Thoughts on a lazy Sunday
Before snoozing off into dreamland, I read a chapter of Bill Bryson's entertaining history of science, A Short History of Nearly Everything, every evening.
This explains why, when reading a splendid review of Einstein's Clocks, Poincare's Maps in today's New York Times, I was thoroughly familiar with the story of a French longitude-measuring team that went through hell on earth trying to take precise readings in the Andes. (Beset by disease, angry natives, forbidding terrain, and foul weather for seven years, the two lead explorers refused to speak with one another for most of the expedition.) Their project had been commissioned by French polymath Jules Henri Poincare.
Poincare was immersed in measurements and maps, which led him to observe, in 1904, that distance is fixed but time is not. Time is sort of free-floating except in relation to other times. The very next year, Albert Einstein, who had been reviewing patent applications for all sorts of clocks and synchronizers, applied took this "time is relative" meme to simultaneity, which led him to conclude that time is relative to the speed of light.
From a cognitive point of view, it's interesting that neither Poincare nor Einstein came up with their insights out of thin air. If your job involves maps or clocks, it's only natural that you'd hypothesize about distance or time.
The review describes some characteristics of time in terms we can all understand (unlike most of the scientific writing on the subject):
There are as many different times as there are cultures. Some reflect changes as natural as the seasons, as arbitrary as the week or as old as the year; others, like the times of narrative, change with the life of the mind. Still others were first imagined in the fertile final years of the 19th century -- like modern industry's time clocks and time studies and the railroads' convenient longitudinal time zones.
In this one sentence, the review captures the discovery and nature of Einstein's relativity:
Time would always be relative to that speed, whatever change you used to describe it. It is, Einstein said, ''what you measure with a clock,'' but anything that can count more or less equal increments of any change is a clock too, including the earth and the stars. Change is not what you measure with time; time is what you measure with changes.
Some people have asked me why I write about so many different things on this blog. Others simply ask why.
Amigos, recording and reflecting is one way I learn things and stick them in memory. You've heard that if you really want to learn something, try teacking it to someone else? Well, you're here, aren't you?
Thanks for helping me learn more about time. And whatever else pops up today.
Posted by Jay Cross at August 17, 2003 09:59 AM | TrackBack
