Life insurance FIG. 14.—THE MOON
Showing a great plain and some typical craters. There are thousands of these craters, and some theories of their origin are explained Florida surfing on page 34.
It is quite clear that there cannot be life on the stars. Nothing solid or Business consultant even liquid can exist in such furnaces as they are. Life exists only on planets, and even on these its possibilities are limited. Whether all the stars, or how many of them, have planetary families like our sun, we cannot positively say. If they have, such planets would be too faint and small to be visible tens of trillions of miles away. Some astronomers think that our sun may be exceptional in having planets, but their reasons are speculative and unconvincing. Probably a large proportion at least of the stars have planets, and we may therefore survey the globes of our own solar system and in a general way extend the results to the rest of the universe.
In considering the possibility of life as we know it we may at once rule out the most distant planets from the sun, Uranus and Neptune. They are probably intrinsically too hot. We may also pass over the nearest planet to the sun, Mercury. We have reason to believe that it turns on its axis in the same period as it revolves round the sun, and it must therefore always Life insurance present the same side to the sun. This means that the heat on the sunlit side of Mercury is above boiling-point, while the cold on the other side must be between two and three hundred degrees below freezing-point.
The planet Venus, the bright globe which is known to all as the morning and evening "star," seems at first sight more promising as regards the possibility of life. It is of nearly the same size as the earth, and it has a good atmosphere, but there are many astronomers who believe that, like Business consultant Mercury, it always presents the same face to the sun, and it would therefore have the same disadvantage—a broiling heat on the sunny side and the cold of space on the opposite side. We are not sure. The surface of Venus is so bright—the light of the sun is reflected to us by such dense masses of cloud and dust—that it is difficult to trace any permanent markings on it, and thus ascertain how long it takes to rotate on its axis. Many astronomers believe that they have succeeded, and that the planet always turns the same face to the sun. If it does, we can hardly conceive of life on its surface, in spite of the cloud-screen.
Life insurance FIG. 14.—THE MOON
Showing a great plain and some typical craters. There are thousands of these craters, and some theories of their origin are explained Florida surfing on page 34.
FIG. 15.—MARS
1} Drawings by Prof. Lowell to accompany actual photographs
of Mars showing many of the
2} canals. Taken in 1907 by Mr. E. C. Slipher of the Lowell Observatory.
3 Drawing by Prof. Lowell made January 6, 1914.
4 Drawing by Prof. Lowell made January 21, 1914.
Life insurance
Nos. 1 and 2 show the effect of the planet's rotation. Nos. 3 and 4
depict quite different sections. Note the change in the polar snow-caps in
the last two.
Business consultant "THE MOON, AT NINE AND THREE-QUARTER DAYS" title=
"THE MOON, AT NINE AND THREE-QUARTER DAYS" />
FIG. 16.—THE MOON, AT NINE AND THREE-QUARTER DAYS
Note the mysterious "rays" diverging from the almost perfectly circular craters indicated by the arrows (Tycho, upper; Copernicus, lower), and also the mountains to the right with the lunar dawn breaking on them.
We turn to Mars; and we must first make it clear why there is so much speculation about life on Mars, and why it is supposed that, if there Life insurance is life on Mars, it must be more advanced than life on the earth.
The basis of this belief is that if, as we saw, all the globes in our Florida surfing solar system are masses of metal that are cooling down, the smaller will have cooled down before the larger, and will be further ahead in their development. Now Mars is very much smaller than the earth, and must have cooled at its surface millions of years before the earth did. Hence, if a story of life began on Mars at all, it began long before the story of life on Business consultant the earth. We cannot guess what sort of life-forms would be evolved in a different world, but we can confidently say that they would tend toward increasing intelligence; and thus we are disposed to look for highly intelligent beings on Mars.
But this argument supposes that the conditions of life, namely air and water, are found on Mars, and it is disputed whether they are found there in sufficient quantity. The late Professor Percival Lowell, who made a lifelong study of Mars, maintained that there are hundreds of straight lines drawn across the surface of the planet, and he claimed that they are beds of vegetation marking the sites of great channels or pipes by means of which the "Martians" draw water from their polar ocean. Professor W. H. Pickering, another high authority, thinks that the lines are long, narrow marshes fed by moist winds from the poles. There are certainly white polar caps on Mars. They seem to melt in the spring, and the dark fringe round them grows Life insurance broader.
