attraction and repulsion of e- and p+

delplace

I would like to know if electrical charge is the only way to explain attraction and repulsion of e- and p+.

malawi_glenn

yes

but, you can also imagine the Pauli Principle making up a "repulsive force". Consider e.g. degenerate matter, such as white dwarfs, metals, H2 molecule etc.

delplace

could you explain e.g. degenerate matter.

malawi_glenn

It is better for you to google it, and then ask more specific questions:

http://en.wikipedia.org/wiki/Degeneracy_pressure

http://www.wisegeek.com/what-is-degenerate-matter.htm

http://www.daviddarling.info/encyclo...te_matter.html

http://www.123exp-science.com/t/01554105619/

http://www.sfu.ca/~boal/390lecs/390lec28.pdf

e.g. means "exempli gratia" = latin for "for example"

scientific language often uses these abbreviations (http://en.wikipedia.org/wiki/List_of_Latin_phrases )

i.e. and c.f. is together with e.g. the most used ones

delplace

does it means that in degenerate matter like dwarf stars two e- can attract ?

malawi_glenn

No I said that the pauli principle can make up a REPULSIVE 'force' ....

i.e you can have both repulsion from electric force and the pauli principle

delplace

But I read in your internet links that electrons can fuse in neutron stars of course at very high pressures and temperatures. Do you know if ITER experiments reaching these very high temperatures will be close to these extrem conditions ?

malawi_glenn

this is simplified:

white dwarfs are degenerate matter of electrons, protons and neutrons, recall that the pauli principle are between IDENTICAL fermions.

in neutron starts, the gravity force is stronger than the degenerate pressure for the mixture of electrons, protons and neutrons, so the electrons will be fused into the protons -> making up more neutrons, so that in the end you have body of only neutrons.

if the gravity force is even stronger, so that it is stronger than the degenerate pressure between neutrons, then you will get a black hole...

Now temperature is no the only interesting thing. ITER will not, as far as i know, have such a high density that degeneracy effects will emerge.

malawi_glenn

It is also really fun that a professor in physics, which call himself scientist expert, don't know what degenerate matter is ;-)

delplace

you can not be expert in every things I am expert in non newtonian fluids mechanics and heat transfer but I never worked on these cosmological theories. I can give you the shear rate value in a plate heat exchanger because I do many experiments and I perfectly measure pressure drops, flow rate and viscosities but I never been in neutron stars to se what it happens with electrons protons and neutrons. I am sure you never measure it also :-)

malawi_glenn

degenerate matter is basic quantum physics :-P

so how can you claim you have a quantum theory of gravity if you don't even know basic quantum physics?

anyway, why did you ask "But I read in your internet links that electrons can fuse in neutron stars of course at very high pressures and temperatures"?? If there is something you don't understand about degeneracy pressure, ask it.

I doubt that in 20min you could read all the links I gave you.

And one does not have to be inside a neutron star to measure these things.. we can observe it by means of telescopes etc.

delplace

why gravity becomes so high in neutron stars ? even if I am not a specialist of cosmology, and considering the huge amount of paper I published 15 years ago I think I have good rest and I am sure you find my questions interesting :-)

malawi_glenn

The gravity is from the initial star, the higher mass it had, the higher the gravity field in its centre. So when the star collapse when its central nuclear fusion halts, it will (very rapidly, faster than 1 second) shrink (there is no outward radiation pressure from the centre that can overcome the inward directed gravity force). First the star will become a white dwarf, but if the gravity force still is greater, it will pass this stage (very very quick) and become a neutron star. And if the gravity is even stronger, it will pass and become a black hole.

http://www.ast.leeds.ac.uk/~knapp/StarFates.pdf

http://www.studyphysics.ca/sci30/fate.pdf


I don't think your questions are interesting, well maybe for a freshman in physics... ;-)

And this is not cosmology, it is astrophysics.

delplace

of course I know all of these things but sometimes you have to ask the false to know the true :-)
I am also a good mathematician playing with differential geometry since 20 years mainly for fluid mechanics applications. And I used Elie CARTAN mathematical support to extend GR equations to infinitely small systems.
You know we have to be modest simply because it is difficult to measure things at these scales and to medelize them. In fluid mechanics we are using dimensionless numbers to overcome scaling problems then for atomic and astronomic theories...

malawi_glenn

sure, whatever...

FastFreddy

malawi_glenn and delplace,

You're both experts in your respective fields. Can you please both demonstrate your professionalism by refraining from guttersnipe attacks? I am looking for knowledgable professionals to consult with. So please act accordingly.

jtbell

They stopped almost three months ago.