And then Phyllis would roll over onto him and kiss him, and he would enter the realm of sex, where different rules seemed to obtain. For instance, though he liked Phyllis less and less as he got to know her better, his attraction to her did not correlate to this, but fluctuated according to mysterious principles of its own, no doubt pheromone-driven and hormonally based; so that sometimes he had to steel himself to accept her touches, while other times he felt alive with a lust that seemed all the stronger because it was so unmixed with affection. Or more senseless still, a lust actually heightened by dislike. This last reaction was rare, however, and as the stay at Arena went on, and the novelty of their affair wore off, Sax more and more frequently found himself distanced from their lovemaking, and inclined to fantasize during it, and fall very deeply into Stephen Lindholm, who appeared to be thinking about caressing women Sax did not know or had scarcely heard of, like Ingrid Bergman or Marilyn Monroe.

• • •

One dawn, after a disturbing night of that sort, Sax got up to go out on the ice, and Phyllis stirred and woke, and decided to come along.

They suited up and went out into a pure purple dawn, and hiked in silence down the near moraine to the side of the glacier, ascending it by a trail of steps cut into the ice. Sax took the southernmost flagged trail across the glacier, intending to climb the west lateral moraine as far upstream as he could go in a morning.

They made their way between knee-high crenellations of ice, all holed like Swiss cheese, and stained pink with snow algae. Phyllis was charmed as always by the fantastic jumble, and commented on the more unusual seracs, comparing those they passed this morning to a giraffe, the Eiffel Tower, the surface of Europa, etc. Sax stopped often to inspect chunks of jade ice that were shot through with an ice bacteria. In one or two places the jade ice sat exposed in suncups turned pink with snow algae; the effect was strange, like a vast field of pistachio ice cream.

So their progress was slow, and they were still on the glacier when a sequence of small tight whirlwinds popped into existence one after the next, like something out of a magic trick: brown dust devils, glittering with ice particulates, in a rough line that bore down the glacier toward them. Then the whirlwinds collapsed in some fluctuation, and with a clattery bang a gust struck them hard, whistling downslope with a surge so powerful they had to crouch into it to keep their balance. “What a gale!” Phyllis exclaimed in his ear.

“Katabatic wind,” Sax said, watching a knot of seracs disappear in the dust. “Falling off Tharsis.” Visibility was dropping. “We should try to get back to the station.”