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Orbiting Electrons, Radiation, and Stability of Universe
Name: Miikka
Status: student
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
I have understood, that a charged particle, which is
accelerated, will radiate electromagnetic energy. This happens even
when the speed of the particle is constant, but the direction of its
movement and hence its velocity is changing. So a charge with
uniform speed traveling on a circular path will radiate energy (e.g.
in a cyclotron). My question is, why does an electron in an orbital
around the nucleus of an atom not radiate, unless it is moving form
one orbital to another? I suspect, that this has something to do
with the fact, that there are only a fixed number of possible
orbitals for electrons in an atom. If the electron does not radiate
energy when it is in an orbital, does that mean that it is not
influenced by any forces? Otherwise it would be false to state,
accelerated charges always radiate energy.
Replies:
"Classical" electrodynamics predicts that an accelerating charged particle
emits radiation.
On the macroscopic scale, this is/was true. However, Bohr, Planck, and other
scientists at the time recognized that this behavior could not apply to
atoms and molecules. The only resolution was that the "classical" law did
not apply to atoms and molecules. This 'ad hoc' assertion led to the Bohr
model for the hydrogen atom. His assertion that electrons could only exist
in certain stable orbits conflicted with the existing classical model but
agreed with the experimental result.
So there is an intellectual choice: Revise the theoretical model, or, ignore
the experimental result. In fact there is no choice. Science is based upon
what can be observed and measured, or upon adherence to the model (dogma).
For science only the former is ultimately acceptable.
Vince Calder
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Update: June 2012
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