Our first few weekends at the site were pretty straightforward: a whole lot of digging and recording. It got to the point where I could recognize the different colors of rock and soil, and had somewhat of an idea what they meant—some of them formed only in conditions where water had been present, others were evidence of volcanic activity, and so on. And I started to recognize the fossils, too. We dug up dozens of those little spiral seashells I found my first day on site, which Erick said were similar to the cephalopods that were common on prehistoric Earth. There were fossilized plants, too; not only spider weeds, but beautiful ferns with curled, wispy fronds. Every fossil we uncovered gave me a thrill of excitement as I’d imagine how ancient Mars must have looked, so different from the pseudo-Earth we’d terraformed it into.

Apart from the fossils, the things I dug up most frequently were shards of glass. It seemed like every day I was uncovering one of these broken, blue-tinted fragments. The first time I found one, I thrilled at the thought that we’d finally found a sign of, as Henry put it, my Little Green Men.

“Don’t get excited, Isaak,” Scylla said as I held it to the light. “There’s glass like that all over the site. Professor G says it’s tektite. That’s natural glass that forms from the heat of a meteor impact. And there’s probably a billion impact sites here. Mars was like a meteor magnet or something.”

I frowned down at the smooth fragment in my hand. “Is tektite usually as clear as this? I always thought it was more like rock, or crystal. And look how flat it is. This looks man-made.”

Scylla hesitated, then took the piece from me, running a gloved finger over it. “I dunno. I’ve never seen tektite in real life. But Professor G ought to know what he’s talking about, right?” She tossed it back to me. “I mean, how else would this much glass have gotten here? We dig it up almost every day. It’s not exactly like Martians could have put it there.” She shrugged. “Maybe it’s because the chemical makeup of the ground is different here than on Earth.”