the middle of November the opportunity had passed. Humanity had begun to organize itself again into its respective communities.
The Prime Minister returned to London, feeling less unfavourably disposed towards Nortonstowe than might perhaps be expected. For one thing he had passed the time of the crisis far more comfortably than he would have done at Downing Street. For another he had shared the agony of suspense with the scientists at Nortonstowe and there is always a bond between those who have shared a common stress.
Before the Prime Minister left he was warned that there was no reason to suppose that the emergency was at an end. At a discussion, held in one of the laboratories attached to the shelter, it had been generally agreed that Alexandrov’s prognostication was correct. Marlborough said:
“It seems fairly certain that the Cloud is settling into a disk at a pretty high inclination to the ecliptic.”
“Disk stable configuration. Obvious,” grunted Alexandrov.
“It may be obvious to you, Alexis,” broke in Kingsley, “but there’s an awful lot about this business that’s not obvious to me. By the way, what would you put the outer radius of the disk at?”
“About three-quarters of the radius of the Earth’s orbit, about the same as the radius of the orbit of Venus,” answered Marlborough.
“This settling down into a disk must be a relative way of speaking,” Marlowe began. “I suppose you mean that the bulk of the material of the Cloud is settling into a disk. But there must be quite a lot of material spread through the whole of the Earth’s orbit. This is obvious from the stuff that’s hitting our atmosphere all the time.”
“God-awful cold in shadow of disk,” announced Alexandrov.
“Yes, thank goodness we’re clear of the disk, otherwise there’d still be no Sun,” Parkinson said.
“But remember that we shall not stay clear of the disk’ — this from Kingsley.
“What d’you mean by that?’ asked the Prime Minister.
“Simply that the Earth’s motion around the Sun will carry us into the shadow of the disk. Of course we shall come out of the shadow again.”
“Damn cold in shadow,” grunted Alexandrov.
The Prime Minister was worried, and with some justice.
“And how often, may I ask, is this appalling state of affairs likely to arise?”
“Twice a year! According to the present position of the disk, in February and August. The lengths of time for which the Sun will be eclipsed depends on how thin the disk gets. Probably the eclipse will last for somewhere between a fortnight and a month.
“The implications of this are certain to be extremely far-reaching,” sighed the Prime Minister.
“For once we agree,” remarked Kingsley. “Life on the Earth is not going to be impossible but it’ll have to be carried on in far less favourable circumstances. For one thing people will have to get used to living together in quite large numbers. We shall no longer be able to afford to live in individual houses.”
“I don’t follow.”
“Well, heat is lost from a building at its surface. Is that clear?”
“Yes, of course.”
“On the other hand, the number of people that can be housed and sheltered in a building depends essentially on its volume. Since the ratio of surface to volume is much less for a large building than for a small one it follows that large buildings will house people at a far lower fuel consumption per head. If there is to be an endless repetition of periods of intense cold, our fuel resources will admit of no other arrangement.”
“Why do you say “if”, Kingsley?’ asked Parkinson.
“Because so many queer things have happened. I won’t be satisfied with our predictions of what is going to happen next, until I can really understand what has happened already.”
“It might be worth while mentioning the possibility of long-term climatic changes,” remarked Marlowe. “Although this may not be of very great importance in the next year or two, I can’t see how it can fail to be vitally important in the long run — assuming we’re going to have these bi-annual eclipses of the Sun.”
“What have you in mind, Geoff?”
“Well, surely we can’t avoid moving into a new Ice Age. Past Ice Ages show how delicately the Earth’s climate is balanced. Two periods of intense cold, one in winter and the other in summer, must tip the balance on the Ice Age side — the Ice Age plus side, I would say.”
“You mean that ice sheets will sweep down over Europe and North America?”
“I can’t see how it can be otherwise, although it won’t happen in the next year or two. It’ll be a slow cumulative process. As Chris Kingsley says, Man’ll have to come to terms with his environment. And I guess the terms won’t be altogether to his liking.”
“Ocean currents,” said Alexandrov.
“I don’t understand,” said the Prime Minister.
“What I imagine Alexis means,” Kingsley remarked, “is that there is no certainty that the present pattern of ocean currents will be maintained. If it isn’t, the effects might be completely disastrous. And this might happen quite quickly, quicker than an Ice Age.”
“You said it,” nodded Alexandrov. “Gulf Stream go, gets bloody cold.”
The Prime Minister felt he had heard enough.
During November the pulse of mankind quickened. And as Governments got matters more and more in hand the desire for communication between the various pockets of humanity strengthened. Telephone lines and cables were repaired. But it was to radio that men turned in the main. Long wave radio transmitters were soon working normally, but of course they were useless for long distance communication. For this, short wave transmitters were put into operation. But the short wave transmitters failed to work, and for a reason that was soon discovered. The ionization of the atmospheric gases at a height of about fifty miles turned out to be abnormally high. This was giving rise to an excessive amount of collisional damping, as the radio engineers called it. The excessive ionization was caused by the radiation from the very hot upper reaches that were still producing the blue shimmering nights. In short, radio fade-out conditions were operative.
There was only one thing to be done: to shorten the transmitting wave-length. This was tried down to a wave-length of about one metre, but still the fade-out continued; and no suitable transmitters on still lower wave- lengths were available, since lower wave-lengths were never widely used before the coming of the Cloud. Then it was remembered that Nortonstowe possessed transmitters that would work from one metre down as far as one centimetre. Moreover the Nortonstowe transmitters were capable of handling an enormous quantity of information, as Kingsley was not slow to point out. It was accordingly decided to make Nortonstowe a world information clearing-house. Kingsley’s plan had borne fruit at last.
Intricate calculations had to be performed and, as they had to be done quickly, the electronic computer was put into operation. The problem was to find the best wave-length. If the wave-length was too long the fade-out trouble would continue. If the wave-length was too short the radio waves would stream out of the atmosphere away into space instead of being bent round the Earth, as they must be to travel from London to Australia, let us say. The problem was to compromise between these extremes. Eventually a wave-length of twenty-five centimetres was decided on. This was thought to be short enough to overcome the worst of the fade-out difficulty, and yet not to be so short that too much power would get squirted out into space, although it was recognized that some loss must occur.
The Nortonstowe transmitters were switched on during the first week of December. Their information- carrying capacity turned out to be prodigious, as Kingsley had predicted. Less than half an hour on the first day was sufficient to clear the whole backlog of information. To begin with, only a few Governments possessed a transmitter and receiver, but the system worked so well that soon many other Governments were lashing up equipment at all speed. Partly for this reason the volume of traffic through Nortonstowe was quite small at first. Also it was difficult to appreciate initially that an hour’s talk occupied a transmission time of a small fraction of a second. But as time went on, conversation and messages became longer, and more Governments joined in. So transmission at Nortonstowe rose gradually from a few minutes a day to an hour or more.
One afternoon, Leicester, who had organized the building of the transmission system, rang Kingsley and asked him to come along to the transmitting lab.
“What’s the panic, Harry?’ asked Kingsley.
“We’ve done a fade!”
