In the Ocean of Night

Gregory Benford published In the Ocean of Night in 1977, built up from shorter pieces that had appeared over the previous four years. It opens the sequence of novels and stories he called the Galactic Center, and it was nominated for the Nebula Award in 1977 and for the Locus Award the year after.

The story begins in 1999, with Nigel Walmsley, a British scientist working as an astronaut for NASA, sent to attach a thermonuclear device to a comet called Icarus that is on a collision course with India. The comet turns out to be large, solid and made of nickel and iron rather than the loose ice the astronomers had expected.

Walmsley is under orders to plant the weapon and withdraw so that it can be detonated. He argues for putting it into a large fissure in the object instead, and what he finds there starts the long argument about first contact that runs through the rest of the series. The novel is hard science fiction in the sense that its plot depends on the physics, and it is one of the books on which Benford's reputation rests.