Across the Sea of Suns

Across the Sea of Suns, a 1983 hard science fiction novel by American author Gregory Benford, is the second installment in his Galactic Center Saga. It follows scientist Nigel Walmsley, who, after encountering an extraterrestrial machine in the previous book, continues his search for life aboard an expeditionary spacecraft and uncovers evidence of a major conflict in the galaxy.

In 2021, radio astronomy on the Moon detects life on a tide-locked planet orbiting a nearby red dwarf. Earth’s governments convert a space colony into the interstellar ship *Lancer*, powered by a modified Bussard ramjet design derived from studying a crashed alien vessel found in the Mare Marginis. By 2056, the *Lancer* arrives and finds a primitive nomadic race that communicates using organs adapted to emit and receive electromagnetic radiation, called “EMs.” A satellite about 100,000 years old orbits the planet, a relic of the EMs' own technology, not directly tied to the meteor shower that destroyed their civilization.

Back on Earth, mysterious spaceships drop sea creatures named Swarmers and Skimmers, which disrupt international commerce. Swarmers attack ships by swarming and head-butting them until they sink, while Skimmers jump and skim like dolphins. The creatures multiply, and Swarmers begin attacking humans and their structures at sea.

The expedition’s first contacts go wrong. An attempt to enter one of the two satellites triggers a massive retaliation, killing most of the crew. Contacting the EMs in person confuses them, as they expected a reply directly from Earth. When the EMs try to communicate with the messenger via radar, they accidentally cook him alive. The standby team misinterprets this as a deliberate attack and massacres the EMs.

Nigel works with mathematicians and experts to interpret the EMs’ transmissions. His analysis reveals that their advanced civilization attracted the attention of machines, which attacked with orbital bombardments that leveled cities and cracked the planet’s crust, permanently altering the ecosphere. The EMs used genetic engineering to adapt their bodies with silicon and transistors for a nervous system. Because the satellite is programmed to react only to high technology, not inbuilt biological features, the EMs can broadcast their message to other biological races unmolested.

Two-way communication is established, but new orders fro