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Introduction to Astronomy - For the Use Od Science Classes and Elementary ...
John Isaac Plummer
No preview available - 2010
aberration of light altitude amount angle aphelion apparent diameter appear astronomical atmosphere attraction axis bodies bright called cause centre circle comet compared cone conjunction density determined difference direction disc diurnal diurnal motion earth eccentricity effect equal equator equatorial equinox Explain Give greater greatest 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 mean solar measured Mercury meridian miles moon moon's motion nearly node object observations opposition orbit parallax pass penumbra perihelion phenomena planetary plumb-line point of Aries polar pole position radius rays refraction revolving round right ascensions rings rotation round the sun satellites Saturn seen shadow sidereal period similar solar day solar eclipse solar system solstice spots stations sun's superior planets supposing surface synodical period telescope tion transit twilight Uranus varying 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.