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Introduction to Astronomy - For the Use Od Science Classes and Elementary ...
John Isaac Plummer
No preview available - 2010
61 Cygni aberration of light altitude amount angle aphelion apparent diameter appear astronomical atmosphere attraction axis bodies bright called cause centre circle colour comet compared conjunction density determined difference direction disc diurnal diurnal motion earth eccentricity effect equal equator equatorial equinox Explain fixed stars force Give gravity greater heat heavens hemisphere hence horizon inclined inferior conjunction inferior planets interval Jupiter known latitude length less libration light longitude lunar eclipse magnitude Mars mass mean distance measured Mercury meridian meteors miles moon moon's motion nearly Neptune node object observed opposition orbit parallax pass penumbra perihelion perturbations phenomena planetary point of Aries polar pole position radius refraction revolving round right ascensions rings rotation round the sun satellites Saturn seen shadow sidereal sidereal period similar solar day solar eclipse solar system solstice spots sun's supposing surface synodical period syzygy telescope tion transit Uranus velocity Venus visible zenith
Page 54 - 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.
Page 69 - On it place a globe, two feet in diameter; this will represent the Sun; Mercury will be represented by a grain of mustard seed, on the circumference of a circle 164 feet in diameter for its orbit; Venus a pea, on a circle 284 feet in diameter; the Earth also a pea, on a circle of 430 feet; Mars a rather large pin's head, on a circle of 654 feet...