Fred Hoyle - The Black Cloud

“Isn’t there a flaw there, Chris?’ Leicester chewed his pipe, and then pointed with it. “If discharges are going on, the oscillations might be quite rapid. Both the messages from the U.S. and China were long, over three minutes. Perhaps the oscillations last about three minutes. Then you can understand why we get short messages complete, like those from Brazil and Iceland, while we never get a complete long message.”

“Ingenious, Harry, but I don’t believe it. I was looking at your signal record of the U.S. message. It’s quite steady, until the fade-out starts. That doesn’t look like a deep oscillation, otherwise the signal would vary even before the fade-out. Then if oscillations are going on every three minutes, why aren’t we getting a lot more messages, or at any rate fragments of them? I think that’s a fatal objection.”

Leicester chewed his pipe again.

“It certainly looks like it. The whole thing’s damn strange.”

“What do you propose to do about it?’ asked Parkinson.

“It might be a good idea, Parkinson, if you were to ask London to cable Washington asking for transmissions to be sent for five minutes every hour, starting on the hour. Then we shall know what messages are not being received, as well as those that do come through. You might also like to apprise other Governments of the situation.”

No further transmissions were received during the next three days. Whether this was due to fade-out or because no messages were sent was not known. In this unsatisfactory state of affairs a change of plan was decided on. As Marlowe told Parkinson:

“We’ve decided to look into this business properly, instead of depending on chance transmissions.”

“How do you intend to do that?”

“We’re arranging to point all our aerials upwards, instead of more or less towards the horizon.Then we can use our own transmissions to investigate this unusual ionization. We’ll pick up reflections of our own transmissions, that is to say.”

For the next two days the radio astronomers were hard at work on the aerials. It was late in the afternoon of 9 December by the time every arrangement had been made. Quite a crowd assembled in the lab to watch results.

“O.K. let her rip,” said someone.

“What wave-length shall we start on?”

“Better try one metre first,” suggested Barnett. “If Kingsley is right in supposing that twenty-five centimetres is on the verge of transmission, and if our ideas on collision damping are correct, this ought to be about critical for vertical propagation.”

The one-metre transmitter was switched on.

“It’s going through,” Barnett remarked.

“How do you know that?’ Parkinson asked Marlowe.

“There’s nothing but very weak return signals,” answered Marlowe. “You can see that on the tube. Most of the power is being absorbed or is going right through the atmosphere into space.”

The next half hour was spent in gazing at electrical equipment and in technical talk. Then there was a rustle of excitement.

“Signal’s going up.”

“Look at it!’ exclaimed Marlowe. “It’s going up with a rush!”

The return signal continued to grow for about ten minutes.

“It’s saturated. We’re getting total reflection now, I’d say,” said Leicester.

“Looks as though you were right, Chris. We must be quite near the critical frequency. Reflection is coming from a height of just under fifty miles, more or less where we expected it. Ionization there must be a hundred to a thousand times normal.”

A further half hour was spent in measurements.

“Better see what ten centimetres does,” remarked Marlowe.

There was a pressing of switches.

“We’re on ten centimetres now. It’s going right through, as of course it ought to,” announced Barnett.

“This is unbearably scientific,” said Ann Halsey. “I’m going off to make tea. Come and help, Chris, if you can leave your meters and dials for a few minutes.”

Some time later while they were drinking tea and conversing generally, Leicester gave a startled cry.

“Heavens above! Look at this!”

“It’s impossible!”

“But it’s happening.”

“The ten-centimetre reflection is rising. It must mean that the ionization is going up at a colossal rate,” Marlowe explained to Parkinson.

“The damn thing’s saturating again.”

“It means the ionization has increased a hundredfold in less than an hour. It’s incredible.”

“Better put the one-centimetre transmitter on, Harry,” Kingsley said to Leicester.

So the ten-centimetre transmission was changed to a one-centimetre transmission.

“Well, that’s going through all right,” someone remarked.

“But not for long. In another half hour the one-centimetre will be trapped, mark my words,” said Barnett.

“Incidentally what message is being sent?’ asked Parkinson.

“None,” answered Leicester, “we’re only sending C.W. — continuous wave.”

“As if that explained everything,” thought Parkinson.

But although the scientists sat around for a couple of hours or more nothing further of note happened.

“Well, it’s still going through. We’ll see what it looks like after dinner,” said Barnett.

After dinner the one-centimetre transmission was still going through.

“It might be worth switching back to ten centimetres,” suggested Marlowe.

“O.K. let’s try again.” Leicester flicked the switches. “That’s interesting,” he said. “We’re going through on ten centimetres now. The ionization seems to be dropping, and pretty rapidly too.”

“Negative ion formation probably’ — from Weichart.

Ten minutes later Leicester whooped with excitement.

“Look, the signal’s coming in again!”

He was right. During the next few minutes the reflected signal grew rapidly to a maximum value.

“Complete reflection now. What shall we do? Go back to one centimetre?”

“No, Harry,” said Kingsley. “My revolutionary suggestion is that we go upstairs to the sitting-room, where we drink coffee and where we listen to music played by Ann’s fair hand. I’d like to switch off for an hour or two and come back later.”

“What on earth is the idea, Chris?”

“Oh, just a hunch, a crazy idea, I suppose. But perhaps you’ll indulge me for once in a way.”

“For once in a way!’ chuckled Marlowe. “You’ve been indulged, Chris, from the day you were born.”

“That may be so, but it’s scarcely polite to remark on it, Geoff. Come on, Ann. You’ve been waiting to try out the Beethoven Opus 106 on us. Now’s your chance.”

It was an hour and a half or so later, with the opening chords of the great sonata still ringing in their heads, that the company made its way back to the transmitting lab.

“Try the one-metre first, just for luck,” said Kingsley.

“Bet you that one-metre is completely trapped,” Barnett said as he clicked on various switches.

“No, it’s not, by John Brown’s body,” he exclaimed a few minutes later, when the equipment had warmed up. “It’s going through. It just isn’t believable, and yet it’s as plain as a pikestaff on the tube.”

“What’s your betting, Harry, on what’s going to happen next?”

“I’m not betting, Chris. This is worse than “spot the lady”.”

“I’m betting it’s going to saturate.”

“Any reasons?”

“If it saturates I’ll have reasons, of course. If it doesn’t there won’t be any reasons.”

“Playing safe, eh?”

“Signal going up,” sang out Barnett. “Looks as though Chris is going to be right. Up it goes!”

Five minutes later the one-metre signal saturated. It was completely trapped by the ionosphere, no power getting away from the Earth.