A supernova would sound like 10 octillion two-megaton nuclear bombs exploding.A supernova, however, just might be the most brutal concert in the universe. When a star explodes, the massive detonation expels stellar material far into space, and that matter could theoretically provide a medium through which sound vibrations might travel. Assuming you survived the blast—the initial shock wave would travel up to 20,000 miles per second and carry 1044 joules of energy—it would sound like "10 octillion two-megaton thermonuclear devices detonated simultaneously," says Charles Liu, an astrophysicist at the City University of New York College of Staten Island. "When those guts hit your eardrums, you'll hear it. That is, as long as your eardrums stay attached."