Sound in space is a question whose answer is both yes and no. In space, there is no sound that’s audible to humans. However, space, being an imperfect vacuum, consists of particles, namely the solar wind released by the sun, that act as a medium for sound waves. The speed of sound through the interplanetary plasma in Earth’s orbit is about 50 km or 31 miles per second.
Plasma
Through plasma, sound waves can travel at a much higher pace due to the high temperature and low density. While the speed of sound in plasma is considerable, it does not even compare with the solar wind. It has audible frequencies but due to the limited amount of plasma, cannot be heard directly. Found everywhere in the universe, plasmas can be vital in telling us information about their formation and internal properties that stars have. Astronomers are able to measure these waves through the analysis of changes in the brightness of a star, which then helps specify its age, mass, and other properties. It is interesting to note that supermassive black holes also possess the capability to generate plasma ripples. These ripples can produce actual musical notes, however, they are way too deep to be heard by humankind.
Sound Possibilities
As far as sounds that can be heard in outer space are concerned, there is potential in planets like Saturn’s moon Titan and Earth. For instance, Mars has a lower average sound speed as compared to Earth. This is because of its unique atmosphere. Studies have also been conducted on Venus and Mars, through probes with microphones that have provided valuable insights into phenomena like wind speed and the like. So, it can be safe to say that, while we may not hear them, the universe is full of vibrations and waves that produce sound. They just might not be directly perceptible to us.