Page 89 of Project Hail Mary

I pull a pair of calipers out of the toolkit I keep in the tunnel and measure the sphere’s diameter. It’s 4.3 centimeters. From that I work out the volume, multiply by the density of iron, and get a much more precise and accurate mass of 328.25 grams.

“I was only off by one percent,” I grumble.

“You talk to you, question?”

“Yes! I’m talking to me.”

“Humans are unusual.”

“Yes,” I say.

Rocky stretches his legs.“I sleep now.”

“Wow,” I say. This is the first time he’s had to sleep since we met. Good. This will provide me some time for some lab work. But how much time?

“How long do Eridians sleep?”

“I not know.”

“You don’t know? You’re Eridian. How can you not know how long Eridians sleep?”

“Eridians not know how long sleep last. Maybe short time. Maybe long time.”

They sleep unpredictable amounts of time. I guess there’s no rule saying sleep has to evolve as a regular pattern. Does he at least know a range of times it might be?

“Is there a minimum time? A maximum time?”

“Minimum is 12,265 seconds. Maximum is 42,928 seconds.”

I often get strangely specific numbers from Rocky on things that should be rough estimates. It took me a while to figure out, but I finally did. He actually is coming up with rough, round numbers. But they’re in his units and in base six. It’s actually easier for him to convert those values to base-ten Earth seconds than it is for him to think directly in Earth seconds.

If I converted those values back to Eridian seconds and looked at the numbers in base six, I bet they’d be some round number. But I’m too lazy. Why un-convert data he already converted? I’ve never seen him be wrong on arithmetic.

Meanwhile, I have to divide by 60 twice on a calculator just to convert from one of my own planet’s units to another of my own planet’s units. He’ll sleep for a minimum of three and a half hours and a maximum of almost twelve hours.

“I understand,” I say. I head back toward the airlock.

“You observe, question?”Rocky asks.

He watched me sleep, so it’s only fair he offer to let me watch him. I’m sure Earth scientists would jump all over the place to learn anything about what an Eridian sleeping looks like. But I finally have time to do some deep analysis of xenonite and I’m justdyingto know how xenon bonds with other elements. If I can get any of my lab equipment to work in zero g, that is.

“Not necessary.”

“You observe, question?”he asks again.

“No.”

“Observe.”

“You want me to observe you sleep?”

“Yes. Want want want.”

Through unspoken agreement, a tripled word means extreme emphasis.

“Why?”

“I sleep better if you observe.”