Letters to the editor

Wet Earth
Erin Wayman’s article “Faint young sun” (SN: 5/4/13, p. 30), about how the early Earth stayed warm enough for liquid water, made me wonder about the effect of the temperature of the planet itself. A hotter core, thinner crust, more volcanism — wouldn’t those factors in addition to atmospheric influences affect surface temperature?
Virginia Bruce, via e-mail

“For the present-day climate, internal heat provides only 0.02 percent of the energy input to the climate system,” says Georg Feulner of Germany’s Potsdam Institute for Climate Impact Research. Scientists estimate that heat flow 3.8 billion years ago was three times as high as today, still negligible compared with energy from the sun. — Erin Wayman

Planet search
Kudos to Eva Emerson for her editorial “Discoveries help reveal our place in the universe” (SN: 5/18/13, p. 2). She clearly defines the challenges in identifying a “true” Earthlike planet with current technologies. Too often, articles make claims on the distribution of hot Jupiters and Earthlike planets without considering the prejudicial nature of sampling techniques. This is why I have read Science News for over 20 years.
Robert Powell, Austin, Texas

Richard Marshall and Earl Kooi manipulated the chemical structure of cornstarch at the Corn Products Refining Company, not the Corn Projects Refining Company as misstated in “Sweet confusion” (SN: 6/1/13, p. 22).