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photo_urls[1] = "http://www.astrobio.net/albums/powers/aam.jpg";
photo_captions[1] = "In this picture we see the nucleus of the sodium atom. We cannot even guess how the 12 protons and 11 neutrons in it are placed. This nucleus is not painted an even grey  its edge is of a somewhat lighter tone which gradually merges into the darker hue in the center. The meaning of this difference of tone is again different from that in drawings -7 to -11. Here a darker grey denotes greater density of electric charge. As a new element there is a gamma ray, full of astonishingly penetrating power, coming in from the left. Its wave length is only a millionth of an angstrom unit, which itself is a hundred millionth of a centimeter! Looking back on the whole series of 40 pictures we find that in only 10 of them (3 to -6) is life known to exist. In other scales there may, however, be forms of life we do not yet know. ";
photo_urls[2] = "http://www.astrobio.net/albums/powers/aal.jpg";
photo_captions[2] = "Now the nucleus of sodium has become of appreciable size, and also in the inset the nucleus of the hydrogen atom (a proton) is clearly  visible . As was pointed out in -4, there is no question of the objects themselves being  visible , as we are dealing here with dimensions which are a hundred million times smaller than the wave lengths of light. Light functioned only up to that drawing. So did color, which could play an appreciable role in only 14 domains of scale (#10 to -3)  11 to 26 could give no more than white spots on a black background. ";
photo_urls[3] = "http://www.astrobio.net/albums/powers/aak.jpg";
photo_captions[3] = "This is already the third jump we have made since we saw the atom from the outside in -8 and we are still in the seemingly endless emptiness of the inside. The chance of our meeting an electron has again become a hundred times smaller. The color in consequence is again a lighter grey. The wave length of the gamma ray has increased to 5 centimeters. The grain of salt which was only half a millimeter when we saw it in actual size on the girl's hand has now become an unthinkably huge cube with sides of more than 50,000 kilometers. The nucleus of the sodium atom is 0.7 millimeters and of hydrogen 0.2 millimeters. ";
photo_urls[4] = "http://www.astrobio.net/albums/powers/aaj.jpg";
photo_captions[4] = "It will be noticed that the tone that symbolizes the probable presence of an electron is again a lighter grey than that of the previous drawing, because the actual area depicted in the square is here again reduced to 1/100th. The sinusoid coming from the left shows the wave length of a typical gamma ray (wave length here 5 millimeters) such as is emitted from a radium-dial watch. The girl of picture 1 would on this scale have a length of about 15 million kilometers! The salt crystal would now be more than 3000 kilometers high. The sodium nucleus would be 0.0333 millimeter, the hydrogen nucleus (a proton) 0.01 millimeter. ";
photo_urls[5] = "http://www.astrobio.net/albums/powers/aai.jpg";
photo_captions[5] = "Again in this picture darkness of tone denotes the probability that an electron will be found in a certain place. As the sodium atom is here drawn at a 10 times larger scale, the area depicted in it is only 1/100th that of #-8. The probability that an electron will be found there will be that much smaller and the shading in consequence is made lighter. The same holds for the hydrogen atom in the inset. The nucleus of the sodium atom is in the center. Its size on this scale is only 7 microns. Twelve electrons are whirling around this nucleus at speeds of about 1,000 kilometers per second in reality, or a thousand million times more on this imagined magnified image. The sinusoid drawn shows the wave length of the finest X-rays on this scale. In the inset a quarter of a hydrogen atom is visible. ";
photo_urls[6] = "http://www.astrobio.net/albums/powers/aah.jpg";
photo_captions[6] = "The sodium (1) and chlorine (2) atoms of the salt crystal are clearly indicated. The shading here and in later pictures has only a symbolic value: a darker grey only means that the probability is greater that an electron will be found there than in a place that is more lightly shaded. As to the oxygen molecules (3) moving in the air, their average speed at a temperature of 10° Centigrade (= 50° Fahrenheit) would be 470 meters per second (= 1,000 miles per hour) in reality. In the image that speed would be 108 times greater, that is, more than 100 times the speed of light! In the inset the helical structure of the flagellum which could be recognized in -7 can no longer be seen, as again only hydrogen atoms are indicated, and all other atoms behind them (oxygen, carbon, and nitrogen) are left out. In the corner is one quarter of a hydrogen atom. ";
