The New Heavens |
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100-inch Hooker telescope 100-inch mirror 100-inch telescope 20-foot interferometer angle angular diameter Antares Apennines aperture astronomer atmosphere Betelgeuse celestial centre chemical close double stars components density disk distance driving-clock earth electric Ellerman experiment feet fifteenth magnitude form of interferometer gaseous geuse giant Betelgeuse giant stars heliometer helium Herschel holes hydrogen inch in diameter instrument interference fringes laboratory large telescopes light-years linear diameter lines lunar Apennines magnetic field Mare Imbrium mass measure the diameter ment method Michelson interferometer miles in diameter moon motion Mount Wilson Observatory mountains narrow vertical number of stars object-glass observations orbit pencils of light phenomena photographic plate physicist physics plane radiation red star reflecting telescope reflector rotation second of arc seen separately solar system spectra spectroheliograph spectroscope spectrum star images stellar evolution stellar universe sun-spots tele telescope tube temperature tests theory tion titanium oxide upper end vacuum tubes vapor Yerkes Observatory
Popular passages
Page 10 - These phenomena agree with the supposition that the stars of our firmament, instead of being scattered in all directions indifferently through space, form a stratum, of which the thickness is small, in comparison with its length and breadth ; and in which the earth occupies a place somewhere about the middle of its thickness, and near the point where it subdivides into two principal laminae, inclined at a small angle to each other.
Page 8 - ... the hand and club of Orion. The glorious multitude of stars of all possible sizes that presented themselves here to my view was truly astonishing; but, as the dazzling brightness of glittering stars may easily mislead us so far as to estimate their number greater than it really is, I endeavoured to ascertain this point by counting many fields, and computing, from a mean of them, what a certain given portion of the milky way might contain.
Page 48 - ... occasionally depart considerably from the calculated results, because at present no serious attempt has been made to take into account rotation, which may modify the conditions when sufficiently rapid. That appears to be the next step needed for a more exact study of the question. Probably the greatest need of stellar astronomy at the present day, in order to make sure that our theoretical deductions are starting on the right lines, is some means of measuring the apparent angular diameters of...
Page 8 - ... would have better suited the idea of an expanded firmament of three dimensions; but the observations upon which I am now going to enter still farther illustrate and enforce the necessity of considering the heavens in this point of view. In future, therefore, we shall look upon those regions into which we may now penetrate by means of such large telescopes, as a naturalist regards a rich extent of ground or chain of mountains, containing strata variously inclined and directed, as well as consisting...
Page 10 - The remarkable progress of modern astronomy is mainly due to two great instrumental advances: the rise and development of the photographic telescope, and the application of the spectroscope to the study of celestial objects.
Page 10 - the stars of our firmament, instead of being scattered in all directions indifferently through space, form a stratum of which the thickness is small, in comparison with its length and breadth; and in which the earth occupies a place somewhere about the middle of its thickness, between the point where it subdivides into two principal laminae inclined at a small angle to each other.
Page 8 - ... had not light enough to effect. The portion of this extensive tract, which it has hitherto been convenient for me to observe, is that immediately about the hand and club of Orion. The glorious multitude of stars of all possible sizes that presented themselves here to my view was truly astonishing; but, as the dazzling brightness of glittering stars may easily mislead us so far as to estimate their number greater than it really is, I endeavoured to ascertain this point by counting many fields,...
Page 12 - Globular star clusters, containing tens of thousands of stars, are on so great a scale (according to Shapley) that light, travelling at the rate of 186,000 miles per second, may take 500 years to cross one of them, while the most distant of these objects may be more than 200,000 light-years from the earth. The spiral nebulae, more than a million in number, are vast whirling masses in process of development, but we are not yet certain whether they should be regarded as "island universes...
Page 8 - Hitherto the sidereal heavens have, not inadequately for the purpose designed, been represented by the concave surface of a sphere, in the center of which the eye of an observer might be supposed to be placed.
Page 80 - Darwin, in his recent presidential address before the British Association for the Advancement of Science...