The size of a shoebox, a mysterious bronze device scooped out of a Roman-era shipwreck at the dawn of the 20th century has baffled scientists for years.
Now researchers have stunningly established it as the world's oldest surviving astronomy computer.
A team of Greek and British scientists probing the secrets of the Antikythera Mechanism has managed to decipher ancient Greek inscriptions unseen for over 2 000 years, members of the project say.
"Part of the text on the machine, over 1 000 characters, had already been deciphered, but we have succeeded in doubling this total," says physician Yiannis Bitsakis, member of a multi-disciplinary team of researchers from universities in Athens, Salonika and Cardiff, the Athens National Archaeological Museum and the Hewlett-Packard company.
"We have now deciphered 95 percent of the text," he says.
Scooped out of a Roman shipwreck located in 1900 by sponge divers near the southern Greek island of Antikythera, and kept at the Athens National Archaeological Museum, the mechanism contains over 30 bronze wheels and dials and is covered in astronomical inscriptions.
Probably operated by crank, it survives in three main pieces and some smaller fragments.
"(The device) could calculate the position of certain stars, at least the Sun and Moon, and perhaps predict astronomical phenomena," says astro-physicist Xenophon Moussas of Athens University.
"It was probably rare, if not unique," he says.
The rarity of the Antikythera Mechanism precluded its removal from the museum, so an eight-ton "body scanner" had to be assembled on-site for the privately-funded project, which used three-dimensional tomography to expose the unseen inscriptions.
The first appraisal of the mechanism's purpose was put forward in the 1960s by British science historian Derek Price, but the scientists' latest discovery raises more questions.
"It is a puzzle concerning astronomical and mathematical knowledge in antiquity," says Moussas. "The mechanism could actually rewrite certain chapters in this area."
"The challenge is to place this device into a scientific context, as it comes almost out of nowhere... and flies in the face of established theory that considers the ancient Greeks were lacking in applied technical knowledge," says Bitsakis, also of Athens University.
The researchers are also looking at the broader remains of the Roman ship - believed to have sunk around 80 BC - for clues to the mechanism's origin.
One theory under examination is that the device was created in an academy founded by the ancient Stoic philosopher Poseidonios on the Greek island of Rhodes.
The writings of 1st-century AD Roman orator and philosopher Cicero - himself a former student of Poseidonios - cite a device with similarities to the mechanism.
"Like Alexandria, Rhodes was a great centre of astronomy at the time," says Moussas. "The boat where the device was discovered could have been part of a convoy to Rome, bearing treasure looted from the island for the purpose of a triumph parade staged by Julius Caesar."
The new findings are to be discussed at an international congress scheduled to be held in Athens in November. - Sapa-AFP