photo_urls[7] = "http://www.astrobio.net/albums/powers/aag.jpg";
photo_captions[7] = "Magnification here is ten million times, and the structure of the salt crystal can be shown. Distances between the successive layers of sodium (1) and chlorine (2) atoms in the lattice of the crystal are known, though its height would be 5 kilometers on this scale. To the left oxygen (3) and nitrogen (4) molecules are moving about as air at average distances indicated. Nitrogen molecules are more than 3 times as numerous as oxygen. In the inset a schematic sketch is given of just one strand of the flagellum, and even so only the hydrogen atoms on the near side are indicated. Otherwise the representation would become unintelligible, as the other atoms behind them are not placed in regular rows as they are in the salt crystal. Total width of the protein molecule including the amino acids which are bound to the strand is indicated (5). ";
photo_urls[8] = "http://www.astrobio.net/albums/powers/aaf.jpg";
photo_captions[8] = "This scale has a magnification of a million. The electron microscope therefore can no longer give us clear images, for at most it can magnify 100,000 times. A more schematic image is therefore unavoidable, that is, a diagram rather than a photographic enlargement. Yet we know that there would still be living creatures. We show the infantile paralysis virus (1), already visible in -5, and one of hoof and mouth disease (2). The latter is about the smallest now known. Apart from the viruses shown there exist several with shapes sharply different from these wholly or nearly spherical forms. The sinusoid (3) shown is of an ultraviolet ray. The dots in the upper left quadrant indicate molecules of the air. The inset has the flagellum composed of three strands as already shown in -5. The height of the salt crystal on this scale would be 500 meters. ";
photo_urls[9] = "http://www.astrobio.net/albums/powers/aae.jpg";
photo_captions[9] = "On the upper layer of keratin (1) a number of viruses are crowded together, as they often actually are on the skin. One of the larger ones is smallpox (2). A bacteriophage (3) of medium size as we saw in the previous drawing is shown here very distinctly from an electron- microscopic observation - just to give its size and shape, for it would not be likely to lie here by itself! Many molecules could be shown on this scale. Some starch molecules (4) are drawn. The inset shows the helical structure of the flagellum (5) as seen in the electron microscope. The flagellum clearly is composed of three strands wound into what looks like a cord. Magnification is here 100,000 times, about the maximum that can be reached with the electron microscope. The height of the salt crystal on this scale would be 50 meters. ";
photo_urls[10] = "http://www.astrobio.net/albums/powers/aad.jpg";
photo_captions[10] = "The electron microscope helps us to get an idea of the shapes of some of the living creatures. We see a diphtheria bacillus (1) and a colon bacillus (2), which itself is being attacked by bacteriophages (3), as well as a smallpox virus (4). We see how keratin of the skin is curling up (5) before falling off. Some gold leaf (6) left on the girl's hand, possibly from book binding, demonstrates its extreme thinness  in fact this gold leaf is so thin that you could use it to cut a bacterium, such as is depicted near it, in two, if only you could hit it. The visible rays from the sun are symbolically represented by two sinusoids (waves) with the wave lengths of red (7) and violet (8) light. The inset shows the typhoid bacillus (9) with its flagella (10). The salt crystal's height on this scale would be 5 meters. ";
photo_urls[11] = "http://www.astrobio.net/albums/powers/aac.jpg";
photo_captions[11] = "The height from where we are supposed to be looking has now been reduced to 0.5 millimeters or 500 microns. This is the last domain of scale in which an impression of color can be gotten by the human eye. The living creatures here are bacteria. We see some on the girl's hand: colon bacilli (1) and diphtheria bacteria (2), tubercle bacilli (3), and pneumonia bacteria (4). The bacterium in the inset in the lower right corner can now be recognised as a typhoid bacillus (5), such as humans may  carry  unknowingly for a long time. Its flagella (by which it moves) are clearly shown. We shall magnify it separately in an inset at the same place in the following pictures. This means that what is shown in the small quarter circle will each time be magnified 10 times, so that it will fit into fhe large quarter circle in the next picture. ";
