The Wrong North

The class had already gone back to the bus. Maya and Soren stayed at the rock face because Mr. Adebayo said whoever finished the sketch could sit up front, and neither of them cared about the front of the bus.

"He said the stripes are lava," Soren said. He held his compass flat on his palm. "Layer after layer. Older at the bottom."

"Then why is my compass being weird," Maya said.

"It's not weird. North is that way."

"No. Watch." She crouched and pressed her compass right up against a dark band low in the wall. The needle drifted, hunted, and settled. Then she slid it up to the band above it. The needle swung and settled somewhere else. She slid it back down. It swung back.

Soren put his own compass to the low band. He did it again. He did it a third time, the way he did anything he didn't believe yet.

"The rock is pulling it," he said.

"The rock is pulling it different in different stripes."

"Some stripes more. Some stripes"—he moved the compass down one—"the other way. That one's backward."

Maya sat down in the gravel. "Say backward again."

"Backward. This band, the needle wants to point at the ground instead of away. Like the north end got homesick." He frowned at it. "Rocks don't do that."

"These do." She was already touching bands, top to bottom, calling it out. "Normal. Normal. Backward. Backward. Normal. It's not random. It's in chunks."

"Lava's just melted rock," Soren said slowly, thinking it through out loud. "When it cools, it's soft to the magnetism, and then it goes hard. So whatever the magnetism was doing that day, the rock keeps it. Like a photograph."

"A photograph of what, though."

"Of north. Of where north was when this layer cooled."

Maya went quiet, and then she said it fast. "North moved."

"North doesn't move. North is north."

"North moved," she said again, and pointed at the backward band. "That day, when that lava cooled, a compass would have pointed that way. At Antarctica. The whole thing flipped over."

Soren looked at the wall. He looked at it the way you look at a friend who just said something you can't take back.

"That's the Earth," he said. "You're saying the Earth's magnetism flipped. The actual field. The one my compass uses right now."

"The bands are stacked in time. Bottom is old." Maya ran her finger up the rock like a timeline. "So it went normal, then flipped, then flipped back. Over and over. However long it takes to pile up this much lava."

"Thousands of years for each stripe, probably," Soren said. "Maybe way more."

They were both quiet then. "Okay but here's the part I don't like," Soren said. He pressed his compass to the boundary line, the exact place where a normal band met a backward band. The needle didn't settle. It wandered. It couldn't decide. "Look. Right at the switch, it doesn't know where to go."

Maya leaned in. The needle drifted a slow circle and stopped nowhere.

"Because when it was cooling right here," she said, "north wasn't anywhere yet. It was in between."

"You can't be in between north and south."

"You can if the field is turning off to turn around." She said it and then heard herself say it. "Soren. The field went weak. Almost gone. Then it came back pointing the other way."

"How weak."

"Weak enough that a compass just spins. Like this one. Like it's doing right now on this line."

Soren sat back on his heels. He got his notebook out of his jacket and opened it against his knee and drew the wall, band by band, marking each one with a little arrow, up or down, and at the blurry boundary he drew no arrow at all, just a question of empty space, and his hand was not quite steady doing it.

"So somewhere in here," he said, tapping a boundary, "there was a whole stretch of years where nobody's compass worked. Birds that use the field, turtles that use the field. All of them, for thousands of years, with the sky's magnet turned almost off."

"And they made it," Maya said. "They're still here. It happened and the world kept going."

"It happened a lot." He counted the backward bands with the tip of his pencil. "One. Two. Three. Four in just this cliff."

"Four times the north you're standing under has been the south."

Soren looked up at her. "It's not finished, is it. There's no rule that says it stopped."

Maya didn't answer that. She was pressing her compass to the very top band, the newest lava, the one that matched the world they lived in. The needle pointed cleanly to the sea, to the real north, steady and sure.

"This one's normal," she said. "This one's us."

"For now," Soren said.

"For now." She slid the compass down one band, into the past, and the needle turned to point at her chest instead. She held it there. "There's going to be a top band above this one someday. A layer that hasn't cooled yet."

"And an arrow in it," Soren said.

"And we don't know which way the arrow points."

The bus horn sounded, one long complaint, far up at the parking lot. Neither of them moved. Soren had his pencil on the blank space of the boundary line, right where the field forgot which way to face.

Maya lifted her compass off the rock and held it flat in her open hand, out in the ordinary air, away from the stone. The needle wobbled, hunted, and swung back to the true north it had always trusted.

She watched it hold still, and she did not fully believe it anymore.