• Publications
  • Influence
The Two Earths of Eratosthenes
This essay shows that Eratosthenes’ result of 252,000 stades for the Earth’s circumference follows from a solar distance that is attributed to him, indicating not only a lower limit for the size of the Earth, but also an upper limit, based on the assumption that the Sun is at a finite distance.
On the epoch of the Antikythera mechanism and its eclipse predictor
A series of constraints are applied, in a sort of sieve of Eratosthenes, to sequentially eliminate possibilities for the epoch date of the Antikythera mechanism, finding that the solar eclipse of month 13 of the Saros dial almost certainly belongs to solar Saros series 44.
Longomontanus’ Model for the Longitudes of Mars
When at the beginning of 1600, Kepler arrived to work with Tycho Brahe, Longomontanus, Tycho’s principal assistant, who was working with a model for Mars that predicted with remarkable accuracy its
Ptolemaic planetary models and Kepler’s laws
Abstract In this article, we aim at presenting a thorough and comprehensive explanation of the mathematical and theoretical relation between all the aspects of Ptolemaic planetary models and their
Solar Anomaly and Planetary Displays in the Antikythera Mechanism
Recent scholarship has greatly improved our understanding of the structure and function of the Antikythera mechanism.1 One unresolved issue is whether the mechanism included a display of the
On the Pin-and-Slot Device of the Antikythera Mechanism, with a New Application to the Superior Planets
(ProQuest: ... denotes formulae omitted.)Perhaps the most striking and surprising feature of the Antikythera mechanism uncovered by recent research is the pin-and-slot device for producing the lunar
Two problems in Aristarchus’s treatise on the sizes and distances of the sun and moon
The book of Aristarchus of Samos, On the distances and sizes of the sun and moon, is one of the few pre-Ptolemaic astronomical works that have come down to us in complete or nearly complete form. The
On the Determination of Planetary Distances in the Ptolemaic System
In 1975, Imre Lakatos and Elie Zahar claimed that the determination of planetary distances represents excess empirical content of Copernicus’s theory over that of Ptolemy. This claim provoked an