5-' 



KNowunci 



IKIIRUARV, 1912. 



Sl'N Si'OTS. 



I iinaj^iiu- tliat Sun spots have tluii oii};iii in 

 similar large meteors or meteoric swarms collidiiif,' 

 and releasing the solar energy. The spot it.self is 

 probably the storm in the jjhotosphere that follows 

 the actual volcanic explosion : the dark spots, which 

 are still intensely luminous, being due to expansion. 

 The volcanic scar pn>babl\- remains in its position 

 on thi' Sun whilst the storm travels on the surface. 

 The associated irregular luminous masses are 

 jirobably regions of compression. Perhaps the 

 uprushing hot material from the interior would also 

 be more luminous than that which has expanded, 

 cooled and is descending. 



Spots are often associated together, sometimes 



give l(R) much prominence to this tentative sugges- 

 tion, ;is I have discussed the idea in some detail in 

 "The Hirth of \\f)rlds and Systems ' in " Harper's 

 Library of Living Thought." 



The Sun's LAYi=:t<s. 



We have still to offer suggestions of explanations 

 of the four ensphering luminous atmos|)heres of the 

 Sun. The ])hotosphere. the reversing layer, the 

 chromosphere and the corona. 



The idea that the ])hotos|)here is a carbon cloud 

 formation, although very beautiful and a remarkably 

 logical scientific induction, is probably not true, as 

 the absolute temperature of the Sun's photosphere 

 is almost certainlv twice as high as that at which 



Coiismcud H FiGCRE 55. n. Ellis. 



Smoothed Curves of Sun Spot Frequency (Wolf), compared with corresponding curves, showing the \'ariation in Diurnal 

 Range of the Magnetic F^lements of Declination and Horizontal Force, from Observations made at the Uoyal Observatory. 



Greenwich. 



long ranks appear at once. This may lie due to 

 bursting meteors, as we see them burst in the 

 Earth's atmosi)here, or they may be due to meteoric 

 swarms with subordinate nuclei, breaking up under 

 the Sun's differential tidal attraction. In connection 

 with this point, photographs of comets" nuclei and of 

 star clusters should be taken with very large 

 telescopes to bring out and detect subordinate 

 centres. Dynamically such subordinate centres seem 

 certain sometimes to form in many swarms. 



Whilst I think the general mottling of the Sun's 

 surface to be due to Zodiacal meteors, I believe the 

 larger Sun spots to be due to meteors that are parts 

 of entrapped comets that have been torn to pieces 

 by the Sun, comets entrapped by Jupiter and 

 brought so close to the Sun as to partly impact. 

 Schuster's investigations seem to me to point to the 

 fact that more than one, perhaps many, comets have 

 been so entrapped. The great eleven-year period 

 suggests that a very large cometic swarm narrowly 

 escaped complete impact and so became a forked 

 double nutinrii' swarm. However. T iln not \\;mt to 



sublimed carbon can exist. I believe this intcnseK" 

 luminous envelope to be the surface of aerostatic 

 pressure. The gravitation energy of the Sun. about 

 twentv-eight times that of the Earth, must double 

 the density of the surface gas at a very small depth. 

 What this depth is it would be difficult to sa\ . 

 because temperature must increase enormously as 

 well as pressure. The thermodynamics of the 

 problem is \cr\- complex. I strongly suggest that, 

 before trxiiii; to master this very po|ndar account. 

 students shall read the short statement of the 

 dynamical theory of gases, and the contrast of gaseous 

 pressure and kinetol as given on pages 106 to 109 in 

 " The Birth of \\'orlds and Systems." 



I take it, then, that the photosphere is the limit 

 area of statical support. I shall try to show that all 

 above this surface is dynamically supported, and docs 

 not follow the statical laws of the dynamical theory 

 of gases as to pressure and volume. These layers 

 are jirobabh- in rapid motion, and are sup|)orted by 

 their high kinetol. 



Although atom-sortiui; or selective molecular escape 



