Project Hessdalen: What the Instruments Recorded

~ Saturday, June 22, 2019 ~

In the winter of 1984, a team from Østfold University College arrived in Hessdalen with radar equipment, magnetometers, and a spectrum analyser. They were there for five weeks. In the first week they recorded fifty-three observations, several confirmed simultaneously by both visual sighting and radar return. What the instruments showed over the following decades is worth setting out carefully, because the data is more specific — and more strange — than most popular accounts suggest.

Erling Strand, who led the 1984 campaign, had been methodical about establishing baseline conditions before drawing conclusions. The first task was confirmation: were the lights physically real in the sense of being detectable by instruments that did not depend on human perception? The answer came quickly. Radar returns matched visual sightings. The lights were there.

Radar, speed, and the problem of invisibility

Radar data produced results that sit awkwardly with most natural explanations. On several occasions, a light visible to observers disappeared — and the radar echo continued for more than two hours. Whatever produced the visual phenomenon was not the only thing the instruments were tracking. Something with radar reflectivity persisted after the optical emission ended.

Movement speeds measured by radar reached eight kilometres per second in some events. The fastest reliable estimate is approximately 30,000 kilometres per hour. These figures are not errors or instrument artefacts; they are consistent across multiple measurement runs. There are also stationary hover events and slow oscillatory events. The same valley, the same geological substrate, appears to produce phenomena at very different scales of behaviour.

The spectral finding

The most important single result from Hessdalen instrumentation is the optical spectrum. The spectrum is continuous. There are no spectral lines.

This matters because spectral lines are the signature of combustion and of specific gas emissions. A burning chemical leaves a line spectrum — characteristic bright or dark lines at specific wavelengths. The Hessdalen lights produce nothing of the kind. The spectrum resembles plasma emission or stellar photospheric radiation, not combustion.

The estimated surface temperature, derived from the spectral data, is approximately 5,000 Kelvin — roughly comparable to the surface of the sun. Most of the energy is radiated in the ultraviolet range, which means the visible light is a fraction of the total output.

Chemical analysis detected hydrogen, oxygen, and nitrogen — consistent with ionised air — alongside silicon, iron, scandium, and titanium. The last four are consistent with airborne particulate matter from the valley’s ore deposits. Both components need to be explained; most theories account for one better than the other.

The laser experiment

In 1984, researchers directed a laser beam at an active light. In eight of nine attempts, the flashing frequency of the light doubled.

I want to be careful here. This result implies that the phenomenon responds to an external electromagnetic stimulus. I am not prepared to say what that means beyond the data itself. But it is not a result that any straightforward natural explanation currently accounts for, and it has not been explained away.

Later campaigns and the EMBLA project

The 1984 campaign established the infrastructure; subsequent work deepened the record. The automated measurement station installed in 1998 provides continuous monitoring. The EMBLA Project (2000–2002), a collaboration between Østfold University College and the Istituto di Radioastronomia in Bologna, added radio and radar data from Italian instrumentation. Bjørn Gitle Hauge’s 2010 paper in Acta Astronautica represents the most complete single-source summary of the spectral and radar record.

The 2024 VLF electromagnetic survey by Vargemezis and colleagues adds subsurface data: very low frequency signals indicating electrically active geological structures beneath the valley floor. This is new. It changes what we know about the substrate, without yet changing the conclusion that no unified model accounts for all the observed behaviour.

One observation for a later piece: the continuous spectrum and the rapid movement characteristics described above bear some resemblance to descriptions in historical accounts of mass light sightings in Central Europe. This is a thread I intend to follow separately. I am noting it here only because the spectral data is where the comparison has any traction.

In this series

Sources