Page 9 of Project Hail Mary

I press a few buttons, but nothing happens. I turn it over to get a look at the battery compartment. Maybe I can find a drawer with batteries in it if I know what kind it needs. I spot a little red plastic ribbon coming out of the back. I give it a pull and it comes out entirely. The stopwatch beeps to life.

Kind of like “batteries included” toys. The little plastic tab was there to keep the battery from running down before the owner uses it for the first time. Okay, this is a brand-spanking-new stopwatch. Honestly, everything in this lab looks brand-new. Clean, tidy, no signs of wear. Not sure what to make of that.

I play with the stopwatch for a while until I understand the controls. Pretty simple, really.

I use the tape measure to find out how high the table is. Anyway, the table’s underside is 91 centimeters from the floor.

I pick up a test tube. It’s not glass. It may be some kind of high-density plastic or something. It certainly didn’t break when it fell 3 feet to a hard surface. Anyway, whatever it’s made of, it’s dense enough for air resistance to be negligible.

I lay it on the table and ready the stopwatch. I push the test tube off the table with one hand and start the stopwatch with the other. I time how long it takes to hit the ground. I get about 0.37 seconds. That’s pretty darn fast. I hope my own reaction time isn’t skewing the results.

I note the time down on my arm with the pen—I haven’t found any paper yet.

I put the test tube back and repeat the test. This time I get 0.33. I do it twenty times total, noting the results, to minimize the effects of my error margin in starting and stopping the timer. Anyway, I end up with an average of 0.348 seconds. My arm looks like a math teacher’s chalkboard, but that’s okay.

0.348 seconds. Distance equals one-half acceleration times time squared. So acceleration equals two times distance over time squared. These formulas come easily to me. Second nature. I’m definitely skilled at physics. Good to know.

I run the numbers and come up with an answer I don’t like. The gravity in this room is too high. It’s 15 meters per second per second when it should be 9.8. That’s why things falling “feel” wrong to me. They’re falling too fast. And that’s why I’m so weak despite these muscles. Everything weighs one and a half times as much as it should.

Thing is, nothing affects gravity. You can’t increase or decrease it. Earth’s gravity is 9.8 meters per second per second. Period. And I’m experiencing more than that. There’s only one possible explanation.

I’m not on Earth.

Okay, take a breath. Let’s not jump to wild conclusions. Yes, the gravity is too high. Work from there and think ofsensibleanswers.

I could be in a centrifuge. It would have to be pretty big. But with Earth’s gravity providing 1 g, you could have these rooms at an angle running around a track or on the end of a long solid arm or something. Set that spinning and the aggregate centripetal force plus Earth’s gravity could be 15 meters per second per second.

Why would someone make a huge centrifuge with hospital beds and a lab in it? I don’t know. Would it even be possible? How big would that radius have to be? And how fast would it go?

I think I know how to find out. I need an accurate accelerometer. Dropping things off a table and timing them is all well and fine for rough estimates, but it’s only as accurate as my reaction time on hitting the stopwatch. I need something better. And only one thing will do the job: a small piece of string.

I search the lab drawers.

After a few minutes, I have half the drawers open and have found just about every form of lab supplies except string. I’m about to give up when I finally find a spool of nylon thread.

“Yes!” I pull off a few feet of thread and cut it with my teeth. I tie a loop on one end and tie the other end around the tape measure. The tape measure will be playing the role of “dead weight” in this experiment. Now I just need something to hang it from.

I look above me at the hatch over my head. I climb up the ladder (easier now than ever before) and put the loop over the main latch handle. Then I let the tape measure’s weight pull the string taut.

I have a pendulum.

Cool thing about pendulums: The time it takes for one to swing forward and backward—the period—won’t change, no matter how wide it swings. If it’s got a lot of energy, it’ll swing farther and faster, but the period will still be the same. This is what mechanical clocks take advantage of to keep time. That period ends up being driven by two things, and two things only: the length of the pendulum and gravity.

I pull the pendulum to one side. I release it and start the timer. I count cycles as it sways back and forth. It’s not exciting. I almost want to fall asleep, but I stay at it.

When I hit the ten-minute mark, the pendulum is barely moving anymore, so I decide that’s long enough. Grand total: 346 full cycles in exactly ten minutes.

Onward to phase two.

I measure the distance from the hatch handle to the floor. It’s just over two and a half meters. I go back downstairs to the “bedroom.” Again, the ladder is no problem. I’m feeling so much better now. That food really did the trick.

“What’s your name?” the computer asks.

I look down at my sheet toga. “I am the great philosopher Pendulus!”

“Incorrect.”

I hang the pendulum on one of the robot hands near the ceiling. I hope it’ll stay still for a while. I eyeball the distance between the robot hand and the ceiling—I’ll call it a meter. My pendulum is now four and a half meters lower than it was before.