A 65ft blade from the 290ft turbine fell off and a second was bent in the mysterious incident in Conisholme, Lincs, on Wednesday.
Hundreds of local witnesses claimed to have seen bright flashing spheres in the skies above the turbine, and many are convinced the damage was caused by a flying saucer.
Scientists at manufacturers Enercon have been looking into the mystery, and dismissed the theories that either a chunk of ice thrown from another turbine, or frozen urine dropped from a passing plane, was the cause.
A source told The Sun: "It is impossible to get a lump of ice on a wind turbine blade big enough to cause that kind of damage, let alone be flung from one to another.
"Also, turbines have sensors in the blade. If they detect ice forming they turn themselves off.
"Additionally, any large lump of ice would not have melted so quickly in the cold weather and would probably have left a dent in the ground. No debris was found other than remains of the turbine.
"If there is a rational explanation, the investigation will find it."
A lightning strike has also been ruled out, as there were no burn marks.
Ministry of Defence insiders have reportedly said the UFOs could be unmanned stealth bombers on test flights. Unmanned stealth bombers, but MOD they don't exist!
It is also possible that one of the blades had simply not been securely fixed, and fell off bending the other on its way down.
The results of the investigation being carried out by forensic scientists in Germany should be disclosed within a week.
Dale Vine, managing director of Ecotricity which owns the turbine, said: "We've ruled out ice from other turbines or passing jets.
"We've examined the turbine, the fallen blade and the surrounding area. We have been crawling all over it. To make one of these blades fall off, or to bend it, takes a lot."