The Black Cloud

by Fred Hoyle; Fred Hoyle

  ‘And I think we can go a little further concerning future observations,’ Herrick went on. ‘Optical observations will be prosecuted here with all energy. And we feel that work by the Australian radio astronomers will be complementary to ours, particularly with regard to keeping a watch on the line of sight motion of the Cloud.’

  ‘That seems to sum up the situation admirably,’ agreed the Astronomer Royal.

  ‘I propose that we proceed with the report at full speed, that we four sign it, and that it be communicated to our respective Governments forthwith. I hardly need say that the whole matter is highly secret, or at least that we should treat it as so. It is rather unfortunate that so many are aware of the position, but I believe that we can rely on everybody proceeding with great discretion.’

  Kingsley did not agree with Herrick on this point. Also he was feeling very tired, which no doubt made him express his views rather more forcibly than he would otherwise have done.

  ‘I’m sorry, Dr Herrick, but I don’t follow you there. I see no reason why we scientists should go to the politicians like a lot of dogs thumping our tails, saying “Please, sir, here’s our report. Please give us a pat on the back and perhaps even a biscuit if you feel so disposed.” I can’t see the slightest point in having to do with a crowd of people that can’t even run society properly during normal times when there’s no serious stress. Will the politicians pass statutes to stop the Cloud coming? Will they be able to prevent it cutting off the light of the Sun? If they can, then consult them by all means, but if they can’t, let’s leave them out of the picture altogether.’

  Dr Herrick was quietly firm.

  ‘I’m sorry, Kingsley, but as I see it the United States Government and the British Government are the democratically elected representatives of our respective peoples. I regard it as our obvious duty to make this report, and to maintain silence until our Governments have made a pronouncement on it.’

  Kingsley stood up.

  ‘I’m sorry if I seem brusque. I’m tired. I want to go and get some sleep. Send your report if you wish, but please understand that if I decide to say nothing publicly for the time being, it will be because I wish to say nothing, not because I feel under any form of compulsion or duty. And now if you’ll excuse me, I’d like to get round to my hotel.’

  When Kingsley had gone, Herrick looked at the Astronomer Royal.

  ‘Dr Kingsley seems a trifle … er …’

  ‘A trifle unstable?’ said the Astronomer Royal. He smiled and went on:

  ‘That’s not very easy to say. Whenever you can follow his reasoning, Kingsley is always very sound and often brilliantly deductive. And I am inclined to think this is always so. I think he seemed rather odd just now because he was arguing from unusual premises, rather than because his logic was faulty. Kingsley probably thinks about society in quite a different way from us.’

  ‘Anyway I think that while we work on this report it would be a good idea if Marlowe were to look after him,’ remarked Herrick.

  ‘That’s fine,’ Marlowe agreed, still struggling with his pipe, ‘we’ve got a lot of astronomy to talk about.’

  When Kingsley came down to breakfast the following morning he found Marlowe waiting.

  ‘Thought you might like to drive out for the day into the desert.’

  ‘Spendid, there’s nothing I’d like better. I’ll be ready in a few minutes.’

  They drove out of Pasadena, turned sharply right off Highway 118 at La Canada, then cut through the hills, past the side road to Mount Wilson, and so on to the Mohave Desert. Three more hours’ driving brought them under the wall of the Sierra Nevada, and at last they could see Mount Whitney plastered with snow. The far desert stretching towards Death Valley was veiled in a blue haze.

  ‘There are a hundred and one tales,’ said Kingsley, ‘of what a man feels like when he’s told that he’s only got a year to live – incurable diseases, and so on. Well, it’s odd to think that every one of us probably only has a little more than a year to live. A couple of years hence, the mountains and the desert will be much the same as they are now, but there’ll be no you and me, no people at all to drive along through it.’

  ‘Oh my God, you’re much too pessimistic,’ grunted Marlowe. ‘As you said yourself, there’s every chance that the Cloud will sweep to one side or the other of the sun, and give us a complete miss.’

