For a local week our routine remained the same, survey, take samples, don’t even think about asking questions. But out in the silent blue valleys I could feel the presence of the artefacts, just over the horizon.

One day after observances I was walking beside the Sixth as we left. I found myself saying “It’s amazing that our landing site was so close. We could easily have come here and never noticed anything unusual.” She stared at me expressionlessly. “Or maybe someone knew to send us here.”