Dec. 25, 2000 -- How does he do it? Santa Claus visits homes all over the world on Christmas Eve, but when you consider how many homes there are, how little time he has, and how much he has to carry — that is when you truly appreciate jolly old St. Nick.

ABCNEWS’ Robert Krulwich started the Santa investigation with a simple question: How many stops must Santa make?

There are 2.2 billion children under 18 on the planet. But since most Muslim, Hindu, Jewish and Buddhist children do not expect a visit from Santa, 85 percent of the 2.2 billion kids get taken off the list.

At this point, the math gets a little difficult, so Krulwich turned to a Stuyvesant High School teacher in New York City for help. Physics teacher Stanley Teitel assumes there might be 2.5 kids in each home on Santa’s list. In those homes, there is probably at least one good kid. This is where the math gets really difficult.

“OK, we’re assuming that there are approximately 132 times 10 to the sixth, that’s 132 million Christian homes worldwide,” Teitel said.

The next question is: How much time does Santa actually have to do this job?

Well, if the 132 million homes are evenly distributed around the surface of the Earth and if Santa heads west in a kind of random, zigzag pattern across 24 time zones — constantly staying in darkness as much as he can — he’d cover about 175 million land miles. The oceans don’t count, since fish don’t get gifts. He would have about 31 hours to do it. “That’s 1,178 homes per second,” Teitel said. “Every second he must hit 1,178 homes.”

So when Santa arrives at each home, he has a scant 8/100,000 of a second to park the sleigh, heave himself down the chimney, fill the stockings, take care of the tree, eat the cookies, drink the milk, head back up the chimney and get back on the sled.

And the scene repeats itself every second. And Santa wouldn’t be Santa if he wasn’t carrying a huge sack of toys. If each child gets one toy, averaging 2 pounds each, that must be multiplied by 330 million children.

The total — 660 million pounds. And that does not include Santa himself who, on close inspection, is not thin. So that means somebody has got to haul a sleigh that weighs the equivalent of four times the tonnage of the Queen Elizabeth 2. So how many Rudolphs, Prancers, Dancers and Blitzens does it take to pull such a huge weight?

It’s a bit more than you might have heard in the past. In fact, Teitel calculates that Santa would need, 2.2 times 10 to the fifth, or, 220,000 reindeer.

Imagine 220,000 reindeer going at a speed that the reporting team calculated at 7,800 times the speed of sound. That would create a sonic boom that would wake up every child on the planet.

So, the final question is: Are we dealing here with something from the familiar physical universe?

“I would suspect not,” Teitel says. “I would suspect we’re dealing with someone who’s very special, and has been given powers to be able to do his job.”

Well, after all, Santa Claus is a saint.