Automated sensors recording unexplained lights show temperature changes and electromagnetic signatures inconsistent with known phenomena. Data continues to accumulate.
A Valley of Unexplained Lights
In the Hessdalen valley, a 12-kilometer stretch of rural central Norway, luminous orbs of unknown origin appear in the sky. These lights, observed both day and night, manifest as bright white, yellow, or red phenomena. Their behavior is erratic; some move with incredible speed, others sway slowly, and many hover for over an hour.
Reports of these strange lights date back to at least the 1930s. The frequency of sightings peaked dramatically between December 1981 and mid-1984, when residents and tourists reported 15 to 20 events per week. This surge in activity prompted a formal scientific inquiry. In the summer of 1983, Project Hessdalen was established to investigate the phenomena. An initial field study in early 1984 documented 53 separate light observations. Although the frequency has since decreased to about 10-20 sightings annually, the mystery remains.
The Automatic Measurement Station
To gather continuous data on these unpredictable events, the Hessdalen Automatic Measurement Station (AMS) was established in August 1998. Often called the "Blue Box," this automated observatory is equipped with an array of sensors to record the lights and their environmental context. The station includes multiple cameras (black-and-white, color, and CCD), a magnetometer to measure magnetic field fluctuations, and radio receivers for detecting electromagnetic signals, including very low frequency (VLF) emissions.
The station's data reveals events that are hard to explain. The lights have been recorded on radar, showing they are physical targets, yet they often appear invisible to the naked eye or cameras. During one observation, a light reacted to a laser beam by doubling its flashing frequency. Radar tracking has clocked some phenomena moving at speeds up to 30,000 km/h. Spectroscopic analysis of the light has detected elements including silicon, iron, titanium, and scandium, a rare-earth element found in the local geology. Hypotheses for the lights' origin range from piezoelectricity generated by quartz in the rocks to natural plasma formations or the combustion of scandium-rich dust, but no single theory accounts for all the observed data.
💡Fun Facts
During the peak activity in the early 1980s, witnesses reported up to 20 distinct light sightings per week.
The fastest phenomenon recorded by radar was traveling at an estimated 30,000 km/h.
In one documented instance, researchers pointed a laser at a flashing light, which responded by doubling its flash rate until the laser was turned off.
The station's instruments have detected objects on radar that were simultaneously invisible to optical cameras.
The Hessdalen valley is a natural area and is always accessible. The Automatic Measurement Station is a research facility and not open to the public, but its data is often shared online.
Admission
Free to visit the valley.
Accessibility
The area is a rural mountain valley with varied terrain. Viewing points may be accessible by road, but the landscape can be rugged.