Could Santa deliver gifts to all the world's children in one night?

Of course he can, with help from Nasa, Einstein and 360,000 reindeer. Scientists have been wrestling with the feasibility of Santa's job description since the 1850s. The latest thinking is that delivering one kilogram of presents to the world's 2.1 billion children (regardless of religious denomination) is entirely realistic, with a little lateral thinking.

Scientists at the American space agency, Nasa, reckon the man from Lapland relies on an antenna that picks up electromagnetic signals from children's brains to know what presents they want. Assuming an average of 2.5 children per house Mr Claus must make 842 million stops tonight to fill his orders.

By allowing a quarter of a mile between each stop, he must travel 218 million miles with about a thousandth of a second to squeeze down each chimney, unload a stocking, eat a mince pie, swig cooking sherry and get his sleigh airborne again. To achieve this he must travel at 1,280 miles per second. Travelling east to west, he can stretch Christmas Day to 31 hours.

To have enough presents, Santa's sleigh must carry 400,000 ton of gifts. With the average non-turbocharged reindeer capable of pulling only 150kg, Father Christmas would need 360,000 reindeer to heave his vehicle skyward.

The cavalcade would have a mass of about 500,000 tons which, at the required speed, would cause each reindeer to vaporise in a sonic boom flattening every tree and building within 30 miles. Father Christmas would have a mass of two million kilograms, causing him to combust when his reindeer come to their sudden halt. Piffle.

First, Einstein's theory of relativity dictates that the faster an object travels, the slower time appears to pass. So at the speed he is travelling, .0001 of a second allows Santa to perform his tasks at leisure pace. Second, as an expert in quantum physics, Mr Claus knows wormholes in the fabric of universe allow him to move instantly from one dimension and place to another. His sleigh is a time-machine powered by an unknown fuel which any economy on the world would have on its Christmas list.