Erratum
The article "American Physical Society panel gives a long-term yes to electricity from the sun" (News and Comment, 16 Feb., p. 629) contains an error in the fourth paragraph. The first sentence in the paragraph should read: "Ehrenreich portrayed the future of solar cells as bright, calling attention to a decrease in their costs by a factor of 5 in the past 5 years and citing the prospects for further advances."