Bickerton. — On Cosmic Impact. 551 



more than a tenth, then the two stars would become orbitally 

 connected 



47. Such a pair, when thus connected, would form a per- 

 manent double star. It is the opinion of Proctor and other 

 astronomers that impacting stars becoming orbitally connected 

 could not make double stars, as they think such stars would 

 impact again. But they overlook the fact that the nebula 

 that retarded their escape and formed an important factor 

 after the first impact, will have dissipated before they return. 



48. Hence the eccentricity will lessen greatly, and, as a 

 rule, instead of impacting again they will be scores of millions 

 of miles away at perihelion. In fact, they will have about 

 the eccentricity that double stars are known to have. 



49. There is a possibility of a second impact when the 

 graze has been a very small fraction, or if one of the stars 

 were multiple. But the period of the subsequent recurrence 

 of impacts, after the first recurrence, would lessen in point of 

 time. On calculating the dates of the apparently recurrent 

 star, " The Pilgrim," viz., 945, 1264, and 1572, this is proved 

 to be the case. The dark bodies producing these impacts 

 must be of absolutely stupendous dimensions. The dark 

 bodies producing Nova Aurigae were probably 8,000 and 4,000 

 times the mass of the sun respectively. 



50. Double stars should be more often variable than 

 single stars. Struve has proved that they are hundreds of 

 thousands of times more variable than ordinary stars. 



51. We should expect them also to be more frequently 

 coloured. This, too, is most strikingly the case. 



52. We should look for them to be associated with nebulae. 

 Herschel says the association of nebulas and double stars is 

 most truly remarkable. 



53. They should be highly eccentric. This is also well 

 known to be the case. 



54. A large number of agencies tend to render the orbit 

 less eccentric. These are fully discussed in my papers of 

 1880. 



NEBULiE. 



55. If stars come into partial impact, the tendency to form 

 definite nebulae, other than planetary or cometic, seems to be 

 entirely destroyed by the outrush of the high-velocity gas. 

 This is not the case with the impact of nebulas. 



56. Impact may take place between nebulae, between star- 

 clusters, between meteoric swarms, and between any two 

 similar or dissimilar celestial bodies. The graze may be little 

 or large ; the original bodies may have had a small or great 

 proper motion ; and all these peculiarities will tend to vary 

 the results. 



