I want to point out the very good work that is constantly and methodically carried out by amateur astronomers of Ricerche UAP Polesine leaded by Mr. Jerry Ercolini. Since not-a-few years they quite well equipped with optical and electromagnetic measurement instrumentation, are monitoring the area of Polesine in the southern part of region Veneto, very close to the borders with Emilia-Romagna region. During the years they have obtained many videos of anomalous luminous phenomena that, similarly to some other areas of the world, are reported recurrently in their location. Quite recently they were able to obtain a sufficiently well exposed optical spectrum. A few days ago Jerry sent to me his very well done report, where they also show – as a quite crucial comparison – the difference of the spectrum of a Chinese lantern and the spectrum of a true luminous anomaly. I asked Jerry his permission to analyze the spectrum that they obtained. He gently sent to me the original spectrum. My preliminary analysis, after calibrating the (low-resolution) pixel spectrum in wavelength using polynomial fitting (accuracy = ± 3 Å), shows that the most important spectral lines are due to Oxygen. So far, I think that the analysis is only preliminary even if line identification in my opinion should be considered “better than only tentative” in spite of the very low resolution of the spectrum.
With available time more work will be done again in order to refine my previous analysis and to attempt an identification of the remaining unidentified spectral lines (I have some suspicion that some of them might be due to atmospheric Aerosol). For spectral analysis I have used RSPEC software (wavelength calibration) and VSPEC software (line database for line identification). The spectrum has not been normalized yet to continuum (using another polynomial interpolation), and the sensitivity curve of the used camera has not yet been subtracted. At first it was just necessary to attempt a first line identification.
So far we wanted to try to see which physical process produces spectral lines. I estimate that the identification with Oxygen lines is 70% correct. That is also logical: an external ionizing cause is expected to excite atmospheric gases. But I have never seen, even if a low-resolution grating was used here, such lines so well defined (even if most of them are the result of blending of several close lines, due to the low spectral resolution used).
Spectral analysis is an extremely important procedure when we study such phenomena using the methods of astrophysics, and its importance is twofold: 1) to distinguish well-known manmade or natural light phenomena; 2) to try to ascertain the physical nature of true luminous anomaly. So far we know that an external ionizing source is suddenly triggered inside our atmosphere (especially at low heights) and this quite peculiar phenomenon (which is often passed as “UFO”) happens at specific locations in the world. Very probably the triggering cause comes from some geophysical mechanisms that are typical of the territory (piezoelectricity, triboluminescence, Radon gas emission, “natural battery mechanism” are among the most important causes). But the reason why such light balls are so almost perfectly spherically shaped (due to some plasma confinement mechanism) and characterized by relatively long duration is still a mystery. The Hessdalen lights phenomenon in Norway is prototypical of this class of phenomena.
In any fact the possibility to find atmospheric emission spectral lines in the spectra of such phenomena may allow us to calculate the temperature of the ionizing phenomenon (presumably a plasma and/or a kind of electric discharge) after measuring the intensity (equivalent width) of the lines and the density of the number of atmospheric atoms that cause the formation of spectral lines.
I think that as soon as I will be free of my present commitments I would like to visit the area during one of Jerry’s (and his friends) skywatching session to his area. If I will be lucky enough (in addition to monitoring the area using my VLF-ELF spectrometer too) I would like to obtain a spectrum of the same kind of light phenomenon using my new high-resolution Wide Field Slitless Multiplexer Spectrograph. Of course high-resolution (5 x 10^3) can allow us to obtain a much more precise identification of spectral lines, and maybe also of a possible Zeeman effect if a very strong magnetic field (as I might expect) is inside the plasma that produces such lights, maybe confining the plasma itself inside a semi spherically-shaped object.
Physical research on this kind of phenomena is going on. The important concept to be stressed here is that any type of “nocturnal light” can be analyzed using the methods of physics and astronomy. Witness reports (which sometimes might be useful to guide instrumented research and to make some statistics, when possible), if they do not bring to us precise data that can be converted into numbers, are just “fried air”. These very strange phenomena can be analyzed scientifically indeed, whatever their true nature may be. It’s time to turn page and to make so that Physical Science (and only that) enters into force here. Otherwise such phenomena (or similar ones) will be left in the hands of the irrational. But, apart from the rigor of scientific method, an open mind is absolutely necessary for this kind of investigation. Otherwise we’ll go nowhere.