photo_urls[12] = "http://www.astrobio.net/albums/powers/aab.jpg";
photo_captions[12] = "To see this picture, taken from a height of only 5 millimeters, we should need a microscope. Again there is a member of the animal kingdom visible: one of the water mites we saw on the previous drawing, a cyclops (1). This is again not the most likely thing to happen, that it would lie thus comfortably with its feelers over the edge of the cut in the girl's finger, but it could happen! In the section of the skin we notice the horny keratin layer (2) on top. Under it is the Malpighian layer (3) with its numerous cells and the orifice of a sweat duct (4). Under that lies the Corium (5) with its nerve papillae (6), small blood vessels (7), and fat cells (8). We see how the mosquito's proboscis (9) sticks into the skin. In the smaller of the two quarter circles in the right hand bottom corner we can now just see the bacterium (10). ";
photo_urls[13] = "http://www.astrobio.net/albums/powers/aaa.jpg";
photo_captions[13] = "We have now come down to 5 centimeters above the girl's hand, and with a magnifying glass we can distinguish the grooves in its skin. On it we notice some small organisms (1): water mites and bacteria. They got there, probably, when the girl put her hand in the water of a ditch nearby. In the right hand bottom corner inside the quarter circle there is a bacterium, which however is so small that we can't see it. In the cut we see a section of the epidermis. In a real cut in a finger not all the detail shown here could be distinguished, but it is interesting to include it. The malaria mosquito is clearly visible: its large compound eyes (2), feelers (3), and jaws (4)  also its proboscis (5), with which it is busy stinging the poor child. We see the flexible sheath (6) bent in a curve as it touches the skin. ";
photo_urls[14] = "http://www.astrobio.net/albums/powers/aan.jpg";
photo_captions[14] = "The living creature portrayed in this drawing is a mosquito, to be exact an anopheles, or malaria mosquito. We can see this from the way it sticks up its hind legs. This is the first strange coincidence, for from the first series of pictures we know that it was in December that the scene occurred, and this insect is rather rare in Holland in winter. We notice that there is a little cut in the girl's finger. Right in the center of the tiny square in the middle is a minute white spot. It is a grain of salt which stuck to the girl's hand, having been left there, we may assume, after she ate her lunch. As it is not exactly the thing we would most expect to find there, it will be evident that there is a special reason for choosing it. That reason will appear later. ";
photo_urls[15] = "http://www.astrobio.net/albums/powers/abn.jpg";
photo_captions[15] = "We said before that the reason why we took as the initial picture this little girl with her cat was that we wanted to find out in how many of the total number of domains of scale living creatures are known to occur. We have found them so far only in pictures 1, 2, and 3. Now we shall continue to look for representatives of the living world in all succeeding scales. Rather strange coincidences will occur in the following pictures: unexpected things coming together on the hand of this child! We feel justified, however, in bringing them together, as this helps us to compare their sizes. In this and all the remaining pictures, of course, the small square in the center encloses what is to be found in the next picture, rather than in the preceding one as in the first series  and the tiny square (beginning with #0) shows the area of the second following picture. ";
photo_urls[16] = "http://www.astrobio.net/albums/powers/aao.jpg";
photo_captions[16] = "In the center of this second illustration we see a square 1.5 centimeters on each side and in it the picture of the opposite page to one-tenth size, for the sake of comparison. Shown to the same scale are two automobiles, a smaller and a larger type, and also a strange object which at first we hardly recognize as the front part of a whale. A long and unlikely story would certainly be needed to make the presence of a whale at this place and time plausible or even possible. For our present purpose, however, we shall not be held back by such considerations  our aim in putting the poor dead whale there lying on its side is only to enable us to compare the size of the young human being with one of the largest living creatures, also a mammal. Later this will enable us to observe in how many of the domains of scale living creatures occur. ";
