THE AGE OF THE EARTH.

Lake Wakatip Mail, Issue 4015, 1 September 1931, Page 1

THE AGE OF THE EARTH.

“The age of the earth is at least 2,000,000,000 years, according to a committee of scientists appointed by the National Research Council, who have been investigating the problem for the past four years, writes .Mr Watson Davis, managing editor of Science Service in “Current Mister v.”

'The radioactive minerals uranium and thorium, which spontaneously disintegrate niio lead. gi\e the best clue to the earth's ago. by eaieinlly analysing the radioactive minerals and their products in a sample of rock, it is possible to tell how long it has been in existence.

"Ibe oldest rock in the world, whose age lias been determined in this way, is a piece of uianinite or uranium bearing rock hom Sinvava Rain, Carelia, Russia. It is 1.852,000,000 years old, and, as it occurs in rocks that were intruded into the sin rounding rocks, which, therefore, must lie older, the scientists conclude that the age of the earth must be in round numbers at least 2,000,000.000 years. Estimates of the age of the earth have been multiplied by more than twenty during the last three decades. "The old idea that the amount of salt in the ocean is an index of the earth’s age was found by the National Research Council committee to be unreliable, as only 100,000.000 years can be accounted for by lids method. At the turn of the century this was a favourite figure for the earth’s age. “Professor Alois F. Kovarik, Yale physicist, and Professor Arthur Holmes, geologist, of Durham University, England, have explained the methods of age determination. They are based on the fact that the radioactive elements uranium and thorium disintegrate spontaneously ai constant, deteiminable rates and yield load whose atomic weight varies according' to the proportion contributed bv its radioactive patents. ?

“Professor diaries Scliucliert, of Yale, compared the radii active ago lesults with evidence from the thickness of layers of the catlh. Piofoss r E, \V. Brown, Vale astionomei, concluded that while (hero are no known astivimmical methods, the 2,000,000.000 year ago is consistent with astronomical probabilities.”