Science
Space Salesmen
By MAURICE GOLDSMITH
It will probably be about five years before the first man steps out on to the surface of the Moon. It will be much longer before interplanetary travel is a reality. Each planet has its own special gravity problems. We shall need to know much more about these before we can begin to think of solving them. But interstellar, travel may not pose the same difficulties, and it is with this that the Russians are now concerned. Their emphasis is on the Universe. Their scientists believe that in galaxies other than our own there may be sentient beings. They want to greet them.
What is the reality behind this vision? Are there beings in other worlds? How shall we be able to cover the vast distances of space and return to tell the story? Our own Sun (it deserves a capital letter—for it is now a geographical loca- tion) is a star. It is one of many which form our Galaxy, which is the Milky Way. The Universe is made up of thousands of galaxies, each of which contains hundreds of millions of stars. In the Milky Way alone there are esti- mated to be 100,000 million. Many stars are surrounded by a system of planets, each one of Which may have one or more satellites.
Mr. Christopher Shawcross, QC, gave fright- ened voice to this the other day. He wrote to Academician Sedov, President of' the Inter- national Astronautical Federation, declaring that the people of this planet of ours may be placed in jeopardy from the possibility of exploration, if not invasion, by inhabitants of other planets from far beyond the solar system. But will it be possible to make contact with these other worlds?
The nearest star with its own planetary system outside of our solar system is Proxima Centauri. It is four and one-third light-years distant. If we could travel at the speed of light (186,000 miles every second, or six million million miles in a year) we could reach that star in four and one- third years. But, an aspect of Einstein's Rela- tivity Theory makes it appear than once we can travel at the speed of light we shall be able to do the journey in a few days. It will not take over a million years to go to our 'nearest galaxy, Andromeda, but a few months.
There is another exciting aspect of interstellar travel. It may give us the possibility of life (almost) eternal. Again, according to Einstein, we would grow old less rapidly if we Were travelling at the speed of light : our whole metabolic pro- cess would be slowed down. Theoretically, a return journey to Proxima Centauri would take a few days. On return, however, we would find those on Earth would be eight years older. And a few months' journey to Andromeda would mean that on return everybody left behind originally would not even be memories—for the Earth would be some two million years older!
But there is a contradiction here. Why should we not consider the space-traveller as staying still and the Earth as travelling? Would the Earth, then, not grow old? This is all at the moment, very complicated. Only actual experiment will provide an answer. It has been suggested, however, that a solution may be that the space-traveller would travel in a different kind of space, a kind of sub-space. In fact, a few months ago, Professor Tom Gold—formerly at Cam- bridge and now at Harvard—pointed out that hydrogen atoms, the raw material for new stars, when they appear in our Universe from elsewhere must have a temperature of about 100,000,000° Centigrade. Professor Gold does not say where these atoms come from, but if they do come from another universe we may assume that a traveller moving at the speed of an atom of hydrogen with a temperature of that order could pass speedily from one universe to another. Thus, there may be an indefinite number of universes acces- sible to us at different energy levels.
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