  ‘Look, Marlowe, I didn’t want to press you too much yesterday, but if you’ve got a photograph going back a number of years you must have a pretty good idea of whether or not there’s any proper motion. Did you find any?’

  ‘None that I could swear to.’

  ‘Then surely that’s pretty good evidence that the Cloud is coming dead towards us, or at any rate dead towards the Sun.’

  ‘You might say so, but I can’t be certain.’

  ‘So what you mean is that the Cloud is probably going to hit us, but there’s still a chance that it might not.’

  ‘I still think you’re being unduly pessimistic. We’ll just have to see what we can learn during the next month or two. And anyway, even if the Sun is blotted out, don’t you think we can see it through? After all it’ll only be for about a month.’

  ‘Well, let’s go into it from scratch,’ began Kingsley. ‘After a normal sunset the temperature goes down. But the decline is limited by two effects. One is the heat stored in the atmosphere, which acts as a reservoir that keeps us warm. But I reckon that this reservoir would soon become exhausted, I calculate, in less than a week. You’ve only got to think how cold it gets at night out here in the desert.’

  ‘How do you square that with the Arctic night, when the Sun may be invisible for a month or more? I suppose the point is that the Arctic is constantly receiving air from lower latitudes; and that this air has been heated by the Sun.’

  ‘Of course. The Arctic is constantly warmed by air that flows up from tropical and temperate regions.’

  ‘What was your other point?’

  ‘Well, the water vapour in the atmosphere tends to hold in the heat of the Earth. In the desert, where there’s very little water vapour, the temperature goes down a long way at night. But in places where there’s lots of humidity, like New York in summer, there’s very little cooling at night.’

  ‘And what does that lead you to?’

  ‘You can see what will happen,’ continued Kingsley. ‘For the first day or two after the Sun is hidden – if it is shut out, that’s to say – there won’t be a great deal of cooling, partly because the air will be still warm and partly because of the water vapour. But as the air cools the water will gradually turn, first into rain, then into snow, which will fall to the ground. So the water vapour will be removed from the air. It may take four or five days for that to happen, perhaps even a week or ten days. But then the temperature will go racing down. Within a fortnight we shall have a hundred degrees of frost, and within a month there’ll be two hundred and fifty or more.’

  ‘You mean it’ll be as bad here as it is on the Moon?’

  ‘Yes, we know that at sunset on the Moon the temperature declines by over three hundred degrees in a single hour. Well, it’ll be much the same here except that it’ll take longer because of our atmosphere. But it’ll come to the same thing in the end. No, Marlowe, I don’t think we can last out a month, even though it doesn’t seem very long.’

  ‘You reject the possibility that we might keep warm the same way as they keep warm in winter in the Canadian prairies, by efficient central heating?’

  ‘It’s just possible I suppose that some buildings are sufficiently well insulated to stand the tremendous temperature gradients that’ll be set up. They’ll have to be very exceptional, because when we build offices and houses, and so on, we don’t build with these temperature conditions in mind. Still I’ll grant you that a few people may survive, people that have specially well designed buildings in cold climates. But I think there’s no chance at all for anyone else. The tropical peoples with their ramshackle
houses will be in a very poor case.’

  ‘Sounds very grim, doesn’t it?’

  ‘I suppose the best thing will be to find a cave where we can get deep underground.’

  ‘But we need air to breathe. What should we do when that gets very cold?’

  ‘Have a heating plant. That wouldn’t be too difficult. Heat the air going into a deep cave. That’s what all the Governments that Herrick and the A.R. are so keen on will do. They’ll have nice warm caves, while you and me, Marlowe my boy, will get the icicle treatment.’

  ‘I don’t believe they’re quite as bad as that,’ Marlowe laughed.

  Kingsley went on quite seriously:

  ‘Oh, I agree they won’t be blatant about it. There’ll be good reasons for everything they do. When it becomes clear that only a tiny nucleus of people can be saved, then it’ll be argued that the lucky fellows must be those who are most important to society; and that, when it’s boiled down and distilled, will turn out to mean the political fraternity, field-marshals, kings, archbishops, and so on. Who are more important than these?’

  Marlowe saw that he had better change the subject slightly.

