Norwegian scientists now believe they are nearing a solution to the Hessdalen UFO-mystery which has puzzled experts for more than 25 years.

The so-called Hessdalen lights have been seen ever since the 1940's and have since 1984 been monitored by volunteers.

Hessdalen is a small valley in the central part of Norway. At the end of 1981 through 1984, residents of the Valley became concerned and alarmed about strange, unexplained lights that appeared at many locations throughout the Valley. Hundreds of lights were observed. At the peak of activity there were about 20 reports a week.

Project Hessdalen was established in the summer of 1983. A field investigation was carried out between 21st of January and 26th of February 1984. Fifty-three light observations were made during the field investigation.

An automatic measurement station was put up in Hessdalen in August 1998.

According to the scientists, it is now clear that the phenomen is not UFO-related, but are luminous balls containing some form of energy.

"We have pictures which show the optical spectre, and can therefore determine which elements they are made of", says researcher Erling Strand of the Oestfold College.

However, he says much work remains before he is ready to give the final answer.