On the sun, what you can't see can fry you. The sun rotates so slowly that it takes about a month to complete one turn, meaning that activity on its farside is hidden for up to two weeks at a time. If a giant magnetic storm is brewing on the farside, it will hit Earth with a flood of radiation as it finally rotates into view. That happened in 2003, when the unexpected blast knocked out communications satellites and interfered with airplane navigation systems. Now scientists using NASA's Solar and Heliospheric Observatory (SOHO) satellite can peer right through the sun and anticipate such storms well before they hit.
The secret is learning to "see" the sun in sound, says Phil Scherrer of Stanford University. Every second about 7,000 California-size bubbles of hot plasma rise to the surface of the sun and pop, creating a cacophony of sound waves. As the ...
