experiment disproves the existence of luminiferous ether en.wikipedia.org/wiki/Luminiferous_aether
Apr
15
comment About blackholes
The reason behind it is that if mathematics fits 99% of the way the only tool we have to guess there is this. Other wise we are at the realm of science fiction.
Apr
15
comment About blackholes
We have General Relativity for those regions. Very near the actual singularity quantum mechanics has to come into play, and no, at the moment the only theories with both quantized gravity and particle physics are string theories , but are at the research stage. The BICEP2 results show that research ingenuity can push the unknown to exponentialy small fractions of the second, so maybe in the future we will have some data. Now we trust the extrapolation of mathematics of GR and SR towards the 0,0,0.
Apr
15
comment About blackholes
No, they could not. They cannot exceed the speed of light. If they could there would not have been a limit of c, and no special relativity. special relativity has been validated with very many observations and experiments and has not been falsified ( of course).
Apr
15
comment About blackholes
I would expect so, that their infalling velocity could be a percentage of the velocity light, but "vibrating" has no meaning in this picture.
Apr
15
comment How are magnetic and electric fields transmitted?
an accelerating charge has a computable probability of radiating photons as it is accelerated, and it is easier to compute the spectrum classically once we know how to go from one framework to the other hyperphysics.phy-astr.gsu.edu/hbase/particles/synchrotron.html . One off happens seldom in specific interactions of known particles.
Apr
15
comment How are magnetic and electric fields transmitted?
For a static field these virtual photons will have a wavelength approaching infinity and they will collectively build up the electric field, and here the classical formalism is much more practical. The quantum mechanical tells us that the effect will propagate with the velocity of light. QM the probability of interaction is what can be predicted and measured and that will be infinitesimal, due to 1/r and h bar. The heisenberg uncertainty principle constrains tiny dimensions. see my answer here : physics.stackexchange.com/questions/107397/…
Apr
15
comment What happens when one of the photons in entangled state gets destroyed?
You have the cart before the horse. Physics mathematical models can never be proven correct. They are continuously validated by new experimental evidence but one solid experimental disagreement can throw the whole theory back to square number one. Physics theories can only be falsified, not proven.
Apr
15
answered How are magnetic and electric fields transmitted?