What is the science behind Santa's carrying bag?

Question

Each year without fail the notorious serial house breaking old man always deliver the present to all the children in the world, yes you heard me now that's billions and counting, and a piece of coal for each juvenile delinquent (at his discretion, don't argue). Remember this is the man that grew bushy white beards first spotted many many years ago, still possesses beer belly, sitting on a broken wheelchair and must rely on his guide-deers for direction and there must be a trick in the big bag that he's always carrying around. Please use magic sparingly can science and technology of the 22nd century C.E. help to decipher the mystery hidden in the bag? Seriously I had a stockpile of coal and this time I'm going to lift the curse... with science! Handwavium only applies to everything excluding the bag.

Answer 1

I would say, it's somewhat the kind of bag that is asked around here a few days ago: how-can-it-be-bigger-on-the-inside

So to summarize the answer there, his bag would have one of the following technologies:

1. Extradimensional expanded bag. This is what have been done before. Before economic recession, the elves just working 9 to 5 all day producing toys and any good kids probably want throughout the year then stop on Christmas eve. Bold the word probably, because sometimes what they see in their crystal snowball wouldn't show what the kids really want, so they need to make an assumptions.

After they finish packing all the gift, they round it up on Santa's bag. This bag is not an ordinary bag, as this bag interior stretch its 3-dimensional space properties to an added higher dimension, so its interior volumes can be folded to almost infinitely.

Then you'd ask do the higher dimension exist? for now, scientist still argue since there's no direct proof about it, but you can read more about it here (the physics stack exchange) and here. And how Santa had access to this kind of technology? That is still a mystery, but it's a possible feat for an unaged likely immortal devout old man with golden heart. While of course some of brightest mind throughout history also wouldn't mind to cooperate and help him in secret, advancing his technology so people nowadays still believe in miracles.

2. It's a wormhole gate. That connected to His factory that located on the north of the Northern pole. Where live a group of elves doing overtime on Christmas eve. They tracking Santa gps data and compare it with tagged gps data of kids around the world, so when Santa reach his hand inside the bag, the elf staff will send him the right gift for the right kid.

This kind of aided workflow had been implemented since 9 years ago, when Santa forgot to give a wrong gift to a wrong kid.

Nowadays, the elves surveyor division also monitored parents and kids social media, also their e-commerce account wishlist, to make sure they give the right thing to the right kids. Since inexpressive kids before would just receive a reindeer sweater, or encyclopedia, despite they good behavior throughout the year.

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The sled technology:

The sled is almost ordinary sled, while he use the ancient wood scavenged from Noah's ark (a type of wood that hasn't been grown since the Big Flood). This wood is very lightweight but durable with its structure can be compared to birds wing bone.

The real magic here would be the also likely immortal deer (or maybe they are cloned). But nevertheless, they've been trained to not afraid of heights and run under the enchantment of the pixie's dust. The dust of pixies comes with many kinds of chroma, And the exact golden pixie dust is what you needed to be weightless and grants you to flight, negating normal gravity effect.

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About how can he pull it off in time:

This is the last trick and whether you like it or not, actually there's no magic involve here.

At first long ago, lived a legendary eccentric old man that in his spirit of Christmas begun to give a present to kids first is just a nearby neighborhood kids who received it. Then news began spreading, soon more and more kids expected his gift every year. He then knows that he can't stop, that his act had been tradition and to stop means he would end a 'miracle' that he created.

So every year long he always experiments and upgraded his technique and workflow, to give more good kids a present they'd want. And believe it or not, the fact is every year he failed. There would always another child who didn't get his present, but there also exist peoples and non-peoples who successfully find his house and knocking his front door, tell him that they are a fan of his work and offer him a thing or two to help him.

So his team is expanding, and by the time his legends globally spread. You'd be surprised at how much work he should do right now since almost any grown parents that want to spread his legend of miracles is feel obliged to help him do his work. At this rate, he just needs to be seen by a small group of peoples riding his sled (even no need to be flying anymore, since pixie dust is scarce this day), while almost everyone who celebrates Christmas would credit him for the gift that've been given to good kids.