Condign volumes 1 to 3

Read from the scan by GLM-OCR; expect the odd misread word.

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bubbles by sonic (i.e. sound air pressure) shock waves. While this can be easily reproduced under laboratory conditions under water, and the light emitted extends from IR to UV, covering the entire human eye spectrum, it is not clear whether the conditions could (perhaps exceptionally) exist in the atmosphere. If this is so, then sonoluminescence could be a candidate source for the very short UAP events (e.g. <1 second), which are frequently found when examining the UAP reports. Although it is some 60 years since the discovery of the effect little serious work on understanding and quantifying the phenomenon has been done - mainly because of lack of measurement technology.

11. The science behind the sonoluminescence effect can be summarized as:

- A very small volume must be present (appearing, for example, as a gas bubble (cavity) in water) which must contain a gas other than pure oxygen or nitrogen. However, even a 1% impurity is sufficient to invoke sonoluminescence.

- Successive rarefactions and compressions must be present for the gas to pulsate rapidly.

- The radius of the gas bubble will expand when the pressure goes negative (e.g. for a bubble in water the radius can typically change from 4 to 40 microns).

- The sudden collapse (Rayleigh 1917) reaches supersonic velocities (1.4 kilometres per second quoted), stopping only when the gas in the bubble reaches a 'hard core' minimum radius (when the molecules can get no closer together).

- Photons of several eV energy level are emitted, at which time the temperature is estimated as being in the tens of thousands of degrees K. At this point the bubble surface is reported to 'bounce', with a surface acceleration which exceeds millions of g, causing a non-linear amplification effect (focussing) of the energy

Several alternative theories are currently proposed for the micro-detail of the effect. However it is clear that flash duration depends upon, among other factors, the intensity of the emission and the gas/water mixture. The longest flashes occur with the brightest emissions. The effect is also pressure dependent.

There are close analogies with cavitation bubbles in sonar.

12. The fact that this effect can be seen by the unaided eye was perhaps first reported in the original version of EXODUS (20:18); where "and all the people saw the sounds". This was removed in later translations (presumably as being impossible!) If the sonoluminescence effect can be produced, even under exceptional conditions in the atmosphere, it may account for some UAP reports.