Sir J. W. Lubbock on Shooting Stars. Ill 



believe, been seen which indicate the existence of volcanos, 

 which might discharge small bodies with great force, and thus 

 give rise to satellites of the earth. 



The case is widely different as regards the sun. Changes 

 of enormous magnitude are continually witnessed on its sur- 

 face, which indicate the action of forces agitating the mass 

 probably in a state of fluidity. Recently I have observed spots 

 which were even visible to the naked eye, and of which, on 

 the following and succeeding days, not a trace could be found 

 by a good telescope. 



If a body were thrown up from the sun's surface, it must, 

 omitting all consideration of the planets, describe an ellipse 

 having the centre of the sun in one of the foci ; and thus, 

 however great the force by which the body may be sup- 

 posed to have been discharged, it must return to the sun, 

 and, impinging upon it, would not perform even one entire 

 revolution. If however we consider the action of the other 

 planets, and especially of Jupiter, it seems by no means im- 

 possible that in returning, a body so discharged might clear 

 the sun, and perform many complete revokitions round the 

 primary, that is, it might become a comet (or shooting star). 

 It would be interesting to ascertain how much the perihelion 

 distance of such a body might be lengthened under given 

 circumstances by the action of Jupiter; or whether, under 

 any hypothesis of the configuration of the planets, the perihe- 

 lion distance of any known comet could be brought under 

 '004647. Le Verrier suggests that some of the comets may 

 have become fixed to our system and retained by the action 

 of Jupiter; and that in consequence of the same action, they 

 may again wanJer in space and cease to belong to this system*. 

 But may not such bodies owe their origin to the same forces, 

 of which the existence is indubitable, which operate on the 

 surface at any rate of the sun's mass ? and if so, it is by no 

 means impossible that by calculating the perturbations of some 

 comet for the past, especially one whose perihelion distance 

 is small, it may be traced back to its origin, and the very year 

 ascertained when it left the solar mass. 



The phajnomena of shooting stars may possibly throw light 

 upon the question of the extent to which an atmosphere ex- 

 tends capable of affording any sensible resistance to the mo- 



♦ " Dans un certain iioinbre de si^cles toiitefois, die atteintlra de nou- 

 vcau I'orbitc de Jupiter, dans une direction opposfc a cclle par laquelle 

 elle a pu arriver dans le systume pianetaire : et son cours sera certainement 

 encore nne fois alterc. Peut-etre niume Jupiter la rcndra-t-il aux espaces 

 aux(|uel8 il I'avait dcrobee." — Le Verrier, Comptes Rcndus, Dec. 20, 1847, 

 p. 925. 