photo_urls[17] = "http://www.astrobio.net/albums/powers/aap.jpg";
photo_captions[17] = "In the center we now see a tiny square, the sides of which are only 1.5 millimeters in width (abbreviated 1.5 mm.). It clearly represents the illustration two pages before: #1. The child (1) in it is barely visible, but the cars (2) can easily be distinguished and the whale (3) shows up nicely in its full length of some 30 meters, which is about the record length these fellow-mammals reach. The U-shaped building (4) tells a story of the war years, when the German military built it during the occupation of the Netherlands. After the liberation it was rebuilt and enlarged to become the central building for the Werkplaats Children's Community. The long building (5), typical of Holland, is a bicycle shed. Note that the number of each picture corresponds with the exponent of the power of 10 in the statement of the boldface line below each caption giving the scale. ";
photo_urls[18] = "http://www.astrobio.net/albums/powers/aaq.jpg";
photo_captions[18] = "It is surprising that already in this fourth illustration the child, who filled the greater part of the first picture, has completely disappeared. The reason, as we said in the introduction, is that each time we jumped upward, we had to go ten times higher than we were, in order to produce an image at a scale one-tenth that of the one before. If we viewed the little girl from a height of, say, 5 meters in picture 1, we had of necessity risen to 50 meters to see #2, to 500 meters for #3, and now we look down from a height of 5000 meters. That is higher than Mont Blanc, Europe's highest mountain! No wonder that the huge whale can now hardly be distinguished. We notice a strange wavy line reaching the school building. We wonder what that is. The next drawing will show. ";
photo_urls[19] = "http://www.astrobio.net/albums/powers/aar.jpg";
photo_captions[19] = "We have now jumped to a height of 50,000 meters or 50 kilometers, that is more than 30 miles, and we notice a second effect of our jumps: not only are all lengths we see reduced tenfold each time, but the area which comes into our field of vision increases a hundredfold. So the above illustration covers a square 15 kilometers on a side, and we see Bilthoven (1) as a suburb of Utrecht (2). A dotted wavy line symbolizes a radio wave of 298 meters wave length reaching Bilthoven from the transmitter southwest of Utrecht, called  Hilversum  after the town (3) where its studios are. The 1.5-centimeter square in the middle gives again, as it has done each time, a reduced representation of the preceding illustration. As this illustration contains a photograph of a detailed plan of Bilthoven, it just shows the houses, though very minutely. ";
photo_urls[20] = "http://www.astrobio.net/albums/powers/aas.jpg";
photo_captions[20] = "Here we see the central part of the Netherlands. The small square in the middle of course shows the town of Utrecht, and the tiny square inside is the twice-reduced picture of illustration 4. There is Bilthoven, and... there is the little girl: we know she must be there, but we cannot see her! The drawing has now become like a geographical map of central Holland. We see the largest towns: Amsterdam (1), The Hague (2), Rotterdam (3), also the rivers Rhine (4) and Meuse (5). The bay in the North used to be the Zuyder Zee. It now has become a lake, the  Yssel Lake , named thus after the Yssel (6), the arm of the Rhine which flows into it. In the Yssel Lake new land (7) is being reclaimed by making dykes (8) and removing the water by pumping. In the lower right center the town of Arnheim (9) is shown. ";
photo_urls[21] = "http://www.astrobio.net/albums/powers/aat.jpg";
photo_captions[21] = "Whereas picture 5 gave us the villages of a local district, and #6 the towns of a country, this 7th drawing covers part of a continent - Western Europe - and shows a number of its countries. Actually 15 different countries are wholly or partly visible, as well as 10 of their capitals and a number of rivers, too many to mention by name. The map further shows three seas - the North Sea, the Baltic, and the Adriatic - and a portion of one of the oceans, the Atlantic. As a square 1500 kilometers on a side is covered, the spherical shape of the earth becomes visible  one of the parallels of latitude is drawn to demonstrate this, but the curvature is still so slight that the map can still be thought of as flat. It will need one more jump to reveal it as part of the surface of a sphere. ";
