Why are there Statues on Easter Island

High definition satelite images have shown how the icons have been moving all over the island. Since the first landing of Europeans on the island in 1722, the solid statues of Easter Island - known as Rapu Nui by its residents - have confused us. Until then, the history of the 887 statues - or Moai in the Rapa Nui tongue - had been forgotten from the Rapu Nui group.

So why did the islanders' forefathers put so much trouble into the Moai, which is as big as forty foot and weighs up to 75 tons, which corresponds to twenty middle-class vehicles? How could so few humans on a secluded island - the closest populated country, Pitcairn Island with about 50 inhabitants, is 2,075 kilometers away - move the Moai up to 18 kilometers across jagged ground without even helping big critters?

Moai are representing forebears who watch over their offspring, which is why so much trouble and importance has been put into them, and why almost everyone looks into the interior instead of into the sea. It was difficult to find a definite response to the second issue - and some proposals were odd, such as the assertion of the once beloved writer Erich von Daniken that the Moai were the craft of the alien.

Also very unlikely are the moai, which are driven through the atmosphere by igneous flames in the quarries where they were cut, or which are made locally by the Rapa Nui humans who form earth. A challenge for the archeologists was that few streets from the mine lead to the ceremony platform known as Ahu, where the moai were built.

Last moai were cut about five hundred years ago, so it is likely that many of the moai transportation routes were hidden by nature's flora and man. University of Hawaii's Lipo and Terry L. Hunt began testing this theory with panoramic photos - monochrome photos that are susceptible to all visual spectrum lengths - taken via Rapu Nui by the QuickBird spacecraft in December 2001 and February 2002.

Very small - about 17 sq km, a quater the area of Manhattan - Rapu Nui makes it simple to study the satellites, which occupy 85% of the island's 70 centimetre area. Dr. Lipo and Dr. Hunt were looking for several traces of old streets - changes in flora due to dense soils, hollows full of sediments of soil pebbles and pebbles from saisonal runoffs, built-up shores, erosive samples and otherwise unexplained clues.

Satelite picture of the old street section (A) with round pattern (6-8m) on the northern side (B). On the pictures these characteristics showed up as grey scale variants. Supported by local polls, the pictures identify almost 32 kilometers of old Moai streets that radiate like radiant marks from the Rano Raraku stone pit into all parts of the island.

The latest extra visual analyses by archeologist Gabriel Wofford, also from the University of Hawaii, may have unearthed other old streets, although they still need to be confirmed by means of imagery. With the web of rediscovered old streets, Dr. Lipo and Dr. Hunt considered the Rapu Nui claim for generation that the Moai were "walking giants".

" Archaeologists developed a way for small crews to swing the moai from side to side with cables and move it forward in gradual movements, while a third crew behind the moai prevents it from toppling over. Moai seem to be designed for this mode of transportation - they are leaning slightly when standing up, making it relatively simple to keep them in motion.

University of Hawaii's staff is part of a burgeoning fellowship of astronomy experts; professionals who use spacecraft and distant vision technologies to find antique places or characteristics that are invisible to the unaided eye. Dr. Jason Ur, an archeologist at Harvard University, for example, investigated Iraq and, together with his co-workers, discovered almost 1,200 possible locations using imagery taken by espionage spacecraft in the sixties.

Sarah Parcak, a lecturer at the University of Alabama in Birmingham, used satellites to help us find possible locations for 17 Egypt's 15th pyramid, 1,000 abandoned graves and 3,100 people. The archeologist Damian Evans, who runs the University of Sydney's Cambodia research center, and William Saturno, Associate Professorship of Archeology at Boston University, used outer-space archaeology to study Lingapura, the old Angkoran imperial city in north-western Cambodia.

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