Problems in Astrophysics

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A.&C. Black, 1903 - Astrophysics - 567 pages
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Page 158 - May not the periodicity of sun-spots, and the connection between two such dissimilar phenomena as spots on the sun and magnetic disturbances on the earth, be due to a periodically recurring increase in the electric conductivity of the parts of space surrounding the sun? Such an increase of conductivity might be produced by meteoric matter circulating round the sun. 6. What causes the anomalous law of rotation of the solar photosphere...
Page 460 - In the same paper is given an account of some nebulous stars, one of which is thus described : "Nov. 13, 1790. A most singular phenomenon ! A star of the eighth magnitude, with a faint luminous atmosphere of a circular form, and of about 3
Page 123 - On page 40, the same author says: "The sun went out as suddenly as a blown-out gas jet, and I became as suddenly aware that all around there had been growing into vision a kind of ghostly radiance, composed of separate pearly beams, looking distinct each from each, as though the black circle where the sun once was bristled with pale streamers, stretching far away from it in a sort of crown. This was the mysterious corona, only seen during the brief moments while the shadow is flying overhead.
Page 461 - ... in diameter. The star is perfectly in the centre, and the atmosphere is so diluted, faint, and equal throughout, that there can be no surmise of its consisting of stars ; nor can there be a doubt of the evident connection between the atmosphere and the star. Another star not much less in brightness, and in the same field with the above, was perfectly free from any such appearance.
Page 54 - The final impression, which our mind involuntarily receives in contemplating these fundamental relations is that of a wonderful mechanism of nature, the functions of which are performed with never-failing certainty, though the mind can follow them only with difficulty and with a humiliating sense of the incompleteness of its perception.
Page 315 - These stars revolve around their common centre of gravity in an elliptic orbit whose semiaxis major is six times the diameter of the stars. The plane of the orbit passes through the sun ; the eccentricity is 0.2475...
Page 125 - This died out somewhat suddenly some 5' or 6' from the sun, I could not determine the height precisely, and then there was nothing ; the rays so definite to the eye had, I supposed, been drawn into nothingness by the power of the telescope ; but the great fact was this, that close to the sun, and even...
Page 212 - ... greater strength in the star spectrum gives to some well-known solar groups (notably the b group) quite an unfamiliar aspect. In a Herculis only a comparatively few of the strong metallic lines remain, while the bands are deep, and beautifully distinct. It is impossible to avoid the conclusion that the edges of the zones bordering on the dark bands are bright — much brighter, that is, than the average continuous spectrum...
Page vii - The author's intention, as announced in the preface, "is not so much to instruct as to suggest. It represents a sort of reconnaissance, and embodies the information collected by scouts and skirmishers regarding practicable lines of advance and accessible points of attack. .... Before attempting to add to our store of learning, we must realize what is already possessed.
Page 90 - The reduction of the latitudes of the spots is not yet completed. The result of these observations may be thus briefly stated. As we pass from minimum to maximum, the lines of the chemical elements gradually disappear from among those most widened, their places being taken by lines of which at present we have no terrestrial representatives. Or, to put the result another way — at the minimum period of sunspots when we know the solar atmosphere is quietest and coolest, vapours containing the lines...

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