Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: EvaH on 12/12/2018 17:44:52

Title: How fast do electrons travel around the nucleus?
Post by: EvaH on 12/12/2018 17:44:52
Gaither wants to know:

How fast do electrons travel around the nucleus? Is the speed of the shell and/or temperature related? Do electrons in the innermost/same shell travel at the same speed for every molecule?

What do you think?
Title: Re: How fast do electrons travel around the nucleus?
Post by: Halc on 12/12/2018 18:13:47
My answer is not any sort of expert reply, but electrons work at the quantum level, and quantum objects may not have a position unobserved, hence a statement about their speed may be meaningless.  The principle of counterfactual definiteness (there being a meaningful state in absence of measurement/interaction) may or may not hold, but it is in direct conflict with the principle of locality which says information cannot travel faster than light.  I find the latter one more offensive to violate, so I put little faith in the former.

Perhaps somebody who knows their subatomic physics better may post a reason why it is meaningful to speak of the speed of electrons in the various shells.
Title: Re: How fast do electrons travel around the nucleus?
Post by: syhprum on 12/12/2018 18:56:35
It is a very old fashion idea to think of Electrons zipping around the nucleolus of an atom like planets orbiting a star modern thinking is much more subtle.
Title: Re: How fast do electrons travel around the nucleus?
Post by: alancalverd on 14/12/2018 09:00:54
In a word, they don't. They can't. An orbiting electron would emit energy and spiral into the nucleus.
Title: Re: How fast do electrons travel around the nucleus?
Post by: yor_on on 14/12/2018 12:34:48
Heh, well Lunds university actually 'photographed' those electrons 'in motion', so to speak. But they would have to be faster than the speed of light in a vacuum to do a 'orbit', which to me would be a bit presumptuous of them. They better be defined by HUP (Heisenberg's Uncertainty Principle), or as 'standing waves' that falls out into a 'particle' in your observation. That will allow for taking those photographs, as well as keeping them inside the speed of light.