Web edition: November 13, 2001
PHYSICISTS STUDY EFFECTS OF STRONG WINDS ON SKYSCRAPERS
Another official government investigation is getting under way in Washington. The men involved in the new probe are studying a problem of vital concern to every city in America.
The investigators working now are scientists, and their problem is to find out whether skyscrapers—including the 10- and 20-story skyscrapers of the average American city—are safe. The government is anxious to know if giant structures give adequate protection to the thousands of people who work within their lofty walls.
One key question the probing scientists seek an answer to is this: Just what is the effect of terrific winds on skyscrapers—winds that often make the tallest buildings sway?
In charge of Uncle Sam’s investigation, the only government skyscraper probe ever attempted, is the U.S. Bureau of Standards, with a capable staff of technical experts equipped with unique new instruments.
Scientists, led by Dr. H.L. Dryden, authority on aerodynamics for the Bureau of Standards, have already launched their research program. They have acquired a miniature model of the titanic Empire State building, which is being tested under various conditions of wind velocity. A picture of the model appears on the front cover of this issue of the Science News Letter.
LATE DIVISION OF EMBRYO CAUSES DIFFERENCES IN TWINS
Conjoined twins have been regarded by scientists as unquestionably of the type in which each pair has a single origin in one egg cell or ovum—identical twins, the biologist calls them. And yet they are far from identical.
The answer to this disconcerting puzzle is given in the theory of how twins are formed propounded by Dr. H.H. Newman of the University of Chicago in a report to the American Genetic Association, published in the Journal of Heredity.
Separate identical twins are formed by the separation into two parts of an embryonic cell mass derived from a single fertilized egg cell. What would have developed into the left half of the single person doubles itself and becomes a whole person.
At a certain state in its development, the egg cell mass begins to develop a right and a left side. These are like each other, but like the mirror reflection of each other rather than an exact duplication. In the same way, your right hand is not exactly like your left, but like its image in a mirror.
If the separation that makes the twins takes place before this stage at which asymmetry develops, it is indicated by Dr. Newman’s report that the two resulting individuals are likely to be almost exact duplicates of each other—more alike than the left side of your face is like the right side.
If, however, the separation takes place after the asymmetry becomes established, the resulting twins are more likely to appear as mirror images of each other. One may be right-handed and the other left-handed. The hair of one will grow in the opposite direction from that naturally taken by the hair of the other. The finger or palm prints of the left twin are likely to be reversed.
EARTH AND SISTER PLANETS BORN WHEN STAR RAN INTO SUN
Earth and its sister planets were born when, ages ago, the sun was struck a glancing blow by a passing star, Prof. Willem de Sitter, Dutch astronomer and “universe maker,” affirmed in an address to the Washington Academy of Sciences and the Society of Sigma Xi.
An actual collision between the wandering star and the sun instead of a near approach is favored by Prof. de Sitter as the most plausible explanation of the way in which the sun obtained its whirling family of satellites. Dr. Harold Jeffreys, British scientist, suggested this collision theory of the planetary system’s origin to explain the way the sun and the planets rotate on their axes. The idea that the planets were thrown out of the body of the sun by the attraction of another celestial body passing at a very short distance dates back to 1861. Prof. De Sitter declared that the Laplacean nebular hypothesis that held sway for over a century has now yielded to the collision theory of the solar system’s origin.