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22476
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location Greece
age 74
visits member for 3 years, 2 months
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Retired experimental particle physicist.

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


Apr
14
comment Why does Einstein say contradictions arise from treating the EM field as lines of force?
May be the quote is about optical light rays, carrying momentum and able to provide force on impact. The fields are either electric or magnetic, so two different forces. The video shows how the electric generates magnetic and the magnetic electric by tracing the closed paths.
Apr
14
comment When does 'energy' turn to matter?
I would like to add here that specifically the e+e- colliders create out of energetic electrons Psis, if the invariant mass (IM) of the electrons is at the mass of Psi and a lot of other mesons, Z bosons if the their IM is on the Z . see page five in pdg.lbl.gov/2013/reviews/rpp2013-rev-cross-section-plots.pdf .
Apr
14
comment What happens when one of the photons in entangled state gets destroyed?
Please note that an atom absorbs a photon, i.e. the electron changes energy level, and the atom becomes excited. If, from the deexcitation and the related quantu numbers one can infer that the absorbed photon was left handed then the other one will be right handed. I think that quantum mechanics has been working for so long on so many situations that it is not necessary to do a separate experiment.
Apr
14
revised What is a particle?
expanded with pictures
Apr
14
answered What is a particle?
Apr
14
answered CMB curly B-modes and dark matter
Apr
13
comment From Quantum Mechanics to Classical Mechanics
also classical electromagnetism from quantum, photons to electromagnetic waves is shown in this blog motls.blogspot.com/2011/11/…
Apr
13
answered What happens when one of the photons in entangled state gets destroyed?
Apr
13
comment Does gravity cause Archimedes' principle and how?
Maybe you should read up on Archimedes principle en.wikipedia.org/wiki/Archimedes%27_principle . It explains how in liquids dense material goes to the bottom. Stratification happened mainly in the magma phase of the earth.
Apr
13
comment How can a pion with neutral charge exist?
The charged pions cannot do the same because charge is conserved and it takes the weak interaction for a pi- to decay into a mu and two neutrinos. for the feynman diagrams see for pi0 www-zeus.physik.uni-bonn.de/~brock/feynman/vtp_ss06/chapter02/… for pi- www-zeus.physik.uni-bonn.de/~brock/feynman/vtp_ws0506/chapter02/… . The electromagnetic is many orders of magnitude larger than the weak and that is why it comes first in pi0
Apr
13
comment How can a pion with neutral charge exist?
The crucial part that is missing in the duplicate's answer is that the annihilation must go through either the weak or the electromagnetic interaction. This is because even though quark and antiquark are continually created by and destroyed into gluons the strong force is such that it binds all strongly interacting particles in a "bag". So an annihilation into gluons is "more of the same" for the neutral pion. It takes the electromagnetic to annihilate the quarks.
Apr
12
comment Interpretation of Heisenberg's uncertainty principle
i have answered something similar recently here physics.stackexchange.com/questions/107397/… . The particle nature of the wave nature appear as a function of the experiment looking at the quantum mechanical "entity" within the HUP constraint. Outside it it is classical particle behavior. also answer to another similar question here physics.stackexchange.com/questions/103294/…
Apr
12
answered What is the reason behind why a quantum particle cannot be at rest?
Apr
12
comment If the current is increased, is there more charge flowing or is it moving quicker?
capacity for batteries is a very well defined term ( not to be confused with capacitance that capacitors have).en.wikipedia.org/wiki/Battery_capacity#Capacity_and_discharge
Apr
12
comment How is the Plane of the Solar System oriented to the Sun's motion through space?
Have a look at this tallbloke.wordpress.com/2010/01/18/… which describes the motion with respect to the galaxy
Apr
12
comment Why Don't Birds Stall?
ideo of birds intentionally stalling to catch food thrown youtube.com/watch?v=bqhXSntug3s
Apr
12
comment Time passing faster now as compared to 50 years (or 1000yrs) back ?
It is called aging.
Apr
12
answered Why do we set $x^0 = ct$ instead of $x^0 = t$?
Apr
12
comment What if photons are not the fastest particles?
@Jim The experimenter would think it went faster than c, if shortcuts are not in the theoretical framework he/she has.
Apr
12
comment What if photons are not the fastest particles?
Well, information transfer is limited by c by why should c be defined by information transfer? it is defined by physical measurements. Information is a meta level on the physical method, imo.