AYESHA RASCOE, HOST:
Finish decorating your tree, hang those stockings and grab some cookies. Christmas Eve is nearly here, and Santa is hard at work preparing for his big night.
(SOUNDBITE OF SONG, "SANTA CLAUS IS COMING TO TOWN")
JACKSON 5: (Singing) Santa Claus is coming to town. Santa Claus is coming to town.
RASCOE: Now, a lot of people may wonder, how does Santa deliver gifts to about 2 billion kids in one night? Well, here's an answer for you - physics. Gaute Einevoll is a physicist at Norwegian University of Life Sciences. He's written about the physics of Santa's big night and joins us now from Oslo. Welcome.
GAUTE EINEVOLL: Thank you. Thank you.
RASCOE: OK, let's start with the biggest questions on people's minds. How does Santa, one person, move quickly enough to deliver all of these gifts to all of these children? I mean, 'cause there's only 24 hours in a day.
EINEVOLL: Yeah, it's true. But luckily, all the good children are living all across the world. So there's, like, different time zones. So he has actually a little bit more than 24 hours, maybe more like 30 hours. Another thing that helps is that I think in U.S., typically, Santa comes by in the middle of the night. In Europe, at least in Norway, he comes in the evening.
RASCOE: What about the speed? Does he have to go really, really fast?
EINEVOLL: Yeah, he has to go really, really fast. But I mean, we are used to living in three dimensions, right? Left, right, straight ahead and up and down. Modern physics, especially something called string theory, has shown that it could be more than three dimensions. Things which are far away in, like, three dimensions can be really close in four dimensions. And if you were living on a sheet of paper and then you feel, like, two points far away on this sheet of paper when it's lying out straight, when you curl up the paper, these two points can be very close, right? If you're just able to jump through the paper - much, much shorter distance.
RASCOE: So what about the weight of all those gifts?
EINEVOLL: I think he's using space, right? We just - like, we have the International Space Station going in orbit. We think that he makes a lot of the presents up in space also, using materials from, like, asteroids and whatever - like, comets and stuff. So, like, we'll also be - humans are planning to do maybe in the future. So we think that he has a lot of gifts stored up there also, which are just sort of filled up there during the year. And when Christmas Eve comes, then you can have all this little sort of gifts, packages returning to Earth.
RASCOE: Well, you know, my kids are very interested in how Santa knows whether they are naughty or nice. And I really want to be able to tell them because I tell them that he knows when they're acting up.
EINEVOLL: No, that's true. So again, this is where modern science comes in to help. Well, it seems like in many of these, like, Christmas hats or these woolen caps that children use, Santa has some recording electrodes that is recording their brain signals from the children's heads. And then from that, he can sort of find out whether is naughty or nice. It's quite a big problem to get all this information. This is maybe also an important role for Rudolph. And how does Santa get all these signals that is coming from all these hats, from all these children? Well, they need strong antennas, and they shouldn't be too far away. So I think we believe that Rudolph's antlers and then, of course, Santa maybe has to find out and to analyze all the signals - probably have some very strong computers up there.
RASCOE: Speaking of computers and stuff like that, there's a lot of automated technology nowadays. Do you think that Santa could be using any of that to make his job easier?
EINEVOLL: Absolutely. I think - particularly, I mentioned this thing of dropping gifts from outer space. I think drones are probably helping Santa because we are sort of getting more, more and more people. We have more children and maybe more of them are nice also...
(LAUGHTER)
EINEVOLL: ...So Santa should use all technologies available.
RASCOE: Before I let you go, I want to set the record straight. There is some controversy that is percolating right now about whether Santa lives in Norway or Finland.
EINEVOLL: Yes. Yeah.
RASCOE: Like, what is your take on that?
EINEVOLL: I thought this was settled long time ago. Of course he lives in Norway.
RASCOE: (Laughter).
EINEVOLL: Santa spends a lot of time on the North Pole. He, like, resides at the North Pole, right? And it's even in our name.
RASCOE: Yes, Norway.
EINEVOLL: Exactly.
RASCOE: (Laughter).
EINEVOLL: Our friends in Finland are a little bit cheeky when they sort of - (laughter) they claim that he lives up in the north of Finland. As we know, there are also some, like, wannabe Santas. But the true Santa, the one that really comes to the children, he lives in Norway.
RASCOE: Gaute Einevoll is a Santa expert and physicist at Norwegian University of Life Sciences. Thank you so much and Merry Christmas.
EINEVOLL: Merry Christmas to you, too.
(SOUNDBITE OF DEAN DELORENZO'S "SANTA CLAUS IS COMING TO TOWN (INSTRUMENTAL)") Transcript provided by NPR, Copyright NPR.
