Another massive near-future, near-space yarn from the author of Voyage (1997). As NASA space jockey Geena Bourne acrimoniously splits from her geologist husband, Henry Meacher, Venus explodes into nova-like brilliance. The explanation, scientists think, involves superstrings: the planet's wreckage produces massless black holes. Geena returns to work, while Henry travels to Edinburgh to investigate a large Moon rock gathered by the last Apollo mission 30 years ago and left untouched since. Silvery ``Moonseed'' dust escapes from the lab, however, and ``infects'' the ancient volcanic rocks underlying the city, converting them into novel crystalline forms using superstring energies. Within days, Edinburgh is engulfed by volcanic eruptions. Moonseed spreads rapidly around the globe, chewing up the planet's crust, and producing more terrestrial turbulence. Henry, who's developing a theory (is Moonseed some sort of hive organism? or alien nanotechnology that converts planets into spaceships?) must get to the Moon to gather crucial evidence. Geena's the best pilot available, though rundown NASA will need lots of Russian hardware and technical help. Henry confirms that the Moon, too, is infected with Moonseed, but something massive is inhibiting its full development. With Earth doomed to meltdown, the Moons clearly the only safe haven for what's left of humanity. But can it be made habitable in time to receive millions of refugees? Baxter revels in the gritty, practical details of space flight and moon-walking; his alien threat is an intriguing and original one, though unconvincingly developed. But the padding (too many minor characters and unnecessary scenes) slows the pace to a crawl.