"The hum?" asked Deirdre again. When he nodded, she said: "What are you going to do now? What do you think makes the hum?"
"I'm trying hard not to guess what makes the hum," Terry told her. "Insufficient data. I need more. I think I'll ask what other odd phenomena have turned up in this neighborhood. Foam-patches on the sea? I can't imagine a connection, but still...."
He swung the little boat alongside the docked Esperance and held out his hand to help Deirdre to the dock. His hand was wholly steady again. She accepted the help.
"We'll go to the tracking station?"
"Yes. Everybody seems to be there," said Terry.
They heard a babble of voices coming from the satellite-tracking station. As they approached the buildings, Terry looked around. Off at one side there was the very peculiar aerial system by which tiny artificial moons circling the earth could be detected by their own signals. Minute spheres and cylinders and spiky objects and foolish-looking paddle-wheels, whirling in their man-appointed rounds, sent down signals with powers of mere fractions of a watt. This system of aerials picked up those miniature broadcasts and extracted remarkable amounts of information from them. It was possible to determine the satellites' distance more accurately, by a comparison of phase-changes in their signals, than if steel tape measures were stretched up to make physical contact with them. The accuracy was of the order of inches at hundreds of miles. Floating where the stars were bright and unwinking lights against blackness and the sun was a disk with writhing arms of fire, the small objects sent back information that men had never possessed before and did not wholly know what to do with now that they did. And there were other objects in the heavens, too. There were satellites which no longer signaled back to earth. Some had their equipment worn out. Some objects were satellites which had failed to function from the beginning. Some were mysteries.
The bolide of the night before was a mystery. As Terry and Deirdre entered the wide verandah of the recreation building for the station's personnel, they heard Dr. Morton protesting, "But that's out of the question! I agree that we never know any more about what the Russians throw out to space than what we find out for ourselves. That's true! But this wasn't a terrestrial object! If it was a satellite that wasn't launched right, it had to be sent up from Russian territory. It wasn't. That's positive! If we assume it was a satellite that had already made several orbital turns, we must admit it would be an impossible shift in apogee for it to come down at the angle it did!"
Deirdre and Terry sat down as someone else said hotly, "Our observations were wrong. They had to be! The earth's magnetic field couldn't affect the speed of an object outside the atmosphere! Our observations say it slowed down. It couldn't!"
Davis lifted a hand in greeting. The argument stopped for a moment. Deirdre was known, but Terry had to be introduced. He was sitting beside a bald young man who explained in a low tone, as the argument resumed. "They're having fun. They argued for days when our radar picked up an empty second stage in orbit. They're still ready to dispute for hours about a supposed retrograde satellite that was spotted last year, was watched for four turns, and then disappeared. Beer?"
"Too early," said Terry. "Thanks just the same."