Part 9 (1/2)
When we contemplate this radiant Venus, it is difficult, even if we can not forards habitation, to assume that she must be a dreary desert, and not, on the contrary, to hail in her a celestial land, differingwith her sisters in the accoeneral plan of Nature
Such are the characteristic features of our celestial neighbor In quitting her, we reach the Earth, which comes immediately next her in order of distance, 149 million kilometers (93,000,000 miles) from the Sun, but as we shall devote an entire chapter to our own planet, ill not halt at this point, but cross in one step the distance that separates Mars fro, that our planet is the largest of the four spheres adjacent to the Sun Here are their comparative diameters:
The Earth = 1 In Kilometers In Miles
Mercury 0373 4,750 2,946 Venus 0999 12,730 7,894 Earth 1000 12,742 7,926 Mars 0528 6,728 4,172
It will be seen that Venus is almost identical with the Earth
MARS
Two hundred and twenty-six millions of kiloravitating in an orbit exterior to that which the Earth takes annually round the same center
Unfortunate Mars! What evil fairy presided at his birth? From antiquity, all curses seem to have fallen upon hie, the protector of ar the peoples, it is he who pours out the blood of Huain, as in the case of Mercury and Venus, the appearance has originated the idea Mars, in fact, burns like a drop of blood in the depths of the firmament, and it is this ruddy color that inspired its na whiteness of Venus made her the Goddess of love and beauty Why, indeed, should the origins of ht elsewhere than in astrono to the presumptive influence of Mars the defects inherent in its own terrestrial nature, this world, unwitting of our sorrows, pursued the celestial path marked out for it in space by destiny
This planet is, as we have said, the first encountered after the Earth
Itsobt is very elongated, very eccentric Mars accomplishes it in a period of 1 year, 321 days, 22 hours, _ie_, 1 year, 10 months, 21 days, or 687 days The velocity of its transit is 23 kilometers (145 miles) per second; that of the Earth is 30 (19 e distance of 149 million kilometers (93,000,000 miles) froe distance of 76 million kilometers (47,000,000 ated it follows that at certain epochs the two planets approach one another by so less than 60 million kilometers (37,000,000the best observations upon our neighbor of the ruddy rays
The oppositions of Mars arrive about every twenty-six reatest proximity, when this planet approaches to within 56 million kilometers (34,700,000 miles) of the Earth, occur only every fifteen years
Mars is then passing perihelion, while our world is at aphelion (or greatest distance frolobe presents to us an apparent diameter 63 times snifies 63 tinitude as our satellite vieith the unaided eye, and an instruer in diameter
In di almost half the size of the Earth In diameter he measures only 6,728 kilometers (4,172 miles), and his circumference is 21,125 kilometers (13,000 miles) His surface is only 29/100 of the terrestrial surface, and his volume only 15/100 of our own
This difference in volume causes Mars to be an earth in raphy, his y, we seem to see in space a reduction of our own abode, with certain dissimilarities that excite our curiosity, andto us
The Martian world weighs nine tiht of the Earth by 1,000, that of Mars would be represented by 105 His density is much less than our own; it is only 7/10 that of the Earth A lobe, would weigh only 26 kilograms
The earliest telescopic observations revealed the existence of s upon the surface of Mars The progress of optics, adnifications, exhibited the form of these patches more clearly, while the study of their motions enabled the astronomers to determine with remarkable precision the diurnal rotation of this planet It occurs in 24 hours, 37 ly a little longer on Mars than on the Earth, but the difference is obviously inconsiderable The year of Mars consists of 668 Martian days The inclination of the axis of rotation of this globe upon the plane of itsobt is much the saous to ours in intensity, while twice the length, the Martian year being almost equal to two of our years The intensity of the seasons is indeed more accentuated than upon the Earth, since the orbit of Mars is very elongated But there, as here, are three quite distinct zones: the torrid, the telacial
By means of the telescope we can follow the variations of the Martian seasons, especially in what concerns the polar snohich regularly aggregate during the winter, andthe heat of the summer These snows are very easily observed, and stand out clearly with dazzling whiteness The reader can judge of theure, which su one of the recent oppositions of Mars (1900-1901) The size of the polar cap diminished from 4,680 kilometers to 840 The solstice of the Martian su on July 6th
So the Martian ust, as never happens with our polar ice
Hence, though this planet is farther away from the Sun than ourselves, it does not appear to be colder, or, at any rate, it is certain that the polar snows are much less thick
On the other hand, there are hardly ever clouds on Mars; the Martian atmosphere is almost always limpid, and one can say that fine weather is the chronic state of the planet At tiions, but they are soon dissipated, and the sky clears up again
[Illustration: FIG 40--Di the summer]
Since the invention of the telescope, a considerable nu Mars under every aspect, and the agreeives us a sufficient acquaintance with the planet to adraphy, and of drawing out _areographic_ ed of fros here reproduced, as made (February, 1901) at the Observatory of Juvisy, and froeneral chart drawn fros 41, 42 and 43)