Connecticut western news., 1876-11-24
GROWTH OF THE EARTH.
Pref. YounG's Idcn on the ssubiect---l
 -. Interesting Paper. ..-

Pref. Youns,s Iden on tho snbiect---Au 1 i Interesting Paper. ........f
 "Since meteoric matter is continually falling upon the earth, she must of course be growing larger, and the daily number of meteors is so immense that it would be natural to suppose that the increase might be quite appreciable in 8 few centuries. It is not so, however 1;
 the surface of the earth is so enormous,
 compared with the quantity of meteoric
 matter, that, even on the most favorable hypotheses, her diameter would grow only about an inch in five hundred. mil lion years by accessions of this kind. A few figures will make this clear
 GAS to the number of visible meteors,
 there is substantial agreement among authorities. The estimate of Professor Newton is as large as that of any one, I believe, and he puts it at 2, ,50O, ,O00 per diem, which number we will use. As to their average weight there is more difference of opinion. Probably, how ever, the most careful and best founded investigation is that of Professor Hark- ness, published in his report upon ob- servation of the November meteors of 1866 and his conclusion is that the mass of ordinary shooting stars does not differ greatly from one grain. Profes- sor Newcomb appears also to concur in this estimate. There are reasons. which it would take too long to discuss, for thinking that this value is likely to be somewhat too small but on the other hand it is almost absolutely certain that the average mass cannot be as great as one-fourth of an ounce. To be on the safe side, we will assume one hundred grains as the mean weight of the visible shooting stars. rsr. .r-..~ sap .vv.s.5
 Remembering that the pound is 1000 grains, we shall then find nearly 107, 900 pounds, or about fifty tons, for 4 the total weight of one day's supply of shooting stars. An allowance must also be made for the meteors too small to be visible (which are known by teles- copic observations to be very numer- ous), and for the matter brought down by aerolites. If we double the quantity stated above we shall certainly be abun- dantly liberal, and this will giveus 214,- 900 pounds day, or about 78, ,164, 900 pounds per year, as the earthis rate of growth in weight. .s..t.t..,,l I.....5
 "Her increase of bulk depends upon the density of the meteoric matter, and probably this density does not differ much from that of ordinary soil, or nearly three times that of water. If so. each cubic foot would weigh about 1871 pounds, and the annual meteoric accest sion to the bulk of the earth would be not far from 417, 900 cubic feet. A cube about seventy-fve feet on each side would be little larger. It would take more than four millions such to make pile as large as Mount Washington. Now, since the surface of the earth is about 5,4S4 millions of millions of square feet, it follows that the annual supply of meteoric matter, if spread uniformly, would form layer whose thickness would be only 1-13, 155, GOO, ,000 a foot, or very nearly II, 100, ,000, 900 of an inch. In other words, even on such extravagantly favorable hypotheses as we have assumed, the formation of 8 sheet of meteoric matter covering the earth to a depth of one inch would re- quire period of eleven hundred mil lions of years.
 elf we suppose meteorio matter to have been just as abundant in space as now, since the beginning of time, and that the velocity of the earths orbital motion has remained unchanged, and that the effects of her atmosphere and of her gradual shrinkage under the ac- tion of gravity can be neglected, then 1t can be shown by an easy course of req soning, which would, however, hardly suit these columns, that her diameter must have grown during her whole ex- istonce at the same uniform rate as now, and we find that to build her up to her present dimensions by such process of aggregation must have taken period of at least twenty-seven and half millions of millions of years. .--..-s
 "It is not intended to assert, however, that the earth was really formed in this way and even if it was, the above esti- mate is of little value except as indi- eating the order of magnitude involved; since there is no certainty whatever not even a probability-t in the early stages of the formation of the planetary system circumstances nearly enough re- sembled the present to warrant any con- clusion. Nor must it be forgotten that the probable estimates of Hardness and others as to the weight of meteors would lengthen all the periods of time mem tioned from ten to one hundred fold We have given the smallest values pos sible." ..a.aa1 ..... .- .gz