Popular Astronomy, And, The Orbs of HeavenG. Routledge and Sons, 1860 |
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Popular Astronomy, And, The Orbs of Heaven Ormsby MacKnight Mitchel Obegränsad förhandsgranskning - 1860 |
Popular Astronomy, And, the Orbs of Heaven Denison Olmsted,Ormsby MacKnight Mitchel Ingen förhandsgranskning - 2015 |
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angle Annual variation aphelion apparent diameter appearance ascending node asteroids astronomers attraction celestial celestial sphere centrifugal force changes Cincinnati Observatory circle circular clock comet computed conjunction determined direction discovered discovery disk disturbing DUDLEY OBSERVATORY earth earth's orbit Eccentricity ecliptic entire equal equator exact examination exerted fact fall figure fixed stars globe gravitation heavens hence Hipparchus hypothesis inclination inferior conjunction instruments Jupiter Jupiter's Kepler law of Kepler laws of motion light line of nodes Longitude lunar major axis Mars mass Mean distance measure Mercury meridian millions of miles moon moon's orbit move nearly observation Observatory pass perihelion period of revolution phenomena planet planetary orbits pole position precisely present problem radius reached retrograde revolution in days revolving ring rotation round satellites Saturn seen Sidereal revolution space spots sun's center surface telescope tion transit Uranus velocity Venus vernal equinox visible visual ray weight worlds
Populära avsnitt
Sida 302 - Law of gravitation: Every particle of matter in the universe attracts every other particle with a force varying directly as the product of their masses and inversely as the square of the distance between them.
Sida 186 - ... modern terms, they knew the " law of the inverse ratio of the square of the distance from the centre of the revolution." Some have thought, that in Empedocles's system the foundation of Newton's was to be found ; imagining, that under the name of
Sida 359 - Such is a summary of the hypothesis of La Place on the origin of the solar system. This hypothesis explains, in the most satisfactory manner, the three most remarkable phenomena presented by the planetary motions. " 1st. The motion of the planets in the same direction, and nearly in the same plane. " 2d. The motion of the satellites in the same direction as their planets.
Sida 32 - CR a radius of the earth perpendicular to the visual ray SC, and SR the visual ray drawn to the extremity R of the radius, the angle RSC is the solar parallax, and in case it were possible to measure that angle, as the angle SCR is a right-angle, the remaining parts of the triangle RSC become known by computatation. Thus it appears that the problem of measuring the sun's distance from the earth resolves itself into obtaining the value of the sun's horizontal parallax, or the angle under which the...
Sida 118 - a singular phenomena connected with the snow-zone, which, so far as I know, has not been noticed elsewhere. On the night of July 12, 1845, the bright polar spot presented an appearance never exhibited at any preceding or succeeding observation. In the very centre of the white surface was a dark spot, which retained its position during several hours, and was distinctly seen by two friends who passed the night with me in the observatory. It was much darker, and better defined than any spot previously...
Sida 57 - These planes are inclined to each other, under an angle of 3° 23' 28".5, one half of the orbit of Venus lying above, or north of the ecliptic, the other half lying below, or south of the ecliptic. The point in which Venus passes from the north to the south side of the ecliptic is called the descending node. She returns from the south to the north of this plane through the ascending node, and the line joining these two points is called the line of nodes. The transits of Venus, unfortunately for astronomical...
Sida 136 - The third, viz. that the squares of the periodic times are proportional to the cubes of the mean distances...
Sida 209 - Hence a sun, weighing twice as much as the central orb of the solar system, would (at the same distance) attract with a double force. The same is true of the earth ; and if it were possible to hollow out the interior of the earth until its weight were reduced to one-half of what it is now, its power of attraction would be diminished in the same exact proportion. Thus, to know with what power the sun or any planet or any satellite attracts a body at a given distance, we are compelled to ascertain...
Sida 119 - I observed for the first time a small bright spot, nearly or quite round, projecting out of the lower side of the polar spot. In the early part of the evening the small bright spot seemed to be partly buried in the large one. After the lapse of an hour or more my attention was again directed to the planet, when I was astonished to find a manifest change in the position of this small bright spot.
Sida 319 - We shall see hereafter that the centrifugal force at the earth's equator is equal to ^|T of the force of gravity. Now, if the sun rotated in the same time as the earth, and their diameters were equal, the centrifugal force on the equators of the two orbs would be equal. But the sun's radius is about 111 times that of the earth, and if the period...