How can Santa Claus deliver all the presents?
Let’s just assume Santa Claus does exist, that way we can play this game in the right frame of mind!
A jolly and fun-loving character, he has one of the hardest jobs in the world: to distribute presents to children all over the world in just one night.
If we take into account that, according to the United Nations Fund for Children (UNICEF), there are about 2,000 million under 18s on the planet, and almost all of them well-behaved, how can this elderly and rather rotund fellow possibly perform such a feat?
Roger Highfield, author of The Physics of Christmas, calculated that on the night of 24 December, Santa has to make nearly 850 million stops and for this, if travelling in the opposite direction to the rotation of the Earth, he would have another 24 hours to carry out his mission.
But even so, this amount of time is still extremely short for such an undertaking.
The key lies in the speed at which Santa must travel.
According to Highfield, editor of the magazine New Scientist, for Santa to carry out his job, he would need to reach more than 6,000 times the speed of sound, that is, 300,000 kilometres per second ... Impossible!
So the answer does not appear to lie in the principles of classical physics, because following them would have tragic consequences: one dead Santa in his first commendable attempt to imitate light.
Fortunately, for those who still believe in Santa, modern physics can help us understand why he continues to leave presents without anyone noticing him.
Speaking from the European Council for Nuclear Research (CERN) laboratories in Geneva, doctor in Experimental High Energy Physics, Daniel Tapia told BBC Mundo: "Just because nobody has seen him, does not mean he doesn’t exist,"
"Maybe the reason why Santa Claus has never been seen is because, at least for that one night, he behaves like a quantum phenomenon," .
"In quantum mechanics, the Heisenberg uncertainty principle tells us that if we know one variable well, we cannot know the other one exactly. We know what speed Santa will be travelling, but not his position."
Santa can be anywhere in the world at any time on Christmas Eve. "That may be possible if Santa Claus is a superposition of quantum states, in other words a collection of Santas diffused all across the planet."
Following the Mexican physical theory, each of the quantum states of Santa would give a gift to each child who must be asleep at the time.
But what happens if a child sees him that night? "You would know his exact position, which would cause the quantum state to collapse and no more presents could be distributed," the researcher said with some disappointment.
So the wonder of Santa depends on never seeing him, because if you do then he ceases to exist.
THE CLOUD OF RELATIVITY
In order to prevent a sleepless child from spoiling the surprise for thousands of other children, Santa could resort to his vast scientific knowledge.
"Children should not believe those who say that Santa Claus is not real because there is no way he could deliver toys all over the world in one. There is a way and it is based on plausible science," said Larry Silverberg , professor of mechanical and aerospace engineering at the University of North Carolina, U.S..
In a paper he presented in 1997, Silverberg argued that Santa is very clear about the principles of Albert Einstein’s theory of relativity and, unlike us, is an expert at manipulating and controlling time and space.
Thanks to his extraordinary knowledge of physics, Santa created a cloud of relativity in which space, time and light are perceived in a completely different way from the how they are perceived outside this cloud..
"Inside the cloud, Santa has months to deliver the presents. From the inside, he sees the world frozen," explains Silverberg in his documents made available to BBC Mundo.
Those of us outside that cloud would only see one fleeting moment. And six months inside it is barely a blink of an eye for us. That is why Santa is in no rush to deliver the presents.
According to Silverberg, Santa literally has all the time in the world,
A BUNDLE OF NANOSTRUCTURES
Santa could also rule out leaving his house and opt for the benefits of nanotechnology.
Gerardo Herrera, a physicist from the Research Centre for Advanced Studies, Mexico (CINVESTAV), told BBC Mundo that scientists at the Karlsruhe Institute of Technology in Germany and Imperial College, London, found a way to make an object disappear from view in three dimensions, in other words, they made it invisible.
"Researchers placed a microscopic object into a mass of gold nanostructures which distorted the light in order to turn the object around so that it became invisible," said Herrera.
However, Santa will have to wait a bit to make use of this discovery, because at the moment you cannot get the same results with objects the size of a ball or a doll.
When it is possible, perhaps in a few years, Santa Claus will have more time to distribute gifts around the world, said Herrera.
"He would be able to hand them out at a more leisurely pace a few days before Christmas. He could leave them out of sight using a set of nanostructures that makes them invisible until the night of 24 December. Then, with a simple phone call and using GRID computing, he could make them appear, all from the comfort of his own home at the North Pole," the physicist mused.
On his busiest night, Santa could also ask for help from the US space programs agency.
"At the moment, NASA has several propulsion systems and heat dispersion technology, but none, as far as I know, could meet Santa Claus’s speed requirements," Clinton Cragg, chief engineer of the Engineering and Safety Center NASA (NESC) told BBC Mundo.
However, an orbiting spacecraft like the Space Shuttle or the International Space Station (ISS) could serve as a Santa gift collection point, added Cragg, the expert behind the capsule which allowed the rescue of the 33 Chilean miners.
"So, Santa Claus would not have to carry the world’s gifts in one trip, thus allowing him to do his work more quickly. The speed required to maintain in orbit (the ISS and Shuttle) would be high enough to keep up with Santa Claus’s frenetic pace," said Cragg.
THE SUPER SPACE SLEIGH
As it’s only once a year, perhaps instead of travelling in the comfort of a cloud, Santa might prefer to feel the thrill of piloting a super sleigh. But what would that sleigh be like?
"It's not like the ones we know. It is round and is equipped with advanced technology. It has a capsule at the front with a huge window, two huge rockets at the sides and an enormous fuel tank at the back," Pete Rodriguez, an aerospace engineer with NASA for more than 30 years, described to BBC Mundo.
"Every time Santa has to stop to leave gifts, he’ll open a hatch to release a little aeroplane which is programmed to take the right gift to the right child."
For Santa to cover the entire planet, he has to leave from the North Pole, reach the South Pole and go back again. He has to do these two trips 48 times while the Earth rotates so that nobody is left without a gift.
"He's busy all year preparing his Christmas Day deliveries and with technology, it can be done," Rodriguez declared.
But if Santa Claus did not apply in time for the necessary permits to use NASA’s ships, then it is possible that, on the actual night, he won’t be able to deliver..
Who can help?
"What Santa Claus needs to do on Christmas Day is a huge logistical operation," Jim Daniell, Head of Public Relations of the delivery firm UPS told BBC Mundo.
"We would advise him to make use of the most advanced technology and to ask his elves for help. It’s not a job you can do alone."
Speaking to BBC World, Ian Silverton, director of operations for FedEx in Spain and Portugal, agreed with this view, saying "If Santa asked to borrow our star technological tool, I would give him the tracking and tracing."
Another possibility would be something like the Delivery Information Acquisition Device (DIAD IV) from UPS, as its battery lasts almost all day, fits in one hand, has 128 megabytes of memory and runs on the Windows CE.NET operating system.
"It's a small but powerful computer that would allow him access to the global positioning system (GPS), monitor deliveries and communicate with his headquarters in the North Pole," said Daniell.
Thanks to wireless networks, Santa Claus would be able transmit data in real time, receive the latest information about a child who is still awake and take full advantage of his geographical position in order to make as many deliveries as possible in the shortest time .
Santa also could use the Roadnet software. Using algorithms, it designs and plans daily routes for UPS drivers.
Whether by delving into the imagination, or by scientific or technological means, the question of how Santa delivers all the presents in one single night will continue to keep awake generations of children, a few scientists and maybe the odd journalist or two.