photo_urls[22] = "http://www.astrobio.net/albums/powers/aau.jpg";
photo_captions[22] = "Until now we have been getting each time a wider view of our  world.  We now see the whole of it as a limited dwelling place in the surrounding blackness of space. Whereas in the last picture we could see countries, we now can see five of the six continents: only Australia does not come into the picture. We notice that the northern part of the globe is in shadow  as the picture was taken on December 21st at noon, the sun was in the south, and daylight did not reach farther north than the Arctic Circle. This shaded part of the earth in reality would have been much darker. It has, however, been left a dark grey, in order to show the visible portions of North America and northeast Asia. The North Pole (1) and the equator (2), as well as the meridians and the parallels of latitude for every 15 degrees, are shown as dotted lines. ";
photo_urls[23] = "http://www.astrobio.net/albums/powers/aav.jpg";
photo_captions[23] = "The earth, which reached nearly to the large square on the previous page, now fits into the small square. The distance we have had to travel straight up, to get its size thus reduced, is tremendous: according to our reckoning in drawings 4 and 5, we should be now 500,000 kilometers up, or about 312,500 miles - more than the distance to the moon. From here we see the earth as a planet spinning counterclockwise in the empty, dark, surrounding space. The sun, in the south, makes it shed its shadow toward the north. Two faint dotted lines mark the limits of this  umbra  (1). Another dotted line (2) gives the path along which the earth moves, from right to left. Many faraway stars would be visible, but these are left out in this drawing and others that follow, to concentrate attention on our  immediate surroundings . ";
photo_urls[24] = "http://www.astrobio.net/albums/powers/aaw.jpg";
photo_captions[24] = "It must have struck the reader that in the last two illustrations the shaded part of the earth was not of even darkness, but was clearly lighter on the left hand side. The cause of this becomes clear in this picture. In it we not only see the earth (1), its umbra (2) and the path (3) along which it moves, but we notice around the earth what looks like a circle. This line (4) is the path or orbit of the moon as it moves around the earth. The actual position of the moon (5) on that December 21st when we were supposed to make our celestial jump of exploration is shown. It now is clear that as the moon was there on the left, the night on earth was lit up on that side. As light travels 300,000 kilometers per second (that is, 3 centimeters on this scale), we see that it would need 1.3 seconds to cover the distance from the moon to the earth. ";
photo_urls[25] = "http://www.astrobio.net/albums/powers/aax.jpg";
photo_captions[25] = "In the preceding drawing, the actual shape of the moon's orbit appears to be practically a circle. As a matter of fact, it is not exactly a circle, but the difference is so slight that it is only visible in the position of the earth, which is in one focus of the ellipse, and therefore not in the center. There actually would be a slight flattening of the circle, because we are perpendicular above the earth, and therefore not straight above the plane of the moon's orbit, which itself makes a small angle with the earth's. These factors have been taken into account in composing the curve (6), i.e., the orbit as it would really appear to us from above  but they are small even in #10 and in this drawing they are not noticeable. It shows the earth (1), the moon (5), and its orbit (4)  the earth's umbra (2), and its orbit (3), which now can be seen to be very slightly curved. ";
photo_urls[26] = "http://www.astrobio.net/albums/powers/aay.jpg";
photo_captions[26] = "The tiny circle (1) in the center of the smallest square is now the moon's orbit. The earth's position is marked by a dot, although the dot is much too large and actually the earth would be invisible on this scale. Its orbit (2) is now clearly curved. Under the earth's orbit another curve (3) is drawn. That is the orbit of the planet Venus, which moves around the sun as the earth does and in the same direction: in this drawing, from right to left. The size of the sun, if it were drawn at this scale, would be 1.4 millimeters. We will repeat here that the black area of the above square would in reality be studded with a multitude of stars. We leave them out in this drawing and in the following drawings for the reason stated earlier. ";
