In his article, 'Study of UFOs Could Advance Our Science' in the July-August issue of Integra (the journal of Intertel), Ken Wear argues that it's "pointless to argue the cause or source of (UFO) sightings. He also makes the case that whether aliens really crashed at Roswell in 1947 is immaterial, and what we should really be focussed on is gathering hard scientific evidence.
Unfortunately, Wear limits himself to only one species of evidence: "spectrographic". The problem is that this limits the phenomenon to the expectation it is a light source and not much more.
Fortunately, astronomer Peter Sturrock, in his book: The UFO Enigma: A new Review of the Physical Evidence, is not so limited in his approach.Reports of UFOs, as Sturrock indicates, can be at least subjected to statistical tests (e.g. z-test, chi-squared) to test a stated null hypothesis. (This was the approach largely used by Jacques Vallee in his "orthotenic network' approach and to a lesser extent by astronomer J. Allen Hynek in assaying sightings from Project Blue Book).
But Sturrock goes much much further, in showing how hard evidence (IF it exists) can actually be sifted, collected and produced for the scrutiny of skeptics (such as Bill Nye who appeared last month on Larry King Live - giving Stanton Friedman and other UFO theorists a hard time). The primary thrust of Sturrock is that actual physical residues and signatures are critical in terms of analysis of the phenomenon.
In terms of a scientific process of investigation, say for UFOs that leave ground traces, Peter A. Sturrock notes the following are all of use ( pp. 94-95):
“Soil has the capability of retaining the effects of several processes including mechanical, thermal, magnetic, radioactive, and physico-chemical":
i)Mechanical – A continuous or brief mechanical pressure distorts the soil, and this can be measured by a penetration instrument.
ii)Thermal – Measurement of the quantity of water in the soil as compared to other nearby control samples, allows determination of the amount of energy required to reduce the water content to that level.
iii)Magnetic: Some soils have a high magnetic remanence. In this case it is useful to examine the magnetic pattern of the soil with the help of magnetometers either in situ, or in a laboratory.
iv)Radioactivity: Soil samples can be analyzed either in situ, of in the lab using recovered samples.
v)Physico-chemical: Samples from the trace region and control samples (recovered far from trace region) can be analyzed for molecular, atomic and isotopic composition.
Even if only photographic (or video) imagery is available, numerous additional physical analyses can be applied (cf. p. 178-179):
Basic film properties:
i)Measurement of the diameter of the film’s crystals
ii)Obtaining the Modulation Transfer Curve (plot of response vs. spatial frequency)
iii)Obtaining spectral sensitivity curve (log of sensitivity vs. wavelength in nm*)
1 nm = 1 nanometer = 10^-9 m
i)Linear measurements made on an enlarged print – in tandem with elevation angles made using a surveyor’s transit of the location and objects in the vicinity (buildings, Mountains etc)
ii)Micro-densitometry scans: e.g. using the Joyce Loebl Recording Micro-densitometer to ascertain variations in optical density in the print. The result is obtained as a scan through the disc image (of the UFO for example)
iii)Black and white enlargements on different wavelength sensitive papers: Comparison between UFO (disk) images on panchromatic and blue-green paper may show features visible in one, that are not evident in the other (cf. Fig. 25-7, p. 185, with dome on disk visible on panchromatic image (a) not visible on blue-green sensitive paper (b).
iv)Computer-based contrast enhancement: e.g. digitize negatives using a scanning densitometer. Comparisons of enhancements using various filters (e.g. blue, green, orange, etc. ) show differential detail that must be accounted for. (E.g. Figs. 25-9, 25-10, and 25-11 on pages 188-89). Digital enhancements may include high-reverse contrast images of the disk itself, e.g. Fig 25-20 on page 207 of Sturrock, which discloses the left side of the particular disk is not a circular extension of the rest of disk – but is rather flattened to some unknown extent.
The upshot of the above methods and approaches, is that if one is diligent enough in approaching the evidence that does exist (whether optical, or via the medium of soil) it should be possible to satisfy even the most hard-nosed skeptic. The best approach is clearly to use the image-film and soil signals in tandem. As opposed to merely offering flickering images on film as the claimed "hard proof". (Which it will not be to folks like Nye).
In the end, there are far more avenues for investigative approach than spectrographic analysis, though that shouldn't be left out!