62 FROM NEBULA TO NEBULA 



regular in outline. Such, however, are not the largest 

 specimens of their genus; for there are a few nebulse, 

 e.g., Orion, that have probably been produced by the con- 

 temporaneous explosion (or perhaps collision) of more 

 than one star. 



6. It is a grave mistake to estimate the mass of a 

 star by the amount of light it emits, as foolish, indeed, 

 as it would be to select artificial lights by their physical 

 size instead of by their intensity. Astronomers in 

 general labor under the delusion that there is no natural 

 limit to the sizes of stars, hence we find them speaking 

 of such a star as Canopus, for example, as being a 

 6 ' thousand times the mass of our sun. ' ' Could we behold 

 the surface of a B star at close range, we should see it, 

 not as a smooth expanse, but as one stippled with millions 

 upon millions of jets of incandescent materials rising 

 thousands of miles skyward, literally pumping out the 

 star's gravistatic heat. It may well be doubted whether 

 a star can exist, as such, with a mass more than a 

 hundred times that of our sun. 



7. Another feature respecting these B stars is the 

 broadening or blurring of their spectral lines, indicating 

 at the same moment approach and recession, or, as the 

 astrophysicist would express it, both minus and plus 

 radial motions. This phenomenon is obviously due to 

 the combination of jets, some in the act of rising and 

 others in the act falling; both impressions, of course, 

 registering themselves on the photographic film to- 

 gether. 



8. Inasmuch as, like all other things, stars can grow 

 only where there is food for growth, we should expect 

 to find a greater proportionate number of these giant 

 B stars in the Milky Way than in the regions of scantier 

 pasturage. This is just what observation proves to 

 be the case. Incidentally it may be stated as a general 

 rule, that the "older" their spectra, the larger the mem- 

 bership of a given class, for according to my theory the 

 so-called "old" stars are those of small mass. 



