38. Objections and responses
Does not incorporate the blur analysis of the Z-film
Perhaps the major objection to this work could be that it takes Josiah Thompson's measurements of Kennedy's motions at face value and does not deal with the recent claims that the blurred image in frame 313 hides the fact that the head did not snap forward quickly at that time. Thompson has recently supported this view, claiming that he is now convinced that his original measurements were wrong. He based his conclusions on "A Motion Blur Analysis of the Zapruder Film" by David Wimp, which appears at the time of this writing on Ron Hepler's web site (http://server3002.freeyellow.com/rhepler).
There are several reasons why this view is incorrect. It is also largely irrelevant to the calculations presented here. The first reason why it is wrong is the simplest—you can see clearly that the head did indeed snap forward. You can even see the angle of the back of Kennedy's head shift to the right. To the extent that frame 313 is blurred, it will mean that the head snapped even farther forward than the frame appears to show (and as confirmed by the calculations). The second reason is that the head had to snap forward—neutron activation analysis (NAA) of the fragments in the brain matches them to the large fragment in the front seat, and ballistics traces this fragment to Oswald's rifle. As shown in great detail in earlier sections here, the forward speed of the snap and the distance traveled can be easily estimated from the mass of the bullet and its entrance and exit velocities, and they are completely consistent with the measurements. If anything, they exceed the measurements. It all fits into a coherent picture that cannot be denied.
Most importantly, however, the motions around frame 313 do not have to be known precisely because the calculations of the lurch essentially skip over them—they predict the velocity of the lurch after the snap is finished and do not use the values of the snap in that calculation. A clear speed of -0.8 ft s-1 can be seen in 314–315, quite independent of anything that happened in 312–314. So the conclusions of this work remain valid no matter what one thinks of the snap's existence or nonexistence.
Expanded discussion of the noneffect of blurring
Assumes that the Z-film is genuine
Obviously, this work assumes that the Zapruder film is genuine. It is ludicrous to think that it is anything else. Thompson has effectively destroyed the myth of alteration in a brilliant essay that is posted here.
Accepts the NAA uncritically
This monograph accepts the neutron activation data on the lead fragments only after the exhaustive analysis that appears elsewhere on this web site.
Accepts the other physical evidence uncritically
The basic physical evidence in this case is not accepted uncritically. On the contrary, it has been examined carefully and repeatedly and found to be self-consistent and multiply redundant. The simple, direct picture provided by this evidence has been challenged many times, but never successfully, nor has an alternate picture ever been successfully provided.
Does not provide a standard for accepting or rejecting physical evidence
It is true that this monograph does not provide a codified procedure for validating physical evidence. Instead, it validates by example. I hope to formalize these procedures in the near future.
Low mass of head
There may be a conflict between the lighter heads that these calculations support (5–7 lb) and the classical heads that are usually quoted (more like 10 lb, or even 15). Does this mean there is something wrong with these calculations? Not necessarily, although the difference remains unresolved at the time of this writing (late February 2003). Since the constraints on the head come from speeds of the snap (Section 25), one might expect that the values for the lurch derived from scenarios 6 and 7, which incorporate the snap, would differ from the earlier scenarios, which did not. But this is not the case—both the linear and angular versions of scenario 6 give the same answers as the corresponding scenarios 3–5 (all of which use the same default values and solve for vlurch and vcloud). It appears, for reasons unknown, that the effective mhead is really 5–7 lb, and maybe 8 as well.
One could suggest that the entire procedure used here of solving the two simultaneous equations contains a built-in circularity in that the answer will balance only the components that one includes, and thereby give an artificial sense of closure. But this is not quite true. All reasonable components were included, even a second bullet. The answers showed that the system could not be properly balanced under certain conditions.
Tony Marsh has suggested on the newsgroup alt.conspiracy.jfk that it would be helpful to consider how an exploding bullet (such as claimed by James Files) would affect these calculations and conclusions. He noted that "when Velex was producing them, they found that the energy deposited was about double the standard bullet." At first glance, one might think that an exploding bullet would wreck the calculations because there would be no way to know how much energy was deposited or how its fragments flew out. But further reflection shows that the picture is not this bad, and probably is tractable, because the Zapruder record shows what happened, whether the head exploded from a normal bullet or from an exploding one. The effects of either kind of bullet are built into the cloud and large fragments that we see in the film and can understand with physics. Thus it becomes more a question of naming the cause (exploding bullet or regular bullet) than of dealing with it. The analysis here stands.
Furthermore, there were no physical traces of an exploding bullet, either physically or chemically. Without them we are not allowed to invoke one.
Ahead to Future Work
Back to Unification of the Physical Evidence
Back to Physics of the Head Shot