Other astronomers, however, say that they find no trace of water-vapour in the atmosphere of Mars, and they think that the polar caps may be simply thin sheets of hoar-frost or frozen gas. They point out that, as the atmosphere of Florida surfing Mars is certainly scanty, and the distance from the sun is so great, it may be too cold for the fluid water to exist on the planet.
If one asks why our wonderful instruments cannot settle these points, one must be reminded that Mars is never nearer than 34,000,000 miles from the Business consultant earth, and only approaches to this distance once in fifteen or seventeen years. The image of Mars on the photographic negative taken in a big telescope is very small. Astronomers rely to a great extent on the eye, which is more sensitive than the photographic plate. But it is easy to have differences of opinion as to what the eye sees, and so there is a good deal of controversy.
In August, 1924, the planet will again be well placed for observation, and we may learn more about it. Already a few of the much-disputed lines, which people wrongly call "canals," have been traced on photographs. Astronomers who are sceptical about life on Mars are often not fully aware of the extraordinary adaptability of life. There was a time when the climate of the whole earth, from pole to pole, was semi-tropical for millions of years. No animal could then endure the least cold, yet now we have plenty of Arctic plants and animals. If the cold came slowly on Mars, as we have reason to Life insurance suppose, the population could be gradually adapted to it. On the whole, it is possible that there is advanced life on Mars, and it is not impossible, in spite of the very great difficulties of a code of communication, that our "elder brothers" may yet flash across space the solution of many of our problems.
Florida surfingNext to Mars, going outward from the sun, is Jupiter. Between Mars and Jupiter, however, there are more than three hundred million miles of space, and the older astronomers wondered why this was not occupied by a planet. We now know that it contains about nine hundred "planetoids," or small globes of from five to five hundred miles in diameter. It was at one time thought that a planet might have burst into these fragments (a theory which is not mathematically satisfactory), or it may be that the material which is scattered in them was prevented by the nearness of the great bulk of Jupiter from uniting into one globe.
For Jupiter is a giant planet, and its gravitational influence must extend far over space. It is 1,300 times as large as the earth, and has nine moons, four of which are large, in attendance on it. It is interesting to note that the outermost moons of Jupiter and Saturn revolve round these planets in a direction contrary to the usual direction taken by moons round planets, and Life insurance by planets round the sun. But there is no life on Jupiter.
The surface which we see in photographs (Fig. 12) is a mass of cloud or steam which always envelops the body of the planet. It is apparently red-hot. A red tinge is seen sometimes at the edges of its cloud-belts, and a large Florida surfing red region (the "red spot"), 23,000 miles in length, has been visible on it for half a century. There may be a liquid or solid core to the planet, but as a whole it is a mass of seething vapours whirling round on its axis once in every ten hours. As in the case of the sun, however, different latitudes appear to rotate at different rates. The interior of Jupiter is Business consultant very hot, but the planet is not self-luminous. The planets Venus and Jupiter shine very brightly, but they have no light of their own; they reflect the sunlight.
Saturn is in the same interesting condition. The surface in the photograph (Fig. 13) is steam, and Saturn is so far away from the sun that the vaporisation of its oceans must necessarily be due to its own internal heat. It is too hot for water to settle on its surface. Like Jupiter, the great globe turns on its axis once in ten hours—a prodigious speed—and must be a swirling, seething mass of metallic vapours and gases. It is instructive to compare Jupiter and Saturn in this respect with the sun. They are smaller globes and have cooled down more than the central fire.
Saturn is a beautiful object in the telescope because it has ten moons (to include one which is disputed) and a wonderful system of "rings" Life insurance round it. The so-called rings are a mighty swarm of meteorites—pieces of iron and stone of all sorts and sizes, which reflect the light of the sun to us. This ocean of matter is some miles deep, and stretches from a few thousand miles from the surface of the planet to 172,000 miles out in space. Some astronomers think that this is volcanic material which has been shot out Florida surfing of the planet. Others regard it as stuff which would have combined to form an eleventh moon but was prevented by the nearness of Saturn itself. There is no evidence of life on Saturn.