The Squeezing Moon

The planetarium was closing and the rain would not stop, so Maya and Soren ended up at the kiosk nobody used, the one with the sticky button and the little screen that played the same clip over and over.

"Push it again," Maya said.

Soren pushed it. A moon appeared, orange and yellow and sick-looking, with a plume of something spraying off the edge like a fountain caught mid-splash.

"That's Io," Soren said, reading the tiny label. "A moon of Jupiter. Those are volcanoes. It says it's the most volcanically active thing in the whole solar system."

"More than Earth?"

"More than Earth."

Maya leaned in until her nose almost touched the screen. "That's wrong," she said.

"It's not wrong, it's on the sign."

"No. Something's wrong with it. It's too small." She tapped the orange moon. "Volcanoes need heat inside. Earth has heat inside because Earth is huge. Big things stay hot. My grandma's soup stays hot in the big pot and cold in the little bowl."

Soren looked at her. This was Maya being sure of something before she could say why, which he had learned not to argue with directly.

"So a moon that small should be a cold rock," he said slowly. "Frozen all the way through. Dead."

"Right. But it's the busiest one. That's backwards." She stood up straight. "Push it again."

He pushed it. The plume sprayed. Io moved a little as it went around Jupiter, and Jupiter sat there enormous in the corner of the clip, striped and heavy.

"Wait," Soren said. "Watch the moon, not the volcano."

They watched the moon.

"It's not a perfect circle," Maya said.

"The orbit?"

"The moon. Look at the edge when it's close to Jupiter versus when it's far."

He pushed the button four more times. He counted under his breath each loop. By the fourth he was nodding.

"It bulges," he said. "When it's close it stretches toward Jupiter. When it swings out it relaxes. It's getting pulled into an egg shape and then let go. Over and over."

"Every single orbit," Maya said.

"Every single orbit forever."

They stood with that for a second. Outside, rain slapped the skylight.

Maya picked up the free paperclip from the little dish by the kiosk, the ones somebody left for no reason. She bent it open, then closed, then open.

"Feel this," she said, and pressed the bent spot against the back of Soren's hand.

"It's warm."

"I didn't heat it. I just bent it." She bent it again, fast, twenty times, and pressed it back. "Now?"

"Hot. Almost too hot."

"That's not from the sun. That's not from anything burning. That's just me bending it." She held the metal up. "The bending is the heat."

Soren took the paperclip and bent it himself, watching the little joint of it. He didn't fully believe things until his own hands had done them. He bent it until the joint got warm under his thumb, and then he believed it completely.

"Jupiter is bending the whole moon," he said. "Not a paperclip. A whole moon. Squeezing it into an egg and letting go, thousands of times, all the time, and the inside heats up from the bending."

"That's the fountain," Maya said, pointing at the frozen plume on the screen. "That's rock so hot it melts. From getting squeezed."

"No radioactivity," Soren said. "No leftover heat from being born. Earth's insides are hot from those. Io doesn't need them." He pushed the button again just to watch it. "It's hot because it's being held too tight."

A staff member in a green vest came by rattling a set of keys, the kind of adult who wanted the room empty more than she wanted anyone to understand it.

"Five minutes, you two," she said. "That kiosk's getting replaced next month, honestly. Nobody watches it."

"What replaces it?" Maya asked.

"Something about the ice moons, I think. Europa." She checked her clipboard like the answer might be printed there, found nothing, and moved off jingling.

Maya turned back to Soren. "Europa. That's another Jupiter moon."

"It's ice," Soren said. "Cracked ice all over the surface. I've seen the pictures. Way out there where the sun's just a bright star. It should be frozen solid to the core."

Maya went quiet. Then she picked the paperclip back up and bent it, slow this time, watching her own fingers.

"But it's getting squeezed too," she said. "Same Jupiter. Same pulling."

"Not as hard as Io. Io's closer."

"Not as hard. But some." She bent the clip once, gently, and pressed it to his hand. "Warm, not hot."

"Warm, not hot," Soren agreed. His voice had gone careful. "Warm enough to melt ice but not rock."

They looked at each other.

"Under the ice," Maya said.

"There'd be water," Soren said. "Liquid water. An ocean. Under miles of ice, on a moon a billion kilometers from the sun, with no sunlight touching it at all." He put his hand flat on the kiosk. "Kept liquid by nothing but Jupiter squeezing it."

"An ocean that's warm because it's being held too tight," Maya said.

Soren pulled the notebook out of his back pocket. He turned to a clean page and drew a circle, and inside the circle a smaller circle, and between them he wrote the word ocean, and his hand was not quite steady doing it.

"You okay?" Maya asked.

"There could be a whole dark ocean out there," he said. "Nobody's seen the bottom of it. Nobody knows what's in it. And the only reason it isn't ice is that a planet won't stop hugging it."

The staff member flicked the main lights off in the next room. The kiosk screen got suddenly brighter in the dark, the orange moon glowing, the plume caught forever mid-spray.

Maya reached past Soren and pushed the sticky button one more time.

Io swung close to Jupiter and stretched. It swung wide and relaxed. The fountain of melted rock sprayed up into black space, over and over, for as long as they stood there watching, which was longer than they were supposed to.