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Analysis of Mechanical Traces Left Probably by Ball Lightning

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Polak W.

Advances in Science and Technology. Research Journal

2021

tom Vol. 15, no 4

182--191

A possible ball lightning (BL) incident, reported in a local TV as a thunderbolt which during heavy storm entered the room through one of windows and left it through the other, is analyzed. Precise reports, concerning the course of the incident and caused damages, were collected over the next few days in talks with seven eyewitnesses. To verify the reports, photographic documentation, pieces of the window panes, front-window meshes and other fragments of damaged objects were collected simultaneously on the scene. Reconstruction of the glass panes in the laboratory and analysis of Wallner lines existing on surfaces of radial cracks of the panes enabled to identify the direction of force causing the pane breakage. Since the forces turned out to be external for both windows, it excludes the reported movement of BL through the room. From the analysis of traces, the object which destroyed the window pane from the outside should have the following properties differing from those of an ordinary stone: it should be able to break the mesh mechanically on a small circular area, then becoming a larger and softer object be able to push the glass pane forcefully and violently. BL may be responsible for the damages if a solid-like non-hot BL core, capable to explode, is assumed. It is postulated that the BL core is composed of positively-charged crystalline nanoparticles of covalently-bonded nitrogen ions N+ and electron gas inside.

Prediction of Size of Iron Spherules Formed from Melted Micrometeoroids

100%

Polak W.

Advances in Science and Technology. Research Journal

2023

tom Vol. 17, no 6

388--393

Movement of liquid iron micrometeoroid in the Earth atmosphere is simulated to find the time-dependence of its acceleration, velocity and coordinates as well as the length of luminous trajectory when the micrometeoroid is still melted. In the simulations it is assumed that the maximum size of the stable droplet is determined by aerodynamic fragmentation of the moving droplet occurring when the Weber number exceeds its critical value. Two different initial altitudes h of droplet formation were analysed: 80 km and 50 km, both for a wide range of initial velocities between 6 and 20 km/s. Depending on their initial velocity, exceeding the Earth’s escape velocity equal 11.2 km/s, the maximum radius of solid spherules, emerging from solidified final droplet, is predicted here to lie between (a) 55 and 100 μm for h = 80 km, and (b) 10 and 30 μm for h = 50 km.