Voreppe luminous disc
A French physicist driving near Grenoble saw a disc brighter than the full Moon, also reported along a 250 km line from Clermont-Ferrand.
1976 CE · 45.30, 5.64 · status: unexplained
The account
On 5 November 1976 the scientist, identified as 'Dr S.', watched the slightly flattened disc move between mountains, which let him bracket its distance at 9–36 km. GEPAN, then newly formed, used the case as an example of a well-reported sighting.
The sceptical view
A bright bolide crossing the region could account for widely separated sightings, though the reported slow movement does not fit well.
The researched reading
A physicist saw a brilliant disc that he could place between mountains. A bolide or re-entry is possible, but the slow motion keeps the case open.
| Explanation | Weight | Why |
|---|---|---|
| Something known, misidentified | 36% | A disc brighter than the full Moon seen over a long distance is the signature of a bolide or a re-entering rocket body; the reported slow movement fits a re-entry better than a meteor. |
| Genuinely anomalous | 32% | A scientist bracketed its distance between mountains and others reported it elsewhere; GEPAN used it as an example of a well-reported unexplained case. |
| A poorly understood natural phenomenon | 10% | A luminous atmospheric plasma has been suggested for some bright, slow lights, without supporting data here. |
| Secret human technology | 8% | Military aircraft or test devices over the Alps are possible but would not be brighter than the Moon. |
| A known natural phenomenon | 6% | Moonlit cloud or a lenticular cloud lit from below is possible but would not be brighter than the Moon. |
| Perception, memory or mind | 6% | A trained physicist driving is a careful observer, but distance brackets from mountains rest on judgment. |
| A hoax or fabrication | 2% | No sign of invention. |
Official position: The case was investigated (initially by the gendarmerie) and cited by GEPAN as a well-reported sighting; no explanation was given.