The Solar System: A Study of Recent ObservationsG.P. Putnam's sons, 1908 - 310 páginas |
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Términos y frases comunes
absorption amount of heat aphelion appear astronomers atmosphere attraction average axis body bright brilliant canals cause centre changes comet craters curve dark density determined diameter direction disc distance earth earth's surface eclipse edge energy equator equatorial extremely feet gases globe gravitation greater heavens heliometer Herschel inch inferior conjunction irregular Jupiter known latitude lifting force light lines Lowell LOWELL OBSERVATORY lunar markings Mars Martian mass measures Mercury meteors method million miles minute moon moon's motion mountains moving nearly nebula Neptune observations Observatory ocean orbit parallax particles pass path pendulum perihelion photographs planet polar portions position radiation rays recognised revolve ring rotation satellites Saturn seen sidereal period solar constant solar parallax solar system spectrum speed spots stars sun-spot sun's synodic period telescope temperature theory tidal friction tides tion to-day transit Uranus varies velocity Venus visible water vapour wave
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Página 156 - The squares of the periods of revolution of any two planets are proportional to the cubes of their mean distances from the sun.
Página 257 - They have likewise discovered two lesser stars, or satellites, which revolve about Mars ; whereof the innermost is distant from the centre of the primary planet exactly three of his diameters, and the outermost, five ; the former revolves in the space of ten hours, and the latter in twenty-one and a half...
Página 162 - Every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distance from each other.
Página 14 - But whilst gazing upon them in a perspective of about half a mile, we were thrilled with astonishment to perceive four successive flocks of large winged creatures, wholly unlike any kind of birds, descend with a slow even motion from the cliffs on the western side, and alight upon the plain.
Página 97 - ... it is most probably also inhabited, like the rest of the planets, by beings whose organs are adapted to the peculiar circumstances of that vast globe.
Página iii - Professor Poor shows by what steps the precise Knowledge of to-day has been reached and explains the marvellous results of modern methods and modern observations.
Página 216 - Mars for two years he was able, by looking at the moon through an opera glass, to see, or fancy he saw, lines and markings upon its surface similar to those of Mars. This phenomenon is not to be regarded as a pure illusion on the one hand, or an exact representation of objects on the other. It grows out of thft spontaneous action of the eye in shaping slight and irregular combinations of light and shade, too minute to be separately made out, into regular forms.
Página 153 - The line joining the planet to the sun sweeps out equal areas in equal times.
Página 166 - HALL,* that the gravitation of the Sun is not exactly as the inverse square, but that the exponent of the distance is a fraction greater than 2 by a certain minute constant.
Página 159 - To imitate the motions of the planets in these orbits Mercury must...