The recovery slowed in 2010 and again in 2011, as the dips in the red line show.
By knowing how big the star really is, and the dips in light from the planetary crossings, astronomers can measure the exact size of any planet.
The game does not account for the dips in renewable supply that occur at night or on still or cloudy days.
"As people chose to buy the dips in Apple, I think that gave people a little bit more conviction to buy other names," said Michael James, senior trader at Wedbush Morgan in Los Angeles.
NASA's Kepler spacecraft, to be launched in 2007, will look for the dips in starlight caused by planets passing in front of their parent stars, and could find "hundreds of Earths," said Dr. Charles Beichman of NASA's Jet Propulsion Laboratory.
Across the retail business, sales have slowed with the dips in the economy, and surfwear has another worry: how long the trend can last in a world of constantly shifting style, led by notoriously fickle teenagers.
