Sound requires a pressure wave.
Pressure waves require gas.
In principle, because interplanetary space is filled by the interplanetary medium and the solar wind at a density of a few atoms per cubic centimeters, interplanetary space can support very low frequency pressure waves. Near the surface of the Sun, and into its corona, the density of gas falls of dramatically, but you still have a medium that can support pressure waves. On can imagine that if you could record a long enough episode of these disturbances, and then play them back so that their frequency was shifted electronically into our audible range, the Sun might indeed 'roar'. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer .