Malenfant did so. “There are… ripples.”

“Tidal effects. I thought so.”

“Tidal?”

“Malenfant, that hoop may not be material.”

“If it ain’t material, what is it?”

Folded time.

That was Michael, skimming easily around the artifact, as if he’d been born in this tiny gravity.

Malenfant snapped, “What the hell does that mean?”

Cornelius said, “He’s saying this thing might be an artifact of spacetime.” He labored at the instruments the fireflies were deploying. The instruments, sleek anonymous boxes, were connected to each other and to a central data-collection point by plastic-coated cables, light pipes, and diagnostic leads. The cluster of instruments was powered by a small radiothermal isotope power generator. The cables refused to uncoil properly and lie flat. Cornelius stared at chattering data, avoiding the stern mystery of the thing itself. “I have a gravity gradiometer here. I’m picking up some strange distortions to the local gravity field that… I need to figure out some kind of gravity-stress gauge that will tell me more.” Mumbling on, he tapped at his softscreen with clumsy gloved fingers.

Malenfant understood not a damn word. He had the feeling Cornelius wouldn’t be much help here.

He walked back to the center of the hoop. That sheet of silent darkness faced him, challenging.

Abruptly the sun emerged from behind a hill to his left, as Cruithne’s fifteen-minute day rolled them all into light once more. His shadow stretched off, to his right, over the crumbled, glistening ground, shrinking as he watched.

The sunlight dimmed the eerie blue glow of the hoop. But where the light struck the hoop’s dark interior, it returned nothing: not a highlight, not a speckle of reflection.

He reached out a hand, palm up, to the dark surface.

No.

Michael was beside him. The kid reached up and grabbed Malenfant’s arm, trying to pull it back. But Michael was too light; his feet were dangling above the regolith, tethers snaking languidly around him.

Malenfant lowered him carefully.

Michael bent and rummaged in the asteroid dirt. He straightened up, hands and sleeves soiled, holding a pebble, an irregular chunk of breccia the size and shape of a walnut. He threw the stone, underarm, into the hoop.

It sailed in a straight line, virtually undisturbed by Cruithne’s feeble gravity.

Then the stone seemed to slow. It dimmed, and it seemed to Malenfant that it became reddish, as if illuminated by a light that was burning out.

The stone disappeared.

Michael was looking up at him, grinning.

Malenfant patted his helmeted head. “You’re a scientist after my own heart, kid. Hands on. Let’s go find that rock.” He started to work his way around the artifact to the far side. The ropes were awkward, and clipping and unclipping the tethers took time.

Michael stared around at the ground beneath the hoop. He was still grinning, the happiest he’d been since he had left Earth. My stone is not here.

“Dear God,” Emma said. “Just as we saw when the firefly went through.”

“Yeah. But seeing it for real is kind of spooky. I mean, where is that stone now?”

Michael found another stone, dug out of the dirt, and he threw it into the black surface. The stone slowed, turned red, winked out. This time it looked to Malenfant as if it hadflattened as it approached the surface.

“Malenfant.”

He turned. Emma was pointing.

The surface was churned up, pitted and cratered — but then, so was the surface all over the asteroid. What made this different was what lay in the craters.

Scraps of flesh. Dead squid, bodies crushed and broken, disrupted by vacuum, desiccated, life-giving fluids lost to space.

He loosened his tether and tried to get closer to her.

“There was a war here,” Emma said.

“Or an execution. Or—”

“Or suicide.” He felt Emma’s hand creep into his. “It’s just like home.”

“What do you mean?”

“Maybe these are the ones who explored the artifact. The Sheenas. Or maybe some of them were touched by the downstream signal.”

“Like Michael, and the other children.”

“Yes. And the others feared them, feared what they had become, and killed them.”

Or maybe, Malenfant thought, the smart ones won. He wasn’t sure which was the scarier prospect.

“What have we got here, Cornelius?”

“Ask the boy,” Cornelius snapped. “He’s the intuitive genius. I’m just a mathematician. Right now I’m trying to gather data.”

Malenfant said patiently, “Tell me about your data, then.”

“I didn’t know what to measure here. So I brought everything I can think of. I have photodetectors so I can measure the light that’s reflecting off that thing, and the light it emits, at a variety of energies. I have a gravity gradiometer, six rotating pairs of accelerometers, that they use in nuclear submarines to detect underwater ridges and mountains from variations in the gravity pull — nice plowshare stuff.

“There’s a powerful magnetic field threading the artifact. Did I tell you that?

“Oh, and I have particle detectors. Solid state, slabs of silicon that record electrical impulses set off by particles as they pass through. Nothing very elaborate. I even have a lashed-up neutrino detector that is showing some results; Malenfant, that thing seems to be a powerful neutrino source.”

Cornelius was talking too much. Spooked, Malenfant thought. Handling this less well than the kid, in fact. “What is an artifact of spacetime?”

Cornelius hesitated. “I shouldn’t have said that. I’m speculating.”

Malenfant waited.

Cornelius straightened up stiffly. “Malenfant, I feel like an ancient Greek philosopher, Pythagoras maybe, confronted by an electronic calculator. If we experiment we can make some guess about its function, but—”

And Emma was yelling. “Michael!”

Michael had taken off all his tethers. He looked back at Emma, waved, and then made a standing jump. In the low gravity he just sailed forward, tumbling slightly.

Emma grabbed for him, but he had gone much too far to reach.

He hit the black surface, square at the center, just as he’d clearly intended. He seemed to Malenfant to flatten — his image became tinged with red — and then he shot away, as if being dragged into some immense tunnel.

There was a screech in Malenfant’s headset, a howl of white noise loud enough to hurt his ears. He saw Emma and Cornelius clap their hands to their helmets in a vain attempt to block out the noise.

After a couple of seconds, mercifully, it ceased.

But Michael was gone.

Emma was standing before the artifact. “Michael!” The burnished hoop was gleaming in her gold faceplate. Malenfant couldn’t see her face. But he knew that tightness in her voice.

He looked for something practical to do. Emma was unteth-ered, he saw. He bent and picked up loose tethers and clipped them to her belt.

She turned to him. “So,” she said. “What do we do now?”

“Malenfant.” It was Cornelius. “Listen to this.” He tapped at his softscreen, and a recording played in Malenfant’s headset. Words, too soft to make out.

“It’s the screech,” Cornelius said. “It came from the artifact, a broad-spectrum radio pulse that—”

“Turn up the volume, damn it.”

Cornelius complied.

It was, of course, Michael — or rather, his translated voice.

I found my stone.

Emma Stoney:

The three of them beat a hasty retreat back to the dome.

Cornelius dragged off his suit, went straight to his softscreens, and started working through the data.

Malenfant patiently gathered up the discarded equipment. He hooked up their backpacks to recharge units. And then he got a small vacuum cleaner to suck up the loose dust.