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345173
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location Greece
age 75
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Retired experimental particle physicist.

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


May
13
revised How to determine a strong or weak interaction (Strange particles)?
corrected quark content
May
13
answered How to determine a strong or weak interaction (Strange particles)?
May
13
comment How to determine a strong or weak interaction (Strange particles)?
This is wrong. quarks have other quantum numbers that do not allow them to annihilate, even the up and down are separate quantum numbers ( baryon numbers) and have to match to annihilate as happens in the pi0 messon, when it goes to the next fastest, electromagnetic two gamma.
May
12
comment Synchronized rotation of the moon
In this spaceacademy.net.au/library/notes/solastrl.htm there exists a table with relative effects of planets on the sun. It is the changes in the gravitational force that will create the tides ( they are really second order deformations of pliable mass) and these are very small on the surface of the sun, if I remember correctly even Jupiter is of the order of milimeters.
May
12
comment Synchronized rotation of the moon
@garyp Dissipation is a part of the transfer of momentum to the earth. The dissipation happens even after locking, just the two bodies are in a sort of lowest state, the angular momentum exchanged such that the lock remains. The moon could have had earth tides when it was liquid or had a liquid core on which the crust could move , as the earth's does with the tides ( called earth tides to distinguish from sea tides).
May
12
answered Synchronized rotation of the moon
May
12
comment Entropy and how it applies to everyday activities like eating food
@JamalS that comment is from 2011 !!!
May
12
answered How come this paper clip is “ floating” on the subway floor?
May
11
comment Physics and Skin Color: What differences do physicists observe between different skin colors?
p.s. It is interesting that I know of one blond German girl married to a Greek whose hair turned brown in Greece. Her melanin went into action not only on her skin ( she was naturally blond). Good night.
May
11
comment Physics and Skin Color: What differences do physicists observe between different skin colors?
All bodies of matter emit black body radiation according to their temperature with a coefficient that differs, emissivity it is called. Emissivity plays also the inverse role in absorption of radiation for a given frequency. I do not know if there exists a difference in human skin . Here they think yes juro.uga.edu/2010/boc2010/mize_2010.pdf . In any case it will not be more important than wearing dark or light clothes maybe in a crowd. A white dressed crowd would reflect more light than a dark dressed crowd.
May
11
answered Physics and Skin Color: What differences do physicists observe between different skin colors?
May
11
comment What does this quantum experiment says about quantum world?
Here is the arxiv arxiv.org/abs/1208.0034
May
11
comment Why are so many things squared in Physics?
I think squares come in because of the symmetry of most things happening in space and time. If not squares, the square root of squares ( as with the 1/r potential of gravity). In a Tailor expansion for any function the first power changes sign and is useless for most physical descriptions. Same with the third power. The fourth will have a much smaller coefficient ( in useful functions).
May
10
awarded  Revival
May
10
comment Why didn't we replace our SI units with a better system?
I think that your proposal ignores that a very small number of students studying in physics courses will become theoretical physicists, the rest will be following other disciplines where the SI units are OK, except I agree that a more stable definition of the kilogram should be found.
May
10
comment Why didn't we replace our SI units with a better system?
Physicists too start as children progress to graduate students and there we already have the c=1 etc, but we have an intuitive grasp of units from the ones that came naturally
May
10
comment Why didn't we replace our SI units with a better system?
While we are at it , why don't we replace the decimal system with the binary system? The digital came because we have 10 fingers. Think how you would teach a child to count; counting on fingers was natural and probably in our DNA :)
May
10
revised Heating effects of microwaves
deleted 3 characters in body
May
10
answered Heating effects of microwaves
May
10
answered Temperature behavior over time of black or white cars in hot, sunny regions