The 4th Hellenic Conference with topic “Aristarchus of Samos” took place on the 17th, 18th and the 19th of October on the island of Samos. It was organised by two university departments in Greece, the Pedagogic Department of Primary Education and the Department of Mathematics of the University of the Aegean, as well as by the Cultural Foundation “Nikolaos Dimitriou” in Samos and the Centre for Research on Science and Education. The conference took place in two cities of Samos, Pythagorion and Karlovassi. The areas covered by the conference included the astronomy before Aristarchus (Babylon and Egyptian periods), the work of Aristarchus (in both mathematics and astronomy), the astronomy after Aristarchus (Hellenistic and Arabic periods, as well as the period staring from the middle ages until Copernicus) and, finally, the interactions between the astronomical work of the Babylonians, ancient Egyptians, ancient Greeks, Indians and Chinese.

We mention indicatively some of the questions discussed and some of the problems posed during the conference:

• Investigation of the history of the emergence of non-geocentric and non-geostatic conceptions during the whole period of the ancient Greek astronomy, from the Pythagoreans to Aristarchus of Samos;
• Whether the heliocentric hypothesis of Aristarchus is a “singular point” – in the sense of Kuhn – within the field of the existing perceptions in the science of that time or not;
• Which were the obstructions towards a general acceptance and predominance of Aristarchus’ hypothesis;
• How the passage from the geocentric model of Ptolomeus to the heliocentric model of Copernicus was made, whether Copernicus’ model is a continuation of Aristarchus’ theory or an extension of Ptolomeus’ system;
• What is the relation between astronomy and astrology,
• Which were the conceptions of Christian scholars during the first Christian centuries concerning the geocentric, geostatic and heliocentric theories of the ancient times as well as the cosmological views they formulated.

Finally, a desire was expressed to hold a scientific meeting with topic “Pythagoras of Samos” in the future.