“What!”
“Yes, right out. You can see it over here. A message was coming through from Brazil. Look how the signal has gone completely.”
“It’s fantastic. Must be an extremely rapid burst of ionization.”
“What d’you think we ought to do?”
“Wait, I suppose. It may be a transient effect. In fact it looks rather like it.”
“If it goes on we might shorten the wave-length.”
“Yes, we might. But scarcely anybody else could. The Americans could work up a new wave-length pretty quickly, and probably the Russians as well. But it’s doubtful if many of the others could. We’ve had enough trouble getting ’em to build their present transmitters.”
“Then there’s nothing to do but hang on?”
“Well, I don’t think I should try transmitting, because you’ll never know if the messages get through. I should just leave the receiver on recorder. Then we shall have any stuff that happens to come through — if conditions improve, that is to say.”
There was a brilliant aurora-type display that night, which the Nortonstowe scientists took to be associated with the sudden burst of ionization high in the atmosphere. They had no idea of the cause of the ionization, however. Very large disturbances of the Earth’s magnetic field were also noted.
Marlowe and Bill Barnett discussed the matter as they strolled around, admiring the display.
“My God, look at those orange-coloured sheets,” said Marlowe.
“What baffles me, Geoff, is that this is obviously a low-level display. You can tell that from the colours. I suppose we ought to have a shot at getting a spectrum, although I’d swear to it from what we can see right now. I’d say that all this is going on not more than fifty miles up, probably less. It’s in just the place where we’ve been getting all the excessive ionization.”
“I know what you’re thinking, Bill. That it’s easy to imagine a sudden puff of gas hitting the extreme outside of the atmosphere. But that would produce a disturbance much higher up. It’s difficult to believe this is due to impact.”
“No, I don’t think it possibly can be. It looks to me much more like an electrical discharge.”
“The magnetic disturbances would check with that.”
“But you see what this means, Geoff? This isn’t from the Sun. Nothing like it from the Sun has ever happened before. If it’s an electrical disturbance, it must come from the Cloud.”
Leicester and Kingsley hurried along to the communication lab after breakfast the following morning. A short message from Ireland had come in at 6.20. A long message from the U.S. had started at 7.51, but after three minutes there had been a fade and the rest of the message was lost. A short message from Sweden was received about midday, but a longer message from China was interrupted by fade-out soon after two o’clock.
Parkinson joined Leicester and Kingsley at tea.
“This is a most disturbing business,” he said.
“I can imagine so,” answered Kingsley. “And it’s another queer business.”
“Well, it’s certainly annoying. I thought we’d got this communication problem in hand. In what way is it queer?”
“In that we seem to be on the verge of transmission the whole time. Sometimes messages come through and sometimes they don’t, as if the ionization is oscillating up and down.”
“Barnett thinks that electrical discharges are going on, So wouldn’t you expect oscillations?”
“You’re becoming quite a scientist, aren’t you, Parkinson?’ laughed Kingsley. “But it isn’t as easy as that,” he went on. “Oscillation yes, but hardly oscillations like the ones we’ve been getting. Don’t you see how odd it is?”
“No, I can’t say I do.”
“The messages from China and the U.S., man! We got a fade-out on each of ’em. That seems to show that when transmission is possible it’s only barely possible. The oscillations seem to be making transmission just possible but only by the slightest margin. That might happen once by chance but it’s very remarkable that it should happen twice.”
“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.
