“But I shall have to do a little calculation myself before I can reduce the tabulated numbers to a really convenient form. Before I do that, let’s start the machine finding out about Jupiter.”
Kingsley pressed a number of switches. Then he put a large roll of paper tape into the ‘reader’ of the machine. After pressing another switch the reader began to unroll the tape.
“You see what happens,” said Kingsley. “As the tape is unrolled a light shines through the holes in it. The light then goes into this box here, where it falls on a photo-sensitive tube. This causes a series of pulses to go into the machine. This tape I’m just putting in gives instructions to the machine as to how it is to calculate the disturbance in the position of Jupiter, but the machine hasn’t had all its instructions yet. It still doesn’t know where the intruder is, or how massive it is, or how fast it’s moving. So the machine won’t start working yet.”
Kingsley was right. The machine stopped as soon as it had reached the end of the long roll of paper tape. Kingsley pointed to a small red light.
“This shows that the machine has stopped because the instructions aren’t complete yet. Now where’s that piece of tape we got out last time? That’s it on the table by you.”
The Astronomer Royal handed over the long strip of paper.
“And this supplies the missing piece of information. When this has gone in, the machine will know all about the intruder as well.”
Kingsley pressed a switch and in went the second piece of tape. As soon as it had run through the reader, just as the first tape had done before it, lights began to flash on a series of cathode-ray tubes.
“Off she goes. From now on for the next hour the machine will be multiplying a hundred thousand ten-figure numbers every minute. And while it does that, let’s make some coffee. I’m peckish, I haven’t had anything to eat since four o’clock yesterday afternoon.”
So the two men worked on through the night. It was greying dawn on a miserable January morning when Kingsley said:
“Well, that’s about it. We’ve got all the results here, but they need a bit of conversion before we can get to work on a comparison with your observations. I’ll get one of the girls to do that today. Look, A.R., I suggest you have dinner with me tonight, and then we’ll go over things with a tooth comb. Perhaps you’d like to slip along now and get a bit of sleep. I’ll stay on until the lab staff comes in.”
After dinner that night, the Astronomer Royal and Kingsley were again together in the latter’s rooms at Erasmus College. The dinner had been a particularly good one and they were both much at their ease as they drew up to the blazing fire.
“Lot of nonsense we hear nowadays about these closed stoves,” said the Astronomer Royal, nodding towards the fire. “They’re supposed to be very scientific, but there’s nothing scientific about ’em. The best form of heat is in the form of radiation from an open fire. Closed stoves only produce a lot of hot air that’s extremely unpleasant to breathe. They stifle you without warming you.”
“A lot of sense in that,” added Kingsley. “Never had any use for such devices myself. Now how about a spot of port before we get down to business? Or madeira, claret, or burgundy?”
“Very nice, I think I’d like the burgundy, please.”
“Good, I’ve got a quite nice Pommard ’57.”
Kingsley poured out two largish glasses, returned to his seat, and went on:
“Well, it’s all here. I’ve got my calculated values for Mars, Jupiter, Uranus, and Neptune. The agreement with your observations is fantastically good. I’ve made up a sort of synopsis of the main results here on these four sheets, one for each planet. You can see for yourself.”
The Astronomer Royal spent several minutes looking over the several sheets.
“This is most impressive, Kingsley. That computer of yours is certainly a quite fantastic instrument. Well, are you satisfied now? Everything fits into line. Everything fits the hypothesis of an external body invading the solar system. By the way, do you have the details of its mass, position, and motion? They’re not given here.”
“Yes, I’ve got those too,” answered Kingsley, picking another sheet out of a large file.
“And that’s just where the trouble arises. The mass comes out at nearly two-thirds of that of Jupiter.”
The Astronomer Royal grinned.
“I thought you estimated at the B.A.A. meeting that it would be
Kingsley grunted.
“Considering the distractions, that wasn’t a bad estimate, A.R. But look at the heliocentric distance, 21.3 astronomical units, only 21.3 times the Earth’s distance from the Sun. It’s impossible.”
“I don’t see why.”
“At that distance it must be easily visible to the naked eye. Thousands of people would have seen it.”
The Astronomer Royal shook his head.
“It doesn’t follow that the thing must be a planet like Jupiter and Saturn. It may have a much higher density and a lower albedo. That might make it a very difficult naked-eye object.”
“Even so, A.R., some telescopic sky survey would have picked it up. You see it’s in the night sky, somewhere south of Orion. Here are the co-ordinates; Right Ascension 5 hours 46 minutes, Declination minus 30 degrees 12 minutes. I don’t know the details of the sky very well, but that is somewhere south of Orion, isn’t it?”
The Astronomer Royal grinned again.
“When did you last look through a telescope, Kingsley?”
“Oh, about fifteen years ago, I suppose.”
“What happened then?”
“I had to show a party of visitors over the Observatory.”
“Well, don’t you think we ought to go up to the Observatory now and see what we can see, instead of arguing about it? It seems to me that this intruder, as we keep calling it, may not be a solid body at all.”
“You mean it might be a cloud of gas? Well, in some ways that would be better. It wouldn’t be so easily seen as a condensed body. But the cloud would have to be pretty localized, with a diameter not much greater than that of the Earth’s orbit. A pretty dense sort of cloud it would have to be too, about 10–10 gm. per cm3. A minute star in the process of formation perhaps?”
The Astronomer Royal nodded.
“We know that the very big gas clouds like the Orion nebula have average densities of perhaps 10–21 gm. per cm3. On the other hand, stars like the Sun with densities of 1 gm. per cm3 are constantly forming within the big gas clouds. This surely means that there must be patches of gas at all densities varying from say 10–21 gm. per cm3 at one extreme up to stellar densities at the other extreme. Your 10–10 gm. per cm3 is bang in the middle of this range, and looks quite plausible to me.”
“There is a great deal of truth in that, A.R. Clouds with that sort of density must exist, I suppose. But I think you were quite right about going up to the Observatory. I’ll give Adams a ring while you finish your wine, and I’ll get a taxi.”
When the two men reached the University Observatory the sky was overcast, and although they waited through the cold damp hours there was no sight of the stars that night. And so it was the following night, and the night after that. Thus did Cambridge lose the honour of the first detection of the Black Cloud, as it had lost the honour of the first detection of the planet Neptune more than a century before.
On 17 January, the day after Herrick’s visit to Washington, Kingsley and the Astronomer Royal again dined together in Erasmus. Again they made their way to Kingsley’s rooms after dinner. Again they sat before the fire, drinking Pommard ’57.
“Thank goodness we don’t have to sit up all night again. I think Adams can be trusted to ring through if the sky clears.”
“I really ought to be getting back to Herstmonceux tomorrow,” said the Astronomer Royal. “After all, we’ve got telescopes there too.”
“Evidently this damn weather has got you down the same as me. Look here, A.R., I’m in favour of throwing our hand in. I’ve drafted a cable to send to Marlowe in Pasadena. Here it is. They won’t be troubled by cloudy skies over there.”
The Astronomer Royal glanced down at the sheet of paper in Kingsley’s hand.
PLEASE INFORM WHETHER UNUSUAL OBJECT EXISTS AT RIGHT ASCENSION FIVE HOURS FORTY-SIX
