We have rated the plausibility of sixteen different hypotheses on a scale of 0-5. These ratings are of course a matter of judgment based on balancing sometimes complex arguments and counterarguments. Other analysts may disagree with our ratings and conclusions. The sixteen hypotheses have been ranked as shown in the table in Fig.38.

Fig 38. Ranking of 16 hypotheses
Rating Hypothesis
very implausible
3rd/4th order rainbows
windscreen reflections
earthquake clouds
somewhat implausible
god-ray patches of sunlight on the sea
sunglitter reflections from lakes in Brittany
aircraft contrails
ship tracks
military exercise
lighter-than air vehicles
barely plausible
sunglitter reflections from the sea off Brittany
direct specular reflections from Guernsey glasshouses
lenticular clouds
somewhat plausible
specular glasshouse reflections scattered from a haze layer
earthquake lights
very plausible
definite identification

We judge that "very plausible" (Band 4) would count as a successful explanation for all practical purposes. Notably, Bands 4 and 5 are empty. That Band 5 is empty is not so surprising, but we might have hoped for something in Band 4.

Two theories stand out by making it to Band 3. Both of these have significant problems keeping them out of band 4. The rating "somewhat plausible" as applied to these two Band 3 theories (specular sun reflections on the haze layer from Guernsey greenhouse glass, and earthquake lights) means that they are attractive in terms of some significant features of the observations, but are still counterindicated by some other significant features. We regard a "significant" feature as one which we ought to require a good reason to discount.

In summary, we are unable to explain the UAP sightings satisfactorily without either a) discounting at least some significant features of the reports, or b) doing violence to at least some conventional meteorological optics or conventional EQL phenomenology. We hope that readers of this report will find it helpful in deciding which (if either) of those courses of action seems the more reasonable and economical.