By Science News Staff

Web edition: November 20, 2009
Print edition: December 5, 2009; Vol.176 #12 (p. 30)

Jovian scars
Page 8 of the August 29, 2009, Science News shows a dark impact scar on Jupiter’s surface. Similar dark areas appeared when Comet Shoemaker-Levy 9 hit. Why are they dark? Clearly, we are not seeing any “subsurface dirt.” Also, the color cannot be due to some dark underlying gas. Could it be an enormous depression in the cloud cover, the bottom of which the light does not reach?
Raul Pettai, Montville, N.J.

Glenn Orton of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., responds: Hard as it is to believe when you live on a planet where the dark stuff is almost always below you and where chemical clouds only seem to exist in Pittsburgh, dark stuff is in the atmosphere at impact sites on Jupiter. The particulate debris from Comet Shoemaker-Levy 9 was dark in the visible range of the electromagnetic spectrum ... and consisted of a combination of material from the comet itself, material from the comet and Jupiter’s atmosphere mixed together chemically in the shock of the impact, and material pulled up from Jupiter’s atmosphere in the rising fireball.... In order [for the scars] to be as black as they are across the entire spectrum, [the material must have been] rich in sulfur and nitrogen. Although we did not see the 2009 July impact itself, the impact “scar” material appears to be spectroscopically indistinguishable from the Shoemaker-Levy 9 debris.

Power over pain
Regarding “‘%&*#$!’ makes you feel better” (SN: 8/1/09, p. 9), pain inevitably brings at least some sense of helplessness, adding to the pain. Anything that restores one’s sense of power can help alleviate the pain. Violating community standards by cursing may give one a sense of power. This is probably a reason cursing makes one feel better.
Henry Close, Douglasville, Ga.

Science, politics
Clyde W. Yancy’s statement (SN: 8/29/09, p. 32), “We’ve got to get health care reform through,” is an editorial. Yancy is entitled to his views, though his authority as a scientist doesn’t extend to politics. Science News is entitled to print political opinions, but reading them is not why I subscribe. I subscribe because Science News is an excellent way for a nonscientist to learn about science.
George Wiley, Baldwin City, Kan.