A Treatise on Astronomy, Descriptive, Physical and Practical: Designed for Schools, Colleges, and Private Students |
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altitude amount angle apparent argument astronomers attraction axis body called cause CHAP circle clock comet comparing compute conceive conjunction correct corresponding course declination describe determine diameter difference direction distance divided earth eccentricity eclipse effect elements equal equator equinox example expression fact figure fixed force give given gravity greater greatest Greenwich heavens Hence horizon horizontal parallax hourly increase interval Jupiter known latitude less longitude lunar magnitude mass mean measure Mercury meridian miles minutes moon moon's motion move nearly node noon observations opposite orbit pass period planet pole position proportion radius represent result revolution right angles right ascension round seen semidiameter side sidereal sine solar stars sun's suppose surface taken tion transit triangle true variation Venus visible whole ର ର ର
Populāri fragmenti
144. lappuse - Jupiter a moderate-sized orange, in a circle nearly half a mile across; Saturn a small orange, on a circle of four-fifths of a mile; Uranus a full-sized cherry, or small plum, upon the circumference of a circle more than a mile and a half, and Neptune a good-sized plum on a circle about two miles and a half in diameter.
139. lappuse - ... appearances of spots seen upon them, render it extremely probable that they subsist in the atmosphere of the planet, forming tracts of comparatively clear sky, determined by currents analogous to our trade-winds, but of a much more steady and decided character, as might indeed be expected from the immense velocity of its rotation. That it is the comparatively darker body of the planet which appears in the belts is evident from this, that they do not come up in all their strength to the edge...
143. lappuse - 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; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across...
80. lappuse - For, by the first of Kepler's laws, the areas described by the radius vector are proportional to the times, and when this is the case, by Art.
118. lappuse - The squares of the times of revolution are to each other as the cubes of the mean distances from the sun.
144. lappuse - As to getting correct notions on this subject by drawing circles on paper, or, still worse, from those very childish toys called orreries, it is out of the question.
141. lappuse - ... and less strongly marked than those of Jupiter, and owing doubtless to a similar cause. That the ring is a solid opake substance, is shown by its throwing its shadow on the body of the planet on the side nearest the sun, and on the other side receiving that of the body.
154. lappuse - ... is leaving behind, must seem gradually to approach, in the same manner as when we walk through a forest, the ranges of trees to which we advance are constantly widening in their apparent distance from each other, while the distance of those we leave behind is gradually contracting.
147. lappuse - Gregorius, of Constantinople, in June, 1337, whose course he describes very accurately. Comets do not all move from west to east, like the planets. Some have a direct, and some a retrograde motion. Their orbits are not comprehended within a narrow zone of the heavens, like those of the principal planets ; they vary through all degrees of inclination. There are some whose plane is nearly coincident with that of the ecliptic, and others have their planes perpendicular to it. Indeed, a slight inclination...
89. lappuse - Whenever the sun is above the horizon of any place, that place is receiving heat; when below, parting with it, by the process called radiation ; and the whole quantities received and parted with in the year...