Spacetime Donuts by Rudy Rucker Page A

assimilation, since before the molecule could actually reach them it would have to enter the VFG field . . . which would, of course, shrink it down to nothing. Nevertheless, it was unsettling to have this flaring Chinese dragon flying towards them.
    They continued shrinking, and soon it was difficult to make out the snakes which were the molecules of plastic. The flickering became more pronounced. It was like looking out into a crowd of people taking flash pictures in a darkened auditorium . . . only each flash was a different brilliant color.
    In general, an atom will emit photons of only one color most of the time, so it was possible to pick out the paths of some of the atoms in the swarm of light flashes around them. They moved in unpredictable zig-zags—like fireflies on an August night.
    As they continued shrinking, three atoms came to dominate the visual field. The closest one gave off blue and occasional green flashes and was floating motionless in front of Vernor as he sat in the pilot's seat. The other two atoms were located directly above and directly below the transparent sphere of the scale-ship. These gave off red flashes and seemed to be vibrating towards and away from the blue flashing atom.
    "H 2 O," Mick exclaimed. "Cool, cool water."
    "Yeah," Vernor said. "That must be it. The angles look just right for those two reds to be hydrogens bound to a nice blue oxygen. This might be a stray water molecule from our breathing. We're inside a molecule." The blue-flashing oxygen atom was drawing closer as the steady, pulsating dance of the red-flashing hydrogen atoms continued. "Pretty soon we're not going to be able to see at all, though," Vernor concluded, as the flashes grew more infrequent.
    "Why not?" Mick asked. "Why shouldn't we be able to see the electrons and the nucleus? They're there, we're still shrinking . . . what's the problem?"
    "There's no way we can see them," Vernor said patiently. "For you to see something it has to send a signal to you. The smaller we get, the less likely it is that a photon will hit us. Once we're smaller than a photon I don't think it even can hit us." He thought for a minute, then continued. "But maybe—"
    Turner finished his sentence for him, delightedly crying, "But maybe you're full of shit!" The darkness around them had filled with an even, milky luminosity. The actual particles of the oxygen atom were becoming visible!
    "This is impossible," Vernor said as they drifted closer to the atom in front of them. It had now grown to the size of a weather balloon. The blue and green flashes had died out as he had predicted . . . they were so small that the chances of a photon from the atom hitting them were infinitesimal. Nevertheless, he could see the atom.
    The electrons formed a sort of cloud or haze around the tiny nucleus, but a haze unlike any he had ever seen. If he glanced at the whole electron cloud there were no lumps, no individual electrons . . . merely the continuous probability distribution demanded by orthodox quantum mechanics. On the other hand, if he focused his whole attention on any limited region of the cloud, a small yellow ball would appear there . . . an electron orbiting the nucleus according to the laws of pre-quantum physics. What he saw depended on what he tried to see! He turned to Mick, "What do you see? Do you see separate electrons or just a cloud?"
    Turner gave him a strange look, "I see little yellow balls whizzing around a tiny pulsing thing in the middle. What kind of cloud you talking about?"
    "The electron cloud, dammit. Electrons don't have both a position and a velocity. Heisenberg Uncertainty Principle. You can't see a particular electron at a particular spot moving in a definite direction with a definite speed. You just can't!" He broke off as an electron the size of a beachball glided serenely across his visual field.
    Mick was silent for a minute, then spoke. "Yeah, I remember that Uncertainty stuff. It was on the Uncle