The Human Division #1: The B-Team by John Scalzi

Schmidt said. “This mission was meant to be secret.”
    Wilson nodded. “Yes, but that’s not anything you and I have to worry about at the moment. We’re still looking for the black box. The good news, if you want to call it that, is that this narrows down considerably the volume of space we need to search.”
    “So we go back to the first scan and start picking through those remaining bits of the Polk, ” Schmidt said.
    “We could do that,” Wilson said. “If we had a month.”
    “This is where you make me look stupid again, isn’t it,” Schmidt said.
    “No, I’m going to spare you this time because the answer isn’t obvious,” Wilson said.
    “That’s a relief,” Schmidt said.
    “To go back to your suggestion, even if we did go through the earlier scans, we’d be unlikely to come up with anything,” Wilson said. “Remember that the CDF wants the black box to be found only by its own people.”
    “That’s why the black box is black,” Schmidt said.
    “Not just black, but aggressively nonreflective,” Wilson said. “Covered with a fractal coating that absorbs most radiation that hits it and scatters the rest of it. Sweep it with a sensor scan and nothing comes back directly. From the point of view of a sensor array, it doesn’t exist.”
    “All right, Harry Wilson, supergenius,” Schmidt said. “If you can’t see it and can’t sweep for it, then how do you find it?”
    “I’m glad you asked,” Wilson said. “When I was thinking about the black box, my brain wandered to the phrase ‘black body.’ It’s an idealized physical object that absorbs every bit of radiation thrown at it.”
    “Like you said this thing does,” Schmidt said.
    “Sort of,” Wilson said. “The black box is not a perfect black body; nothing is. But it reminded me that any object in the real world that absorbed all the radiation thrown at it would heat up. And then I remembered that the black box came equipped with a battery to power its processor and inertial dampener. And that the battery is not one hundred percent efficient.”
    Schmidt looked at Wilson blankly.
    “It’s warm, Hart,” Wilson said. “The black box had a power source. That power source leaked heat. That heat kept it relatively warm long after everything else around it entropied itself into equilibrium.”
    “The battery is dead,” Schmidt said. “Even if it was warm, it wouldn’t be anymore.”
    “That depends on your definition of ‘warm,’” Wilson said. “The design of the black box means that it has some areas inside of it acting like insulators. Even if the battery’s dead, it’ll take longer for the black box to reach a temperature equilibrium with space than it would if it were a solid shard of metal. I don’t need it to be warm like the inside of this room, Hart. I just need it to be a fraction of a degree warmer than everything else around it.”
    The display screen flickered and the ghostly blob of attenuated Polk molecules was replaced by a thermal map that was a deep blue black. Wilson gave the thermal map his attention.
    “So you’re looking for something that’s ever so slightly above absolute zero,” Schmidt said.
    “Space is actually a couple of degrees above absolute zero,” Wilson said. “Particularly inside a planetary system.”
    “Seems like an irrelevant detail,” Schmidt said.
    “And you call yourself a scientist,” Wilson said.
    “No, I don’t,” Schmidt said.
    “Good thing, then,” Wilson said.
    “So what happens if it has entropied out?” Schmidt said. “If it’s the same temperature as everything else around it?”
    “Well, then, we’re screwed,” Wilson said.
    “I don’t love your bracing honesty,” Schmidt said.
    “Ha!” Wilson said, and suddenly the image in the display pitched inward, falling vertiginously toward something that was invisible until almost the last second, and was an only slightly lighter blue-black than everything around it even then.
    “Is that it?”