The discovery of Solaris dated from about 100 years before I was born.

The planet orbits two suns: a red sun and a blue sun. For 45 years after its discovery, no spacecraft had visited Solaris. At that time, the Gamow-Shapley theory — that Life was impossible on planets which are satellites of two solar bodies — was firmly believed. The orbit is constantly being modified by variations in the gravitational pull in the course of its revolutions around the two suns.

Due to these fluctuations in gravity, the orbit is either flattened or distended and the elements of life, if they appear, are inevitably destroyed, either by intense heat or an extreme drop in temperature. These changes take place at intervals estimated in millions of years — very short intervals, that is, according to the laws of astronomy and biology (evolution takes hundreds of millions of years if not a billion).

According to the earliest calculations, in 500,000 years’ time Solaris would be drawn one half of an astronomic unit nearer to its red sun, and a million years after that would be engulfed by the incandescent star.

A few decades later, however, observations seemed to suggest that the planet’s orbit was in no way subject to the expected variations: it was stable, as stable as the orbit of the planets in our own solar system.

The observations and calculations were reworked with great precision; they simply confirmed the original conclusions: Solaris’s orbit was unstable.

A modest item among the hundreds of planets discovered annually — to which official statistics devoted only a few lines defining the characteristics of their orbits — Solaris eventually began to attract special attention and attain a high rank.