Letters

Rise and fall of sea level

If the collapse of the West Antarctic ice cap would raise sea level by 6 meters, and if such a collapse happened less than 750,000 years ago ("Signs of unstable ice in Antarctica," SN: 7/11/98, p. 31), shouldn't there be evidence of that rise somewhere else, in addition to the diatoms and beryllium atoms under the present ice cap?

Clark Waite
Descanso, Calif.

During the peak of the last ice age, sea levels dropped by more than 100 meters. With such large fluctuations, the records are not capable of resolving whether the West Antarctic ice sheet collapsed. —R. Monastersky

Blocking confusion over sunscreens

The average lay person reading the article "Melanoma Madness" (SN: 6/6/98, p. 360) is left confused and concerned about whether he or she is getting the protection expected from sunscreens. With such controversy within the medical community, people are left not knowing if they are putting themselves at risk of developing skin cancer. Consequently, the manufacturers of sunscreens may begin to suffer if people start losing faith in their product.

James Congelosi
Long Island City, N.Y.

Yes, it is confusing, but the medical community is not currently in disagreement about whether people should wear sunscreens, despite the gaps in knowledge. Sunscreens do prevent sunburn. The American College of Preventive Medicine recommends that to reduce risk of skin cancers, people stay in the shade and wear protective clothing. —C. Wu and K. Fackelmann

Wind chimes

In the article, "Ringing Earth's Bell" (SN: 7/4/98, p. 12), global winds were identified as a possible cause of low-level reverberations observed in studies of Earth's so-called free oscillations.

A contributor toward this effect might be prevailing westerlies (in the Northern Hemisphere) as they flow over mountain ranges. The leeward side of the mountains might be lifted much in the same way that an aircraft wing is lifted where the trailing wing surface experiences a reduction in air pressure.

William Britton
Bayville, N.Y.

Looking to the blind

The article "Timely Surprises" (SN: 7/11/98, p. 24) prompts me to ask, do blind people get jet lag? What does Ray Charles do when he travels? It seems to me that a lot could be answered about eyesight versus skin light by testing blind people.

Val Garon
Prairieville, La.

There are indeed researchers studying the circadian rhythms of blind people. Despite a complete lack of visual perception, some blind people do have biological clocks that somehow respond to light, and thus they suffer jet lag. Others have free-running clocks that ignore day-night cycles. —J. Travis

 

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