I was refering to the Greeks prediction that atoms occupied a small fraction of space within matter. … My point was only that the necessary ideas already existed for Copernicus to be able to make the analogy.

But I’ve just explained the atomic idea came about in 1784, not in Greek times. If you have two atoms a distance apart, Greeks said there is vacuum between them. This has nothing to do with void inside atoms.

Copernicus actually built on the work of Aristarchus of Samos, who had a solar system model. Aristarchus was suppressed because everyone else ignored him. Copernicus was taken more seriously because he fiddled a system with circular (not elliptical) orbits and twice as many epicycles as Ptolemy’s earth-centred universe system, to fit the data. The correct model emerged emerged a century after Copernicus when Kepler discovered elliptical orbits were correct.

I thought I made it clear that what the Greeks believed does not correspond to how we now know atoms to behave. I am not saying that anything about their theory was completely correct.

I was merely pointing out to Troublemaker that the concept of atoms existed at the time of Copernicus, and that most of matter was predicted to be empty space.

Ok, I shouldn’t have said “vacuum inside them”, my bad! I was refering to the Greeks prediction that atoms occupied a small fraction of space within matter.

My point was only that the necessary ideas already existed for Copernicus to be able to make the analogy.

“It then follows that there can be no void inside an atom itself. Otherwise an atom would be subject to changes from outside and could disintegrate. Then, it would not be an atom.

“We know this is incorrect. In 1911, Ernest Rutherford discovered the nucleus, demonstrating in the process that a single atom is mostly empty space.”

The first person to publish the prediction that INSIDE atoms (not beetween different atoms!) there is a void was George Louis LeSage (click my name for details) in his essay ‘Newtonian Lucretius’, New Memoirs of the Royal Academy, 1782 (Berlin: Decker, 1784), pp. 404-32.

He had a hard time from his peers, the paper begins with the quotation:

‘In any matter, the first systems make people excessively conclusive, closed, cautions of others. And does it not seem that this truth is the price of some hardening of reason?’ — Fontenelle, in the eulogy of Cassini.

There is a fuller description of this here, or just google it.

Electrons are supposed to be Planck sized strings, according to certain people? Also, that Planck thought he had got the smallest fundamental unit of length (plus time, etc) by dimensional analysis?

Later it was discovered that a much smaller size exists, the black hole radius/even horizon radius. Naturally the ignorant still use the Planck size. (It is convenient for them, as there is no implied physical mechanism for the Planck size which there is for the black hole size, such as trapped electromagnetic energy. I think the stringy people are deliberately steering as far away from simplicity/causality as possible. Hence extra dimensional hype.)

That Skeptic's Circle and link from Uncertain Principals (thanks!) really drove traffic here! At last count (5:00 PM -ish) there were 109 visits to Enceladus. I hoped you enjoyed it.
Now that I done some ego stroking, lets all have a dose of modest…