But we know that it does happen, and Minute Physics is at hand to lay out the current theories for us.
When bubbles underwater cavitate — collapse under negative pressure — the result is a shockwave of sound like the one that mantis shrimps use to blast their prey.
That shockwave isn’t the only result though, as it’s sometimes accompanied by another release of energy in the form of a flash of light. Just what causes this flash, though, is still unclear to physicists.
It could be flammable gasses like xenon catching fire inside the bubble, or it could suggest that the incredible heat inside these collapsing bubbles may be converting other gasses to a form of superheated plasma for a fraction of a second. Also, it could be another thing that we don’t even suspect yet.
These transformations of sound into light — episodes of sonoluminescence — remain ill-understood, but leave it to the folks at Minute Physics to offer as clear a breakdown of what we do know about the phenomenon as you’re likely to find in this video.