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242158
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location Greece
age 75
visits member for 4 years, 4 months
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Retired experimental particle physicist.

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


Mar
16
revised How rigorous can conservation of energy be made?
clarification
Mar
16
answered How rigorous can conservation of energy be made?
Mar
16
comment When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?
@Gareth yes, but note "vacuum" and very "flat surface" which does not apply to a broken rubber band.
Mar
16
comment Is there a sound theoretical argument against inner-shell induced nuclear chain reactions?
I had missed this comment. I am talking of quantum mechanics in a crystal lattice, not thermodynamics. after all crystals have low entropy anyway. seems to me this type of argument would disallow the fermi sea in metals.
Mar
16
revised Is there a sound theoretical argument against inner-shell induced nuclear chain reactions?
added link
Mar
16
comment Is there a sound theoretical argument against inner-shell induced nuclear chain reactions?
This is a clear argument. 1)One "objection", it is based on probabilities of scattering , i.e. no calculations or specific data. 2)it does not take into account the lattice structure which can have collective enhancement effects on probabilities. For example, irrelevant to topic, muons pass crystals without scattering when in the direction of the crystal axis.
Mar
15
answered Did the singularity really existed in the begining of the universe?
Mar
15
comment When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?
It is a saga, science fiction by Asimov en.wikipedia.org/wiki/Foundation_and_Empire
Mar
15
revised Can we have a static point in the universe?
spelling
Mar
15
comment Quantum Wave Mechanics
sorry, but for certain boundary conditions the particle properties are also manifest ( photoelectric effect and all of particle physics experiments tracking electrons etc)
Mar
15
comment Why does ice melts, waits for 100 degrees and THEN vaporises? Why is not the process of expansion of things continuous?
vapor continually comes off any water surface. even ice vaporizes too, that is how clothes can be dried in very cold dry weather. It does not wait, just the functional dependence grows up to 100C maximum vaporization.
Mar
15
comment When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?
You would fall into the HEP ( heisenberg uncertainty principle) with your rubber band. Nanotechnology may reach that stage at some point since they are already manipulating atomic levels, but not your rubber band. The dislocations created by the break cannot be manipulated like lego, i.e. put back in their original molecular position in random material breaks. Melting and soldering is not the same as putting the ends together and expecting a fusion.
Mar
15
answered When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?
Mar
15
revised Can we have a static point in the universe?
added 571 characters in body
Mar
14
answered Can we have a static point in the universe?
Mar
13
comment motion of electrons
This might help physics.stackexchange.com/q/20003
Mar
13
comment How does one detect a single photon?
You misunderstand what you are reading then. The double slit experiment does not have detectors at the slit to start with. There are other experiments that have shown that detectors at the slit destroy the interference pattern, and some new explorations that attribute the spoiling of the interference to the change in the boundary condition of transmission , by interaction with the detectors at the slit.
Mar
13
comment Human and Ultraviolet light
I do not understand. Wien's displacement for 300K ( assumed for the human body) gives 10 microns as the maximum of the shape for a given temperature, way to the right in the first figure, as I said. The temperature for 10nm comes out as 10^6K.
Mar
13
answered What is radiation(in simple words)?
Mar
13
comment What is radiation(in simple words)?
@Qmechanic The OP might be so young that he/she could not know that he/she could find a wikipedia entry. By editing the question you made it seem as if he/she were aware of it and wanting maybe something different. ( hence my first comment) . Possibly the OP is not even aware of the insertion by you, ( except after these comments) You entirely changed the context and partially the content of the question.