Uncovering ancient technology: the computer beneath the sea, from 2 millennia ago. From the article:

More than 2,200 years after it sank beneath the waves, diving archaeologists have possibly found a missing piece of the Antikythera Mechanism, the fantastically complicated, advanced analog “computer” found in a shipwreck off a Greek island. Scanning shows the encrusted cogwheel to bear an image of Taurus the bull.

The Antikythera Mechanism was discovered in 1901, technically speaking. An encrusted lump was salvaged by Greek sponge divers in clunky metal diving suits from the Mediterranean seabed. Not that anybody realized what it was at the time. It would take decades and advanced x-ray technology for scientists to realize that the “rock” was a wondrously advanced sophisticated analog calculator consisting of dozens of intermeshed gears.

The Mechanism could do not only basic math: with dozens of exquisitely worked cogwheels, it could calculate the movements of the sun and moon, predict eclipses and equinoxes, and could be used to track the solar system planets, the constellations, and much more.

We may never know how many cogwheels the original Antikythera Mechanism had. Assessments based on its functions in predicting the behavior of the cosmos range from 37 to over 70. For comparison, the most advanced Swiss watches have four cogwheels….

A half-century later, starting in 2012, underwater archaeologists uncovered hundreds of artifacts, including two massive bronze spears, the life-size bronze representation of an arm, other pieces of marble and bronze statues, mosaic glassware, pieces of bone-inlaid furniture, blue game pawns, a sarcophagus lid, gold rings, and silver coins.

They also found an encrusted, corroded disk, which was pulled from the seabed in 2017.

Like the original Antikythera Mechanism, after nearly 2,100 years underwater, the disk resembled greenish rock. About eight centimeters in diameter, the object still has four metal arms standing proud of the corners, with holes for pins. X-ray analysis shows the disk to bear the engraving of Taurus the bull.

It will be difficult to prove what exactly the Taurus disk is: part of the original Antikythera Mechanism, part of a second such mechanism, if one existed, or something else entirely.

Based on the evidence so far, it looks exactly like other parts of the Mechanism, which had clearly been found incomplete. Based on the etching of the bull that can be seen with scanning, it may well be the gear that predicted the position of the zodiac constellation of Taurus.