Scientists are using helioseismology to study sound waves from the interior of the sun to help understand the activity that occurs at the center of the sun. See
for more information. And I was pleased to just have fun during the last (locally viewable) eclipse watching the shadow move across the face of the sun, by wearing welder's glasses. I'm not sure they were actually safe, but I felt no afteraffects. The best advice though, is to never look at the sun--the article above may prove that true with new meaning.