Astronomy and Astro-Physics Volume 7

Astronomy and Astro-Physics Volume 7

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1888 edition. Excerpt: ... and won a host of friends among the scholars until the spectroscope made belief in its splendid imagery no longer possible. Next in order come the views of Secchi, Faye, Young and Langley. In Secchi's view the spot is formed of a central region--apparently a dark mass--called the nucleus or umbra, or both, surrounded by a part less dark, the penumbra, which is a thin veiling of filaments or currents precipitating themselves towards the center and sometimes crossing it like abridge. The existence of the spot has three periods, its formation, its rest and its extinction. In the first, the visible solar surface, or photosphere is distorted by great agitation. Its irregular movements defy description, and their velocities are enormous. They have no parallel at all in terrestrial phenomena. This solar activity is produced by tremendous forces at work beneath the photosphere, and the spots, and eruption of great whirling masses of incandescent metallic vapors, are the effects. In the period of rest these eruptive masses fall back again into the surface of the photosphere and form a more or less circular umbra or spot, and the central up-rush loses in volume and velocity. Finally the eruptive action is exhausted and the absorbing powers of the vapors seem to be dissipated, the photosphere closes over the umbra and the spot is extinguished. At first the spot was a rent in the photosphere, then later it assumed the funnel shape in more definite outline, and was crowned with beautiful facula, ' and jets of hydrogen and metallic vapors, the former being often abundant, high and bright, while the latter are low and brilliant. This briefly is Secchi's explanation. M. Faye's study of solar spots agrees in the main with the foregoing, and emphasizes more

Product details

  • Paperback | 156 pages
  • 189 x 246 x 8mm | 290g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236571754
  • 9781236571755