Arthur Clarke - Cradle

Affixed to the bottom of almost any boat, the compact telescope could be driven thirty degrees back and forth about the vertical by a small internal motor. The observation schedule for the telescope was usually defined by a preprogrammed protocol. The details of this sequence as well as the critical optical parameters for the telescope were all stored in the system microprocessor; however, everything in the software could be changed in realtime by manual input if the operator desired.

Data from the telescope was carried to the rest of the electronic equipment on the boat by means of very thin fiber optics. These cables were bracketed along the edge of the boat. About ten percent of the pictures reconstructed from this data were then displayed (after some very crude enhancements) on the boat’s monitor in realtime. But all the data taken by the telescope was automatically recorded in the one hundred gigabit memory unit that adjoined the monitor. Another set of fiber optics connected the same memory unit with the boat’s central navigation system and the servomotor actuators controlling the telescopes. These circuits were pulsed every ten milliseconds so that the orientation of the telescope and the boat’s location at the time of each telescope image could be stored together in the permanent file.

Next to the monitor on top of the footlocker, but on the other side from the memory unit, was the system control panel. Dr. Dale Michaels and MOI were famous throughout the world for the cleverness of their inventions; however, these ingenious creations were not so easy to operate. Dale had tried to give Carol a crash course on the workings of the system the night before she had driven down to Key West from Miami. It had been almost useless. Eventually frustrated, Dale had simply programmed into the microprocessor an easy sequence that mosaicked the area under the boat in regular patterns. He then set the optical gains at normal default values, and instructed Carol not to change anything. “All you have to do,” Dr. Michaels had said as he had carefully loaded the system control panel into the station wagon, “is push this GO button. Then cover the panel to make certain that nobody inadvertently hits the wrong command.”

So Carol certainly could not explain to Troy how anything worked. She walked over beside him on the boat, put her arm on his shoulder, and grinned sheepishly. “I hate to disappoint you, my inquisitive friend, but I don’t know any more about how this thing works than I told you when we were setting up all the equipment. To operate it, all we have to do is turn on the power supply, which you have already done, and then push this button.” She pushed the GO button on the panel. A picture of the clear ocean about fifty feet underneath the boat appeared immediately on the color monitor. The picture was amazingly sharp. The threesome watched in wonder as a hammerhead shark swam through a school of small gray fish, swallowing hundreds of them in his awesome rush.

“As I understand it,” Carol continued as both men stayed glued in fascination to the monitor, “the telescope system then does the rest, following a planned set of observations stored in its software. Obviously we see what it sees here on this monitor. At least we see the visual image. The simultaneous infrared and sonar pictures are stored on the recorder. My friend at MOI (she didn’t want to alert them even more by using Dale’s name) tried to explain how I could change between the visual and infrared and sonar images, but it wasn’t simple. You’d think it would be as easy as pushing an “I” for infrared or an “S” for sonar. Nope. You have to input as many as a dozen commands just to change which output signal is fed into the monitor.”

Troy was impressed. Not just by the ocean telescope system, but also by the way Carol, a woman admittedly not educated in engineering or electronics, had clearly grasped the essentials of it. “The infrared part of the telescope must measure thermal radiation,” he said slowly, “if I remember my high school physics correctly. But how would underwater thermal variations tell you anything about whales?”

At this point Nick Williams shook his head and turned away from the screen. He recognized that he was hopelessly out of his intellectual element with all these engineering terms and he was more than a little embarrassed to admit his total ignorance in front of Carol and Troy. Nick also didn’t believe for an instant that Carol had brought all this electronic wizardry on board to find whales that had strayed from their migration route. He walked over to the small refrigerator and pulled out another beer. “And what we’re going to do for the next two hours, if I understand it correctly, is ride around in the boat while you look for whales on that screen?”

Nick’s derisive comment carried with it an unmistakable challenge. It intruded upon the warm and friendly rapport that had been created between Carol and Troy. She allowed herself to become irritated again by Nick’s attitude and fired back her own verbal fusillade. “That was the plan, Mister Williams, as I told you when we left Key West. But Troy tells me that you’re something of a treasure hunter. Or at least were some years ago. And since you seem to have convinced yourself that treasure is really what I’m after, perhaps you’d like to sit here next to me and look at the same pictures to make sure I don’t miss any whales. Or treasure, as the case may be.”

Nick and Carol glared at each other for a few moments. Then Troy stepped between them. “Look, Professor… and you too, angel… I don’t pretend to understand why you two insist on pissing each other off. But it’s a pain in the ass for me. Can’t you just cool it for a while? After all,” Troy added, looking first at Nick and then at Carol, “if you two go for a dive, you’re partners. Your lives may depend on one another. So knock it off.”

Carol shrugged her shoulders and nodded. “Okay by me,” she said. But seeing no immediate response from Nick, she couldn’t resist another shot. “Provided that Mr. Williams recognizes his responsibility as a PADI member and stays sober enough to dive.”

Nick’s eyes flashed angrily. Then he walked over to the deck railing and dramatically poured his new beer into the ocean. “Don’t worry about me, sweetheart,” he said, forcing a smile, “I can take care of myself. You just worry about what you do.”

The ocean telescope microprocessor contained a special alarm subroutine that sounded a noise like a telephone ring whenever the programmed alarm conditions were triggered. At Carol’s request, Dale Michaels had personally adapted the normal alarming algorithm just before she left for Key West so that it would react to either a large creature moving across the field of view or a stationary “unknown” object of significant size. After he had finished the logic design for the small change and sent it to his software department for top priority coding and testing, Dale had smiled to himself. He was amused by his complicity with Carol. This piece of technological subterfuge would certainly convince Carol’s companions, whoever they might be, that she was earnest in her search for whales. At the same time, the alarm would also sound if what Carol was really seeking, supposedly an errant (and secret) Navy missile currently under development, appeared on the ocean floor underneath the boat.

The basic structure for both alarm algorithms was easy to understand. To identify a moving animal, it was sufficient to overlay two or three images taken less than a second apart (at any wavelength, although there was greater accuracy in the process with the sharper visual images), and then compare the data using the knowledge that most of the scene should be unchanged. Significant miscompares (connected areas in the overlay that differed from image to image) would suggest the presence of a large moving creature.