Newstory:Mystery of 2000 yr old computer unlocked

You are not allowed to view links.
Please Register or Login

Scientists unlock mystery of 2,000-year-old computer
Last Updated: Thursday, November 30, 2006 | 12:55 PM ET
CBC News

Scientists have unlocked the secret of an ancient device recovered from a Roman shipwreck, saying the complex mechanism was used to track the movements of the stars and moon.

The machine, believed to be about 2,000 years old, was discovered in 1901 on a shipwreck off the coast of the Greek island of Antikythera and embedded in rock. The strange wheel-like device with complex gears had baffled researchers attempting to determine its purpose.

But a recent study in the journal Nature has revealed the device, known as the Antikythera Mechanism, was actually a complex means of tracking the movements of astronomical bodies for use in navigation.. . . . . . .

Created between 150 BC and 100 BC, the mechanism contained 37 gear wheels in a case of wood and bronze in a contraption that resembled a clock. The gear wheels were designed to track the movements of the sun and moon, and even track eclipses and the irregular orbit of the moon. It may also have been able to follow some of the planets.

Also astonishing is the machine's use of a differential gear, a device known to have been used in the 17th century but often speculated to have been invented years earlier.

The device is an arrangement of gears that permits the rotation of two shafts at different speeds. It is most commonly associated in modern usage with automobiles, which use a differential gear on their rear axle to allow different rates of wheel rotation on curves. The intricacy of the device is also comparable to that of 18th-century clocks. . . . . .

Linkback:

You are not allowed to view links.
Please Register or Login

		Quote:			Posted by Goldfinger
	Another mystery solved..

You are not allowed to view links.
Please Register or Login

The Times   December 01, 2006

Pyramids were built with concrete rather than rocks, scientists claim
Charles Bremner, Paris
Method used only at higher levels
Blocks set using a limestone slurry

How the Egyptians really built a Pyramid
The Ancient Egyptians built their great Pyramids by pouring concrete into blocks high on the site rather than hauling up giant stones, according to a new Franco-American study.

The research, by materials scientists from national institutions, adds fuel to a theory that the pharaohs? craftsmen had enough skill and materials at hand to cast the two-tonne limestone blocks that dress the Cheops and other Pyramids.

Despite mounting support from scientists, Egyptologists have rejected the concrete claim, first made in the late 1970s by Joseph Davidovits, a French chemist.

The stones, say the historians and archeologists, were all carved from nearby quarries, heaved up huge ramps and set in place by armies of workers. Some dissenters say that levers or pulleys were used, even though the wheel had not been invented at that time.

Until recently it was hard for geologists to distinguish between natural limestone and the kind that would have been made by reconstituting liquefied lime

The pair believe that the concrete method was used only for the stones on the higher levels of the Pyramids. There are some 2.5 million stone blocks on the Cheops Pyramid. The 10-tonne granite blocks at their heart were also natural, they say. The professors agree with the ?Davidovits theory? that soft limestone was quarried on the damp south side of the Giza Plateau. This was then dissolved in large, Nile-fed pools until it became a watery slurry.

Lime from fireplace ash and salt were mixed in with it. The water evaporated, leaving a moist, clay-like mixture. This wet ?concrete? would have been carried to the site and packed into wooden moulds where it would set hard in a few days. Mr Davidovits and his team at the Geopolymer Institute at Saint-Quentin tested the method recently, producing a large block of concrete limestone in ten days. . . . . . . .



Linkback:

You are not allowed to view links.
Please Register or Login