Camouflage

well; between his social life and academic life, some wondered when he had time to sleep.
    He pretended to sleep, of course, sometimes in the arms of a graduate student or young professor, which didn’t harm his reputation. He wrote most of his papers in that mode, eyes closed and mind in high gear.
    In the tenth year of his tenure, 2019, everything changed. Like everyone else, he read and saw the news about the strange artifact that Poseidon Projects had brought up from the Tonga Trench. Unlike most people, the changeling felt a shock of recognition.
    It immediately got in touch with the project, and hit an absolute wall: no hiring. Every position filled by people who’d been in it from the start. Thanks, but no thanks. You can read our published data and do your own work.
    Of course the changeling knew they wouldn’t publish all the data. They were in pursuit of profit, not knowledge.
    For the first time in its life it considered revealing its true nature. Want a consultant who can really help you with aliens?
    But not yet.

- 33 -
apia, samoa, 30 may 2021
    E uropa, under its ice surface, was not too difficult. They considered not trying it at all, since the environment—cold saline solution under pressure—wasn’t all that different from the Tonga Trench, where it evidently had been since approximately the dawn of time. Of course that also was a good argument for doing it. The artifact might respond to the familiar.
    It showed no gratitude for Old Home Week, though, sitting as passively as ever, mirroring the ambient temperature but not otherwise acknowledging their efforts. It was a good test for the containment dome’s integrity, which was going to be challenged by Jupiter, but otherwise did nothing other than raise the blood pressure of the observers along with the water pressure inside.
    After Jan had finished her familiar algorithm, they depressurized and drained the dome, and prepared it for Io, the innermost of the four large moons, the Galilean satellites.
    Io’s atmosphere is exotic and variable, but thin almostto the point of being a vacuum. It can get up to about a hundred nanobars and down to one (the air on the top of Mount Everest is 330 million nanobars). The fact that it’s a poisonous mixture of sulfur dioxide and sodium isn’t relevant to human survival; a human would freeze solid in the middle of explosive decompression, not having time to notice that the air smelled bad.
    Still, it was possible that Io’s surface conditions were not unusual in the universe, so they went ahead with the model, a frigid near-vacuum with a scattering of frozen sulfur dioxide on the floor. They varied the temperature from 100 degrees K. to 130 degrees, enough for some of the sulfur dioxide to sublimate, and then fall back as snow.
    The artifact faithfully mirrored the changes in temperature, but otherwise ignored the investigation.
    It wasn’t much of a change to simulate Pluto, just suck out the sulfur dioxide, lower the temperature to minus 233, and put in a dusting of snow: solidified nitrogen, methane, and carbon monoxide, with a squirt of ethane flavoring the nitrogen. To any Earth creature, it would be indistinguishable from Io, but conceivably might make all the difference in the world to you, if you were used to living on a snowball in Hell.
    They used the space suits for the last time—that was a part of the deal, that they record the suits’ performance in the various environments—and then sent them back to NASA. They would be no help for Jupiter.
    F or the other planets, they had simulated surface conditions. That wouldn’t be possible on Jupiter. Theoretical models allowed the possibility of a rocky core, but you can’t get there. As you descend through Jupiter’s increasingly thick atmosphere, it becomes more like a star than a planet—the temperature coming to about thirty thousanddegrees and the pressure about 100 million atmospheres. It’s “liquid metallic hydrogen” there, and if anything could live under those conditions, it was unlikely to find Earth interesting.
    Jan decided to try two Jovian regimes: the one deep enough into the atmosphere that it enjoyed the same air pressure as Earth at sea level, though the temperature was minus 100 degrees C., and the deeper one where the pressure was five atmospheres, but the temperature was an Earth-like zero degrees. In both cases the atmosphere was about 90 percent hydrogen, and the rest helium with a little spicing—methane,