Implications of Closeup Video of Probable Ball Lightning

Ball lightning is an atmospheric-physics phenomenon which, while having been observed repeatedly for centuries, has so far eluded a satisfying explanation.  It appears as a spherical object typically 300-400 mm in diameter with the brightness of a domestic incandescent lamp, and lasts on the order of seconds before vanishing or occasionally exploding.  While it typically occurs in the vicinity of thunderstorms, its connection to conventional lightning is unclear.  It can appear inside closed rooms and metal-skin aircraft, and has been seen to pass through closed glass windows.  Until recently, most of what we know about ball lightning has been limited to eyewitness reports from individuals who see it by chance.  However, the increasing use of security cameras and smartphones has increased the likelihood that ball lightning will produce objective video records which can be analyzed.

 

            We present a video recorded in August of 2023 which shows objects that are probably ball lightning less than six meters distant from the camera.  The objects were in direct or indirect view for approximately two seconds, and the video includes the terminal phase of their existence as they collided with the ground.  Computer-vision analysis of the video has provided quantitative data on the objects' velocity, size, and absolute brightness, all of which are consistent with typical data reported by eyewitnesses in similar events.  The four objects moved at similar trajectories at a rate of about 2.5 m s^-1 until colliding with a grass-covered lawn, whereupon the two larger objects retained a hemispherical shape and changed into bright illuminated patches which faded over a time of about 300 ms.  The emitted optical power of the larger objects was estimated to be 300-600 mW, which is the brightness of a low-power incandescent lamp.  Implications for current theories of ball lightning will be presented at the conference.