"VOYAGE TO THE SKY" "Since earliest antiquity, man has tried to depict the universe around him." "Earth seemed to be a flat, motionless surface strewn with craters and covered by a solid dome from which heavenly bodies hung." "Then, thanks to voyages on land and sea man learned that earth was a spherical mass around which he could travel." "But, trusting in the seeming movement of heavenly bodies, observers imagined a motionless earth around which the sun moon, and stars revolved." "Man thus remained the center of the universe." "The discovery of optical instruments gradually revealed the true structure of the universe." "The meridian telescope allowed man to determine the planets' exact positions and predict their movement." "The equatorial telescope revealed details of their physical appearance." "So earth was no longer the center of creation, but a tiny planet turning on an axis around the sun." "Itself but a simple star lost amid the multitude of its sisters." "Here's an idea of the method used to measure planetary distances" "If, closing one eye at a time, one looks at an object a medium distance away." "Each eye sees this object in a different spot." "In relation to the background in the distance, the closer the object, the greater the difference." "This difference is measured by taking into consideration the space separating the eyes, and calculating the distance separating us from the object with the help of triangulation formulas." "Let us imagine two observers separated by a known distance." "If they both point a telescope, at the moon at the same time each will see it in a different location in relation to the stars." "The difference being greater the further away the observers are from each other." "The observers can measure this difference and deduce there from the distance of earth from the moon." "Approximately 238,600 miles." "We would nee d30 earths like our own to fill in the gap separating us from the moon." "The distance of the sun, measured using the same procedure, is approximately 93 million miles." "A star infinitely far away can be observed at six-month intervals in relation to stars further away, and in the calculations we replace the distance that separated the observers by the distance earth has moved around the sun during that time." "Let us leave earth behind." "The clouds half mashing its continents, reveal the thin layer of atmosphere that surrounds it." "Our globe shrinks very rapidly in space, as, little by little, we approach the uneven surface of the moon first stop on our celestial Voyage." "Half lit by the sun, earth appears four times larger than the moon seen from earth." "We arrive at our satellite." "Here are its rings of mountains, its steep summits, its plains riddled with crevices." "Lacking atmosphere, void of air and water indispensable elements of life, this world that always turns the same side to earth is dead." "Above us, nothing veils the ever-shining stars, while the ground, beneath our feet heated by the sun for fourteen earth days, becomes unbearably hot and then falls to its lowest temperatures during the long lunar night," "but only and always on the same side, the one lit by earth." "Now let's go to Mars, 145 times further away than the moon." "Mars has an atmosphere, but not as great as earth's." "Two miniscule moons shine in its sky, next to our earth and moon which are now reduced to luminous dots." "The light spots that we see here are desert regions." "The dark parts, which from earth appear green during the Martian spring, take on the reddish-brown tones of autumn as the season advances and vegetation is revealed." "Let us leave Mars." "We flee from the sun and cross ever vaster distances more and more quickly." "Escorted by its rings and satellites" "Saturn approaches." "A world of such dimensions that earth could easily pass between the planet and its rings." "The satellite on which we stop is void of air and water, like our moon." "The rings circling Saturn are comprised of multitudes of particles, each of which revolves around the planet at a speed determined by the laws of gravity." "Saturn's atmosphere is quite thick." "Instead of soil the surface is boiling lava." "Like all big planets that have yet to cool down," "Saturn reveals what our own planet must have been like several billion years ago." "On a clear night," "Saturn's satellites shine in the sky, as do its rings, upon which the planet casts its shadow." "Our sun is now but a star and constellations begin to lose their shape." "Traveling at 186,000 miles a second, the speed of light, it would take over four years to reach our close neighbor, Alpha Centauri." "A number of stars are comprised of several suns, whose planetary systems are probably invisible from earth and some of which may have inhabitants that we cannot detect." "Thus, Alpha Centauri breaks down into two stars." "The appearance of a planet beneath this double light vaguely evokes the diversity that the stars' various hues bring to the worlds that escort them." "With ever-increasing speed, we flee this double sun." "At distances that light takes thousands of years to travel, we encounter expanses of luminous gas called "gaseous nebulae."" "Stars most likely emanate from the condensation of these gases." "Stars are not distributed equally everywhere." "They're much denser in regions where they're grouped in clusters than in the vicinity of our sun." "The stars are so bright around a planet of one of these suns that, despite the brightness of that sun they would burst through the atmosphere of a planet like ours in broad daylight." "With the arrival of night, nothing can equal the magic of the sky." "It's no longer a muted light falling from the stars but a glow bright enough to solely illuminate the landscape." "The stars are becoming even scarcer now." "We're approaching the limits of our universe." "Yet beyond, milky spots appear, their spiral forms barely distinguishable." "These are other universes like ours millions of light-years away." "If we crossed the immense abyss separating us from these spirals, we'd see them coalesce, into a multitude of stars each representing a sun like our own." "We would notice the Milky Way as well." "A tiny spot from the vantage point of these systems, where our sun is lost and earth is less perceptible still." "Thus, our little planet, which seems to us the entire universe with its varied landscapes, sun-drenched pla�ns, mountains of eternal snow poles of ice and equatorial heat- all its many manifestations of life " "Our little planet is, among the infinite diversity of the heavens, but an insignificant speck, less than the most minuscule grain of sand cradled by the waves of an immense sea."