photo_urls[27] = "http://www.astrobio.net/albums/powers/aaz.jpg";
photo_captions[27] = "The sun (2) has now come into the picture. It is 1.5 centimeters away from the earth (1). The size of the earth has shrunk to 1.3 micron and even the sun's size should be only 140 microns. The dots denoting them are therefore much too big, for a micron is only a thousandth of a millimeter! Inside the earth's orbit we see the planets Mercury (3) and Venus (4). Outside it are Mars (5) and Jupiter (6) with their orbits. The positions of the planets (just as that of the moon in #10) in this and following drawings are those which they occupied when we undertook our miraculous and timeless journey through space. We will now state more precisely when this was: It was December 21st of the year 1951. In addition to the sun and the planets we see part of the orbit of Halley's comet (7), which comes into our  neighborhood  once every 77 years. ";
photo_urls[28] = "http://www.astrobio.net/albums/powers/aba.jpg";
photo_captions[28] = "The whole solar system is now in view. The sun and the planets nearest it - Mercury, Venus, Earth, Mars - have together been reduced to a tiny circle (1), but the other planets and their wider orbits are clearly seen  Jupiter (2), Saturn (3), Uranus (4), Neptune (5), and Pluto (6). The latter's orbit at one place comes inside Neptune's. The whole orbit of Halley's Comet is here  also its position in 1951 (7). It will be near the earth again in 1986. The elliptic nature of the planets' orbits has been taken into account. In most cases, however, this again means only that the sun is not in the center of an orbit, for the difference of its shape from the circle cannot be seen in any of them except Pluto's. The inclination of the orbits to the plane of the horizon of Bilthoven has been neglected. Light would on this scale travel about 1 centimeter per hour. ";
photo_urls[29] = "http://www.astrobio.net/albums/powers/abb.jpg";
photo_captions[29] = "In this drawing the whole solar system, that is, the sun with all the smaller bodies which move around it, has been reduced to the space of a circle a little over 1 centimeter in diameter. Apart from the planets and Halley's Comet, which were shown in #13 and #14, there are a number of very small bodies, which we leave out because they are too small to be seen from such distances. These pictures really give a wrong impression of what the solar system would look like, for all the orbits are shown. What would be seen would be only the sun as a small star (it would at this distance seem only about 100 times as bright as Venus looks from the earth) and near it the planets, which themselves give no light but are merely lit up by the sun on the sides turned toward it. Light takes nearly 11 hours to travel across the solar system. ";
photo_urls[30] = "http://www.astrobio.net/albums/powers/abc.jpg";
photo_captions[30] = "The tiny circle inside the smallest square now contains the whole field in which the vicissitudes of the solar system take place. If we continue the reckoning we used in drawings 4, 5, and 9, we should be now at a height of 5 million million kilometers above the horizon of that village in Holland from where we started. As we have imagined all along that we are making our trip without spending time, this means that it would have taken the light rays which we now see more than six months to cover the enormous distance from the earth, even though they travel at the rate of 299,800 kilometers per second! It also means that if we had a marvellously good telescope and could see details of events on earth, the events we watched would be those that happened more than six months ago! ";
photo_urls[31] = "http://www.astrobio.net/albums/powers/abd.jpg";
photo_captions[31] = "This seems a very uninteresting picture: it contains no more than one tiny white spot in the center of a black square! That spot, however, stands for the whole solar system, which on this scale would be only little more than 0.1 millimeter in diameter. In reality this illustration therefore is a very interesting one, because we now know and understand that that little speck of light contains not only the sun, but with it, all the planets, comets, asteroids, and meteorites which move around it ... and their orbits! And we now realize that it is quite possible that numberless other stars that we see at night may have such satellites moving around them. All other stars that could be seen besides our sun are still left out, as our aim is primarily to show our own  immediate surroundings.  Light, on this scale, would travel 9.46 centimeters, or about 4 inches, in a year. ";
