The reporting of the activity surrounding the tragic loss of Columbia continues to anger me (“After the Tragedy,” SN: 9/27/03, p. 203: After the Tragedy). Columbia was lost because of program ignorance of a flight condition that should not have been permitted to exist or continue. It is a cruel and self-serving action to criticize a wonderful piece of engineering because its operators have been deficient.
Garden Grove, Calif.
“The U.S. has lost 17 astronauts in space accidents . . . 17 years apart,” according to the article. During that same period, we killed 714,000 people in traffic crashes, yet no scientists have demanded that we ground all automobiles.
Robert N. Rader
Moore Haven, Fla.
Right on time
In the era before global positioning system (GPS) instruments, determining longitude was difficult since it required a fairly accurate clock, in addition to a sextant (“North vs. Northwest: Lewis and Clark diaries provide directional clue,” SN: 10/4/03, p. 213: North vs. Northwest: Lewis and Clark diaries provide directional clue). I was under the impression that one of the clocks Lewis and Clark used was Jupiter’s moon Io, which would have made them pretty sophisticated navigators.
Michael D. Delano
The explorers had a good chronometer, but researcher Robert E. Criss says that not much more is known about it because it was auctioned off after the trip. He didn’t find any mention in the party’s diaries of Jupiter’s moon, but the team did rely on Earth’s moon for some measurements.–K. Ramsayer
The article on waning glaciers (“On Thinning Ice,” SN: 10/4/03, p. 215: On Thinning Ice) states that a loss of 100,000 cubic kilometers of ice would result in a half-meter rise in sea level. That means that if the 32 million km3 polar ice pack melts, sea levels will rise 160 meters. But I have always heard a figure of around 50 feet. Being on a small island in the South Pacific makes the matter less than academic.
D. Eric Hanson
American Samoa Community College
Pago Pago, American Samoa
In fact, researcher Roger B. Barry says that global sea level would rise closer to a quarter of a meter if all the world’s glaciers were to melt, and 70 meters (250 feet) if Greenland and Antarctica went, too.–S. Perkins
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