Breathe, Lucid, breathe.

LucidFlight wrote:Holy guacamole, you went to Oxford?

Yes, Hertford College, in the early '70's.
My tutor was a nuclear physicist. I got an upper 2nd class BA (hons).

I also went to Oxford. We should catch up some time. Anyway, we're getting off-topic again. What are we Oxford types like, eh?

LucidFlight wrote:I also went to Oxford. We should catch up some time. Anyway, we're getting off-topic again. What are we Oxford types like, eh?

If you're not careful, you'll start those rumours again!

DavidMcC wrote:...
That is not what I was taught at university (Oxford), which was that it did indeed have to do with the radfiative collapse of a purely classical atom.
...

Which equation leads to ultraviolet catastrophe in this model you was taught at university (Oxford)?

Up in Liverpool we were shown how Planck solved the issues with the Rayleigh-Jeans formula and Wein's displacement law at differing temperatures*. "Go (ah)ead, laaa..." as they would've intoned (meaning, "The floor is yours, please continue with your exposition.") ...

* Also shown here

newolder wrote:

DavidMcC wrote:...
That is not what I was taught at university (Oxford), which was that it did indeed have to do with the radfiative collapse of a purely classical atom.
...

Which equation leads to ultraviolet catastrophe in this model you was taught at university (Oxford)?

...

Maxwell's equations, applied to an atom.

EDIT: BTW, I certainly don't deny that the classical version of the Planck distribution would also involves a "UV catastrophe".

DavidMcC wrote:...
Maxwell's equations, applied to an atom.

Atoms are about 0.1 to 0.5 nanometers in diameter, how does an ultraviolet catastrophe (wavelengths around 400 nanometers) result from Maxwell’s equations applied to an atom?

newolder wrote:

DavidMcC wrote:...
Maxwell's equations, applied to an atom.

Atoms are about 0.1 to 0.5 nanometers in diameter, how does an ultraviolet catastrophe (wavelengths around 400 nanometers) result from Maxwell’s equations applied to an atom?

400nm is the near UV, not vacuum UV, which almost óverlaps with x-rays.

DavidMcC wrote:...
400nm is the near UV, not vacuum UV, which almost óverlaps with x-rays.

Your source, "10–200 nanometers". How do Maxwell's equations applied to atoms (repeat: less than 1 nanometre diameter) result in an ultraviolet catastrophe?

newolder wrote:

DavidMcC wrote:...
400nm is the near UV, not vacuum UV, which almost óverlaps with x-rays.

Your source, "10–200 nanometers". How do Maxwell's equations applied to atoms (repeat: less than 1 nanometre diameter) result in an ultraviolet catastrophe?

Excited states of atoms can be significantly larger than the ground state.

DavidMcC wrote:

newolder wrote:

DavidMcC wrote:...
400nm is the near UV, not vacuum UV, which almost óverlaps with x-rays.

Your source, "10–200 nanometers". How do Maxwell's equations applied to atoms (repeat: less than 1 nanometre diameter) result in an ultraviolet catastrophe?

Excited states of atoms can be significantly larger than the ground state.

Which textbook(s) (i.e. the one(s) you used at university (Oxford)) show a derivation for this version of ultraviolet catastrophe?

https://en.wikipedia.org/wiki/Hydrogen_spectral_series
Note the wavelength range of the Lyman alpha spectrum.

DavidMcC wrote:https://en.wikipedia.org/wiki/Hydrogen_spectral_series
Note the wavelength range of the Lyman alpha spectrum.

Yes, look over there.... This spectrum is not from a "classical atom" that you wrote of earlier is it?

newolder wrote:

DavidMcC wrote:https://en.wikipedia.org/wiki/Hydrogen_spectral_series
Note the wavelength range of the Lyman alpha spectrum.

Yes, look over there.... This spectrum is not from a "classical atom" that you wrote of earlier is it?

Sure, but the classical atom had to cover the full range of energies.
It's failure had nothing to do with that.

DavidMcC wrote:

newolder wrote:

DavidMcC wrote:https://en.wikipedia.org/wiki/Hydrogen_spectral_series
Note the wavelength range of the Lyman alpha spectrum.

Yes, look over there.... This spectrum is not from a "classical atom" that you wrote of earlier is it?

Sure, but the classical atom had to cover the full range of energies.
It's failure had nothing to do with that.

Such gibberish. I'm out.

Ha! Excuses! The "gibberish" is all yours. The failure of the classical atom was more fundamental than atom size. I have already explained the real reason why classical physics fails to account for atoms, in my first reply to the OP, OK? It has to do with classical EM theory predicting continuous radiative energy loss by an electron orbitting a nucleus, classical style.

Typeo, I hope you are not distracted by the unseemly row I've just had with newolder about UV catastrophies. What matters is the fact that electrons are not suddenly behaving classically when they interact with an atomic nucleus.

DavidMcC wrote:Typeo, I hope you are not distracted by the unseemly row I've just had with newolder about UV catastrophies. What matters is the fact that electrons are not suddenly behaving classically when they interact with an atomic nucleus.

To clarify, there was no “unseemly row”. Rather, “alternative facts” were demolished with evidence.

DavidMcC wrote:

LucidFlight wrote:Holy guacamole, you went to Oxford?

Yes, Hertford College, in the early '70's.
My tutor was a nuclear physicist. I got an upper 2nd class BA (hons).

Upper second? But Oxford didn't have that degree classification in those days, it was first, second or third.