It is not clear that the Greeks rejected heliocentrism at all, let alone any reason other than heresy. On the contrary, Hipparchus refused to choose, on the grounds of Galilean relativity.
Eh? I was under the impression that most of the Greeks accepted geocentrism, eg Aristotle. Double-checking https://en.wikipedia.org/wiki/Heliocentrism#Greek_and_Hellenistic_world and https://en.wikipedia.org/wiki/Ancient_Greek_astronomy I don't see any support for your claim that heliocentrism was a respectable position and geocentrism wasn't overwhelmingly dominant.
The atomists got the atomic theory from the Brownian motion of dust in a beam of light.
Cite? I don't recall anything like that in the fragments of the Pre-socratics, whereas Eleatic arguments about Being are prominent.
Lucretius talks about the motion of dust in light, but he doesn't claim that it is the origin of the theory. When I google "Leucippus dust light" I get lots of people making my claim and more respectable sources making weaker claims, like "According to traditional accounts the philosophical idea of simulacra is linked to Leucippus’ contemplation of a ray of light that made visible airborne dust," but I don't see any citations to where this tradition is recorded.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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