Atmospheric
Optics
Samos Optics
~ Primary and secondary rainbows and (below) 22° halos sighted by Manolis Thravalos (more images) on the Greek island of Samos. Images ©Manolis Thravalos.
Samos, in the eastern Aegean and only a mile from the coast of Asia Minor is famous for its wines and has a long history.
It was the birthplace of Pythagoras (c570 – c495 BC) and Aristarchus (c310 – c230 BC).
Aristarchus first advanced the heliocentric hypothesis that Earth revolves around a fixed sun. Previous ideas of an earth centred Universe had the stars attached to a relatively close sphere. With a moving earth they would appear to oscillate back and forth (parallax) each year. Aristarchus suspected that the stars showed no parallax because they were far more distant. Perhaps other suns. The previously small Universe had become immense.
Failure to detect stellar parallax and other issues remained objections. Ptolemy (c100 – 170 AD) reverted to an earth centred Universe. That, combined with the weight of Aristotle's writings, led to geocentrism again becoming the accepted teaching.
Copernicus, who was aware of the work of Aristarchus, finally restored heliocentrism 1300 years later.
