EARTH'S TEMPERATURE

Hokitika Guardian, 22 July 1931, Page 2

EARTH'S TEMPERATURE

INEXHAUSTIBLE POWER SUPPLY.

STAGGERING REDUCTIONS.

ROOM FOR MUCH INVESTIG-

ATION.

(By PROFESSOR H. 11. SHELDON.)

A friend accosted me the other day. "What,” he asked “is the temperature at the centre,of the earth?” I must confess that at the -moment I had but little idea, and, not having at hand a convenient giant to split it open for me in order that it might be measured, I have attempted to find some estimates of this temperature and data to support them. There are two sources of information that may help us. There, is the volcano which sometimes supplies us with unwanted data (at the most inopportune times, and there is temperature data taken at deep oil wells by various scientists.

"SKATING ON THIN ICE.” It would appear from all the data obtained that wo ore "skating on thin ico.” We would not have to go through more than twenty or fchiry miles to strike something deoidedly interetemgi to say the least-. Just how far we would have to go is difficult tp say. The rate of increase of temperature varies'over a considerable range. In South Dakota the temperature increases from one degree Fahrenheit in 45 feet to one in 20 feet. In other localities there i* wide divergence. At Fairmont W. Va., a temperature of 170 degrees was found in a 7500-foot well, while at Longmont, Col., a temperature of 212 was found at 6600 feet. This temperature is high enough to boil water at ordinary pressure s.

There w'as recently published in » scientific monthly an estimate of the’ temperature at the centre of the earth, based upon average figures for the rate of temperature rise in the last 1000 feet of the seven deepest wells that have been measured.' The staggering figure arrived at was 443,000 degrees Fahrenheit. AN UNBELIEVABLE TEMPERATURE. As the author points out, this is unquestionably a ridiculous figure- AYe have never had temperature measure- , m^nts.,te^ e fi,. .thipi,,tyy.oJpijps. below the surface. Taking the radius of the earth as 400 miles, that means that at our greatest depth we still had 3998 miles to go to reach the centre. It obvious that using the rate we find near the surface and assuming that it continues, is much like measuring the rate of growth of a child for the first few weeks of life and computing how big it would become by the time It had reached the 'age of eighty years. We might compute into existence a race of giants who could use our buildings m footstools.

It is also unlikely that the temperature of the interior of the earth would be greater than that of the sun, which is about 11,000 degrees Fahrenheit. On the other hand, this is the outside and not the inside temperature of the sun. The latter is unquestionably very much higher. DEPTH OF MOLTEN LAVA. If we compute how far we would have to go to reach a temperature sufficient to supply molten lava, it is apparent that twenty to thirty miles would do it. It is at this depth that volcanoes are believed to arise through faults in rock formation. It is unlikely though, that that at this depth the material is molten, as the earth’s crust and its weight must be enormous. This would cause the material to behave as a solid ■although the temperature was very high. It becomes molten when the pressure is relieved, due to rock slippage, and this gives birth to volcanic eruptions. The temperature of the discharged material is what we should expect from our computations based on oil well measurements.

On the other hand, there are those who will disagree with us. There are those who believe that the is a cold mass and that the radiation'which escapes from its surface each year is generated by the disintegration of radium in the rocks. The quantity of radium appears to be about right to satisfy this theory. They attribute the heat observed as we go down in an oil well, either to this radio-activity or tochemical changes in the oil itself. They say that the temperature at which we find volcanic magma is likewise due to chemical changes whiclToccur in it when pressure is relieved, which were prevented previous to that time by the high pressures. That the increase in temperature is greater in oil fields than in neighbouring areas tends to. bear out this contention. In fact, the rate of increase in the temperature with depth is being studied as a possible means of locating oil wells.

ROOM FOR INVESTIG ATION. If the interior of the earth were a freely flowing liquid we would probably be correct in assuming that the temperature throughout was about 3000 degrees. As a fact, experiment, shows

that, what ever may be its temperature, its elasticity is about like that of rigid steel. Owing to the groat pressure and density it probably behaves much like a solid. The rate of movement of particles inside is consequently likely to be very slow. Perhaps if we could bore a shaft five miles deep’ave might supply the world, with power indefinitely. But so far, we lack the machinery to do it. Future generations will doubtless laugh at our feeble attempts and vast expenditure for power. At the present time much genuine research is being done. It is a peculiar fact that we know more about stars millions of light years away from us than we know of what lies a few miles beneath our feet. Perhaps if we could look down we might feel far less comfortable and secure as we go about our daily tasks than we do now.—(A.A.N.S.)