"As to their point of origin we can only make guesses really. They are coming toward us with Sirius—and thousands of other stars—at their back. Of all, Sirius is the nearest, being approximately nine light years away. This means that they must have spent at least 1600 years on that trip across space. Dr. James Downey of Earth has recently shown us how to lengthen life almost indefinitely, so the problem of old age need not be considered. A supply of air and water would, of course, be no great problem with the Waterson apparatus for electrolyzing CO back to carbon and oxygen, using atomic energy fuel. Water, of course, is merely transmuted and recombined and thus automatically purified for use. A sufficient reserve of very dense materials could easily be carried that would make up for any losses by transmutation to the necessary gases. As yet we have not been able to make foods from energy, carbon, and oxygen and hydrogen, but I believe you, Dr. Lange, have made very considerable progress along that line, have you not?"
"I intended announcing at this meeting," said Dr. Lange, "the development of a commercial method of manufacturing any one of the sugars and several proteins directly from rock or water, by a transmutation and building-up process. The method has been developed."
"Then," continued the Martian, "there would be no need of carrying any great amount of food. That problem is settled.
"As there would be no resistance encountered in space, once the machine had been accelerated to its definite speed of 1000 miles per second, on leaving Sirius it would be able to make the trip across space with no expenditure of energy, until it reached its goal and slowed down to the speed of a planet. Hence no great amount of matter-fuel would be needed to drive the machine.
"But the problem of heating seems to me to be insoluble. Interplanetary space we have the radiations of the sun to depend upon, and they are decidedly sufficient, usually superfluously so. But in the infinite depths of interstellar space, there is only darkness and a perfect reservoir for radiations. There would be continuous cooling by radiation, and no sun to warm the ship. I could understand how the ship might carry enough matter to warm it for one hundred years, but in sixteen hundred years so much energy must be radiated that the entire mass would not suffice. Nothing short of an entire planet would be sufficient. Polished walls would reduce the radiation, but still it would be too high. I can not understand it—unless these men can endure a temperature of but twenty or thirty degrees above absolute zero—then they could make it quite readily—but two hundred and forty degrees below zero Centigrade means that air—nearly everything would be solid, except a few rare gases. No it seems impossible—yet we have the evidence! I can not understand how they have made this terrible migration, but I know that there are many different units. I believe two thousand or more was the number you mentioned Horus Mal?"
"There seem to be a very considerable number of separate signals that we can distinguish. I consider the two thousand a very conservative estimate," replied Horus Mal, the Martian radiation engineer.
"Then," continued Mansol Korac, "we must decide on some plan of meeting them."
The Martian sat down and for some time there was silence in the great hall. At last President Waterson rose slowly to his feet. His face showed his concern. In times of emergency he always felt that these men here were responsible for the welfare of the twenty billions of human beings they controlled. And he was their leader, and therefore the responsibility was his.
"Mansol Korac, could you point out to us the approximate location of the approaching ships?" asked Waterson and handed him a small hand light and pointed to the great map of the system above them.
"I cannot be very exact, Mr. President; I do not know their location very definitely, but I should say about here, proceeding thus." The dazzling beam of white light stabbed up to the ceiling high above, and a sharp circle of light a foot across appeared, just within the orbit of Uranus, but well beyond Saturn. Then it slowly moved inward toward tiny glowing Mars. They were within the Solar System, but had not yet reached the Inner Ring of planets. Doubtless they who could make a trip across the great Void had the energy of matter at their disposal, and probably the disintegration ray. They would have no difficulty with the planetoids, they could merely beam them out of existence if they came too near.