How Lovely Are Thy Branches: A Young Wizards Christmas by Diane Duane

Channel’?”
    “This could either be very good or very very bad,” Ronan said as the TV guide came up. “…’The Christmas Invasion…’ Well, okay. Fair play to them. ‘Bugs Bunny’s Looney Tunes Christmas Tales’? Surely you jest. …‘The Big Little Jesus?’ Is that actually in black and white?” And then a dumbfounded pause. “’ Santa Claus Versus the Martians ’? What in the name of the sludge at the bottom of the Powers’ bottomless Bucket is that??”
    “Probably something about the True Meaning of Christmas,” Dairine said, folding down crosslegged in front of the TV and filching the remote from Nita.
    Ronan flopped down beside her, looking genially scornful. “Might as well ask about the true meaning of life.”
    “If you see any pigs around,” Nita said, relieving Dairine of the remote and moving another page down in the onscreen TV guide, “might try asking them…”
    “Does he even do Christmas?”
    “He’s everywhere,” Kit said. “Why wouldn’t he?”
    “Pigs?” Kit’s father said from where he’d wound up on the sofa next to Filif, sounding a little bemused. “Why would there be pigs?”
    “Um…”
    “Is this one of those explanations that’s going to make me sorry I asked?”
    Nita laughed. “No. Just confused. But you won’t be alone, not at all.”
    Kit started attempting to explain the Transcendent Pig to his father. Nita, listening to this process with one ear, found it to be going about the way she’d thought it would. She turned her attention instead to the group in front of the TV. This had briefly flipped to one of the video channels, where some boy band was singing “Santa Claus is Coming To Town”. “…He knows when you are sleeping… He knows when you’re awake…”
    From the nearby easy chair, Tom snickered. “’Kindly old elf or CIA spook?’”
    “Yeah, exactly,” Ronan said, “Between the intelligence-gathering and the coming-down-your-chimney-to-eat-your-food stuff, it’s all a bit creepy.”
    “Not to mention unlikely, in terms of the physics,” Dairine said. “You figure, four hundred million kids under ten on earth, give or take… Say a hundred ten million households, right? And let’s assume there’s at least one good kid in each…”
    Ronan flopped back on the floor and covered his eyes. “So adult centric. I distrust the math already.”
    “And then you’ve got, what, thirty-one time zones to deal with over the entire Christmas Eve period? And Earth’s rotation. Do the math and you get sort of a thousand visits a second, rounding up. A hundred ten or so million stops…forget the evenness of the statistical distribution, it’ll make you crazy…”
    “It’s making me crazy already.”
    “So the sleigh has to be doing six hundred fifty-odd miles per second, right? Even though it has to be carrying at least three hundred thousand tons’ worth of payload even if everybody’s getting nothing but Lego and Barbies. Then you have nine reindeer, counting Rudolph, and forget ‘tiny’ if they’re pulling a load like that, which pushes the whole business up to about the mass of the QEII —”
    “Was math even meant to be used for these purposes? I really have my doubts.”
    “And all this is happening in atmosphere, remember, like a constant spacecraft re-entry. Fourteen quintillion joules of energy per second getting expended isn’t going to do them any good, they’ll all be vaporized before they hit the fourth or fifth house. And then there’s the G force—”
    Filif had slipped out of his ornaments again for a little while and was looming over this discussion with some confusion. But apparently the G force became too much for him. “It’s very nice as a physical -universe explanation,” Filif said, “but of course the methodology’s completely flawed.”
    Dairine peered up at him. “What?”
    “Well, since this being is plainly one of the Powers, if a bit of an anarchic or chaotic one,” Filif said, “why