MAGNETIC STORMS

Bay of Plenty Times, Volume LXIV, Issue 11934, 28 January 1936, Page 1

MAGNETIC STORMS

EVERY ELEVEN YEARS CAUSED BY SUNSPOTS Sir James Jeans has been telling the English Royal Institution of the spots many times as large as the Earth which have recently been seen crossing the Sun. Sir James said that these sunspots are huge bubbles of gas rising from the centre of the Sun to its surface, where they burst and shoot off as electrically charged particles at a speed of over a million miles an hour. They hit the Earth and give rise to a magnetic storm 30 hours after the spot directly faces it. All our magnetic weather is caused by sunspots, and our ordinary weather is probably influenced by them. They vary in number from year to year, their greatest activity occurring every eleven years, a period coinciding with that of our magnetic storms.

The spots have now passed their minimum activity, and will reach their maximum in 1939. The Rings on the Trees.

Astronomers have closely studied the relation of sunspots to magnetic storms, and Mr E. W. Maunder found that they occur when a big spot is near the centre of the sun, and recur 25 days later, when the sun has completed a revolution. Some years ago Professor Douglass of Arizona University began to investigate the rings on trees for the purpose of finding out if there are any periods In which they grow at a greater rate, for when the weather Is wet and hot these rings ai-e thicker. He found that every eleventh ring is thicker than the others, many of which show evidence of years of drought. When Mr Maunder heard of these investigations he wrote to the professor, and it was found that the maximum growth of the trees coincided with the maximum years in the records of activity of sunspots. No Sunspots for 70 Years.

A remarkable discovery added confirmation to this conclusion. Professor Douglass found that from 1650 to 1725 there had been no abnormal growth in his trees, and Mr Maunder from the records kept at Greenwich was able to state that there were practically no sunspots between 1645 and 1715.

In his lecture Sir James Jeans called attention to another important piece of evidence from Africa. The height of the water in Lake Victoria rises almost exactly as sunspot activity increases, proving that every 11 years there is greater rainfall. How far these investigations will help science to fortell the weather remains to he seen.