The question was breathtaking in its simplicity, cosmic in its implications, and overwhelming in its idiocy.

If all one billion Chinese jumped off chairs at exactly the same time, would the Earth be thrown off its axis?

"It's the kind of question you hear when you're a kid," says Ed Zotti, who earns a living solving this type of mystery. "So I knew we had to answer it."

The obvious first step was to call the Chinese consulate and arrange an experiment.

"They laughed," Zotti says.

When it became obvious that the solution to the Great Leap Forward would have to be purely theoretical, Zotti called up a friendly physicist at the University of Wisconsin. Together, they figured out that getting onto the chairs would amount to pushing the Earth down, and jumping off would allow it to spring back. Action and reaction would thus cancel each other, and the world would remain safe for less bizarre forms of depredation.

And yet . . . if the Chinese could somehow magically appear on their chairs without climbing up there first, they would indeed make a certain thud upon landing.

*"The momentum of all that weight, if it hit simultaneously, would equal the explosion of about 500 tons of TNT," says Zotti.

Surely Ann Landers and Dear Abby don't have to deal with questions like these.

"The questions in the Straight Dope are a living monument to the indomitable power of human curiosity, and the lengths to which people will go to get to the bottom of things," says Zotti.

The Straight Dope -- which runs in about a dozen alternative newspapers, including Washington's City Paper -- is supposedly written by Cecil Adams, a legendary figure who combines the knowledge of the Library of Congress with the charm of a Marine drill sergeant ("If ignorance were Corn Flakes, you'd be General Mills" he tells one hapless correspondent).

Actually, Cecil Adams has as much physical reality as Betty Crocker. Since 1978, he's been represented by Zotti, now 34. It's a low-profile job that frequently requires the brutal disillusioning of the public.

*"The rumor is often much better than the truth, and so when you tell the truth, people get irritated," Zotti says. "They want to believe the lyrics to 'Louie Louie' are obscene a long-standing, inaccurate rumor that was caused by the Kingsmen's miserable vocalizing . They want to believe there are canals on Mars, or that the moon is bigger when seen on the horizon."

*The column's readers tend to be most obsessive about sex and death. Some of the tamer questions in these categories deal with eunuchs, G spots, and whether a man really could live by bread alone.

"Obviously, these are your basic concerns," says Zotti. "Who else can you ask? Your alternative is your buddies in the locker room, but Cecil is never embarrassed."

The column gets several dozen questions a week, a number of them written on bar napkins. While Zotti claims "there is no question so obscure it cannot be answered," about half the ones he receives have already been dealt with, are semi-crazy ("How many telephone poles are there in Chicago?"), or fall into the realm of "who cares?" ("I could have sworn I saw Joan Collins in this 1951 movie . . . ").

When the column began 13 years ago, readers were very interested in methods of combatting cockroaches, and there was a furious discussion of the efficacy of boric acid. Now that the average reader -- the majority of whom seem to be male -- is in his mid-thirties and moving upscale, "they're more concerned about virility and balding."

Most of their questions seem both inexplicable and unanswerable: Why are taxis yellow? Whatever happened to TV's Channel One? How did escape artist Harry Houdini really do his tricks?

The column answers all with amazing aplomb, in spite of a relatively simple research process. What Zotti calls "the full might of the Straight Dope team" (basically himself) goes to the library and checks out the magazine and computer indexes.

"You can find out an awful lot of stuff without having to go very far," he says. "For any topic, there's always someone who has devoted his life's work to researching it. All you've got to do is to find him and grill him."

He also does some of his own experiments. When a reader wondered which was cheaper, driving with the windows open and the air conditioner off or the other way around, Zotti devoted part of a vacation to finding out.

"On the one hand, if the air conditioning is on, that uses up more gas," he explains. "But if the windows are open, you have more drag and turbulence, and could get poorer gas mileage." Penny-saving drivers eventually were informed that -- in Zotti's car, at least -- it was cheaper to keep the windows up and the air conditioner on.

When a collection of the columns was recently published (The Straight Dope, Ballantine, $3.95), one reviewer said it represented a positivistic attitude toward phenomenology: There's an answer to every question, if you only look in the right place.

"That took me aback," Zotti says. "I was doing it to pay the rent. If the Straight Dope gives us reason to hope, my hope is that I'll be able to afford raspberries next winter at $3.99 a carton."