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229100
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location Greece
age 74
visits member for 3 years, 6 months
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Retired experimental particle physicist.

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


Jul
19
comment For a planet which has a temperature gradient, hot in the center and cooler on the surface, why do we get absorption lines?
so you really mean planet? I will edit because as is it is very confusing
Jul
19
comment Has the photon both gravitational and inertial mass?
The photon in the standard model has 0 mass, no adjectives attached. en.wikipedia.org/wiki/Standard_Model . This question belongs to science fiction. I reacts to to gravity through its energy, by special and general relativity rules that have been validated over and over. Mass is defined as the length of the four vector describing a particle and it is an invariant. en.wikipedia.org/wiki/Invariant_mass
Jul
18
answered If there were fundamental forces weaker than gravity, would we know about it?
Jul
18
comment What is the frequency of a photon emitted by an accelerated charged particle?
there are spectra for brehmsstrahlung en.wikipedia.org/wiki/Brehmstrahlung ands synchrotron in en.wikipedia.org/wiki/Synchrotron_radiation
Jul
18
answered Could Dark Matter particles that don't couple to quarks or leptons have been produced?
Jul
17
comment How to understand “accelerating charge radiate” using intuition?
OK, the animation is about a single bunch of photons. Maybe after "nudge into the charge" you should put in parenthesis "giving an instantaneous d(v)/dt " or some such, would make this clear. nudge is too general.
Jul
17
comment How to understand “accelerating charge radiate” using intuition?
It is a pretty annimation but at what point does the acceleration enter? it looks unifromly moving.
Jul
17
answered When you measure position of an electron in a energy pure state, what happens to the energy?
Jul
17
answered How to understand “accelerating charge radiate” using intuition?
Jul
17
comment Can an electron spontaneously be emitted/ejected from a hydrogen atom?
In a sense, the probability that the ground state bound electrons can be found very far away allows for the interactions between atoms to form molecules, crystals, and lattices in general. Matter as we found it.
Jul
16
comment If dark energy is accelerating the expansion of the universe, why can't I feel it?
Yes, from each point (x,y,z,t) in every direction. Please note that if it were not for the cohesive forces (gravity, nuclear electromagnetic) we would not be able to measure expansion anyway! It is the fact that our local surroundings do not change that we can see everything else expanding and an accelerated expansion in our time frame.
Jul
16
comment If dark energy is accelerating the expansion of the universe, why can't I feel it?
The acceleration comes from all around each point, not from one direction as when you are in a plane. It is weak enough so that it does not pull clusters apart or galaxies or planets or atoms.
Jul
16
answered If dark energy is accelerating the expansion of the universe, why can't I feel it?
Jul
15
comment How is the theory of partial coherent light related to quantum-mechanics?
Spectral lines are measurement in my book, a measurement is a numerical value attached to an observation. Quantum mechanics has nothing to do with the definition of measurement. I see you consider a measurement "strange" because it is not explainable by solutions of classical equations. I suppose that by "measurement processes" you are wrapping around the probabilistic nature of each measurement? My answer to "how much can be explained" would be : none; otherwise quantum mechanics would not have been necessary. The crux is the probability postulate, the Born rule.
Jul
15
revised How is the theory of partial coherent light related to quantum-mechanics?
added 1291 characters in body
Jul
15
comment Does the Higgs boson give mass to ALL other particles?
@Michael It is amusing but the mexican hat is part of the logo of physics.stackexchange. Have a look at the top left of PHYSICS
Jul
15
revised Does the Higgs boson give mass to ALL other particles?
elucidation necessary because of edit in question
Jul
15
comment Does the Higgs boson give mass to ALL other particles?
@Michael sorry, there has been a drastic edit to the question I did not notice. there was an extract in the previous edition that did mention the hat. People should not make drastic changes to the content of the question.
Jul
15
comment Does the Higgs boson give mass to ALL other particles?
@Michael look at the wiki link for higgs, the mexican hat. It is not mentioned in this question, so you must be confusing this with another answer
Jul
15
revised Does the Higgs boson give mass to ALL other particles?
expansion after comments