Silence.

Xiaoling carefully translated for Fraq in her fat-lipped whisper. They were using her because this was a delicate moment, and Fraq did not want his somewhat limited Anglish to confuse meaning. Plus, he got time to think. The response was qualitative at best. “He says, beyond a million years.”

Okay, old. But how old? Rachel bored in, looking straight at Fraq. “We know that. Who came here, exactly?”

After translation from Fraq’s glottal chirps and clicks, the answer was, “An earlier form of my species.”

A stir around the room. “Your kind has altered itself?” she persisted.

The answer: “We had to, after we lost our ability to inhabit our home world. Our climate spun out of control.”

She would have liked to follow that line of inquiry, in this sudden moment when Fraq seemed willing to reveal things, but Rachel stayed on point. “My question is, what if they came here in one of the eras when Mars was wet and warm?”

Zuminski said, “You bring up good issue. Mat might be able to extend itself even onto the surface in those times. Would have cloud cover against some of the ultraviolet. Could harvest resources when they flowed on the surface.”

Rachel nodded, surprised that Zuminski had come into agreement so quickly. “Certainly, if Fraq’s kind came then, the Mat would’ve been easier to find.”

Hassan seemed startled, mouth puckered. “Your point is…?”

“The flooding might be the Mat’s way of recalling that era. It recognized Fraq, could tell he was different from us—right? Because it echoed his shape in its wall.”

Rachel turned and confronted the whole gathering, clustered around the tables. Many of them had set dict-typing on their computer slates, getting all this down. “So maybe the Mat was saying, ‘Hello, I remember you. Those times were like this, wet, right?’—then the flood.”

To his credit, Hassan paused only a few seconds. He leaned forward, hands clasped before him, and said, “That is an intriguing idea. It sent us an explicit reminder of a past era. A demonstration is always better than talk.”

Zuminski had a concentrated look, too. He said, “The Mat, yes, it does not think digitally, true. It can count, but does not seem to think that ability is important. What it does see as vital is geometry. Our studies with it show this. It knows all of Euclid, can tell a dodecahedron from a sphere instantly. Yes. So it would use a direct expression, real fluids, not some idea of how to count the past.”

Some others chimed in with comments, mostly about seismic signatures they got on the surface. There were vibrations from distant sites undergound at the same time, some complex wave phenomenon that some—mostly the mathematical types, similar to the SETI Library mathists—thought were encoded signals. Could this be a way of fast information transport around the planet?

“My point,” one of them said, “is that in times of stress, a big movement of fluids in their water basin”—he showed on the wall screen a vivid subsurface chart that plotted the big caverns, some loaded with water and hydrogen sulfide gas—“can slam against its sides and send a fast seismic signal at the speed of sound. Faster than the Mat can convey information through its usual means, visual shows on tunnel walls. That we know for sure.”