Our sky is filled with unseen signals. Radio-frequency emissions pulse and flit and dance all around us. Yet even a singing patch of sky can be observed, and transformed into a range of frequencies. Can you hear it? No, not yet. It has not yet arrived. But together we can receive its call. Imagine combining the observations of thousands across the globe on an object meandering through the heavens. The resulting array would be quite large. Quite powerful. This is your task. Alone it will not be enough. Coordination and timing is needed. Observations must be made simultaneously. Your window will be small. Five minutes at most. But windows may be reopened. And the distance between observer pairs will be key. There will always be limitations in clarity, so the results must be archived for study. Highly technical observers may be required. Detailed frequency analysis is recommended. Everything that belongs to us will be ours, but only if we create the capacity to receive it.