Are there men on Mars? What lies behind the misty veil of far-off Venus? Do creatures like the prehistoric monsters of Conan Doyle's "Lost World" inhabit the steaming jungles of Venus, a young world only now in the making? These thrilling questions are asked, but not conclusively answered -
There are two planets which experts are now studying closely. Just what will it mean to make space voyages to them?
One of these planets is Venus.
The other is Mars.
It is the planet Venus which, during its passage round the Sun, approaches nearer to us than any other. When it is nearest to us Venus is only some 26,000,000 miles away. Here I use the word "only" because, though a distance like this seems at first glance vast enough, it is really quite a short distance when you think of those truly enormous distances which separate many of the other bodies out there in space - distances so huge that ordinary people seem hardly able to grasp them.
When, for example, one's friends who study the stars mention that the Milky Way system is something like 180,000 million million away from the Sun, and that some of the other distances out in space are even greater than that, one has simply got to give it up. Figures so stupendous just give one a headache, and make one think that a planet like Mars, which sometimes comes within 35,000,000 miles of the Earth, is almost a next-door neighbour.
It was not so long ago that, though it was thought men from this Earth might perhaps get to the Moon one day, the idea of going all those millions of miles to Mars or Venus seemed incredible.
It isn't any longer.
What is going to make that dream come true is the coming of atomic power. This mighty new energy will alter everything. It on a space voyage to Mars or Venus we had to rely on any power we could employ here and now, such as liquid or solid fuel, it might take weeks for a space-ship to cross from our Earth to either of these planets. And the vessel would have to carry such a load of fuel that there would be precious little room for the crew, who would have to face a very uncomfortable time indeed while making so long a voyage in such cramped quarters.
But as soon as we can use atomic power to drive our space-flying vessels we shall have so much energy in reserve, and shall be able so to increase our speeds, that the timetables of our voyages to the planets will shrink from weeks to days, while an atomic power-unit will be so much more compact, and will take up so much less room, that we shall be able to have ample quarters for our crews, and to give them every kind of comfort while they are on their journeys across space. We shall, in fact, make space-travel thoroughly comfortable as well as enormously fast.
One of the fascinating things about our great coming age of wonders is to picture the sort of things our first space-voyagers may find when they actually alight on, and begin exploring, planets such as Venus and Mars.
Although Venus is the planet which comes nearer to us then any other, it is a body about which our experts can tell us very little. This is because the planet is hidden from our gaze, always, by the mist and cloud which surround it. Venus is in a very early stage in its evolution as a planet. It is here one needs to remember that each of the planets goes through its regular life-history in the wonderful story of our vast solar system. At first, in its very earliest days, everything is in a more or less liquid or molten state, with land masses just beginning to form themselves out of hot, steaming swamps, and with seas, mountains, and other features of the landscape gradually beginning to take shape. It needs vast periods of time for these changes to take place - many, many millions of years.
Venus is still young as a planet.
Our Earth is much older, and Mars is older still.
The older a planet grows, the colder it grows, and as it gets colder and colder it loses air and moisture, and this means that neither plants nor any kind of life can find enough to support them; and in the end, without air, moisture, or living thing, the planet goes rolling on and on through space, a cold, dead world.
Our Earth has vast ages ahead of it before it grow cold and old.
The same applies, only more so, to the planet Venus - which, as I have said, is a very young world compared with ours. But Mars is not in such a happy position. It has already gone through one stage after another until the time has come when it is beginning to lack air and moisture, and if there is life on Mars things must be growing more and more difficult for whatever sort of being may inhabit this planet.
The belt of air around Mars grows more and more thin.
Water to keep plant-life going is getting more and more scarce. There are some experts who think that life, if there has ever been any on Mars, may have already found thing too difficult to keep up the fight for existence, and that the planet has already become lifeless and desolate.
No the other hand, that stage may not yet have been reached. This is one of the questions we may solve, when space-voyagers from this Earth are able to reach and explore the surface of Mars.
As for Venus, there are any number of riddles to which we may find the answers once we can set foot on its surface, and see what is really taking place behind that veil of cloud which hides the planet.
Venus has a special interest for Earth-folk because it is nearer in its size to our globe than is any other body out in space. For this reason it has sometimes been spoken of as the "twin-sister" of the Earth. Actually Venus is not quite the same size as out globe. It is just a trifle smaller.
It has a diameter of 7,700 miles; that of the Earth is 7,927 miles.
Not only is Venus very like our world in size; but those who have make a special study of it believe that conditions on Venus may be more like those of this Earth than is the case with any other planet.
One thing in favour of a growth of plant and other forms of life on Venus is that the planet is reckoned to have a fairly considerable belt of atmosphere round it. Another fact shown by studies of Venus is that it must be very hot and steamy on the planet - very much hotter than even the hottest weather we get on this Earth. One expert has said that anyone from this Earth who alighted on Venus would feel he had stepped into something like a hot-house.
According to some figures worked out not long ago, Venus is thought to be in the stage our Earth was in something like a thousand million years ago. Though nobody can be certain, it is believed that great zones of the surface of Venus are still in a more or less molten state, and that other tracts are nothing more than vast swamps which will, as time goes on, gradually harden until they are solid ground. It is reckoned, too, that there must be huge stretches of dense steamy jungle-growth.
On all these beginnings of a world the Sun must beat down fiercely, as Venus is nearer the Sun than we are.
It is easy enough to imagine how fascinating it will be for space-explorers from this Earth to make a voyage to Venus.
As they stand looking about them, after disembarking from their space-ship, they will see a world actually in the making. They will be able to form a picture in their minds of what this Earth of ours must have looked like many, many millions of years ago.
There is one great question which those making studies of Venus always have at the back of their minds. It is this. As this planet is so like ours, and as we suppose there came a stage on our Earth, ages ago, when, in addition to plants and vegetation, some first living things in the shape of reptiles and other primitive creatures began to move sluggishly through our swamps and jungles, may not the same sort of thing be likely to happen - or may already have happened - away out there on the hot, steamy surface of Venus?
A fascinating question, that!
It makes one long for the day when it becomes possible to organise a first space-voyage from our Earth across the Venus. From the beginnings of life on that planet - if such beginnings are really found - scientists on this Earth may learn things which throw fresh light on many a question to which, so far, it has been impossible to find any definite answer. The first voyagers to explore the surface of Venus may come back to us with tidings which not only throw fresh light on this particular planet, but which may also help us in seeking answers to many another question which still puzzles those who gaze from their observatories in different parts of the world, studying all that telescopes and other delicate instruments can tell them about Sun, Moon, and planets.
Wonderful discoveries our astronomers have already made, but our crowning triumphs, with all that they may mean, cannot come till we reach the age of space-travel between our globe and the other planets.
Still to be solved in the mystery of Mars.
Why, by the way, has Mars been called the "red" planet?
The answer is that it is because of what astronomers see when they look at Mars through their telescopes. Quite a large part of the surface of the planet is now known to be nothing but barren desert, and these great expanses of desert, as we see them from our Earth, have a reddish orange colour. Hence the name "red" for Mars, and very striking indeed this famous planet looks when viewed under favourable conditions, its great desert zones giving a vivid glowing colour that is partly orange and partly red.
There is no body out there in space which has been studied more closely than the planet Mars. But the trouble has been that while one great expert has said one thing, another has said something quite different.
One astronomer, looked at Mars from one part of the world through a powerful telescope, has declared he has seen certain odd markings on the planet which another, viewing the planet from some other part of the globe, has confessed he has not been able to see at all; or even if he has seen something, it has not struck him as being anything like what the first astronomer said it was.
There has, in fact, been more argument about Mars than about anything else our astronomers see when they make their nightly studies of the stars. And it is an argument that still goes on.
It all started a good many years ago when that famous Italian astronomer, Schiaparelli, made a special study of Mars through a very powerful telescope.
Once or twice, when the planet came nearest our Earth, and conditions happened to be particularly favourable, Schiaparelli noticed some markings on Mars which seemed to him very strange.
Were they rivers, or perhaps long narrow valleys or ravines?
Such natural markings are, as a rule, irregular in their appearance or patten. Rivers have a habit of wandering here and there, according to the sort of country they flow through; and it is the same, more or less, with ravines or valleys. But, as they appeared to him through his telescope, these markings on Mars were most oddly regular in the way they stretched across the planet. They did not wind here and there, as might a river. They just seemed to go straight from point to point. They were so regular in their pattern that they seemed as though they might have been marked out with some giant ruler straight across the surface of the planet.
Though he was such a keen observer, Schiaparelli was, at the same time, a cautious man. He would never say anything unless he was quite sure of what he was talking about. And all he would say about these queer markings on Mars was that they seemed to him very odd indeed, and that he thought they needed a lot more study, not only by himself but also by astronomers in other parts of the world.
As a matter of fact, the early reports Schiaparelli had made about his discovery of these lines or markings on Mars attracted keen attention in other observatories in different countries, and one astronomer in particular who became specially interested in everything connected with Mars was Professor Percival Lowell, the great American scientist whose observatory out at Flagstaff, in Arizona, was in a particularly good position for planetary studies, seeing that it stood on very high ground, and in climatic conditions which gave a much clearer view of the skies than was available in low-lying regions.
With a very powerful telescope and other special equipment, and with a team of assistants to help him, Professor Lowell made a long and thorough study of those mysterious lines or markings on Mars to which Schiaparelli had drawn attention. It was some time before the Professor made public the conclusions he had arrived at.
When he did so, they startled the whole world.
Professor Lowell did not mince matters. He came out with the firm statement that, in his opinion, these markings on Mars were not rivers, or ravines, or any natural kind of markings at all. They were, he said, great artificial channels, or canals, which must have been created by beings on Mars who were of a high intelligence and with great engineering skill.
As for the purpose of these canals, some of the biggest of which were reckoned to be as much as 100 miles wide, Professor Lowell said it was to carry water from the Poles of Mars and to spread it among areas nearer the centre of the planet, where it would help in the growth of vegetation.
