Factoring Humanity

The messages from space had been arriving for almost ten years now. Reception of a new page of data began every thirty hours and fifty-one minutes—an interval presumed to be the length of the day on the Senders’ homeworld. To date, 2,841 messages had been collected.

Earth had never replied to any of the transmissions. The Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence, adopted by the International Astronomical Union in 1989, stated: “No response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate international consultations have taken place.” With a hundred and fifty-seven countries comprising the United Nations, that process was still going on.

There was no doubt about the direction the signals were coming from: right ascension 14 degrees, 39 minutes, 36 seconds; declination minus 60 degrees, 50.0 minutes. And parallactic studies revealed the distance: 1.34 parsecs from Earth. The aliens sending the messages apparently lived on a planet orbiting the star Alpha Centauri A, the nearest bright star to our sun.

The first eleven pages of data had been easily deciphered: they were simple graphical representations of mathematical and physical principles, plus the chemical formulas for two seemingly benign substances.

But although the messages were public knowledge, no one anywhere had been able to make sense of the subsequent decoded images…