Dr Karl Kruszelnicki

The ‘truth’ about Santa

COME CHRISTMAS EVE, how does Santa deliver presents to millions of children around the world?

About 2 billion kids are under the age of 18. But only about one-quarter are Christian so, officially, Santa has to visit only 500 million kids. Santa, however, visits ALL children.

On average, 3.5 children live in each house, so Santa visits about 140 million separate homes.

Luckily, Santa has about 30 hours of darkness to deliver the presents – because the Earth rotates! Suppose Santa travels east to west, starts at the leading edge of sunset and then gradually allows the trailing edge of dawn to catch up with him. In this case, Santa’s Christmas night lasts for 30 hours (24 + 6). There are 108,000 seconds in this 30-hour ‘night’. Santa has to visit 1000 houses each second!

But there are about 150 million square kilometres of land on our planet. So, on average, the households are about 1km apart. Santa has to travel a total distance of 150 million kilometres. His average speed is about 1000km/s.

Santa has to accelerate from zero to 1000km/s and back to zero, and do this 1000 times each second. His acceleration is about 400 million g (where g is acceleration due to gravity) – but the average person goes unconscious after five seconds at 5g. Under this ferocious acceleration, Santa’s 100kg body would ‘weigh’ 40million tonnes. Santa would disintegrate into a chunky red mush!

The payload is another problem. Suppose each of the 500 million children gets 1kg of presents. Then the reindeer pull 500,000 tonnes.

The combination of enormous speed, large payload and wind resistance that the lead pair of reindeer dissipate (on their bodies) is about 15 million million million Watts of power. That’s roughly one million times more power than the human race dissipates over our planet!

So how does he do it? The solution is easy – Quantum Physics. On Christmas Eve, Santa is everywhere on the planet, and at the same time – and that proves he is real!