From: J. Maynard Gelinas <j.maynard.gelinas.nul> Date: Wed, 5 Jun 2013 17:11:18 +0800 Archived: Wed, 05 Jun 2013 17:20:43 -0400 Subject: Sturrock/Vallee Sidereal Time Debate Peter Sturrock, Professor Emeritus of Physics at Stanford, wrote an interesting paper statistically comparing just under 12,000 UFO events collected in the Hatch "U" UFO database to Sidereal Time. This paper was published in 2004 by the Society for Scientific Exploration and is available here: http://www.scientificexploration.org/journal/jse_18_3_sturrock.pdf To explain, Sidereal Time is a unified means for astronomers across the world rationalize the Earth's daily rotation and yearly orbit in relation to astronomical objects like stars. This way, the astronomical community knows they are discussing the same objects on disparate calendar days and times across the globe. Here's Wikipedia, which is much more detailed: http://en.wikipedia.org/wiki/Sidereal_time Sturrock stated that his intent was to expand upon previous work done by Claude Poher and Jacques Vallee in the 1970s, which had apparently shown a correlation to Sidereal Time using smaller datasets. The importance of which, as Vallee noted in rebuttal paper, is:. "If UFO sightings tended to occur at a particular value of the local sidereal time this might mean that a specific celestial source was involved in the phenomenon. Therefore searches for extraterrestrial signals (such as SETI) might be conducted in the part of the sky in question." (Pg 1 of the Vallee rebuttal paper) Just a point of opinion, Sturrock's statistical work is very rigorous, showing what a trained scientist with good analytic skills can do with a large dataset. But the paper is a bear to read. Comprising eight sections in the paper, he uses a range of methods to slice up the data. He finally concludes in section four a significant correlation to Sidereal Time. I'll break this post down into two sections, a discussion on Sturrock's paper and then Valle's rebuttal. Sturrock Paper: The Hatch data is broken up into four blocks, taken from 1892 through to 1999. These are: 1892 to 1957; 1957 to 1973; 1973 to 1982; 1982 to 1999. His histograms reflect this breakdown by using four blocks per period analyzed. He starts by breaking down the data into number of events for year (fig 2) and total events per year (fig 3). Fig 2 is particularly interesting as it shows a dramatic increase right in per-year sightings around the mid-1940s. Why is this? I think most would probably argue it was due to media saturation regarding the Kenneth Arnold sighting in 1947. (And it should be noted that Vallee threw out all the pre-1947 data in his rebuttal). Sturrock then breaks the data down into day of week (figs 4 and 5) which show little correlation to UFO reports, the curve fitting perfectly within standard deviation blocks. But in Fig 6, time of day, we see a HUGE curve below and above mean, indicating significant positive activity between 8pm - 11pm and dead time from about 3am to 8pm. EXCEPT for block A (1892-1957), which is still at or below mean but which shows a spike in activity from about 10am through to 7pm. His mean and standard deviation graph in Fig 7 shows that this result is significant and not just a statistical artifact. He then performed an 'hour of year' analysis (fig 8), which broke up events into approx 15 day increments for 24 segments a year. This showed an interesting peak across all blocks from between Jul through Nov, except for block A (1892-1957), which also showed significant spikes from around May to Jul). Then he broke it down to by mean to standard deviation (Figs 9). Note though that Standard Deviation is all over the place. The peaks are significant, but the margin of error is high in some cases. The power spectrum graph in Fig 10 is important. There are two peaks, one at .42 which goes to a count of 308, and one at 1, which goes to a count of 297. He ignores the peak at .42 and focuses on the peak at 1y. This result shows that the amplitude of spikes every year is very high in relation to events across a five year span. That is, the probability of events peaks EVERY YEAR, not every two years or every three years or every five years. Now we get to Section 4, which contains the primary argument for correlation to Sidereal Time. "We know that if the frame rotates with respect to the Earth with a one-day rotation period, there is a very strong modulation, shown in Figures 6 and 7." Figs 6 and 7 are the Time of Day correlations. Those are known to spike at between 8pm and 11pm. "If it were to turn out that many events are due to observations of the planet Jupiter, then one would expect to find a significant pattern in terms of a frame that has the same mean rotation rate that Jupiter has with respect to the Earth." What this means is that the frequency of events happening yearly during peak months is at a very high amplitude every year relative to a scale from 0 to 5 years. Sturrock wants to know If UFO reports were due to a planetary occurrence like Jupiter intersecting that patch of the sky (a celestial misidentification). So he decided to compare synodic period to local sidereal time period. See this Wikipedia entry on orbital periods: http://en.wikipedia.org/wiki/Orbital_period I found this section very difficult to interpret. Please offer corrections if I've made a mistake. But, what he appears to be doing is comparing Hour of Day and Hour of Year clustering peaks for UFO reports with sidereal time to the orbital period for Jupiter. There's a good deal of math where he draws out this comparison, but fig.12 - the result - is very important. The spectral analysis on the top of the graph in fig 12 compares the amplitude of the frequency of events of Sidereal Time on the top to amplitude of the frequency for the synodic period of Jupiter. ??? (corrections please) Notice we see a peak at 1y which goes up to ~125. And at 2y going up to ~75, yet on the bottom of the graph there are no counter negative peaks shooting down to about the same amplitudes. What he's arguing is that if the positive peak is high and the negative peak (Jupiter) is not symmetrical in amplitude, it rules out a synodic period correlation. (if I understand this right) Sturrock then computes two additional graphs in figs 13 and 14 to confirm this. Ultimately concluding: "Since the power spectrum computed from Equation 4.3 is not symmetric in positive and negative frequencies, it appears not to be due to the interplay of the HOD [Hour of Day] and HOY [Hour of Year] modulations. The asymmetry indicates that there is a modulation in terms of LST [Local Sidereal Time]." Meaning, whatever the cause of UFO reports at the same patch of the sky at the same time across the globe, it's not due to Jupiter. The rest of the paper are a series of statistical tests to confirm the result and then a final short concluding statement. Suffice it to say, his additional tests confirm the initial result found in Section 4. So now we move on to a short discussion in Section 8, the most interesting of which is the patch of sky in Local Sidereal Time he argues is the main focus of reported UFO events: "If the effect does indeed have an astronomical origin, it points to a source with right ascension in the range 21.5 Plus/Minus 1.5. Based on the analysis carried out to date, the declination is unknown." And then concluding that his analysis supports the Poher and Vallee analyses of the 1970s. "The analysis reported in this article appears to support the early findings of Poher (1973) and of Poher and Vallee (1975), which were based on independent and comparatively small catalogs." Vallee Rebuttal: In 2007, Jacques Vallee responded to Sturrock's paper. I note that Valle's work is a significantly easier paper to read and understand. http://www.ufoskeptic.org/Vallee_LST.pdf Here is his counterargument synthesized in the abstract: "While a frequency distribution indicative of a correlation with star positions was indeed detected, control with a separate catalogue compiled in France discloses an important artefact: multiple entries for a single, particularly remarkable UFO event have resulted in massively duplicated records. This calls into question the significance of the claimed pattern." The first thing Vallee does is point to a Johnson and Saunders (2002) study which used a different UFO database to determine CE2 type events against sidereal time. What's interesting here is that the Johnson-Saunders study determined a DIFFERENT sidereal time (14:00) from the Sturrock analysis. See Fig 1. Vallee then used the same Hatch "U" database as Sturrock, though a slightly newer revision. He also tossed every UFO event before 1947, arguing that they should be considered an entirely different class of events. However, he confirms the same result as Sturrock (See Fig 2) "This graph matches well with Sturrock’s published distribution. In particular it exhibits the same increase in the frequency of reported events in the range of 20 hours to 23 hours, with a noticeable peak between 21.1 and 21.5 hours of local sidereal time." (Pg. 4) But then, upon further analysis, Vallee found that one particular event (Nov 5th, 1990, in France) had many multiple witness sightings. Vallee realized that Sturrock had counted each sighting of one event as multiple events in his analysis. "Among the UFO events in the Hatch catalog for which a value of LST can be computed there are 56 entries for this single case of November 5, 1990. Such a large block of entries, occurring in such a small interval of LST values, introduces a potential distortion in the statistical correlation. ... When this duplication is removed the frequency distribution becomes that of figure 4, where the rise in frequency around 21.5 hours is less noticeable, although still present." (Pg. 5) OK. So, this means that Vallee is challenging the significance of Sturrock's finding by saying that there were duplicates in the dataset that were erroneously counted. And when Vallee performed a similar analysis with the duplicates removed, he found the same correlation, but with a much small peak of significance. Vallee then went on to perform a similar analysis using a smaller French SERPA database. He discovered a huge peak at the same time as Sturrock (21.5hrs; or 8pm to 11pm). BUT, he then factored out IFOs from the database - Identified objects - and found absolutely no correlation to the Sturrock result of sidereal time at 21.5hrs (or 8pm - 11pm) whatsoever This presumably refuted his prior work with Poher in the 1970s. But he did find a smaller statistical correlation to sidereal time in the early morning hours of between 3am to 5am. "It can be seen that the peak at about 21.5 hours disappears when identified cases are removed from the Sepra catalog. In contrast, the secondary peak between 3.2 and 5.2 hours of local sidereal time on figure 6 actually stands out more sharply on figure 7, with a maximum at 3.8 hours. This particular feature in the distribution survives not only the elimination of IFOs from the list but also a review of the individual cases for possible duplication effects or other biases. At this point we have to consider it as unexplained." So. What does all this mean? First of all, there's the question of whether the Hatch database separates out and classifies UFO events based on relevant 'strangeness' factors. Valle confirmed Sturrock's work with the Hatch database and yet challenged it with the SERPA catalog. Then Vallee seems to argue that the French SERPA catalog has better identification between identified objects and the truly strange, and that this is the result of the discrepancy between Hatch and SERPA. And, ultimately, depending on database, you get different results using the same - or similar - statistical tools. I think the ultimate result here is to challenge the utility of UFO databases for statistical work. Is that true? That is the question to the List. (and, of course, I welcome responses which correct any errors I may have made digging through these papers. Attempting to understand the Sturrock paper, in particular, was quite difficult.) -M Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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