Professor Lowell gave lectures and wrote books to explain his theories. One of the things to which he drew attention was that Mars, as was already known, must be growing very short of moisture, and he said he reckoned this great system of Martian canals had been created so as to make the utmost possible use of what water still came from the Pole of the planet when the winter snows covering these Poles began to melt.
He said that by watching carefully and for a long time the different appearance of the surface of Mars during the changing seasons on that planet, it was possible to note a darkening of the canals as the water from the Poles flowed down through them and caused vegetation to spring up on their banks; and he added that certain dark spots on the planet, at which a number of canals met, must be in the nature of oases, with fertile land surrounding them.
The Professor went on to say that if, as he believed, this canal system on Mars was the work of intelligent beings, then it was a piece of engineering so vast as to be far greater than anything of the kind so far attempted on this Earth. Here, he added, there was one point to bear in mind. Mars was a much older planet then ours. This meant that, if life had started on Mars at about the same time in its history as had been the case on this Earth, then the Martians would have had much longer in which to improve all their scientific and engineering knowledge. This would be quite in keeping with their being able to plan and carry out such a huge engineering enterprise as the transport of water from the Poles to supply other areas of the planet where the natural supplies had begun to fail.
What sort of beings where these Martians - these intelligent beings who, if they really did exist, were able to carry out such marvellous pieces of engineering?
Questions like these poured in on the Professor from all parts of the world.
He could not answer them. Nobody could answer them.
All that he and other scientists could say was this. Nobody should take it for granted that, if there is life on Mars, or on any other planet, the living beings on them are likely to resemble, in their outward appearance or bodily structures, the men and women of this Earth.
There were certain conditions on this Earth which led to life taking the forms it did with us. But on other planets, so far as we can gather, conditions may be so different life, if it has actually begun, may have taken forms very different indeed from anything we know on this Earth.
On some planets, if life exists on them, it must be able to withstand extremes of heat which no living thing on this planet could endure. In the same way, it there is life on certain other planets, then it must be able to carry on in conditions of cold which we on this Earth would find impossible.
We must not make the mistake of thinking that because there may be conditions on other planets which we could not endure on ours, this rules out the chance of there being any form of life on such other bodies. Our scientists already know there are forms of life which can exist in conditions of very great heat or very great cold. But the point is that if life begins on any particular planet, the way it develops after it has begun depends very much on the climatic and other conditions existing; and as our astronomers tell us that such conditions are very different indeed on different planets, we are pretty safe in taking it for granted that the living things on one planet may be quite different from those to be found on any other.
What it all boils down to is this. If one asks: would a Martian, if he exists, be anything like a man of this Earth, the answer is that it is very unlikely he would; but what a Martian would really be like we have no means at all of knowing. All we can do, if we like, is to do what the famous author H.G. Wells did when he wrote The War Of The Worlds - imagine them.
In that book, you may remember, a party of Martians actually managed to cross space and land on this Earth. These Martians, as H.G. Wells imagined them were weird creatures. As Mars is so much older as a planet than the Earth, these Martians had developed their brains to such an extent, and had made machinery do so much for them, that they had in the course of time become little more than heads and brains. They had made so little use of their bodies that these bodies had shrunk till there was not much left of them at all.
These Martians were in fact - at any rate, as H.G. Wells pictured them - little more than big heads with very little in the shape of limbs or bodies, and when they wanted to do anything, or go anywhere, they just climbed into machines which did everything for them that our human legs and arms do for us.
Well, there it is.
You can imagine almost anything you like, and nobody can say you are either right or wrong.
There have been all sorts of arguments since Professor Lowell put forward that wonderful theory of his as to the Martian canals. Some astronomers, looking at Mars from other observatories, said they were very sorry, but that they simply could not agree with the Professor. They said that in their view those markings on the planet were not artificial canals, as made by the inhabitants of Mars to eke out their failing water-supply, but were nothing more than quite natural markings in the shape of big rivers or great valleys.
Other astronomers, however, said that they agreed with the explanation Professor Lowell had put forward.
The thing one needs to bear in mind, here, is that even in the most powerful telescopes Mars appears as a very small and remote object. Sometimes it can be seen much more clearly than at others; while there may be quite a lot of difference in what you can see according to what part of the world you may view the planet from, and whether the atmospheric conditions where you are situated are generally favourable or unfavourable.
So there you have it. One of the most puzzling of all the problems of astronomy is the problem of Mars and of those odd markings which may, or may not, be the canals of a vast irrigation system, and which may, or may not, have been the work of clever beings striving to make the most of their ever-dwindling water supply.
Still bigger and more powerful telescopes may help our astronomers to throw further light on this mystery. So may improvements in photographing the planet under specially favourable conditions.
When all is said and done, however, this Martian riddle is likely to remain as great a riddle as ever until that day comes - sooner, perhaps, than many think - when our first space-vessel from this Earth sets its explorers down on Mars, and they can set about finding out, once and for all, what it is that is actually happening out there on the "red planet" - that mysterious, fascinating planet which has been more talked about, written about, and argued about, than any other of the bodies in the still unexplored vastness of outer space.