Andrew Sean Greer's debut novel, The Path of Minor Planets [2], which first appeared in the United States in 2001 and is now published for the first time in the UK, concentrates on a group of academic astronomers and their families as their careers, loves and lives unfold over the course of 25 years. Their lives - and Greer's novel - are punctuated by a series of reunions on Bukit, an island in the South China Sea, to view and celebrate the return of a comet that Martin Swift, patriarch of this band of researchers, discovered early in his career.

The novel is broken into five sections, organised by the cyclical movement of Comet Swift, which alternate between those marked near perihelion and near aphelion, the points where it is closest to or furthest away from the centre of the solar system, and thus the sun and the earth. It takes the comet 12.2 years to complete the full circuit, so the sections are spaced at intervals of roughly six years: 1965, 1971, 1977, 1983 and 1990.

To this episodic rhythm, The Path of Minor Planets [2] skips through its characters' marriages and divorces, as they have children and grow up or grow old. This is a broad sweep of attention. Nonetheless, it sensitively portrays three central female characters - Denise Lanham, a researcher with a halting love life, Kathy Spivak, wife of one of Swift's protégés, and Lydia, Swift's precocious daughter - as they mature, delivering a rich sense of the vicissitudes of being a woman, whether daughter or wife, mother or professor, mistress or divorcee, in an academic milieu and in the landscape of late 20th-century America.

The temptation to allow the parallels between science and life to run rampant in fiction on such a theme would seem almost irresistible. And, to an extent, this is the case in Greer's novel. That Swift organises both his life and his work according to a jauntily misogynistic axiom - "Never trust a comet or a woman" - is only the most extreme example of the author's tendency to indulge in forced collisions between astronomy and romance.

At times, the characters, too, sense that the links are beginning to grate, as they are employed reflexively by nearly everyone: "Lydia knew that she and her father had grown distant in the way the stars grow distant - because of time's simple expansion - and even this metaphor made Lydia wince."

But at other moments the connections between astronomy and everyday life become more vivid. As the ageing Swift is led in to a planetarium by his daughter and granddaughter, he compares the strange energies that guide human relationships to the gravity responsible for proximate objects' elliptical paths in space:

Swift felt that the two females made this trip up the steps much harder than it needed to be; it was the famous Three-Body Problem. This astronomical issue states that while the Newtonian calculation for one body in space is simple, and while that for two bodies interacting (such as the earth and the moon) is only somewhat harder, the equation for three bodies and their differing gravities is so infinitely difficult that it can't be done.

We might be tempted to go further and say that, while the Three-Body Problem cannot be solved mathematically, it is something like the founding, insoluble problem that sets fictional plots in motion: Him plus Her . . . plus another him or another her. It is in this reversal of the usual trajectory of the novel-of-science genre that we discover the power of Greer's work. Rather than making rote comparisons between the stability of the night skies and the unstable intricacy of human life, The Path of Minor Planets complicates Denise's sense as a girl that even though shouts "might ring inside the house and teachers in school might grade unfairly", nevertheless "she knew the stars were . . . as always, something to count on".

Comets always come back and come back on time, except when they don't - when they have melted away or veered on to a path out of the solar system. It is in this resistance to perfect formalisation that we find their true point of metaphorical contact with the human beings who sometimes analyse but always marvel at them. As one character thinks to himself in the closing pages, "The sky . . . even that forgets."

The Path of Minor Planets
Andrew Sean Greer
Faber & Faber, 288pp, £12.99 [2]

Michael Sayeau is a lecturer in the English department of University College London