Tony Freeth

In at least 400 European caves such as Lascaux, Chauvet and Altamira, Upper Palaeolithic Homo sapiens groups drew, painted and engraved non-figurative signs from at least ~42,000 bp and figurative images (notably animals) from at least 37,000 bp. Since their discovery ~150 years ago, the purpose or meaning of European Upper Palaeolithic non-figurative signs has eluded researchers. Despite this, specialists assume that they were notational in some way. Using a database of images spanning the European Upper Palaeolithic, we suggest how three of the most frequently occurring signs—the line <|>, the dot <•>, and the —functioned as units of communication. We demonstrate that when found in close association with images of animals the line <|> and dot <•> constitute numbers denoting months, and form constituent parts of a local phenological/meteorological calendar beginning in spring and recording time from this point in lunar months. We also demonstrate that the si...

The Antikythera Mechanism, an ancient Greek astronomical calculator, has challenged researchers since its discovery in 1901. Now split into 82 fragments, only a third of the original survives, including 30 corroded bronze gearwheels. Microfocus X-ray Computed Tomography (X-ray CT) in 2005 decoded the structure of the rear of the machine but the front remained largely unresolved. X-ray CT also revealed inscriptions describing the motions of the Sun, Moon and all five planets known in antiquity and how they were displayed at the front as an ancient Greek Cosmos. Inscriptions specifying complex planetary periods forced new thinking on the mechanization of this Cosmos, but no previous reconstruction has come close to matching the data. Our discoveries lead to a new model, satisfying and explaining the evidence. Solving this complex 3D puzzle reveals a creation of genius—combining cycles from Babylonian astronomy, mathematics from Plato’s Academy and ancient Greek astronomical theories.

The Antikythera Mechanism, an ancient Greek astronomical calculator, has challenged researchers since its discovery in 1901. Now split into 82 fragments, only a third of the original survives, including 30 corroded bronze gearwheels. Microfocus X-ray Computed Tomography (X-ray CT) in 2005 decoded the structure of the rear of the machine but the front remained largely unresolved. X-ray CT also revealed inscriptions describing the motions of the Sun, Moon and all five planets known in antiquity and how they were displayed at the front as an ancient Greek Cosmos. Inscriptions specifying complex planetary periods forced new thinking on the mechanization of this Cosmos, but no previous reconstruction has come close to matching the data. Our discoveries lead to a new model, satisfying and explaining the evidence. Solving this complex 3D puzzle reveals a creation of genius-combining cycles from Babylonian astronomy, mathematics from Plato's Academy and ancient Greek astronomical theories. The Antikythera Mechanism is a cultural treasure that has engrossed scholars across many disciplines. It was a mechanical computer of bronze gears that used groundbreaking technology to make astronomical predictions , by mechanizing astronomical cycles and theories 1-9. The major surviving fragments of the Antikythera Mechanism are labelled A-G and the minor fragments 1-75 7. They are partial, damaged, corroded and covered in accretions (Supplementary Fig. S1). Nevertheless, they are rich in evidence at the millimetre level-with fine details of mechanical components and thousands of tiny text characters, buried inside the fragments and unread for more than 2,000 years 7. Fragment A contains 27 of the surviving 30 gears, with a single gear in each of Fragments B, C and D 2,5,7,10. The fragments are a 3D puzzle of great complexity. In 2005 Microfocus X-ray Computed Tomography (X-ray CT) and Polynomial Texture Mapping (PTM) of the Mechanism's 82 fragments 7 added substantial data. This led to a solution to the back of the machine 4,7-9 , with the discovery of eclipse prediction and the mechanization of the lunar anomaly 7 (Supplementary Fig. S20). The front remained deeply controversial due to loss of physical evidence. Many unsuccessful attempts have been made to reconcile the evidence with a display of the ancient Greek Cosmos of Sun, Moon and all five planets known in antiquity. In 1905-06, remarkable research notes by Rehm 1 described Mein Planetarium, with a ring display for the planets that anticipates the model we present here-but mechanically completely wrong due to his lack of data (Supplementary Fig. S17). In the classic, Gears from the Greeks 2 , Price suggested lost gearing that calculated planetary motions, but made no attempt at a reconstruction. Then Wright built the first workable system at the front that calculated planetary motions and periods, with a coaxial pointer display of the Cosmos, proving its mechanical feasibility 3 (Supplementary Fig. S18). Later attempts by Freeth and Jones 9 (Supplementary Fig. S19), and independently by Carman, Thorndike, and Evans 11 , simplified the gearing but were limited to basic periods for the planets. Most previous reconstructions used pointers for the planetary displays, giving serious parallax problems 3,9 and poorly reflecting the description in the inscriptions-see section on Inscriptional Evidence. None of these models (Supplementary Discussion S6) are at all compatible with all the currently known data. Our challenge was to create a new model to match all the surviving evidence. Features on the Main Drive Wheel indicate that it calculated planetary motions with a complex epicyclic system (gears mounted on other gears), but its design remained a mystery. The tomography revealed a wealth of unexpected clues in the inscriptions , describing an ancient Greek Cosmos 9 at the front, but attempts to solve the gearing system failed to match OPEN 1

The Antikythera Mechanism is the oldest known advanced scientific instrument. Without doubt, it is the oldest known analogue computer made with gears and the first known Mechanical Universe and probably Planetarium. Not only was an astronomical instrument suitable for observations, but it also served as a climatological and meteorological device. Certainly, such devices were in use as educational instruments in Antiquity and possibly operated as a cartographic tool. Made by Greek scientists with appropriate knowledge of astronomy, mathematics, physics, engineering and metallurgy, the bronze geared device enabled the constructor to perform specific calculations with gear trains and the user to find the position of celestial bodies in the sky. It was constructed during the Hellenistic period, probably around 150 to 100 BC. The Antikythera Mechanism depicts the position of the Sun, the Moon (its phase), predicts eclipses and shows when the Greek Crown Games should occur: the Olympics, the Pythian, the Isthmian, the Nemean, the Naan, some of the very important festivities that enable the common person to keep the time in a functional calendar very useful in agricultural, fishing and hunting.