photo_urls[32] = "http://www.astrobio.net/albums/powers/abe.jpg";
photo_captions[32] = "For the first time we now show just one star besides the sun  there is no longer fear of confusion, as the whole solar system has been reduced to a point (1). The star marked (2) is the double star called Alpha in the constellation Centaurus. This star, Alpha Centauri, is the star nearest to the earth, if we do not reckon the very faint Proxima Centauri, which may be slightly nearer. Its distance from the earth is about 4 light years, which means that light needs about 4 years to cover that distance. On the scale of this drawing, 1 light year would be 0.946 centimeters, that is, about 1 centimeter. Alpha Centauri is therefore at a distance of about 4 centimeters from the sun. In the drawing it seems nearer. The explanation of this seeming discrepancy is that Alpha Centauri is farther away than the sun from our faraway point of observation. ";
photo_urls[33] = "http://www.astrobio.net/albums/powers/abf.jpg";
photo_captions[33] = "Every time, the jump we make to our next point of observation gets more inconceivably large. From the present one we could no longer see the sun with the naked eye, for without the help of a telescope a star such as the sun is barely visible at a distance of 55 light years, and our point of observation would now be at a distance of 500 light years. It is not surprising that the sun could no longer be seen with the naked eye from that distance, as its size at the scale of this drawing would only be 0.00014 micron, or about the size of an atom! Apart from the sun and Alpha Centauri, 36 stars are shown all of which are known to be at less than 50 light years distance from the sun. They are all where they would seem to be if we looked down on them on December 21st, 1951, at noon. A circle marks the distance of 50 light years from the sun. ";
photo_urls[34] = "http://www.astrobio.net/albums/powers/abg.jpg";
photo_captions[34] = "This little group of stars is of course the same as the one on #19, but seen from ten times farther away. We could give for all of them the names by which the astronomers know them, but we mention only 12 of the best known, putting numbers under the corresponding stars in #19, as there is room for them there. First the sun (1)  then Alpha Centauri (2), Beta Hydri (3), Delta Pavloni (4), Castor (5), Pollux (6), Capella (7), Procyon (8), Sirius (9), Arcturus (10), Altair (11) and Vega (12). No attempt has been made to indicate the relative brightness of the stars shown, for it would be very different as seen from our present faraway point of observation from what it appears to be from the earth. ";
photo_urls[35] = "http://www.astrobio.net/albums/powers/abh.jpg";
photo_captions[35] = "We have now jumped so high that we have come out of the complex of stars to which our solar system belongs, and which we can see on a clear starlit night the galactic system and contains many thousand millions of stars. The sun is only a faintly lighted strip right across the sky: the Milky Way. It is usually called the galactic system and contains many thousand millions of stars. The sun is only a very unimportant one of these, and it is situated not in the center but in the outskirts, which we see in the above drawing. In the tiny square we notice that the sun and its 37 neighbor stars, which in #20 filled the small square, have now become but one dot. The other stars are huddled together in irregularly formed groupings, in which we can hardly discover any clear shape or line. We shall need to make another jump to discover the general form of the galaxy and of the formation of stars nearest to the sun. ";
photo_urls[36] = "http://www.astrobio.net/albums/powers/abi.jpg";
photo_captions[36] = "Here we have the entire galactic system or galaxy, of which on the previous page we saw only what is now in the small square. Our galaxy is a spiral  it has the shape of a disk from which a number of spiral arms protrude. At the center the disk is much thicker than at the edges, where it is quite thin  the bright shining center bulges out. We see this circular disk partly tilted from the side, so that it looks like an ellipse. In the small square we now recognize in the streak of light a rather irregular spiral arm near which our solar system is situated. Apart from this one, other spiral arms can be seen. Below on the right there is a strange nebulous body. It is the Great Magellanic Cloud, a much smaller galaxy, far behind our own Milky Way. The white spots around the galaxy are the hundred and more globular clusters of stars which surround it. ";
