“Freeman Dyson showed that the imperviousness of solid matter is due to quantum degeneracy pressure rather than electrostatic repulsion as had been previously assumed”

I’ve always been taught the reason solid objects don’t pass through each other was because the negative charges on the electrons of the atoms repelled each other… Is that not the case???

Above quote is from wiki on Electron Degeneracy Pressure.

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

OCDC said:

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

Big need for this sort of physics in doktaring?

Dropbear said:

OCDC said:

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

Big need for this sort of physics in doktaring?

Quantum mechanics was my favourite part of second year chem.

Dropbear said:

OCDC said:

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

Big need for this sort of physics in doktaring?

Poltergeists, she has to avoid Poltergeists.

OCDC said:

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

*refers

In my view, electrostatic behaviour is just a specific characteristic of QSM, so to me it seems a bit strong to say the previous description was incorrect. I can understand Dyson’s preference for expressing it in terms of QSM when dealing with things at the atomic level, but.

OCDC said:

Dropbear said:

OCDC said:

I was taught the same reason as you, and probably more recently… Degeneracy occurs to “orbitals” for want of a better term.

Big need for this sort of physics in doktaring?

Quantum mechanics was my favourite part of second year chem.

Yeh I’ve always been keen on degeneracy

Anyway you SMRT people work it hot and let me know if wiki is full of shirt

Been a while since I drew an electron splitting diagram, hold on a tic.

Dropbear said:

“Freeman Dyson showed that the imperviousness of solid matter is due to quantum degeneracy pressure rather than electrostatic repulsion as had been previously assumed”

I’ve always been taught the reason solid objects don’t pass through each other was because the negative charges on the electrons of the atoms repelled each other… Is that not the case???

Above quote is from wiki on Electron Degeneracy Pressure.

If matter were composed of classical point particles kept apart by plain old electrostatic repulsion then it would be compressible to zero volume, making solid matter more rubbery than it actually is. So the quantum effects give extra stiffness that can’t be explained by a classical model. In fact, it’s hard to get rigid solid matter at all out of pure classical physics – quantization reduces the degrees of freedom of the system so we can have stuff like crystals, rather than solids being like jelly.

That Wiki page is just a brief summary, Degenerate matter goes into more detail.

Speaking of stiffness, my mother remarked a few days ago that this product has an unfortunate name.

Oops! Of course, I meant to put that in Chat. Oh well. :)

wouldn’t protons repel each other too, not only electrons?

if you had an errant proton floating around it would repel another proton I bet

536875

Glad someone here recognises wisdom.

wookiemeister said:

wouldn’t protons repel each other too, not only electrons?

if you had an errant proton floating around it would repel another proton I bet

Strong nuclear force > electromagnetic force

IOW it is quantum degeneracy that provides the structure of the atomic orbitals in the first place, which can then ‘push’ on the electron cloud of other atoms/molecules (which are also held apart by degeneracy).

OCDC said:

Been a while since I drew an electron splitting diagram, hold on a tic.

holding.

wookiemeister said:

wouldn’t protons repel each other too, not only electrons?

if you had an errant proton floating around it would repel another proton I bet

Sure. But you don’t normally get stray protons floating around in normal matter, they’re generally shielded by electrons. The nucleus of an atom is much tinier than the atom’s electron “cloud”, so the inverse square law says that when two atoms are in proximity it’s the electron repulsion that is the important thing.

Of course, in a hydrogen plasma it’s a different story, since there you do have naked protons & electrons flying around.

Dropbear said:

Strong nuclear force > electromagnetic force

Certainly, once the protons are close enough to each other. But it takes a lot of energy to overcome the electrostatic repulsion to get them that close. Just ask the people who are trying to build fusion reactors. :) Even in the core of a typical star the odds of fusion occurring are pretty low, which is a good thing, otherwise we wouldn’t have stable stars.

From Proton–proton chain reaction

The proton–proton chain reaction is one of several fusion reactions by which stars convert hydrogen to helium, the primary alternative being the CNO cycle. The proton–proton chain dominates in stars the size of the Sun or smaller.

In general, proton–proton fusion can occur only if the temperature (i.e. kinetic energy) of the protons is high enough to overcome their mutual electrostatic or Coulomb repulsion.

In the Sun, deuterium-producing events are so rare (diprotons, the much more common result of nuclear reactions within the star, immediately decay back into two protons) that a complete conversion of the star’s hydrogen would take more than 10¹⁰ (ten billion) years at the prevailing conditions of its core. The fact that the Sun is still shining is due to the slow nature of this reaction; if it went more quickly, the Sun would have exhausted its hydrogen long ago.

History of the theory

The theory that proton–proton reactions were the basic principle by which the Sun and other stars burn was advocated by Arthur Stanley Eddington in the 1920s. At the time, the temperature of the Sun was considered too low to overcome the Coulomb barrier. After the development of quantum mechanics, it was discovered that tunneling of the wavefunctions of the protons through the repulsive barrier allows for fusion at a lower temperature than the classical prediction.

Even so, it was unclear how proton–proton fusion might proceed, because the most obvious product, helium-2 (diproton), is unstable and immediately dissociates back into a pair of protons. In 1939, Hans Bethe proposed that one of the protons could beta decay into a neutron via the weak interaction during the brief moment of fusion, making deuterium the initial product in the chain. This idea was part of the body of work in stellar nucleosynthesis for which Bethe won the 1967 Nobel Prize in Physics.