Letter: Greenhouse gases
The Dale Meyer, Ph.D., column “Climate change science and politics,” needs a few corrections of his arguments about greenhouse gases warming our planet. The reddish color of sunsets and sunrises demonstrates that longer wavelength light (red) penetrates the atmosphere better than the shorter wavelength light (blue). This property from physics refutes Meyer’s claim that “gases like CO2 act to permit our sun’s short wavelength to pass through our atmosphere.” Hence, longer wavelengths of light pass through the atmosphere better than shorter wavelengths, contrary to his claim.
Since 70 percent of the earth’s surface is water, the average earth temperature is more like 20 degrees C or 68 degrees F, and not 50 degrees C or 122 degrees F, as Meyer claims. According to my reference book, “Horizons, Explaining the Universe,” the sun lit portion of the moon reaches a temperature of 266 degrees F while the dark side of the moon drops to -274 degrees F! As the moon has no atmosphere, the higher temperature is due to the slower rotation, 29.5 days (synodic) of the moon and the fact that the moon reflects (albedo) 7 percent of the radiated solar power, while the earth reflects 39 percent of the solar power. Therefore, the moon absorbs over 1.5 times the power (watts/unit are) absorbed by the earth and its atmosphere. Meyer’s claim that the earth and moon receive the same amount of energy (watt-hours) is false. Energy is power integrated over time. The slow rotation of the moon, about 1/30 of the earth, results in nearly 45 times the energy (watt-hours/unit area) received by the moon.