It’s Cal’s turn to deal the cards and topic. “Water, water everywhere, especially where you wouldn’t expect it.”

Eddie bets a few chips. “Say what, Cal?”

“Oh, this article in one of my Astronomy magazines, says Euclid has an ice problem.”

“None of Euclid’s problems are nice. I barely got out of Geometry class alive.”

“Not that Euclid, Eddie. The European Space Agency’s Euclid space telescope that’s gonna catalog whatever it can see in a third of the sky. They’re looking to pick up everything out to 10 billion lightyears. S’posed to help us chase down dark energy, get a better handle on really big structures and voids, stuff like that. Anyhow, it’s in a potato‑chip orbit around the Earth‑Sun L₂ point like JWST does but twice as far out. The ESA engineers noticed that Euclid‘s readings of some calibration stars were dropping and they figured out it was ice getting in the way.”

“Ice? In space?”

“Yeah, that’s what I said. Turns out all our space missions bring water out with ’em even if they don’t want to.”

Vinnie’s bet doubles the pot. “Ain’t gonna happen. Every ounce of payload gotta have a good excuse or they don’t let it ride.”

“No, really. This ain’t payload, it’s like a stowaway. Mostly in the thermal insulation which has a lot of surface area inside with nooks and crannies where water molecules can stick. Makes no difference to most missions, but when you’ve got world‑class optics that you’re pushing to their limits, a layer of ice a few dozen molecules thick in the wrong place can hurt.”

“Okay, I get there’s problems if the ice is in the optics but you said it was in the insulation. And what’s it even doing there in the first place? If they know it’s gonna be a problem they can just bake it out during construction.”

Chemist Susan chucks a handful of chips into the pot. “Water molecules are small and sneaky. They always surprise you, especially when you don’t want them to. When they’re frozen‑solid ice you’d think they’d stay there, right? Oh, no, they evaporate without going through a liquid phase which lets them migrate around. It’s called sublimation. And do they migrate — just try to keep them out of somewhere. Pour absolute ethanol through humid air, it’s not absolute any more. Dry solids? If the substance has any surface oxygens you’re guaranteed to have water molecules hanging onto them even after you bake the stuff. So, Vinnie — that insulation wrap in the telescope? If it ever saw humidity the fibers are carrying water that could migrate to the optics.”

“Oh yeah, there’ll be humidity. Okay, Baikonur’s pretty much in the middle of a near‑desert, but the Guiana Space Center that France uses is right by the ocean and have you ever looked at a map of Cape Canaveral? That insulation’ll be soggy enough to spew water molecules onto the optics even at space temperatures. C’mon, Kareem, you gonna bet or what?”

“I’m deciding whether to talk about watery moons or the deep‑down Earth water we’re discovering. Jupiter’s moon Europa, for instance. We now know it has a kilometers‑thick shell of ice surrounding an ocean with twice as much water as our oceans put together. Meanwhile,” <meets Susan’s bet> “there’s another huge ocean beneath our feet.”

“Not our feet. This place is built on bedrock.”

“Think below the bedrock, Cal. We live on top of crust, maybe a couple dozen kilometers thick, floating on molten magma. You guys know about subduction, right, where chunks of sea-bottom crust are forced under the edges of continental crust. The further down you go, the hotter things get. The sea‑bottom stuff eventually melts to form lighter magma that ultimately rises to make volcanoes. Thing is, the sinking crust drags water with it, either in cracks or as water of crystallization. A melting chunk releases its water into a kilometers‑thick layer of steamy silicate slurry roughly 400 kilometers below us. That water ‘rains’ upward into our oceans, completing the cycle. Full house, queens and aces. Any challengers?”

Kareem’s surprisingly impatient for a geologist. Nobody counters so the pot’s his. Eddie gets next deal.

~~ Rich Olcott