Page:Scientific Monthly, volume 14.djvu/305
THE PROGRESS OF SCIENCE[1]
ECLIPSES AND THE EINSTEIN THEORY
Einstein will be the moving spirit behind two expeditions that will spend six months or more traveling to Australia this year to have the opportunity of observing the eclipsed sun for six minutes.
May 29, 1919, when the moon last obscured the whole of the sun, photographs taken by British astronomers off the west coast of Africa and in northern Brazil showed a shift of the images of stars that has, in less than three years, shifted the thoughts of even unscientific people to the Einstein theory of relativity. September 20 of this year is the date on which Einstein's theory can again be put to the test of actual observa tion.
In an arid country, whose principal vegetation is a prickly plant that will penetrate even fairly thick leggings, a party of American astronomers, headed by Professor W. W. Campbell, director of the Lick Observatory, will set up an observatory. This site will be in northwestern Australia on a desolate coast, but to compensate for the bleakness of the place and hardship of the journey there, it is expected that the American astronomers will have the clearest skies through which to photograph the stars visible due to the eclipse. An Australian warship will carry the party from Sydney to the temporary observatory site. Close at hand there is a telegraph station, Wollal, which will keep the expedition in touch with the outside world.
But the British, whose expeditions secured the photographs of the 1919 eclipse, are going to compete with the Americans in observing. South of Java, 250 miles, on Christmas Island, they will erect their telescope, and they, too, are hoping for fair weather, with cloudless skies, so that they will settle to the satisfaction of all physicists and astronomers whether or not the sun attracts the star light passing by it.
If chance and the elements do not cooperate with the astronomers this fall, it will mean only a postponement of the day of judgment for Einstein's theory. There are more total solar eclipses coming. Including the one this year, there are three in the next three years.
Nearly a year later, September 10, 1923, San Diego will be the objective of astronomical expeditions or there will be telescopes set up in western Mexico. The time that the telescopes can be in action is only about half of that of this year's eclipse, as the totality will be only three and a half minutes, at about mid-day.
The further in the future the eclipses are, the less favorable they are astronomically but the closer they come to the eastern part of the United States. On January 25, 1925, New Yorkers will see the sun extinguished shortly after it rises, and a number of large observatories will have a chance to observe a total eclipse at home without the necessity of a special expedition. The weather conditions of this eclipse are expected to be the poorest of the three.
After this time, if the evidence for or against Einstein is not sufficient, the world must wait until the next eclipse, August 31, 1932, unless by means of photographic plates, sensitized to blue light only, the powerful yellow light of the sun can be ignored
- ↑ Edited by Watson Davis, Science Service.