The Sun: Ruler, Fire, Light, and Life of the Planetary System |
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Page 10
... angle on whose exact measurement the solution of this problem depends . But even when anyone has pictured to himself the difficulty of determining the exact angle subtended by an inch disc at that distance , and how easily the angle ...
... angle on whose exact measurement the solution of this problem depends . But even when anyone has pictured to himself the difficulty of determining the exact angle subtended by an inch disc at that distance , and how easily the angle ...
Page 14
... angle a м b . As a matter FIG . 4 . of fact , however , even this small angle has to be re- duced considerably ; because from a or b , the Moon would be on the horizon , and the estimate of her posi- tion rendered unsatisfactory by ...
... angle a м b . As a matter FIG . 4 . of fact , however , even this small angle has to be re- duced considerably ; because from a or b , the Moon would be on the horizon , and the estimate of her posi- tion rendered unsatisfactory by ...
Page 16
... angle M ' E s as well as the right angle at M ' , and thus the shape of the tri- angle E M's is assigned , and with it the proportion of E s to E M ' , which is what we require . Let us pause to notice the ingenuity of this method . The ...
... angle M ' E s as well as the right angle at M ' , and thus the shape of the tri- angle E M's is assigned , and with it the proportion of E s to E M ' , which is what we require . Let us pause to notice the ingenuity of this method . The ...
Page 18
... angle included between e m and e ' m ' ; it is easily seen that the angle subtended by the Sun's semi - diameter exceeds this angle by twice the Sun's horizontal parallax . will be convenient to indicate the quantity which-- instead of ...
... angle included between e m and e ' m ' ; it is easily seen that the angle subtended by the Sun's semi - diameter exceeds this angle by twice the Sun's horizontal parallax . will be convenient to indicate the quantity which-- instead of ...
Page 19
... angle be- tween lines directed towards the Sun's centre from dif- ferent parts of the Earth . For convenience , one of the points is taken to be at the Earth's centre as E ( fig . 7 ) . FIG . 7 . E Now , if E s ' represent a line ...
... angle be- tween lines directed towards the Sun's centre from dif- ferent parts of the Earth . For convenience , one of the points is taken to be at the Earth's centre as E ( fig . 7 ) . FIG . 7 . E Now , if E s ' represent a line ...
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Common terms and phrases
angle Ångström aphelion appearance astronomers body bright lines centre chromatosphere clouds coloured consider corona corresponding dark lines deduced determine diameter direction Earth eclipse effect error estimate fact faculæ favourable globe greater Halley's method heat height Herschel hydrogen inferior conjunction ingress length less limb luminous Mars mass matter mean distance measure meteoric miles per second minute Moon Moon's motion noticed observations orbit pass path peculiarity penumbra perihelion phenomena photographs photosphere planets Plate polariscopic portion present prism problem prominences proportion rays recognised regarded regions remarkable researches respecting rotation round Secchi seems seen shown Sir William Herschel slit solar light solar parallax solar physics solar prominences solar spectrum solar spots space spectra spectroscope stars stations Sun can control Sun-spot Sun's disc Sun's distance Sun's surface supposed telescope terrestrial theory tion transit transits of Venus vapours velocity Venus violet visible zodiacal light
Popular passages
Page 451 - I have seen the wild stone-avalanches of the Alps, which smoke and thunder down the declivities with a vehemence almost sufficient to stun the observer. I have also seen snow-flakes descending so softly as not to hurt the fragile spangles of which they were composed ; yet to produce from aqueous vapour a quantity, which a child could carry, of that tender material, demands an exertion of energy competent to gather up the shattered blocks of the largest stone-avalanche I have ever seen, and pitch...
Page 184 - Hence he concludes that the sun has a very extensive atmosphere, which consists of elastic fluids that are more or less lucid and transparent ; and of which the lucid ones furnish us with light. This atmosphere, he...
Page 117 - I obtained a tolerably bright solar spectrum, and brought a flame coloured by sodium vapour in front of the slit. I then saw the dark lines D change into bright ones.
Page 439 - The sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth. By its heat are produced all winds, and those disturbances in the electric equilibrium of the atmosphere which give rise to the phenomena of lightning, and probably also to those of terrestrial magnetism and the aurora.
Page 225 - Looked at in this point of view, we cannot refuse to regard them as organisms of some peculiar and amazing kind ; and though it would be too daring to speak of such organization as partaking of the nature of life, yet we do know that vital action is competent to develop both heat, light, and electricity.
Page 357 - The silvery rays were longest and most prominent at four points of the circumference — two upon the upper, and two upon the lower portion, apparently equidistant from each other . . . giving the spectacle a quadrilateral form. The angles of the quadrangle were about opposite the northeastern, north-western, south-eastern, and south-western points of the disc" (an arrangement corresponding precisely with the observations made at lower levels).
Page 194 - The spots, in this view of the subject, would come to be assimilated to those regions in the earth's surface, in which for the moment hurricanes and tornadoes prevail — the upper stratum being temporarily carried downwards, displacing by its impetus the two strata of luminous matter beneath, (which may be conceived as forming an habitually tranquil limit between the opposite upper and under currents,) the upper of course to a greater extent than the lower, and these wholly or partially denuding...
Page 188 - From experience we can affirm, that the performance of the most salutary offices to inferior planets, is not inconsistent with the dignity of superior purposes ; and, in consequence of such analogical reasonings, assisted by telescopic views, which plainly favour the same opinion, we need not hesitate to admit that the sun is richly stored with inhabitants.
Page 457 - Still, presented rightly to the mind, the discoveries and generalisations of modern science constitute a poem more sublime than has ever yet been addressed to the imagination. The natural philosopher of to-day may dwell amid conceptions which beggar those of Milton.
Page 458 - And still, notwithstanding this enormous drain in the lapse of human history, we are unable to detect a diminution of his store. Measured by our largest terrestrial standards, such a reservoir of power is infinite ; but it is our privilege to rise above these standards, and to regard the sun himself as a speck in infinite extension — a mere drop in the universal sea. We analyse the space in which he is immersed, and which is the vehicle of his power.