University of York | 2015 Mar 23
A chance discovery by a team of researchers, including a University of York scientist, has provided experimental evidence that stars may generate sound.
The study of fluids in motion – now known as hydrodynamics – goes back to the Egyptians, so it is not often that new discoveries are made. However when examining the interaction of an ultra-intense laser with a plasma target, the team observed something unexpected.
Scientists including Dr John Pasley, of the York Plasma Institute in the Department of Physics at York, realised that in the trillionth of a second after the laser strikes, plasma flowed rapidly from areas of high density to more stagnant regions of low density, in such a way that it created something like a traffic jam. Plasma piled up at the interface between the high and low density regions, generating a series of pressure pulses: a sound wave.
However, the sound generated was at such a high frequency that it would have left even bats and dolphins struggling! With a frequency of nearly a trillion hertz, the sound generated was not only unexpected, but was also at close to the highest frequency possible in such a material – six million times higher than that which can be heard by any mammal! ...
Terahertz Acoustics in Hot Dense Laser-Plasmas - Amitava Adak et al
- Physical Review Letters 114 115001 (20 March 2015) DOI: 10.1103/PhysRevLett.114.115001