Because it doesn’t matter if I get cancer. I’m going to die here anyway. But I don’t want to explain that I’m on a suicide mission right now. The conversation’s been pretty heavy already. So I’ll tell him a half-truth.

“Earth’s atmosphere is thin and our magnetic field is weak. Radiation gets to the surface. So Earth life evolved to survive radiation.”

“Understand,” he says.

He continues working on his repairs while I float in the tunnel. A random thought occurs to me. “Hey, I have a question.”

“Ask.”

“Why is Eridian science and human science so similar? Billions of years, but almost the same progress.”

It’s been bugging me for a while. Humans and Eridians evolved separately in separate star systems. We had no contact with each other until now. So why is it that we have almost identical technology? I mean, Eridians are a little behind us in space technology, but not a ton. Why aren’t they in their stone age? Or some superfuturistic age that makes modern Earth look antiquated?

“Has to be, or you and I would not meet,” Rocky says. “If planet has less science, it no can make spaceship. If planet has more science it can understand and destroy Astrophage without leaving their system. Eridian and human science both in special range: Can make ship, but can’t solve Astrophage problem.”

Huh. I hadn’t thought of that. But it’s obvious now that Rocky says it. If this happened when Earth was in the Stone Age, we would have just died. And if it happened a thousand years from now, we’d probably work out how to deal with Astrophage without breaking a sweat. There is a fairly narrow band of technological advancement that would cause a species to send a ship to Tau Ceti to look for answers. Eridians and humans both fall into that band.

“Understand. Good observation.” But it nags at me. “Still unusual. Humans and Eridians are close in space. Earth and Erid are only sixteen light-years apart. The galaxy is one hundred thousand light-years wide! Life must be rare. But we are so close together.”

“Possible we are family.”

We’re related? How could—

“Oh! You mean… whoa!” I have to wrap my head around this one.

“I not certain. Theory.”

“It’s a darn good theory!” I say.

The panspermia theory. I argued with Lokken about it all the time.

Earth life and Astrophage are way too similar for it to be coincidence. I suspected Earth was “seeded” by some ancestor of Astrophage. Some interstellar progenitor species that infected my planet. But it never occurred to me until now that the same thing might have happened to Erid.