Cirrus@Austlit

'In Yalda's universe, light has no universal speed and its creation generates energy. On Yalda's world, plants make food by emitting their own light into the dark night sky. As a child, Yalda witnesses one of a series of strange meteors, the Hurtlers, that are entering the planetary system at an immense, unprecedented speed. It becomes apparent that her world is in imminent danger–and the task of dealing with the Hurtlers will require knowledge and technology far beyond anything her civilization has yet achieved! Only one solution seems tenable: if a spacecraft can be sent on a journey at sufficiently high speed, its trip will last many generations for those on board, but it will return after just a few years have passed at home. The travelers will have a chance to discover the science their planet urgently needs, and bring it back in time to avert disaster.' (Trove record)

The generation ship the 'Peerless' is suffering from a population explosion, and the only way to reduce the number of children is by drastically limiting the food intake of the females, which will trigger a natural response to famine and stop procreation. So population control consists of two barbaric choices: starvation, or suicide.

In a universe where the laws of physics and the speed of light are completely alien to our own, the travellers on the ship Peerless have completed a generations-long struggle to develop advanced technology in a desperate attempt to save their home world. But as tensions mount over the risks of turning the ship around and starting the long voyage home, a new complication arises: the prospect of constructing a messaging system that will give the Peerless news of its own future.