Project Hail Mary

Page 84

So we have to go slower. But going slower means falling toward the planet. Unless I use the engines to constantly maintain altitude. But if I do that, I’d be thrusting directly away from the chain and sample device. The exhaust from the engines will vaporize all of it.

So we’ll thrust at an angle. Simple as that.

It’ll look absolutely ridiculous. The Hail Mary will be tilted to 30 degrees from vertical, thrusting upward at that angle. Below it, the chain will dangle 10 kilometers into the air straight down. The atmosphere behind the thrusters will be in a constant state of ionized fire. It should be quite a show. But it’ll be behind us and the chain will be passing through unaffected air.

All told, our lateral velocity will be just over 100 meters per second. The chain can handle that speed in the thin high-altitude air, no problem. I calculated that it’ll only deflect about 2 degrees from vertical.

Once we feel like we have a sample, we skedaddle. What could possibly go wrong!

I say that ironically.

I’m not the greatest 3-D modeler, but I’m able to make a chain link in CAD reasonably well. It’s not a normal oval link, though. It’s mostly oval, but with a thin opening for another link to enter. Easy to assemble the links, but extremely unlikely for them to rattle apart. Especially when they’re under tension.

I grab a block of aluminum and mount it in the mill.

“This will work, question?” Rocky asks from his ceiling tunnel.

“It should,” I say.

I fire up the mill and it gets right to work. It drills out the mold for a chain link exactly the way I’d hoped.

I pull the workpiece out, dust off the aluminum shavings, and hold it up to the tunnel. “How’s this?”

“Very good!” Rocky says. “We will need many many many chain links. More molds means I can make more at one time. You can make many molds, question?”

“Well.” I look in the supply cabinet. “I have limited amounts of aluminum.”

“You have many items in ship you no use. Two beds in dormitory, for instance. Melt them, make blocks, make more molds.”

“Wow. You don’t do anything by half-measure, do you?”

“No understand.”

“I’m not going to melt a bunch of stuff. How would I even do that?”

“Astrophage. Melt anything.”

“You got me there,” I say. “But no. The heat would be too much for my life-support system to handle. That reminds me. Why do you have so much extra Astrophage?”

He pauses. “Strange story.”

I perk up. Always up for a strange story. He clicks along his tunnel and sits in a slightly wider section. “Science Eridians do much math. Calculate trip. More fuel mean faster trip. So we make much much much Astrophage.”

“How’d you make so much? Earth had a very difficult time making it.”

“Was easy. Put in metal balls with carbon dioxide. Put in ocean. Wait. Astrophage double, double, double. Much Astrophage.”

“Riiight. Because your oceans are hotter than Astrophage.”

“Yes. Earth oceans are not. Sad.”

When it comes to Astrophage manufacturing, Erid was born on third base. The whole planet is a pressure cooker. Twenty-nine atmospheres at 210 degrees Celsius means water is liquid on the surface. And their oceans are far, far hotter than the Astrophage critical temperature. They just put Astrophage in the water, let it absorb heat, and breed.

I’m jealous. We had to pave the Sahara Desert to breed up our Astrophage. All they had to do was throw it in the water. The stored heat energy of Erid’s oceans is ridiculous. A whole bunch of water—multiples of Earth’s total oceans—holding a temperature around 200 degrees Celsius or more. That’s a lot of energy.

And that’s why they can take a century or so to solve the problem while Earth is going to freeze in a few decades. It’s not just their air storing heat. Their oceans store even more. Born on third base. Again.

“Science Eridians design ship and fuel requirements. Journey to take 6.64 years.”

That trips me up for a moment. 40 Eridani is ten light-years away from Tau Ceti, so you can’t get from one to the other in less than ten years from Erid’s point of view. He must mean 6.64 years of time experienced by his ship thanks to time dilation.

“Strange things happen on trip. Crew sick. Die.” His voice lowers. “Now I know was radiation.”

I look down and give him a moment.

“Everyone sick. I alone to run ship. More strange things happen. Engines not work right. I am engine expert. I cannot figure out problem.”

“Your engines failed?”

“No. Not fail. Thrust normal. But speed…not increase. No can explain.”


He clatters back and forth as he talks. “Then more strange: Reach halfway point earlier than should. Much earlier. I turn ship around. Thrust to slow down. But Tau get farther away. How? Still moving toward Tau but Tau moving away. Much confusion.”

“Uh-oh,” I say. A thought creeps into my head. A very disturbing thought.

“I speed up. Slow down. Much confuse. But get here. Even with all mistakes and confusion, I get here in three years. Half of time science Eridian say should be. So much confuse.”

“Oh…oh my…” I mumble.

“Much much much fuel remain. Much more than should have. No complain. But confuse.”

“Yeah…” I say. “Tell me this: Is time on Erid the same as time on your ship?”

He cocks his carapace. “Question make no sense. Of course time is same. Time is same everywhere.”

I put my head in my hands. “Oh boy.”

Eridians don’t know about relativistic physics.

They calculated their entire journey with Newtonian physics. They worked it all out by assuming they could just accelerate faster and faster and the speed of light wasn’t an issue.

They don’t know about time dilation. Rocky doesn’t realize that Erid experienced a whole bunch more time than he did on that trip. They don’t know about length dilation. The distance to Tau Ceti will actually increase as you slow down relative to it—even if you’re still going toward it.

An entire planet of intelligent people put together a ship based on incorrect scientific assumptions, and by some miracle, the sole survivor of the crew was clever enough at trial-and-error problem solving to actually get it to its destination.

And out of that major screw-up comes my salvation. They thought they’d need a whole lot more fuel. So Rocky has boatloads to spare.

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