Contact - Carl Sagan [107]
If you had to meet Palmer Joss in this museum, she thought, and the only thing you had ever talked to him about was religion and the Message, where would you meet him? It was a little like the frequency selection problem in SETI: You haven't yet received a message from an advanced civilization and you have to decide on which frequencies these beings-about whom you know virtually nothing, not even their existence-have decided to transmit. It must involve some knowledge that both you and they share. You and they certainly both know what the most abundant kind of atom in the universe is, and the single radio frequency at which it characteristically absorbs and emits. That was the logic by which the 1420 megahertz line of neutral atomic hydrogen had been included in all the early SETI searches. What would the equivalent be here? Alexander Graham Bell's telephone? The telegraph? Marconi's- Of course.
"Does this museum have a Foucault pendulum?" she asked the guard.
The sound of her heels echoed on the marble floors as she approached the rotunda. Joss was leaning over the railing, peering at a mosaic tile representation of the cardinal directions. There were small vertical hour marks, some upright, others evidently knocked down by the bob earlier in the day. Around 7 PM. Someone had stopped its swing, and it now hung motionless. They were entirely alone. He had heard her approach for a minute at least and had said nothing.
"You've decided that prayer can stop a pendulum?" She smiled.
`That would be an abuse of faith," he replied. "I don't see why. You'd make an awful lot of converts. It's easy enough for God to do, and if I remember correctly, you talk to Him regularly…That's not it, huh? You really want to test my faith in the physics of harmonic oscillators? Okay."
A part of her was amazed that Joss would put her through this test, but she was determined to pass muster. She let her handbag slide off her shoulder and removed her shoes. He gracefully hurdled the brass guardrail and helped her over. They half walked and half slid down the tiled slope until they were standing alongside the bob. It had a dull black finish, and she wondered whether it was made of steel or lead.
"You'll have to give me a hand," she said. She could easily put her arms around the bob, and together they wrestled it until it was inclined at a good angle from the vertical and flush against her face. Joss was watching her closely. He didn't ask her whether she was sure, he neglected to warn her about falling forward, he offered no cautions about giving the bob a horizontal component of velocity as she let go.
Behind her was a good meter or meter and a half of level floor, before it started sloping upward to become a circumferential wall. If she kept her wits about her, she said to herself, this was a lead pipe cinch. She let go.
The bob fell away from her. The period of a simple pendulum, she thought a little giddily, is 2?, square root L over g, where L is the length of the pendulum and g is the acceleration due to gravity. Because of friction in the bearing, the pendulum can never swing back farther than its original position. All I have to do is not sway forward, she reminded herself.
Near the opposite railing, the bob slowed and came to a dead stop. Reversing its trajectory, it was suddenly moving much faster than she had expected. As it careened toward her, it seemed to grow alarmingly in size. It was enormous and almost upon her. She gasped.
"I flinched," Ellie said in disappointment as the bob fell away from her. "Only the littlest bit." "No, I flinched."
"You believe. You believe in science. There's only a tiny smidgen of doubt."
"No, that's not it. That was a million years of brains fighting a billion years of instinct. That's why your job is so much easier than mine."
"In this matter, our jobs are