Ringworld - Larry Niven Page 0,42

line of baby blue shot straight upward.

To look into the vanishing point was to step into another universe, a universe of true straight lines, right angles, and other geometric abstractions. Louis stared hypnotized into the vanishing point. Which point was it, the source or the sink? Did the black wall emerge or vanish in that meeting place?

…from out of the point at infinity, something came at them.

It was a ledge, growing like another abstraction along the base of the rim wall. First the ledge appeared; then, mounted on the ledge, a row of upright rings. Straight at the Liar they came, straight at the bridge of Louis’s nose. Louis shut his eyes and threw his arms up to protect his head. He heard a whimper of fear.

Death should have come in that instant. When it didn’t, he opened his eyes. The rings were going by in a steady stream; and he realized that they were no more than fifty miles across.

Nessus was curled in a ball. Teela, her palms pressed flat against the transparent hull, was staring avidly outward. Speaker was fearless and attentive at the control board. Perhaps he was better than Louis at judging distance.

Or perhaps he was faking it. The whimper could have come from Speaker.

Nessus uncurled. He looked out at the rings, which were smaller now, converging. “Speaker, you must match velocities with the Ringworld. Hold us in position by thrusting at one gravity. We must inspect this.”

Centrifugal force is an illusion, a manifestation of the law of inertia. Reality is centripetal force, a force applied at right angles to the velocity vector of a mass. The mass resists, tends to move in its accustomed straight line.

By reason of its velocity and the law of inertia, the Ringworld tended to fly apart. Its rigid structure would not allow that. The Ringworld applied its own centrifugal force to itself. The Liar, matching speed at 770 miles per second, had to match that centripetal force.

Speaker matched it. The Liar hovered next to the rim wall, balanced on .992 gee of thrust, while her crew inspected the spaceport.

The spaceport was a narrow ledge, so narrow as to be a dimensionless line until Speaker moved the ship inward. Then it was wide, wide enough to dwarf a pair of tremendous spacecraft. The craft were flat nosed cylinders, both of the same design: an unfamiliar design, yet clearly the design of a fusion-ramship. These ships were intended to fuel themselves, picking up interstellar hydrogen in scoops of electromagnetic force. One had been cannibalized for parts, so that it stood with its guts open to vacuum and its intimate structure exposed to alien eyes.

Windows showed around the upper run of the intact ship, allowing those eyes to gauge that ship’s size. In the random starlight, the glitter of windows was precisely like crystal candy sprinkled on a cake. Thousands of windows. That ship was big.

And it was dark. The entire spaceport was dark. Perhaps the beings who used it did not need light in the “visible” frequencies. But to Louis Wu, the spaceport looked abandoned.

“I don’t understand the rings,” said Teela.

“Electromagnetic cannon,” Louis answered absently. “For takeoffs.”

“No,” said Nessus.

“Oh?”

“The cannon must have been intended for landing the ships. One can even surmise the method used. The ship must go into orbit alongside the rim wall. It will not attempt to match the ring’s velocity, but will position itself twenty-five miles from the base of the rim wall. As the ring rotates, the coils of the electromagnetic cannon will scoop up the ship and accelerate it to match the velocity of the ring. I compliment the ring engineers. The ship need never come close enough to the ring to be dangerous.”

“You could also use the ring for takeoff.”

“No. Observe the facility to our left…”

“I’ll be tanjed,” said Louis Wu.

The “facility” was little more than a trap door big enough to hold one of the ramships.

It figured. 770 miles per second was ramscoop speed. The ring’s launching facility was merely a structure for tumbling the ship off into the void. The pilot would immediately accelerate away on ramscoop-fusion power.

“The spaceport facility seems to be abandoned,” said Speaker.

“Is there power in use?”

“My instruments sense none. There are no anomalous hot spots, no large-scale electromagnetic activities. As for the sensors which operate the linear accelerator, they may use less power than we can sense.”

“Your suggestion?”

“The facilities may still be in operational condition. We can test this by proceeding to the mouth of the linear accelerator and