“If you’ve developed an acceleration shield,” he said smiling, “you better hurry and file a patent. You could sell it for a considerable-”
“No, Doc, it wouldn’t be worth much under normal conditions; our shells work better and they evolved from the same principles.”
“Explain away.”
“We put Marygay into a shell and flood-”
“Wait, wait. Absolutely not. A poorly-fitting shell was what caused this in the first place. And this time, she’d have to use somebody else’s.”
“I know, Doc, let me explain. It doesn’t have to fit her exactly as long as the life support hookups can function.
The shell won’t be pressurized on the inside; it won’t have to be because she won’t be subjected to those thousands of kilograms-per-square-centimeter pressure from the fluid outside.”
“I’m not sure I follow.”
“It’s just an adaptation of-you’ve studied physics, haven’t you?”
“A little bit, in medical school. My worst courses, after Latin.”
“Do you remember the principle of equivalence?”
“I remember there was something by that name. Something to do with relativity, right?”
“Uh-huh. It means that.. . there’s no difference being in a gravitational field and being in an equivalent accelerated frame of-it means that when the Anniversary is blasting five gees, the effect on us is the same as if it were sitting on its tail on a big planet, on one with five gees’ surface gravity.”
“Seems obvious.”
“Maybe it is. It means that there’s no experiment you could perform on the ship that could tell you whether you were blasting or just sitting on a big planet.”
“Sure there is. You could turn off the engines, and if-”
“Or you could look outside, sure; I mean isolated, physics-lab type experiments.”
“All right. I’ll accept that. So?”
“You know Archimedes’ Law?”
“Sure, the fake crown-that’s what always got me about physics, they make a big to-do about obvious things, and when it gets to the rough parts-”
“Archimedes’ Law says that when you immerse something in a fluid, it’s buoyed up by a force equal to the weight of the fluid it displaces.”
“That’s reasonable.”
“And that holds, no matter what kind of gravitation or acceleration you’re in-In a ship blasting at five gees, the water displaced, if it’s water, weighs five times as much as regular water, at one gee.”
“Sure.”
“So if you float somebody in the middle of a tank of water, so that she’s weightless, she’ll still be weightless when the ship is doing five gees.”
“Hold on, son. You had me going there, but it won’t work.”
“Why not?” I was tempted to tell him to stick to his pills and stethoscopes and let me handle the physics, but it was a good thing I didn’t.
“What happens when you drop a wrench in a submarine?”
“Submarine?”
“That’s right. They work by Archimedes’-”
“Ouch! You’re right. Jesus. Hadn’t thought it through.”
“That wrench fails right to the floor just as if the submarine weren’t weightless.” He looked off into space, tapping a pencil on the desk. “What you describe is similar to the way we treat patients with severe skin damage, like burns, on Earth. But it doesn’t give any support to the internal organs, the way the acceleration shells do, so it wouldn’t do Marygay any good.. . .”
I stood up to go. “Sorry I wasted-”
“Hold on there, though, just a minute. We might be able to use your idea part-way.”
“How do you mean?”
“I wasn’t thinking it through, either. The way we normally use the shells is out of the question for Marygay, of course.” I didn’t like to think about it. Takes a lot of hypno-conditioning to lie there and have oxygenated fluorocarbon forced into every natural body orifice and one artificial one. I fingered the valve fitting imbedded above my hipbone.
“Yeah, that’s obvious, it’d tear her-say.. . you mean, low pressure-”
“That’s right. We wouldn’t need thousands of atmospheres to protect her against five gees’ straight-line acceleration; that’s only for all the swerving and dodging-I’m going to call Maintenance. Get down to your squad bay; that’s the one we’ll use. Dalton’ll meet you there.”
Five minutes before injection into the collapsar field, and I started the flooding sequence. Marygay and I were the only ones in shells; my presence wasn’t really vital since the flooding and emptying could be done by Control. But it was safer to have redundancy in the system and besides, I wanted to be there.