Modern Astronomy, Its Rise and ProgressOxford University Press, H. Milford, 1926 - 196 pages |
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Common terms and phrases
absolute magnitude announced appear asteroids believed binary bodies canals catalogue Cepheid close clouds cometary comets conclusion confirmed dark detected diameter disc discovered discovery distance dwarfs Earth eclipse Eddington evidence existence fact faint galactic plane galactic system Galaxy Galileo gaseous giant planets giant stars globular clusters Herschel Huggins hypothesis indicated investigation Jupiter Kapteyn known Laplace Lick Observatory light light-years Lowell Lowell Observatory luminosity lunar Mädler Mars Martian mass Max Wolf measured meteors miles Milky million Moon Mount Wilson Mount Wilson Observatory nebulosity Nova objects observations orbit parallax particles period photographic photosphere planetary nebulae Professor prominences proper motions radiation reflector regions remarked result ring rotation satellites Saturn Schiaparelli selenography Shapley Shapley's sidereal system Slipher Solar System space spectra spectroscopic spectrum spiral nebulae spots stellar system sun-spot Sun's surface telescope temperature temporary stars theory tion Uranus variable velocity W. H. Pickering
Popular passages
Page 2 - The squares of the periods of revolution of any two planets are proportional to the cubes of their mean distances from the sun.
Page 4 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it may be compelled by impressed forces to change that state.
Page 4 - To every action there is always an equal and contrary reaction ; or the mutual actions of any two bodies are always equal and oppositely directed.
Page 31 - ... in front of the slit. I then saw the dark lines D change into bright ones. The flame of a Bunsen's lamp threw the bright sodium lines upon the solar spectrum with unexpected brilliancy. In order to find out the extent to which the intensity of the solar spectrum could be increased without impairing the distinctness of the sodium lines, I allowed the full sunlight to shine through the sodium flame, and to my astonishment I saw that the dark lines D appeared with an extraordinary degree of clearness.
Page 82 - Formed a design in the beginning of this week, of investigating, as soon as possible after taking my degree, the irregularities in the motion of Uranus, which are yet unaccounted for; in order to find whether they may be attributed to the action of an undiscovered planet beyond it; and if possible thence to determine the elements of its orbit, etc. approximately, which would probably lead to its discovery.
Page 174 - ... we therefore either have a central body which is not a star, or have a star which is involved in a shining fluid, of a nature totally unknown to us.
Page 4 - ... change of motion is proportional to the applied force, and takes place in the direction in which the force acts...
Page 151 - Nebulae hitherto discovered, whether gaseous or stellar, irregular, planetary, ring-formed, or elliptic, exist within the limits of the sidereal system. They all form part and parcel of that wonderful system, whose nearer and brighter parts constitute the glories of our nocturnal heavens.
Page 31 - I obtained a tolerably bright solar spectrum, and brought a flame coloured by sodium vapour in front of fbe slit. I then saw the dark lines D change into bright ones. The flame of a Bunsen's lamp threw the bright sodium lines upon the solar spectrum with unexpected brilliancy.
Page 148 - In his paper of 1785 he admitted that 'in all probability there may not be two or three of them in the heavens, whose mutual distance shall be equal to that of any other two given stars, but it should be considered that when we take all the stars collectively there will be a mean distance which may be assumed as the general one'.