There was one advantage in such a new beginning. All the diseases and parasites that had plagued humanity since the beginning of time would be left behind, to perish in the sterilizing fire of Nova Solis.

Data banks, “expert systems’ able to handle any conceivable situation, robots, repair and backup mechanisms — all these had to be designed and built. And they had to function over a timespan at least as long as that between the Declaration of Independence and the first landing on the Moon.

Though the task seemed barely possible, it was so inspiring that almost the whole of mankind united to achieve it. Here was a long-term goal — the last long-term goal — that could now give some meaning to life, even after Earth had been destroyed.

The first seedship left the solar system in 2553, heading towards the Sun’s near twin, Alpha Centauri A. Although the climate of the Earth-sized planet Pasadena was subject to violent extremes, owing to nearby Centauri B, the next likely target was more than twice as far away. The voyage time to Sirius X would be over four hundred years; when the seeder arrived, Earth might no longer exist.

But if Pasadena could be successfully colonized, there would be ample time to send back the good news. Two hundred years for the voyage, fifty years to secure a foothold and build a small transmitter, and a mere four years for the signal to get back to Earth — why, with luck, there would be shouting in the streets, around the year 2800.

In fact, it was 2786; Pasadena had done better than predicted. The news was electrifying, and gave renewed encouragement to the seeding programme. By this time, a score of ships had been launched, each with more advanced technology than its precursor. The latest models could reach a twentieth of the velocity of light, and more than fifty targets lay within their range.