The initial tentative transmissions blossom into a largely one-way torrent of information for the Snark. One day, it asks to visit Earth. A compromise is worked out: the Snark will orbit the Moon until trust is built up. As Nigel is already fully informed, he is assigned to pilot the space ship (armed with another nuke) and meet the Snark. Nigel meets the Snark, which disables his chemical weapons and begins talking to Nigel. It says that organic civilizations and species are inherently unstable; they flash brilliantly and commit suicide sooner or later. The autonomous machines they craft live on long after them, going on and evolving. But they cannot truly compete with the organics, who live "in the universe of essences". That is the reason for the Great Silence. Nigel's superiors order him to use the nuclear weapon, but he refuses. They override him and fire it anyway but the Snark flees the Solar System faster than the missile can follow. The decision to fire is covered up, but Nigel blackmails NASA into letting him go to the Moon; the Snark had directed a transmission at Mare Marginis for unknown parties, and Nigel wanted to find those parties. Four years later, Nigel is now based on the Moon. A fellow astronaut, Nikka, is involved in a crash that accidentally discovers a still active alien spacecraft wreck in the Moon's Mare Marginis – a spacecraft suspiciously armed with a once-powerful anti-spacecraft weapon. Nigel and Nikka explore the wreck, and find a functioning computer with a direct neural interface. Nigel and several others experiment with the computer's neural hook-up, and leave fundamentally changed by it, while the computer becomes inert and unable to reveal any more about its creators. Meanwhile, on Earth, some surprising experiments in human genetics conducted by the aliens are discovered alive in North America.