Documents / Document
This is Volume 2 of the Ministry of Defence report 'Unidentified Aerial Phenomena in the UK Air Defence Region', Defence Intelligence Staff Scientific and Technical Memorandum 55/2/00, dated February 2000 and received 7 December 2000. It gathers 25 working papers on natural and man-made phenomena, meant as a reference for analysing UAP reports. The papers cover ball lightning, radar detection, balloons, satellites, mirages, plasma and similar subjects. One paper compares magnetic field experiments on human volunteers with close encounter reports. It concludes that effects from such fields are 'uncannily similar' to what witnesses describe.
“Sea”13 pages
# UNCLASSIFIED
UK RESTRICTED
'rod-shaped' systems have been seen, and also hollow' spheres.
8. Ball dimension reported vary from a few centimetres to 12-15m in diameter. Some examples had ball diameters of 22cm (inside eastern Airlines Aircraft, 30cm, 50cm, 60cm, 8.5m, 12.8m, and a 38cm (rod). A summary of the scientific factors which control plasma sizing is at paragraph 30, below. Optical illusion effects can clearly change the perception of size. It is important to note that an increase of light intensity can be perceived as an increase/change in size or shape. The balls are sometimes hazy in outline and may not be truly spherical (when not one of the other shapes).
9. Within the bounds of the shapes, described above, there appear to be three structural types:
(a) Balls with a solid appearance with a dull or reflecting surface, or with a solid core in a translucent envelope often 30-50cm in diameter).
(b) A rotating structure.
(c) A burning appearance (often <40cm diameter).
Reports suggest that single balls can break up into smaller ones (or disperse - see para. 12 below).
## MOTION
10. The motion attributes reported are firstly direction/profile, where the phenomena is reported as moving in one or more of the following directions or types of movement:
Cloud-to-cloud
Earth-to-cloud
Cloud-to-earth
- In a horizontal path (55% of occasions and usually of the 'burning' type)
- Climbing and bouncing/rebounding
- Changing course
Movement opposite to wind direction
- Very rapidly point to point (jumping or darting)
- Attracted to enclosures (e.g. indoors/in vehicles/aircraft)
- Rolling (on earth's surface, wet or dry)
- Emerge from Lake
- Turning sharply/abruptly
- Executing parabolic curves
- Spinning or spiralling
- Floating
- Motionless/hovering
- Diving (at high speed)
- Apparently moving at windspeed
- Jumping (to a few metres in height)
- Darting to a conductor (especially water, fences etc.)
- Attaching (to an object) or 'pushing' at an object
- Detracting (and floating away from an object)
- In complex trajectory (20% of reports)
- Vortex-associated
- Float ('squeeze') through a small hole and then expand to a large ball-shape.
11. Velocity Secondly the ball lightning often has velocity in one or more of the following categories.
- Often low velocity (including zero)
- Estimated 100-1200ms $ ^{-1}. $
Frequently the speed is reported (when near the ground) as that of a man walking or running. The spiral or rotational form, which is often vortex-associated, appears to take the form of a hydrodynamic or plasma vortex.
## SOUNDS
12. Many sightings have been made when the ball makes no sound, while others have:
- Hissed (hence confusion with St. Elmo's fire) Document, cited by the archive. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 258 pages are in the text index: search them above, or from the library's search.