Fred Hoyle: The Black Cloud

“Our results in broad outline confirm what Mr Green has already told you. Jupiter and Saturn are out of position and to amounts that are of the general order given by Mr Green. There are some small discrepancies between his results and ours but the main features are the same.

“At the Royal Observatory we have also observed that the planets Uranus and Neptune are out of their positions, not it is true to the same extent as Jupiter and Saturn, but nevertheless in very appreciable amounts.

“Finally I may add that I have received a letter from Grottwald in Heidelberg, in which he says that the Heidelberg Observatory has obtained results that accord closely with those of the Royal Observatory.”

Whereon the Astronomer Royal returned to his seat. Dr Oldroyd immediately addressed the meeting:

“Gentlemen, you have heard presented to you this afternoon results that I venture to suggest are of the very first importance. Today’s meeting may well become a landmark in the history of astronomy. It is not my wish to take up any more of your time as I expect you will have much to say. In particular I expect our theoreticians will have much to say. I should like to begin the discussion by asking Professor Kingsley whether he has any comment he would like to make.”

“Not while the law of slander is still operative,” whispered one professional to another.

“Mr Chairman,” began Kingsley, “while the two previous speakers were addressing us I had ample opportunity to perform a fairly lengthy calculation.”

The two professionals grinned at each other, the Astronomer Royal grinned to himself.

“The conclusion I have arrived at may be of interest to the meeting. I find that if the results that have been presented to us this afternoon are correct, I say if they are correct, then a hitherto unknown body must exist in the vicinity of the solar system. And the mass of this unknown body must be comparable with or even greater than the mass of Jupiter itself. While it must be granted implausible to suppose that the results given to us arise from mere observational errors, I say mere observational errors, it may also be thought implausible that a body of such large mass existing within the solar system, or on the periphery of the solar system, could so far have remained undetected.”

Kingsley sat down. The professionals who understood the general trend of his argument, and what lay under it, felt that he had made his point.

Kingsley glowered at the railwayman who asked to see his ticket as he boarded the 8.56 p.m. train from Liverpool Street to Cambridge. The man fell back a pace or two, as well he might, for Kingsley’s rage had not been assuaged by the meal he had just eaten, a meal consisting of poor food badly cooked, condescendingly served in pretentious but slovenly conditions. Only its price had been ample. Kingsley stamped through the train looking for a compartment where he could bite the carpet in solitary splendour. Moving quickly through a first-class carriage he caught a glimpse of the back of a head that he thought he recognized. Slipping into the compartment, he dropped down by the Astronomer Royal.

“First-class, nice and comfortable. Nothing like working for the government, eh?”

“Quite wrong, Kingsley. I’m going up to Cambridge for a Trinity Feast.”

Kingsley, still acutely conscious of the execrable dinner he had just consumed, pulled a wry face.

“Always amazes me the way those Trinity beggars feed themselves,” he said. “Feasts on Mondays, Wednesdays, and Fridays, and four square meals on each of the other days of the week.”

“Surely it’s not quite as bad as that. You seem quite put out today, Kingsley. In trouble of any sort?”

Metaphorically the Astronomer Royal was hugging himself with delight.

“Put out! Who wouldn’t be put out, I’d like to know. Come on, A.R.! What was the idea of that vaudeville stunt this afternoon?”

“Everything that was said this afternoon was plain sober fact.”

“Sober fact, my eye! It would have been much more sober if you’d got up on the table and done a clog dance. Planets a degree and a half out of position! Rubbish!”

The Astronomer Royal lifted down his brief case from the rack and took out a large file of papers on which a veritable multitude of observations was entered.

“Those are the facts,” he said. “In the first fifty or so pages you’ll find the raw observations of all the planets, day-by-day figures over the last few months. In the second table you’ll find the observations reduced to heliocentric co-ordinates.”

Kingsley studied the papers silently for the best part of an hour, until the train reached Bishop’s Stortford. Then he said:

“You realize, A.R., that there isn’t the slightest chance of getting away with this hoax? There’s so much stuff here that I can easily tell whether it’s genuine. Can I borrow these tables for a couple of days?”

“Kingsley, if you imagine that I would go to the trouble of staging an elaborate — hoax as you call it, primarily with the object of deceiving you, of taking a rise out of you, then all I can say is that you flatter yourself unduly.”

“Let’s put it this way,” answered Kingsley. “There are two hypotheses that I can make. Both at first sight seem incredible, but one of them must be right. One hypothesis is that a hitherto unknown body with a mass of the same order as Jupiter has invaded the solar system. The second hypothesis is that the Astronomer Royal has taken leave of his senses. I don’t want to give offence, but quite frankly the second alternative seems to me less incredible than the first.”

“What I admire about you, Kingsley, is the way you refuse to mince matters — curious phrase that.” The Astronomer Royal reflected thoughtfully for a moment. “You should go in for politics one day.”

Kingsley grinned. “Can I have these tables for a couple of days?”

“What do you propose to do?”

“Well, two things. I can check the consistency of the whole business and then I’ll find out just where the intruding body is located.”

“And you’ll do this how?”

“First I’ll work backwards from the observations of one of the planets — Saturn might be the best one to choose. This’ll determine the distribution of the intruding body, or intruding material if it isn’t in the form of a discrete body. This’ll be much the same thing as the J. C. Adams — Le Verrier determination of the position of Neptune. Then once I’ve got the intruding material pinned down, I’ll work the calculation forwards. I’ll work out the disturbances of the other planets Jupiter, Uranus, Neptune, Mars, etcetera. And when I’ve done that, I’ll compare my results with your observations of these other planets. If my results agree with the observations then I’ll know there’s no hoax. But if they don’t agree — well!”

“That’s all very fine,” said the Astronomer Royal, “but how do you propose to do all this in a couple of days?”

“Oh, by using an electronic computer. Fortunately I’ve got a programme already written for the Cambridge computer. It’ll take me all tomorrow modifying it slightly, and to write a few subsidiary routines to deal with this problem. But I ought to be ready to start calculating by tomorrow night. Look here, A.R., why don’t you come to the lab after your Feast? If we work through tomorrow night, we ought to get the matter settled very quickly.”

The following day was most unpleasant; it was cold, rainy, and a thin mist covered the town of Cambridge. Kingsley worked all through the morning and into mid-afternoon before a blazing fire in his College rooms. He worked steadily, writing an astonishing scrawl of symbols of which the following is a short sample, a sample of the code by which the computer was instructed as to how it should perform its calculations and operations: