nature · Partially resolved
Ball Lightning
Witnesses across centuries describe the same thing: a glowing sphere, sometimes the size of a grapefruit, drifting silently through the air during a thunderstorm before vanishing or exploding. It moves at walking pace, sometimes hovering, sometimes drifting through a room. Then, in a moment, it is simply gone, leaving nothing but the account of whoever happened to be watching.
What we know
Thousands of eyewitness accounts share strikingly consistent details — color, size, duration, a faint hissing sound. Researchers have produced short-lived glowing plasma balls in the lab that mimic some reported features.
The edge
No laboratory analogue has reproduced the full duration, mobility, and energy reported in the field, and no single mechanism explains every account. It is possible more than one distinct phenomenon is being described under one name.
Open questions
Is ball lightning one phenomenon or several conflated by folk description? Why does it appear to pass through glass and walls in some credible reports?
Sit with it
A storm can still produce something that looks like it belongs in a folktale, and modern instruments have caught only fragments of it. The sky keeps a few tricks it hasn't shown us yet.