Life in Other Worlds Richard A. Proctor. 



the geologists, that the interval of between one million 

 ami ten millions of years is the- probable time during 

 which animal lifo will continue ou tho earth. Looking 

 forward to the, tuturo wo have no satisfactory means 

 for our guidance. Wo might even say a few 

 thousand years" was tho limit of time in which 

 the human race could exist with anything 

 lite comfort. W>- do not know, however, what powers 

 man mav have to employ tho moans garnorod upon 

 tiirth. ITo m:iv by souie contrivance, as Ericsson has 

 suggested, be able to u^o those parts t-f tho sun's heat 

 which are at present wasted and lost by radiation. Ho 

 may construct instruments so as to garner up these 

 supplies. One way of Ericsson's rs this: There Is a 

 possibility that you might havo tho sun's heat gathered, 

 that falls on some desert place, and the whole of it em- 

 ployed in lifting up great bodies, and these might bo 

 the. menus of driving machinery. It might bo gathered 

 together in what we may call sun machines, and so em- 

 ployed to drive engines and do that work for which coal 

 is now used. It may be that is tho future to which 

 man's ingenuity tends. 



THE EARTH'S CONTRACTION BALANCING ITS RETARDATION. 



It seems to us to lio within our range, seeing certain 

 physical and natural processes, to say that t^e enrth 

 will one day be the scene of death and desolation. One 

 of these corresponds with the moon's change in rota- 

 tion by which it was worked down until its period was a 

 lunar month. Tlie earth has a tidal wave, which is act- 

 ing as a sort of brake, and slowly but continually 

 reducing the earth's rotation. You will remem- 

 ber that in the former course of lectures I dwelt 

 on that fact. I have since heard news 

 which will be gratifying news for all those who may be 

 terrified with the idea that in a few millions of years 

 that state of iiff.iirs would be brought, about. Prof. New- 

 comb tells me that recent observations on the moon, 

 since 1863, show that the moon is running away from 

 her calculated place. Some change is tailing place in 

 the moon's motion. Astronomers havo too thoroughly 

 mastered the lunar theorv to bo in doubt about that. It 

 must be that a certain change is taniug place in 

 the earth's rotation, and not of the kind I have 

 spoken of not retardation. It is increasing in rate. 

 Here is a strange piece of information, not the first 

 brought to us, by the companion of the earth, its 

 satellite, the moon. It seems to show a retardation in 

 tho moon, and we know from that that the earth is 

 accelerating her motion. It is shown, too, that it is not 

 uniform. We can understand the retardation of the 

 earth, the great tidal wave being opposed to it; but 

 what are the changes which are leading to this accel- 

 era^iou ! It seems to mo in this way. It is a process of 

 cooling. The earth is gradually contracting, and 

 that leads to a hastening of the rotation, and 

 that hastening is to be regarded as counterbalancing tho 

 brake action of the tidal wave. Now it seems as if it 

 more than counterbalances a portion of that, but for 

 eorue reason or other that change is taking place more 

 rapidly than any other. Tho irregularity is then a pro- 

 cess in the interior of that plastic ocean that lies he- 

 Death. It is a curious law, hut we must accept facts as 

 they are presented to us. We thought tho earth was 

 losing in its rotacion, and now we find it is gaining with 

 a variable rate of gain, and (hero Is no clear evidence 

 that it is going to lose its rotation m any measurable 

 manner. 



There is another change by which the earth must 

 gradually he drawn in near to the sun, that the ether 

 must compel the earth to travel more and more inward, 



until at last it must fall into the sun ; hut the period is 

 so long that to our conception it is an infinity of time, if 

 we only recollect tho extreme rarity of the ether that 

 occupies space. Prof. Whewell studied Eneke's comet, 

 and was led to this result : a man drawing a full breath 

 takes in as much air as would form a globe thr;.'e inches 

 in diameter; in order to take in as much air at the 

 pressure on Encke's comet ho would be required todraw 

 iu a globe 6,000 miles in diameter. If liio earth is to be 

 chocked by an atmosphere like thatit must bo in a period 

 of millions of millions ol years, and we can hardly doubt 

 that before that this earth will have ceased to be the 

 abode of life, so that whenever the earth falls into the 

 sun there will be no destruction of life on the surface. 



MERCURY NOT TIIE ADODE OF LIFE. 



Now we will have the room darkened while we apply 

 these considerations to the various planets. I shall have 

 to mention a few facts from my former lectures, but I 

 shall take them for granted and so procoed to apply 

 them. 



The planet Mercury is not studied under favorable cir- 

 cumstances. When it is nearest to us it presents a 

 crescent shape, and when its full front is toward the 

 earth, it is smaller on account of its greater distance. 

 But we feel quite satisfied that it can hardly be the 

 abode of life such as we are acquainted with. The sun 

 pours upon it with from four to ten times as much 

 heat as we have. In this picture you see the sun in 

 the various sizes as seen from the different planets. 

 Tho upper picture shows it as seen from Mercury; here 

 as seen from the earth, from which tho comparison can 

 be made. Here we havo illustrated before us the enor- 

 mous supply of heat poured on Mercury. Upon Venus 

 also it is greater than upon the earth. Another pic- 

 ture shows us the appearance of the sun as seer 

 from Mars. Another shows The appearance 

 from the asteroids. Bat I want to call youi 

 special attention to the sun as seen from Jupiter 

 Saturn, and Neptune. I shall show that the sun is not 

 the cause of the changes there, and when you see the 

 smallness of the sun as seen there, comparing it with 

 the sun we see, you will see that both in Jupiter and 

 Saturn that tiny sun cannot produce tho effects that are 

 ordinarily ascribed to it changes of great activity that 

 we cannot believe to be brought about there by the 

 insignificant sun that would be seen there if those were 

 inhabited worlds. 



VENUS NOT YET HABITABLE CONDITION OF TIIE MOON. 



I pass from the planets Mercury and Venus rapidly be- 

 en use we have so little telescopic information of them. 

 It will probably dispose us to regard them as intended 

 to be the. abode of life but not that yet. Only when the 

 sun has lost the fourth part of his heat in the case ol 

 Mercury, and in the case of Venus one half, will they be 

 inhabitable. When the sun has lost half of his heat, the 

 time will come when Venus will be inhabitable. It will 

 then be with her as with us now. So we loolc forward 

 for millions of years when she will bo inhabited as this 

 earth is. It may be that the piai.ets are inhabited only 

 for a short period, and not necessarily cotemporaueously. 

 Here is Venus. You will see that there are certain 

 markings. I woul.l cail your attention to thb great 

 benefit of the clear atmosphere of America iu observ- 

 ing these marks. Iu England they say they can watch- 

 them and see them in the periods of the rotation. Th6 

 large telescope at Harvard and the other fine ones of 

 A.lvin Clark and others fail to show them. Trie subject 

 seems to me very much as if it were an optical delusion ; 

 that she shines with so much light that th'> eye is de- 

 ceived. Three other pictures of Veaia will be shown. 



