ASTRONOMER’S DISCOVERIES

Bay of Plenty Times, Volume LXV, Issue 12390, 30 July 1937, Page 7 (Supplement)

ASTRONOMER’S DISCOVERIES

VAGARIES OF THE EARTH’S MOVEMENTS Astronomers have made several curious discoveries .lately. Dr. H. Spencer. . Jonas,, the Astronomer Royal, said in his report at Greenwich Observatory recently: The moon is moving off its calculated course. The deviation continues to increase, and is now greater than at any time since 1680. On five'days' in the year ended April 30 Big Ben was more than a second wrong. To a “Sunday Express” correspondent afterward, Dr. Spencer Jones said that the vagaries of the moon had proved that the earth was a bad timekeeper. “The day—the time the earth takes to" revolve on its own axis—is gradually lengthening,” he said. “It is due to. the fact that the friction of the seas on the ocean bed have a braking effect on the earth and slow it down.” The conclusion that the earth is a bad timekeeper upsets ideas about clocks. Astronomers are experimenting with crystal vibrations, trying to produce the perfect clock, independently of the earth. They are able to measure time within an error margin of less than a thousandth of a second a day. But they are not satisfied. Other interesting points in Dr. Spencer Jones’s report were: Sunshine in the year ending April 30 last was the smallest for 40 years. Atmospheric pollution at Greenwich was 25 per cent, worse than in the previous 12 months; and Rainfall from January 1 to April 30, 12.85 inches, had never previously been approached in Greenwich Observatory records for the same period. Big Ben does not receive automatic correction signals, but is corrected by hand. Tests by means of an ordinary radio receiver, with the Greenwich “pips” and Big Ben, showed that on 118 days the error of the clock was not greater than 2-10ths of a second. On 105 days it was between 2-10ths and a half second. And on 49 days it was from a half to one second wrong. ■ Sun-spot activity increased greatly during the year, and considerable magnetic disturbances were recorded at the Abinger Station at times, roughly corresponding to periods of maximum sun-spot intensity.