The Elements of Theoretical and Descriptive Astronomy: For the Use of Colleges and AcademiesClaxton, Remson & Haffelfinger, 1872 - 272 من الصفحات |
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عبارات ومصطلحات مألوفة
altitude angular distance angular semi-diameter appear astronomers attraction axis called celestial body celestial horizon celestial sphere centrifugal force circle coincide comet computed constellation declination density determined diameter direction disc earth earth's centre earth's orbit earth's surface east ecliptic elevated pole equal equator equinoctial geocentric Greenwich heavenly bodies heavens heliocentric Herschel horizon hour angle inferior conjunction inferior planet instance instrument interval Jupiter latitude length light longitude lunar eclipse magnitude mass mean sun meridian meteors miles moon moon's orbit moves naked eye nearly nebula nodes nucleus observed obtained occur opposite parallax particle passes perihelion perpendicular position radius rays refraction represent revolution revolve right ascension rings rotation satellites seen sidereal day sidereal period Sirius solar eclipse spectrum spheroid sun's superior planet supposed synodical period tangent telescope tides tion transit triangle velocity Venus vernal equinox vernier vertical visible zenith distance
مقاطع مشهورة
الصفحة 108 - that 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 distances from each other.
الصفحة 111 - ... for practical purposes, the sun may be considered as being at rest with regard to the other members of the solar system. The planets move about the sun in accordance with the following laws, known as Kepler's Laws: 1. The orbit of every planet is an ellipse, having the sun at one of its foci. 2. If a line, called a radius vector, is supposed to be drawn from the sun to any planet, the areas described by this line, as the planet revolves in its orbit, are proportional to the times. 3. The squares...
الصفحة 204 - Towards the morning of the 13th of November, 1799, we witnessed a most extraordinary scene of shooting meteors. Thousands of bolides, and failing stars succeeded each other during four hours. Their direction was very regular from north to south. From the beginning of the phenomenon there was not a space in the firmament, equal in extent to three diameters of the moon, which was not filled, every instant, with bolides or falling stars. All the meteors left luminous traces, or phosphorescent bands...
الصفحة 248 - Let P be the point of equal attraction between any planet and the one next interior, the two being in conjunction ; P', that between the same and the one next exterior. Let also D = the sum of the distances of the points P, P...
الصفحة 246 - If two forces be represented in magnitude and direction by the two adjacent sides of a parallelogram, the diagonal will represent their resultant in magnitude and direction.
الصفحة 84 - Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces; the whole occupying a complete circle, or broad belt, in the heavens, called the Zodiac.
الصفحة 246 - The resultant of two or more forces is a force which singly will produce the same mechanical effect as the forces themselves jointly. The original forces are called components. COR. In all statical investigations the components may be replaced by their resultant, and vice versa. This is obvious from the admitted mode of measuring forces, 11.
الصفحة 231 - Lyre, and may be seen with a telescope of moderate power. It is small, and particularly well defined, so as in fact to have much more the appearance of a flat oval solid ring than of a nebula. The axes of the ellipse are to each other in the proportion of about 4 to 5, and the opening occupies about half...
الصفحة 51 - When a ray of light passes obliquely from one medium to another of different density, it is refracted or bent out of its course.
الصفحة 100 - A Solar Day is the interval of time between two successive transits of the sun over the same meridian; and the hour-angle of the sun is called Solar Time.