Why does collapsing a bubble with a sound wave produce light?
16 comments
·October 16, 2025tobr
Holy hypertext, this is a hard-to-read post.
dfedbeef
Internet 5.0, every word is a link. Scrolling is done with your brain, clicking is done with by flexing your nostrils
lloydatkinson
I sometimes wonder what people are thinking (or apparently not thinking) when they link to their personal sites and blogs and it's totally unreadable. I think they are so used to it they don't see any problems with it.
defanor
It looks a bit messy to me, neglecting usage of hyperlinks, but at the same time highly legible (does not mess with fonts, colors, or the layout too much), lightweight, works without JS, does not geo-block me or require to solve captchas, not paywalled, not blocked here, is straight to the point. So perhaps still more easily readable than most of the other submissions found on the HN front page.
sophrosyne42
> 1. How do you extract energy out of it? It's surrounded in a water bath that would evaporate leading to cessation of bubble formation.
Sounds like a perfect use-case for the tried and true steam turbine. You can never beat a steam turbine.
sodaclean
Sonoluminescence is not power positive. Fusion would be trivial to prove with a neutron detector- so saying "theres debate" is arguably dishonest.
Sonoluminescence is weird and awesome enough as is: cavitation that produces light.
akshatjiwan
Researchers have reported neutron detection but these results have not been reproduced and some scientists have attributed this detection to 'noise'. Bubbles are tiny they have very small amount of gas in them so detecting that is not exactly straightforward... I think
for example a in a 1um radius bubble the total mass of gas would be ~ 10^-18kg.
Personally I doubt fusion occurs inside bubbles. Even if we take the highest reported temp 30000K that's way below what's required for fusion.
Also bubble literature is full of fantastic claims—one that comes to mind is assertion that pressures of around 10Gpa can be generated which seems highly improbable because that's likely to induce phase change in the fluid.
However it's quite possible that I'm wrong. Because bubble science keeps on throwing new surprises.
sandworm101
Steam is the medium, not a fuel. Low-temp steam just above the boiling point doesnt carry much energy. It would also be very wet, which plays havoc with mechanical systems. I dont see how this tech could ever produce the hot/dry steam needed for turbines.
close04
Collect it directly at the audio jack and skip the water-bubble-light chain entirely. You won’t get out more than the energy of the sound wave you put in, you’ll get quite a bit less actually.
docfort
This was a passion of mine decades ago, but Putterman's lab jump-started interest after the cold fusion debacles. Some fun videos and pictures on the lab website. https://acoustics-research.physics.ucla.edu/sonoluminescence...
HPsquared
I suppose it would also produce nitrogen oxides.
akshatjiwan
Very likely. The hot plasma generated would form oxides when it's cooled. I read a few papers a while back focussed around generating ammonia and other nitrogenous compounds. I can't find the link to the one I read but apparently other researchers are doing something simillar
https://arxiv.org/html/2505.23850v1
In air bubbles NOx would be likely but it would probably lead to nitric acid production after reacting with water. Here's a paper by NASA that pretty much confirms your intuition
https://ntrs.nasa.gov/api/citations/20050215681/downloads/20...
_tk_
What?
A lot of work goes into minimizing cavitation in marine systems as it tends to waste energy and cause damage to propellers. That being said, there has been a lot of research lately into using sustained cavitation to purify and distil water. The energy released can be enough to boil water, kill pathogens, and generate free radicals to further sterilize the water.
https://iwaponline.com/wst/article/86/2/302/89569/Hydrodynam...