A RECENT STAR SHOWER. 201 



the sun. For the latter event to happen, a velocity of 

 about 380 miles per second must be imparted ; and 

 then the body would pass away not only from the sun, 

 but from the solar system, and after a few millions of 

 years had elapsed would pay a visit to some other 

 star. After circling around this star, the body, if it 

 escaped collision with one or other of the worlds 

 circling around the star, and if its course carried it 

 clear of the star itself, would pass away again, and 

 enjoy another interstellar journey lasting for a few 

 millions of years. 



Of course, the same holds with meteors visiting our 

 system from other stars. They reach the neighbour- 

 hood of the solar system after a journey lasting millions 

 of years (even when they come from the nearest star) : 

 and if they escape entanglement in our system, they 

 return to the interstellar depths, though not by the 

 road which brought them here. 



Now the shooting-star systems I have mentioned 

 behave in quite another fashion. They travel round 

 the sun in closed orbits and in periods of moderate 

 length. Most of them do not approach the sun within 

 fifty or sixty millions of miles, so as to exclude all 

 possibility of their having once been expelled from the 

 sun. For even if a body expelled from the sun, instead 

 of returning directly to him, were enabled (through 

 the effects of planetary perturbation) to steer clear of 

 his mass, its course would nevertheless pass very near 

 to him for ever after. 



Whence, then, can these meteor streams come ? 



