Arizona republican., 1892-07-02
THE SUN WILL CEASE.
A TIME MUST COME WHEN HEAT
 FROM THE SUN MUST CEASE.


 5,cOO,OCO Years, but Not 10000, 900.
 The Secret of the suns Heat.
 It seems to be worth while to collect together what may be said on the sub ject of the duration of life on the globe It is a noteworthy fact that the possi- bility of the continued existence of the human race depends fundamentally upon the question of heat. e. If heat, or what is equivalent to heat, does not last, then man cannot last, either. There is no shirking this plain truism.
 Of course it is obvious that the avail able heat generally comes from the sun So far as the coal goes, we have already observed that as it Is limited to quantity it can afford no perennial supply. Doubtless there is in the earth some quantity of other materials capable of oxidation or of undergoing other chemi- cal change, in the course of which and as an incident of such change heat is evolved. The amount of heat that can possibly arise from such sources is strictly limited. There is in the entire earth just a certain number of units of heat possible from such combinations, but after the combination has been ef- fected there cannot be any more heat from this source.
 Then as to the internal heat of the earth due to the incandesceut state of it's interior. Here there is no doubt a large store of energy, but still it is of limited quantity, and it IS also on the wane. This heat is occasionally copious- ly liberated sy volcanoes, but ordinarily the transit of heat from the interior to the surface and its discharge from thence by radiation is slow process. It is, however, sufficient for our present purpose to observe that slow though the escape may be, it is necessarily going on. There is only definite number of units of heat contained in the interior of the earth at this moment, and as they are gradually diminishing and as there is no source from whence the loss can be replenished, there is here no supply of warmth that can be relied on perma- nently.
 It goes without saying that the wei fare of the human race Is necessarily connected with the continuance of the suns benefcent action. If the sun ever ceases to shine, then must it be certain that there is a term beyond which hu- man existence, or indeed organic ex- istence of any type whatever, cannot any longer endure on earth.
 But we have grounds for knowing as a certainty that the sun cannot escape from the destiny that sooner or later overtakes the spendthrift. In his inter- esting studies of this subject Professor Langley gives striking illustration of the rate at which the solar heat is being squandered at this moment. He eremarks that the great coal fields of Pennsylvania contain enough of the precious mineral to supply the wants of the United States for 1, 1,000 years. If all that tremendous accumulation of fuel were to be extract ed and burned in one vast confagration tho total quantity of heat that would be produced would no doubt be stupendous, and yet, says this authority who has taught us so much about the sun, all the heat developed by that terrific coal fire would not be equal to that which the sun pours forth in the thousandth part of each single second.
 When we reflect that this expenditure of heat has been going on not alone for the centuries during which the earth has been the abode of man, but also for those periods which we cannot estimate except by saying that they are doubtless millions of years during which there has been life on the globe, then indeed we begin to comprehend how vast must have been the capital of heat with which the sun started on its career
 And yet we feel certain that the incss- sant radiation from the sun must be producing a profound effect on its stores of energy. The only way of reconciling this with the total absence of evidence of the expected changes is to be found in the supposition that such is the mighty mass of the sun, such the pro digious supply of heat, or what is equiv alent to heat that it contains, that the grand transformation through which it is passing proceeds at rate so slow that during the ages accessible to our obser- yations the results achieved have been imperceptible But the energy of the system is as surely declining as the en- ergy of the clock declines as the weight runs down.
 It seems that tie sun has already dis sipated about fOdr-ffths of the energy with which it may have originally been endowed. At all events, it seems that, radiating energy at its present rate, the sun may hold out for 100000 years, or for 5,O00,0 900 years, but not for 10000 600 years. Here, then, we discern in the remote future limit to the dura- tion of life on this globe. We have seen that it does not seem possible for any other source of heat to be available for replenishing the waning stores of the luminary. It may be that the heat was originally imparted to the sun as the result of some great collision between two bodies which were both dark before tho collision took place, so that, in fact, the two dark masses coalesced into a vast nebula from which the whole of our system has been evolved. Of course it is always conceivable that the sun msy be reinvigorated by repetition of a similar startling process,
 It is, however, hardly necessary to observe that 30 terrific convulsion