On Mars, where the air is spare - a hundred times less dense than on Earth - someone could hear you scream. But you'd have to really strain to get anyone's attention. On the Red Planet, where the wind is high-pitched and faint, even a symphony orchestra will sound as thin as cheap gruel.

Of course, Sol is a big ball of hot gas, but one that - thanks to its endlessly boiling innards - shakes and vibrates. By studying patterns on the Sun's surface, astronomers can learn much about Sol's internal construction.

Studying Sol's interior by looking for analogous patterns on its incandescent face is known as helioseismology, an active - if largely unpronounceable - research area that uses sound as a probe of our home star.

Seth Shostak Quotes