Why was the antikythera mechanism invented

Here we solve this key problem with a mean Sun output, feeding into the Moon phase device as the first output tube adjacent to the central lunar arbor. This is why the mean Sun output is attached via a bar to the previously-mysterious pierced block on Spoke D Fig.

This important idea enables a ring display for the Cosmos, with a single true Sun output for the solar ring. The small approximation inherent in using a mean Sun rather than a true Sun input to the Moon phase is negligible at the scale of the 6 mm diameter Moon phase sphere.

There are great advantages in a ring system of outputs as opposed to a pointer system. It coincides far better with the description of the output display in the BCI. It eliminates the severe parallax inherent in a pointer system with nine outputs. It greatly enhances the astronomical outputs, by enabling the synodic phases of the planets to be described by index-linked inscriptions, as we discuss later Fig.

It leads to a robust and elegant display. The close match between our proposed mechanisms and the data is shown in Fig.

The four spokes of b1 suggest four different functions Supplementary Fig. The mean Sun and inferior planets take up three of these. What is the function of the prominent bearing on Spoke B Fig. Our proposed tooth counts for the gears and their modules Supplementary Discussion S4 mean that the bearing is in exactly the right place on Spoke B.

No other use has previously been found for this bearing. We argue that Fragment D includes epicyclic components for Venus Fig. S13, S14 , that the gear trains follow our 5-gear design Fig.

The prime factors in the period relations combined with the physical evidence then determine the gear trains Fig. For the first time, the features on b1 and the components of Fragment D are fully explained Figs. We conclude that our Venus and Mercury gear trains are strongly indicated by the evidence. There is no surviving direct evidence for the gearing systems that calculated the true Sun and the superior planets.

Inevitably this means choices, though the space available strongly limits these choices, since very compact systems are necessary to calculate the advanced period relations. Figure 6 a-e show how most of the gears for the true Sun and superior planets are reconstructed within the 9. True Sun, Superior Planets and exploded Cosmos gearing. Centre in a : fixed gear 56 , rivetted to a subsidiary plate not seen. Bottom right in a : 64 , shared between Mars and Jupiter; Top left in a : 52 , shared between the true Sun and Saturn.

Left in a : 56 is the epicyclic gear for the true Sun gearing. Clockwise from the top: Saturn , true Sun , Mars , Jupiter. The initial gears for these systems are in front of the CP Fig.

The arbors of the three gears 52 , 56 and 64 go through the CP to drive the mechanisms at the back. The mechanisms are arranged with their outputs in the CCO and are aligned on cardinal axes to facilitate calibration. The planetary periods and gear trains are listed in Fig. Since the tooth counts must include the prime factors of the period relations, there are few viable options.

The true Sun mechanism is a simple 3-gear system, previously proposed 3 Fig. It shares the fixed gear 56 with all the superior planets and it shares 52 with the Saturn mechanism. Hence it only needs one additional gear The superior planets, Mars, Jupiter and Saturn, are arranged clockwise from the top in Fig. All their mechanisms share a fixed gear 56 and follow the same economical 7-gear design shown in Fig. The exploded diagram in Fig.

We reconstruct 34 gears in front of b1 for the Cosmos system. S20 7 —making a total of 69 gears Supplementary Videos S2 , S3. The model follows all our Reconstruction Principles and matches all the evidence Supplementary Discussion S1. Figure 7 combines our present discoveries into an elegant ancient Greek mechanical Cosmos at the front of the Antikythera Mechanism.

Computer model of the cosmos display. Scale marks and index letters for the synodic cycles of the planets are inscribed on the planet rings. Surrounding these, the Zodiac and the Egyptian Calendar 2.

When the Moon and Sun pointers coincide, the Moon sphere shows black for New Moon; when the pointers are on opposite sides, the Moon sphere shows white for Full Moon The Head of the Dragon Hand shows the ascending lunar node ; the Tail the descending node. Small triangles on the true Sun ring, near the pointer, show wider and narrower eclipse limits.

Eclipses are possible if the Dragon Hand is within these limits. When the Moon pointer is before the Head of the Dragon , the Moon is South of the node; after, it is North of the node—conversely for the descending node. A Date pointer is attached to a narrow date ring, showing the date in the Egyptian calendar 2. The planets are identified by semi-precious stones on planetary rings Supplementary Figs.

Closeness-to-node defines the sophisticated eclipse prediction scheme on the Antikythera Mechanism 8 , 23 , with symmetrical limits for lunar eclipses; and asymmetrical limits for solar eclipses, according to whether the Moon is North or South of the node 8 , These wider and narrower limits are indicated by triangles on the true Sun ring. When the Dragon Hand is within the relevant limits, an eclipse prediction glyph can be found on the Saros Dial, with eclipse characteristics listed in the eclipse inscriptions 8 , 23 , If the Dragon Hand is within the wider limits, an eclipse season 23 is in progress—occurring twice each eclipse year , shown by a full rotation of the Sun relative to the Dragon Hand.

As a rule, formulaic and repetitive inscriptions in the Antikythera Mechanism are indexed to their dials: for example, Parapegma inscriptions to the Zodiac Dial 1 , 2 , 7 , 25 and eclipse inscriptions to the Saros Dial 8 , 12 , For each planet, its synodic events— maximum elongations , stationary points , conjunctions and oppositions —occur when the planet is at a characteristic angle from the Sun.

