Things are banging around in the sun, making sound waves like we have
on earth. One thing that makes a lot of noise is the material moving up
from the inside of the sun to its surface. We can't hear that noise
directly, though, because sound waves don't travel in space which is
very close to being a vacuum (sound wave need some material to travel
through). We can tell that things are vibrating on the sun by watching
motions on its surface and changes in the light it produces.
You might be interested in this web page:
The Singing Sun
http://solar-center.stanford.edu/singing/singing.html
Terry