Researchers from Edinburgh University, with the aid of data from the shuttle, discovered an archaeological site on the Hebridean Island of Islay.

They found previously unknown and largely buried roads or "hollow ways" surrounding the island headquarters of the Lords of the Isles at Finlaggan Castle.

The Lords of the Isles were known to be the main economic, military and political power in the Irish Sea during the early Middle Ages. The discovery was made by Gary McKay, a former US naval research laboratory scientist at Nasa's Stennis Space Centre.

Mr McKay now specialises in archaeological work and made the discovery while working with advanced remote sensing archaeology techniques in Edinburgh University's departments of geography and archaeology.

Something odd

He used data from the space shuttle's sophisticated multipolarimetric imaging radar.

Advanced imaging techniques were used

Mr McKay said: "As soon as we had processed the image it was so obvious that something odd was present.

"At first I thought it was just a natural river course, but then realised that this "river" ran up and over the hills completely ignoring the local geological structure - it just had to be artificial."

Ground work by Mr McKay and Dr Mike Cressey, of the university's centre for field archaeology, confirmed the existence of the trackways and suggested they dated to the early Middle Ages.

New insights

The researchers said the roads could cast new light on the economy of the early mediaeval Lords of the Isles.

The detection of one hollow way, which led from Loch Finlaggan to the possible galley ports of Fionnphort and Port Bhoraraic, could give researchers new insights into trade and transport systems.

And evidence that mining played a key part in the Lords' economy much earlier than was previously thought was found in a network of tracks leading to areas around Lochs Ballygrant and Lossit, which contained deposits of lead and silver.