Time to chill out?
"The Big Chill" (SN: 10/4/97, p. 220) might logically stimulate an important question in the reader's mind: When is the next ice age due to start, if past patterns are followed? Although an answer was not given, I suspect from looking at the graph that, contrary to the worries of global warming specialists, the best estimate is "Right now -- in fact, it is overdue."
Daniel J. Shanefield
I wonder if the climatologists might be missing a bigger picture. The latest round of ice ages is a relatively recent phenomenon. None of the models discussed -- variations in the angle of Earth's rotation axis, orbital precession, or variations in orbital eccentricity -- explains why Earth suddenly started experiencing ice ages a million years ago or the prolonged cooling period that apparently preceded it for some tens of millions of years.
I would think that the effects of whatever caused this global cooling and the ice ages collectively should be understood before the presumably smaller orbital effects are deemed to be the explanation.
Lawrence N. Goeller
In "An alphabet for a letter-perfect protein" (SN: 10/4/97, p. 214), the researcher compares the 20-amino-acid code for a protein with the English and Chinese languages: "If you only look at China, you may think it takes hundreds of characters to write a language. But then if you go to England, you see that you can write a perfectly good, functional language with only 26 characters."
Actually, in mainland China's simplified character system there are only seven basic brush strokes that compose a character; this is analogous to the 20-amino-acid code used for forming proteins. It is the order and position of the brush strokes that determine the actual Chinese character formed; the analogy here is to the amino acid sequence that determines the overall protein shape and function.
Thus Chinese characters are in fact a better analog to protein structure than English, further illustrating the author's point that a diverse language can be composed from a simple alphabet.
Ethan B. Gallogly
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