Lewinsky and the Science of Noise

Trying to figure out what’s really going on with the president and Monica Lewinsky--if anything--is a little bit like trying to see stars during the day or hear a whispered secret at a crowded cocktail party: It’s hard to see a real signal for the noise.

For scientists, that’s a painfully familiar problem. They know well how easy it is to mistake random noise for a signal.

Two years ago, scientists announced that they had found ice on the moon; then the “ice” turned out to be some random fidgeting of the instrument. The same fate met house-sized snowballs supposedly pelting the Earth from space.

But scientists can’t afford to dismiss “noise.” Sometimes, what seems like noise turns out to be important signals. For example, military spy planes looking for secret nuclear blasts in the former Soviet Union found random bursts of high-energy gamma rays going off all over the sky like firecrackers; they turned out to be an important astrophysical phenomenon known as gamma ray bursters.

Perhaps the most famous “noise” in the universe is the background glow of radiation left over from the moment of creation, the big bang. When radio astronomers at Bell Labs first tuned in to this signal from 15 billion years ago, they thought it was static. They cleaned the pigeon droppings out of their receiver, hoping that would fix the “problem.”

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Only after they had eliminated all possible sources of “noise” did they accept the fact that what they were hearing was really a signal bearing an important message.

Subsequently, astronomers tried to study the radiation for signs of what the very (very, very) early universe was like. UC Berkeley’s George Smoot saw a signal within the signal, and remarked that it was akin to seeing “the face of God.”

But the “face” was hardly easy to see. As Smoot described the task: “We were looking for tiny variations . . . something less than 1 part in a 100,000--that is something like trying to spot a dust mote lying on a vast, smooth surface like a skating rink. And, just like a skating rink, there would be many irregularities on the surface that had nothing to do with those we sought.”

In other words, noise.

Noise is at the center of many scientific controversies, as well as political ones. For example, are the submicroscopic tube-like forms found on a meteorite from Mars signs of ancient life? Or dried blobs of Martian mud? Are the organic molecules found in the rock really from Mars? Or were they picked up during the meteorites’ stay on Earth?

“That’s the pain,” said Stanford chemist Richard Zare, who did an early chemical analysis of the meteorite. “To make sure [the organic compounds are not from] you or car exhaust from the street, or contamination from the air, or something it picked up in Antarctica.”

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Most desperately, scientists need a way to turn the noises off--just as you need to turn the lights down in a theater to see the movie clearly.

But this requires, first, knowing what the noise actually is, lest they turn off the movie by mistake.

Scientists, therefore, have to become experts on noise.

Astronomers looking at a star, for example, have to subtract every wiggle from the Earth’s atmosphere, every heat fluctuation from the telescope, every stray photon of light from other stars and galaxies and dust clouds in the sky.

The problem is, one person’s signal is another person’s noise. If you’re trying to listen to a concert while people are talking, the conversation is noise. But if you’re trying to listen to the conversation, then the concert is noise.

What’s all this got to do with Lewinsky? Whatever the true signals in the case, everyday people following the story seem to agree on one thing: There’s way too much noise--hearsay, gossip, rumors. . . .

Enough already: Noises off!