Spontaneous Combustion?

[GypsyElder]

What are your Views on Spontaneous combustion, and what do you think the causes really are?


If you don't know what it is:

From Wikipedia Spontaneous human combustion (SHC) is a name used to describe cases of the burning of a living human body without an external source of ignition. There is speculation and controversy regarding SHC - some regard it as a unique and currently unexplained phenomenon, while others feel that cases described as SHC can be understood using current generally-accepted scientific principles. There are about 200 cited cases[1] worldwide over a period of around 300 years; however, most of the alleged cases are characterised by the lack of a thorough investigation, or rely heavily on hearsay and oral testimony. In many of the more recent cases, where photographic evidence is available, it is alleged that there was an external source of heat present (often cigarettes), and nothing occurred "spontaneously."]

There are many hypothesised explanations which account for the various cases of spontaneous human combustion. These generally fall into one of three groups: paranormal explanations (e.g. a ghost or alien caused it), natural explanations that credit some unknown and otherwise unobserved phenomenon (e.g. the production of abnormally concentrated gas or raised levels of blood alcohol cause spontaneous ignition), and natural explanations that involve an external source of ignition (e.g. the victim dropped a cigarette).
Objections to natural explanations usually revolve around the degree of burning of the body with respect to its surroundings. Indeed, one of the common markers of a case of SHC is that the body - or part of it - has suffered an extraordinarily large degree of burning, with surroundings or lower limbs comparatively undamaged.

Suggested explanations
Many hypotheses have attempted to explain how SHC might occur, but those which rely on current scientific understanding say that with instances mistaken for spontaneous combustion, there actually was an external source of ignition, and that the likelihood that truly spontaneous human combustion actually takes place within the body is quite low.[2]

Unverified natural phenomena
Since every human body contains varying strengths of electrical field and the human body also contains flammable gases (mainly methane in the intestines), an electrical discharge could ignite these gases.
SHC victims are sometimes described as lonely people who fall into a trance immediately before their incineration. Heymer[3] suggests that a psychosomatic process in such emotionally-distressed people can trigger off a chain reaction by freeing hydrogen and oxygen within the body and setting off a chain reaction of mitochondrial explosions. This theory has been criticised on the basis that Heymer "seems to be under the illusion that hydrogen and oxygen exist as gases in the mitochondrial cell [sic] and are thus vulnerable to ignition, which is, in fact, not the case."[4] (Mitochondria are organelles found within cells.)
Another theory suggests high-energy particles or gamma rays[1] coupled with susceptibilities in the potential victim (e.g. increased alcohol in the blood) triggers the initial reaction. This process may use no external oxygen to spread throughout the body, since it may not be an oxidation-reduction reaction. However, no reaction mechanism has been proposed, nor has a source for the high-energy particles.
The victim is an alcoholic and has been smoking while drinking or shortly after drinking a strong spirit. There are claims that this raises the blood alcohol level to a point where it ignites; however, this 'explanation' is implausible, since ethanol typically burns only if the concentration is greater than about 23%, whereas a fatally toxic level is about 1%.[5] (To reach a blood alcohol level of 20% would mean drinking many bottles of pure vodka, for example.)
A suggested possibility is that both clothing and the person are caused to burn by a discharge of static electricity. A person walking across a carpet can build up sufficient charge and voltage to create a spark. It is unlikely that this could start a clothing fire, as although the voltage can be high (several thousand volts), the stored energy is very low (typically less than a joule).
The controversial phenomenon of ball lightning has been proposed as one of the causes of spontaneous combustion.