ATHENS, Greece — Imagine tossing a top-notch laptop into the sea, leaving scientists from a foreign culture to scratch their heads over its corroded remains centuries later.

A Roman shipmaster inadvertently did something just like that 2,000 years ago off southern Greece, experts said this past week.

They claim to have identified a handful of puzzling metal scraps found in a shipwreck as the earliest known mechanical computing device, which pinpointed astronomical events.

A team including British, Greek and U.S. scientists used specially developed X-ray scanning and imaging technology to analyze the corroded bronze, revealing hidden machinery and a form of written user's manual.

"We have used the latest technology available to understand this mechanism, yet the technological quality in this mechanism puts us to shame," project leader Mike Edmunds, professor of astronomy at Cardiff University. "If the ancient Greeks made this, what else could they do?"

He spoke at a two-day conference that opened in Athens on Thursday. The team's findings also were published in Nature magazine.

Known as the Antikythera Mechanism — from the island off which the Roman ship sank — the assemblage of cogs and wheels looks like the innards of a very badly maintained grandfather clock. But the first clockwork devices appeared more than a thousand years later in western Europe.

"It was a pocket calculator of the time," said John Seiradakis, a professor of astronomy at the University of Thessaloniki who served on the international team.

Ever since its discovery a century ago, the complex mechanism has baffled scientists.

Edmunds said the 82 surviving fragments, dated to between 140-100 B.C, contain more than 30 gear wheels, and "are covered with astronomical, mathematical and mechanical inscriptions."

"It was a calendar of the moon and sun, it predicted the possibility of eclipses, it showed the position of the sun and moon in the zodiac, the phase of the moon, and we believe also it may have shown the position of some of the planets, possibly just Venus and Mercury," he said.

The box-shaped mechanism — the size of office paper and operated with a hand-crank — could predict an eclipse to a precise hour on a specific day.

The new study of the ancient device, with the aid of Hewlett Packard and the British X-ray equipment maker X-Tek, more than doubled the amount of the inscriptions readable on the mechanism.

"We will not yet be able to answer the question of what the mechanism was for, although now we know what the mechanism did," Edmunds said.