White Crystal Butterflies | Wattys 2021 Shortlist | ✔

Chapter Five

When Krüger and I have warmed up and changed back into indoor clothes, we join Liu and her tablet in the common room. Even Kwon is present, though the thin lines creeping sideways into the graphs on the screen probably mean as little to her as her engineering wizardry does to me. I give the data I know a quick once-over. For a minor moon in the rings of a gas supergiant on the outer edge of a blue-star binary solar system, Mahaha is startlingly earth-like. Assuming, of course, that you're an interstellar immigrant and have lived on the relevant parts of earth. Gravity, temperature, atmospheric pressure, and even rotational period—length of day—all come within a human-tolerable distance of those on humanity's ancestral planet, all of which would lead you to assume Mahaha is habitable if you hadn't visited it yourself.

I spot the graph for wind speed—waffling between calm and gusts of up to eighty kilometers an hour—and the one for temperature embarking on its slow downward slide into nighttime. Radiation is high, humidity is low, and Liu and Krüger are both frowning.

Krüger points to a graph near the bottom of the screen. "This is from the forward sensors, not the ones on the underside?"

Liu nods.

"What the hell."

"Right?"

"Solving the mysteries of Mahaha?" I say.

"No," says Krüger. "Confirming them."

My favourite thing to hear.

Liu points to a cheery yellow line holding as steady as the surface of a helicopter pad. "That's precipitation rate." Snowing constantly. Surprise. "And that"—she slides her finger down the same graph, to a parallel blue line hovering just above the horizontal axis—"is sublimation from the surface."

My eyebrows go up. I don't need a meteorology degree to see what's wrong here; I've spent enough time with scientists to know more than my fair share about the water cycle. The water coming down from the sky on Mahaha is some sixty times more than the water going back up again.

"Updrafts?" says Krüger.

"That's what I thought," says Liu. "But that's not it either."

She taps an icon at the bottom of the page. The screen fills with a rendered 3D map of the surface around the probe. High points are highlighted and labeled with their relative elevations: the Isoptera scanning for its best perch. Liu taps a few more things, and the space above the map surface fills with a moving representation of... well, of something. Air currents or snow or local convection cells. Here and there, a column rises against the grain, but the dominant trajectory is groundwards.

"That's not a water cycle," says Krüger. "That's a waterslide."

"Exactly," says Liu. "And this is the highest sublimation rate we're ever measured."

"Twilight radiation?"

"Yeah."

Twilight radiation is the strongest we get out here. If these measurements were taken at a time of day when maximum ice was getting radiated back into water vapor to rise back into the sky, this is as balanced as the system is going to get. Which is to say, not at all.

Krüger runs a hand into his hair, knocking his glasses askew. "So it snows all the time, but then there's absolutely no sign of where all that water is coming from."

They exchange a look that says more, but neither of them fills Kwon and I in on their hypotheses.

"And then there's the surface movement," says Liu, going back to the graphs. A flock of jagged lines shows the motion of the higher peaks in the area. They're jumpier than a juvenile locust swarm. "The last team here thought it might be seismic activity, right? Well, the probe did a micro-radar test..." She clicks a file, and an error message pops up on screen.