We propose that the planetary rings were engraved with scale marks for these events read by the Sun pointer, with associated index letters beside the scale marks. Figure 8 shows how the index letters would have referenced the formulaic and repetitive events in the FCI. The translation is from a previous publication 12 , where a transcription of the original Greek text can also be seen. The Index Letter scheme is in red. The fragmentary data means that there are still many uncertainties in the lines of text.

Though this indexing scheme is not provable, as the beginning of the lines are lost Fig. S4 , it makes such good sense in enhancing the astronomy on the Cosmos Display and it fits exactly with the line-by-line structure of the FCI. It is striking that the synodic events in the FCI are only those observable on the planetary rings: the customary appearances and disappearances of the planets are omitted, strengthening the indexing hypothesis.

It is difficult to understand how the information in the FCI could have been easily accessed by the user without such an indexing system, which in turn justifies our ring system of outputs. The FCI 9 , 12 enumerates intervals in days between synodic events—probably calculated from epicyclic models, not observations, since the actual intervals are so variable Fig.

The embryonic trigonometry of the Hellenistic age 26 would have made calculating these difficult. Here we propose that the Antikythera Mechanism itself calculated these synodic intervals by counting days on the Calendar Dial between synodic events indicated by the synodic scale marks on the planetary rings—entirely without trigonometry. Figure 7 , Supplementary Figs. S24, S25 , Supplementary Videos S1 — S3 visualize our new model: the culmination of a substantial cross-disciplinary effort to elucidate the front of the Antikythera Mechanism.

Previous research unlocked the ingenuity of the Back Dials, here we show the richness of the Cosmos at the front. The main structural features of our model are prescribed by the physical evidence, the prime factors of the restored planetary period relations and the ring description in the BCI.

Hypothetical features greatly enhance and justify the Cosmos display: a Dragon Hand thematically linking the Front and Back Dials; and an Index Letter Scheme for the synodic events of the planets. Because of the loss of evidence, we cannot claim that our model is a replica of the original, but our solution to this convoluted 3D puzzle draws powerful support from the logic of our model and its exact match to the surviving evidence.

The Antikythera Mechanism was a computational instrument for mathematical astronomy, incorporating cycles from Babylonian astronomy and the Greek flair for geometry. It calculated the ecliptic longitudes of the Moon 7 , Sun 3 and planets 1 , 2 , 3 , 9 , 11 ; the phase of the Moon 10 ; the Age of the Moon 10 ; the synodic phases of the planets; the excluded days of the Metonic Calendar 8 ; eclipses 7 , 8 , 23 —possibilities , times , characteristics , years and seasons ; the heliacal risings and settings of prominent stars and constellations 1 , 2 , 7 , 25 ; and the Olympiad cycle 8 —an ancient Greek astronomical compendium of staggering ambition.

It is the first known device that mechanized the predictions of scientific theories and it could have automated many of the calculations needed for its own design Supplementary Discussion S6 —the first steps to the mechanization of mathematics and science. Our work reveals the Antikythera Mechanism as a beautiful conception, translated by superb engineering into a device of genius.

It challenges all our preconceptions about the technological capabilities of the ancient Greeks. The data that support the findings of this study are available from the corresponding authors upon reasonable request. Rehm, A. Notizbuch unpublished notebooks , research manuscripts and photographs from — Bayerische Staatsbibliothek, Munich, Germany.

Price, D. Gears from the Greeks: the Antikythera Mechanism—a calendar computer from ca. American Philosophical Society. New Ser. Wright, M. A planetarium display for the Antikythera mechanism. Google Scholar.

Counting months and years: the upper back dial of the Antikythera mechanism. Furthermore, Hipparchos is credited with the invention or improvement of several astronomical instruments, which were used for a long time for naked-eye observations. As such it is very tempting to associate Hipparchos as the maker of the Mechanism, especially as he was contemporaneous with date of manufacture of the Mechanism to BC.

Skip to main content. A research team discovered the quantum Getting medication past the brain's unique and protective blood Coal Creation Mechanism Uncovered Nov. However, the machinery must be assembled at the nanoscale which is a considerable First Quantum Simulation of Baryons Nov. This could become a much better solution in Wash-And-Wear Sensors.

Print Email Share. The use of Koine in the numerous inscriptions places the creation of the mechanism in the Greek world, which was geographically large at the time. The festival dial mentions the Olympics in central Greece, the Naa in northwest Greece, and the Halieia on the island of Rhodes. A analysis of the inscriptions by classicist Alexander Jones and colleagues suggests the mechanism could keep track of at least 42 different calendar events.

The Greeks believed that characteristics of an eclipse were related to good and bad omens. Because of this belief, by building in predictive eclipse technology, the creator of the mechanism was letting the user divine the future. The mechanism includes hands or pointers for Mercury, Venus, Mars, Jupiter, and Saturn, all of which are easily visible in the sky, as well as a rotating ball that showed the phases of the moon.

The parts that work these planetary pointers are gone, but text on the front plate of the mechanism confirms, according to Jones and his team , that the planetary motion was modeled mathematically using numerous complex gears—and that it was highly accurate. Since Cousteau explored in the mids, little work has been done at the underwater archaeological site because of the remote location and the depth of the water.

In , marine archaeologists from the Woods Hole Oceanographic Institute and the Hellenic Ephorate of Underwater Antiquities again dove the wreck with the latest, high-tech scuba gear.

They found a massive spread of amphorae and other artifacts. This means that either the Roman ship was vastly larger than previously thought or there is a separate wreck down there. Excavations have been ongoing for several years, with new artifacts brought up constantly. BY Kristina Killgrove.