  ‘Let’s forget about humans for the time being. How about other animals and plants?’

  ‘All growing plants will be killed, of course. But plant seeds will probably be all right. They can stand intense cold and still be capable of germination as soon as normal temperatures return. There’ll probably be sufficient seeds around to ensure that the flora of the planet remains essentially undamaged. The case is very different with the animals. I don’t see any large land animal surviving at all, except a small number of men, and perhaps a few animals that men take into shelter with them. Small furry burrowing animals may be able to get deep enough into the ground to withstand the cold, and by hibernating they may save themselves from dying for lack of food.

  ‘Sea animals will be very much better off. Just as the atmosphere is a reservoir of heat, the sea is a vastly greater reservoir. The temperature of the seas won’t fall very much at all, so the fish will probably be all right.’

  ‘Now isn’t there a fallacy in your whole argument?’ exclaimed Marlowe with considerable excitement. ‘If the seas stay warm, then the air over the seas will stay warm. So that there’ll always be a supply of warm air to replenish the cold air over the land!’

  ‘I don’t agree there,’ answered Kingsley. ‘It isn’t even certain that the air over the seas will stay warm. The seas will cool enough for them to freeze up at the surface although the water lower down will stay quite warm. And once the seas freeze over, there won’t be much difference between the air over the land and the sea. It’ll all get extremely cold.’

  ‘Unfortunately what you say sounds right. So it looks as if a submarine might be the right place to be!’

  ‘Well, a sub wouldn’t be able to surface because of the ice, so a complete air supply would be needed and that wouldn’t be easy. Ships wouldn’t be any good either because of the ice. And there’s another objection to your argument. Even if the air over the sea did stay comparatively warm, it would not supply heat to the air over the land, which being cold and dense would form tremendous stable anticyclones. The cold air would stay on the land and the warm air on the sea.’

  ‘Look here, Kingsley,’ laughed Marlowe, ‘I’m not going to have my optimism damped by your pessimism. Have you thought of this point? There may be quite an appreciable radiation temperature inside the Cloud itself. The Cloud may have an appreciable heat of its own, and this might compensate us for the loss of sunlight, always supposing – as I keep saying – that we do find ourselves inside the Cloud!’

  ‘But I thought the temperature inside the interstellar clouds was always very low indeed?’

  ‘That’s the usual sort of cloud, but this one is so much denser and smaller that its temperature may be anything at all, so far as we know. Of course it can’t be extremely high, otherwise the Cloud would be shining bright, but it can be high enough to give us all the heat we want.’

  ‘Optimist, did you say? Then what’s to stop the Cloud being so hot that it boils us up? I didn’t realize there was so much uncertainty about the temperature. Frankly, I like this possibility even less. It’ll be completely disastrous if the Cloud is too hot.’

  ‘Then we shall have to go into caves and refrigerate our air supply!’

  ‘But that isn’t so good. Plant seeds can stand cold but they can’t stand excessive heat. It wouldn’t be much good for Man to survive if the whole flora was destroyed.’

  ‘Seeds could be stored in the caves, along with men, animals, and refrigerators. My God, it puts old Noah to shame, doesn’t it?’

  ‘Yes, maybe some future Saint-Saëns will write the music for it.’

  ‘Well, Kingsley, even if this chat hasn’t been exactly consoling, at least it’s brought out one highly important point. We must find the temperature of that Cloud and without delay too. It’s obviously another job for the radio boys.’

  ‘Twenty-one centimetre?’ asked Kingsley.

  ‘Right! You have a team at Cambridge that could do it, haven’t you?’

  ‘They’ve started in on the twenty-one centimetre game quite recently, and I think they could give us an answer to this point pretty quickly. I’ll get on to ’em as soon as I get back.’

  ‘Yes, and let me know how it comes out as soon as you can. You know, Kingsley, while I don’t necessarily go along with all you say about politics, I don’t quite like the idea of everything going outside our control. But I can’t do anything myself. Herrick has asked for the whole business to be put on the secret list, and he’s my boss, and I can’t go above him. But you’re a free agent, especially after what you told him yesterday. So you can look into this business. I should get ahead with it as fast as you can.’

