m2 = m1 + 2.5 log (L1/L2)
Put m2 18 and L1/L2 100,000. At that distance, a one-kilometre asteroid would have magnitude 5.5. You could see it with the naked eye.” Webb stabbed the air with a piece of chalk. “But this one is 20.5, fifteen magnitudes fainter. For every five mags you go down, you lose a factor of a hundred in brightness. Ten mags down gives it only one ten thousandth of the intrinsic luminosity of a one-kilometre asteroid, ditto the surface area. This beast is less than a hundredth of a kilometre in diameter. Hey, we can relax. It’s only ten metres across.”
Shafer laughed. “A glorified beachball!”
“Are you sure?” Noordhof wanted to know.
Webb nodded. “At the ninety-nine per cent level. Even if it hits it’ll just be a brilliant fireball in the sky. We get these all the time. Colonel, you’re a fool. You’ve thrown away priceless hours of observing time. Forget the Baby Bears.”
An expression close to terror crossed Noordhof’s face. “I was about to waken the President.” A collective outburst of laughter relieved the tension. Judy headed for the kitchen and started to fill the coffee percolator.
“By the way,” Webb asked, “Where’s André?”
“He’s not in his room,” Judy called through.
“And he’s not up top,” Noordhof said.
Shafer put his hand to his mouth. “Ollie, I haven’t seen Leclerc since lunchtime.”
Webb looked at Noordhof. “Mark, it’s been a bad day. First a blind alley with your laser. Then a false alarm with this beachball. And now it seems that one of your team has gone missing.”
The Tenerife Robot
Judy pulled her dressing gown lapels round her neck and made for the dormitory. Webb, swaying with tiredness, headed in the same direction.
“Where do you think you’re going, Webb?”
“I’d have thought that was obvious, boss.” Webb saluted ironically.
“I’ve given thought to your friend’s automated telescope. The one in Tenerife. You say you can work it from here?”
“I can work it from here. The instructions go to Scott’s Oxford terminal and get routed through. Anyone sniffing cables at Tenerife would believe the operator was in Oxford.”
“With an external phone line? And an open modem?”
“Yes, for direct access. But it’s password protected and I have the password.”
“And your friend?”
“Scott’s in Patras. His wife is Greek and they’re with her family over Christmas. I have an open invitation to use the robotic telescope until it’s properly commissioned.”
“So, with half a million megatons coming in, and a telescope sitting idle, your action plan is to fall asleep.”
“I was waiting for your authorization, remember? Are you telling me you’re getting over your paranoia?”
“I have to balance risks here. Go ahead with it.”
“The sun’s up over Tenerife by now, Mark, but I’ll check that I can access it from here. Meantime, Herb and Kenneth must be turning into icemen, trying to get the spectrum of your beachball. Why don’t you call them back down?”
Webb sat heavily down at the terminal Judy had been at. The chair was still warm. Another small ellipse had appeared on the screen, the disc representing the Earth still firmly inside it. By the time the bolide arrived the Pacific would be in darkness, and a brilliant shooting star would light up the night sky, to be seen only by the uncomprehending eyes of flying fish. He routed the picture over to an empty terminal, and typed in a file transfer protocol. Immediately, the terminal asked for his user-name and password. He gave these and a fresh window appeared on screen: he was now in effect sitting at his own computer in Wadham College. He asked for a second FTP to be opened up, the one linking him to the robotic telescope. Webb was asked for a PIN number. He supplied it and found himself in effect in Tenerife, at the console of Scott’s telescope, in little more time than it took to say Beam me up Scottie. The whole procedure had taken less than thirty seconds.
Webb could now use the mouse to control the movement of the telescope, little numbers at the top right hand of the screen giving the celestial co-ordinates at the centre of the starfield. The shutters of the telescope dome were closed in daylight hours, but he had confirmed that he could contact the telescope from here.
Then he switched to the external camera, mounted on a pillar about fifty yards from the main instrument.
The picture came through immediately. The camera was looking back at the telescope, whose silver dome was gleaming in the morning sunlight. He rotated the telescope dome and saw it swivel immediately. He scanned slowly, and the camera panned over the rocky foreground. A cluster of telescopes came into view, the massive William Herschel conspicuous amongst them. Someone was walking outside the big dome. He carried on scanning, and the camera picked up the tops of clouds further down the mountain; they were above the inversion layer, and the atmosphere was likely very dry. He pressed another button and temperature, pressure, humidity and prevailing wind at the site were displayed. Then he swung the camera over the Tenerife sky; it was cloudless. Everything was operating smoothly. Tonight he would use the robot to search for Atens. As the signal came in to Eagle Peak it would automatically be reproduced a few hundred miles away, at Albuquerque, and the Teraflop would interrogate each picture element on the screen, comparing it with a digitized star chart and the co-ordinates of known asteroids. Any discrepancy would be recorded as a flashing point on the terminal VDU.
The thing would be to get as close as he could to the horizon, close to the sun but before the dawn light flooded the CCDs. Experimentally, he typed in an altitude and azimuth. Again the telescope’s response was swift.
In fact, remarkably swift: there was something odd.
Webb felt his scalp prickling.
His exhaustion suddenly lifted. He typed in another celestial co-ordinate. He tried a third and a fourth, each one with the same amazingly fast response.
He took a surreptitious look around. Shafer was at a terminal, leaning back in his chair, arms flopped at his side. With his eyes half shut and mouth half open, and with his stubble and ponytail, he looked more like a moron in a gangster movie than one of the sharpest scientists on the planet. Noordhof was at the conference table reading some report. Both men seemed past the point of exhaustion. Quietly, Webb logged on to the Internet and navigated his way to an infrared satellite image of Europe and North Africa. The image was less than ten minutes old. Tenerife and La Palma were covered with cloud. No mountain tops protruded above them. And yet the Tenerife camera was showing a clear, sunny sky.
Slowly, a fact almost beyond comprehension sank into Webb’s mind.
The observations from the robot telescope were a fake.
Lake Pepsi
Wallis rolled one of the general’s Havana cheroots from one end of his mouth to the other, spat, and heaved again on the oars. Little whirlpools spun away from the boat and it lurched erratically forwards.
Wallis thought he might as well be rowing a corpse. The CJCS lay back, motionless, a hand trailing in the water. His small mouth gaped open and a strip of hairy stomach lay exposed between his Hawaiian tunic and the top of his trousers.