Study Explains Supersonic Whale Calls as 2-Wave Interference Effect

1 articles · Updated · Gizmodo · Aug 20

Physical Review E findings say whale calls that seemed to outrun sound in seawater were not breaking physics; hydrophones were registering an apparent speedup in the signal’s peak.
2 sound paths created the illusion: a direct call and a surface-reflected echo interfered, shifting the strongest combined peak earlier and making the call appear supersonic to the observer.
John Spiesberger spotted the anomaly while tracking whales near Massachusetts, where hydrophones can locate animals from as far as 62 miles, but near-surface calls are more prone to this mixing effect.
The authors argue the result matches a special-relativity prediction in underwater acoustics, though they say experiments are still needed to verify it and test whether a similar effect can be reproduced with light.