  ‘Don’t worry, I will.’

  The drive was a long one, and it was evening by the time they dropped down through the Cajon Pass to San Bernardino. They stopped for an excellent dinner at a restaurant of Marlowe’s choice on the western side of the township of Arcadia.

  ‘I’m not normally keen on parties,’ Marlowe said, ‘but I think a party away from scientists would do us both good tonight. One of my friends, a business tycoon over San Marino way, invited me to drive over.’

  ‘But I can’t go along and gatecrash.’

  ‘Nonsense, of course you can come – a guest from England! You’ll be the lion of the party. Probably half a dozen film moguls from Hollywood will want to sign you up on the spot.’

  ‘All the more reason for not going,’ said Kingsley. But he went all the same.

  The house of Mr Silas U. Crookshank, successful real estate operator, was large, spacious, well decorated. Marlowe was right about Kingsley’s reception. A super-large tumbler of hard liquor, which Kingsley took to be Bourbon whisky, was thrust into his hand.

  ‘That’s great,’ said Mr Crookshank. ‘Now we’re complete.’

  Why they were complete Kingsley never discovered.

  After polite talk to the vice-president of an aircraft company, to the director of a large fruit-growing company, and other worthy men, Kingsley at last fell into conversation with a pretty, dark girl. They were interrupted by a handsome fair woman who laid a hand on each of their arms.

  ‘Come along, you two,’ she said in a low, husky, much cultivated voice. ‘We’re going along to Jim Halliday’s place.’

  When he saw that the dark girl was going to accept Husky Voice’s plan, Kingsley decided he might as well go along too. No point in bothering Marlowe, he thought. He could get back to his hotel somehow.

  Jim’s place was a good deal smaller than the residence of Mr S. U. Crookshank, but nevertheless they managed to clear a floor space on which two or three couples began dancing to the somewhat raucous strains of a gramophone. More drinks were handed round. Kingsley was glad of his, for he was no shining light of the dancing world. The dark girl was engaged by two men, to whom Kingsley, in spite of the whisky, t
ook a hearty dislike. He decided to muse on the state of the world until he could prise the girl loose from the two bounders. But it was not to be. Husky Voice came across to him. ‘Let’s dance, honey,’ she said.

  Kingsley did his best to adjust himself to the creeping rhythm, but apparently he did not succeed in gaining his partner’s approval.

  ‘Why don’t you relax, sweetheart?’ the voice breathed.

  No remark could have been better calculated to baffle Kingsley, for he saw no prospect of relaxing in the overcrowded space. Was he expected to go limp, leaving Husky Voice to support his dead weight?

  He decided to counter with nonsense of an equal order.

  ‘I never feel too cold, do you?’

  ‘Say, that’s darned cute,’ said the woman in a sort of amplified whisper.

  In a state of acute desperation Kingsley edged her off the floor, and grabbing his glass took a deep swig. Spluttering violently, he raced for the entrance hall, where he remembered seeing a telephone. A voice behind him said:

  ‘Hello, looking for something?’

  It was the dark girl.

  ‘I’m ringing for a taxi. In the words of the old song, “I’m tired and I want to go to bed.” ’

  ‘Is that quite the right thing to say to a respectable young woman? Seriously though, I’m going myself. I’ve got a car, so I’ll give you a lift. Forget about the taxi.’

  The girl drove smartly into the outskirts of Pasadena.

  ‘It’s dangerous to drive too slowly,’ she explained. ‘At this time of night the cops are on the look-out for drunks and for people going home from parties. And they don’t just pick up cars that are driven too fast. Slow driving makes ’em suspicious too.’ She switched on the dashboard light to check the speed. Then she noticed the fuel gauge.

  ‘Hell, I’m almost out of gas. We’d better stop at the next station.’

  It was only when she came to pay the attendant at the station that she discovered that her handbag was not in the car. Kingsley settled for the petrol.

  ‘I can’t think where I can have left it,’ she said. ‘I thought it was in the back of the car.’