The Heisenberg Uncertainty Principle, And How It Probably Can’t Destroy The WorldS

"The Heisenberg Uncertainty Over-ride taps into a limitless pool of destructive energy," Owlman says in Crisis on Two Earths, describing his evil world-destruction plan. But what is the Heisenberg Uncertainty Principle? And could overcoming it really end in explosions?

The one sentence description of the Uncertainty Principle is as follows: Scientists can know the position of a particle, or the velocity of a particle, but not both at the same time.

The Uncertainty Principle has been described as the idea that it is impossible to observe a situation without changing it. There are a hundred documentaries about how, for example, sharks behave. Yet even the most naïve of television watchers will suspect that the shark filmed attacking a diving cage might not behave the same way if it weren't swimming through huge chunks of rotten fish only to run into a guy waving a camera at it. The idea that even a careful scientist influences the outcome of an experiment is easily understood.

That's not the Uncertainty Principle.

The Uncertainty Principle is also often explained by an illustration of why we have such trouble with small particles in general. Human sight is the brain's interpretation of photons that have bounced off other materials. When the materials are large compared to the photons, there isn't much difficulty. Consider mapping out a room using ping-pong balls. Each time a ball bounces back, it would tell the thrower how close the wall is, whether the wall is angled towards or away from the thrower, and if there were any objects on it. It wouldn't be an enjoyable way to spend an afternoon, but it would be possible to form an accurate picture.

Now consider using that technique to map out a human hand. An apple. Another ping-pong ball. Each diminution of scale and weight would result in fewer and fewer details being known. When the ball hits something its own size and weight, the impact itself changes the position and momentum of the object it hits. An accurate picture is impossible.

That's also not technically the Uncertainty Principle, although it comes closer.

The Uncertainty Principle is not a practical problem. Practical problems can be resolved. A camera can be made small and unobtrusive enough not to bother a shark, and the only problem with the mapping experiment is the lack of smaller balls. We can't know both the velocity and the position of, say, an electron because particles on that scale do not behave the way objects on our scale behave.

The heart of the principle is the fact that light is both a particle and a wave. A good way to demonstrate it is by using that most useful of all io9 fascinations; the laser.

Imagine shining a laser through an open doorway. What would the result be? Since the only thing used to measure the position of the photons is a doorway (three feet by six-and-a-half feet), they march through in an orderly fashion and their velocity is predictable. They are confined to a red dot on the opposite wall.

But what if the measurements got more precise than the space of a doorway? Try narrowing the doorway - either with conventional sliding doors, or one of those cool sliding stone exits that always nearly kills Indiana Jones. At first, the result is predictable. The laser beam is cut off on both sides by the narrowing doorway. The space that the remaining photons travel through gets smaller, our knowledge of their position at one point in time gets more precise. And the red spot on the wall will get slimmer. The more the doorway closes, the slimmer the spot on the wall will get.

Until the space between the sides of the doorway reaches a certain point. Then, instead of a tiny dot on the wall, the laser light will branch out, and look like this:

The Heisenberg Uncertainty Principle, And How It Probably Can’t Destroy The WorldS

Notice how there are peaks and valleys to the brightness of the light. That is the wave part of the particle-wave duality. It is what makes it impossible to know both the position and the velocity of a photon. Once the slit becomes small enough for an observer to know, to a certain degree, where the photons passing through it are, the velocity of the photons becomes less predictable. The photons aren't traveling dutifully towards a single dot on the wall. Each one could be going towards any of a number of spots. While researchers can predict the likelihood of a photon ending up in any of those bright spots, they cannot say for certain where the photon will hit.

This isn't a failure of experimentation, or precision. This is an intrinsic property of the photons themselves. This is the reason behind the Uncertainty Principle.

What does that mean for a James-Woods-voiced vigilante with a heart of purest lead, intent on destroying all of mankind?

That depends on how one views the Uncertainty Principle. Einstein famously said, "God does not play dice with the universe." If he was correct, then the Uncertainty Principle is merely a function of our current understanding of the universe. It can be changed as we undertand more, or view things in a different way. Still, the idea that one can ‘tap into a pool of destructive energy' just by knowing where an electron is and where it's going at the same time stretches credibility. It would earn Owlman a Nobel prize, though.

The other possibility is that Owlman's device would change the way quantum particles behaved. It might collapse either the wave or the particle property of an elementary particle. Should he be able to collapse the particle part, the earth wouldn't explode, but since light waves wouldn't travel through a vacuum any more than sound waves would, it would get a bit chilly. The sun's rays wouldn't travel to the earth. The biggest source of energy in the world would be gone. In space, no one can hear you freeze to death.

Taking away the wave part of a photon doesn't seem as disastrous. At first it just seems to make make the laser experiment a lot less fun. The absence of a wave state may, though, make it impossible for the photon to be a massless particle. This would in turn change the speed of light. It might even put an end to the conservation of energy. Which, again, would most likely kill everything on earth by freezing us to death, or starving us to death, or both.

Probably for the best that he failed, even in fiction.