photo_urls[37] = "http://www.astrobio.net/albums/powers/abj.jpg";
photo_captions[37] = "However large the object is, the next jump reduces it to one tenth its size. So here we find our galaxy again, but as an ellipse (1) barely 8 millimeters in length, and inside the small square. The Great Magellanic Cloud (2) is again partly visible, but it lies far behind it. The Small Magellanic Cloud (3) can now be seen, and also two more of the galaxies which are relatively near our Milky Way. They are the Sculptor (4) and the Fornax (5) systems. No other galaxies are drawn, although many further away would be visible, for again we want to concentrate attention on  our own world  and its  nearest neighbors . We must think of our galaxy whirling around, clockwise, only once in 200 million years. And yet this movement gives to our solar system, because it is so close to the edge of the disk, the terrific speed of 216 kilometers per second! ";
photo_urls[38] = "http://www.astrobio.net/albums/powers/abk.jpg";
photo_captions[38] = "In this illustration we show only what astronomers call our local group of galaxies, leaving out all others. There is a general tendency of galaxies to gather in groups, some not numerous, others several hundred or even a thousand strong. How many must be reckoned to belong to our local group it is not possible to say  at these stupendous distances, it is no longer possible to obtain very precise data. It is certain that our local group includes the galaxies numbered 1, 2, and 3 in the previous drawing, and also, in the above illustration, the great spiral in Andromeda called Messier 31 (6) with its companions NGC 147 (7) and NGC 185 (8) and the spiral system Messier 33 in the constellation Triangulum (9). Other galaxies which are usually considered to belong are those numbered 4 and 5 on the previous page and the systems NGC 6822 (10) and IC 1613 (11). ";
photo_urls[39] = "http://www.astrobio.net/albums/powers/abl.jpg";
photo_captions[39] = "Now that our whole local group of galaxies has shrunk to the size of less than 2 millimeters in the center of the small square, we have in the above drawing indicated some of the countless other galaxies and clusters of galaxies which are spread out in all directions. Their distribution is known to be fairly uniform. Naturally the above drawing does not try to be an exact representation. In the two previous ones the galaxies shown were actually placed in the positions they would be in, with reference to our galaxy, if we could look at them from our imaginary point of observation above that place on earth and on that moment when we undertook our fantastic flight. Now, however, all we can do is to sketch a large number of galaxies and groups of galaxies of different sizes and to make their average distance the kind of dimension it is known to be. ";
photo_urls[40] = "http://www.astrobio.net/albums/powers/abm.jpg";
photo_captions[40] = " In this last picture of the series at reduced scales, we naturally find that all galaxies and groups of galaxies, even the largest of them, are reduced to dots of various sizes. It goes without saying that the placing of them has been of necessity quite arbitrary. The object is merely to give a very faint idea of the inconceivably large number of galaxies in the midst of which our Milky Way is placed. The number of galaxies which are visible with our present telescopes is of the nature of a thousand million. The farthest of these would be at a distance from the earth of 2,000 million light years, that is, something like the length of a diagonal of the large square above. What is drawn here is therefore certainly less than what exists. For the galaxies would be much nearer to each other than the picture shows, and they would continue far beyond its confines .... ";
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var photo_count = 40; 

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    //-- it's all good ---
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    //-- any other browser we go low-tech ---
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// - IE5.5 and up can do the blending transition.
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function preload_photo(index) {

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