Electron breakup? Physics shake-up.

Many elementary particles splinter into shards, but not the electron. At least scientists hadn't thought so. According to new theoretical research, however, there are extreme conditions under which even electrons divide.

That radical notion from Humphrey J. Maris of Brown University in Providence, R.I., presents a serious challenge to established ideas in physics. A century's worth of experiments has produced no sign that electrons break up.

"If this suggestion by Maris is clearly confirmed by experimental work, it will have a huge impact," predicts Robert B. Hallock of the University of Massachusetts in Amherst. "It would mean that some of our fundamental understanding of nature is incorrect and needs to be modified."

What Maris has proposed is that loose electrons in ultracold liquid helium might split into fragments when exposed to light. What makes this possible, he claims, is an odd but well-established trait of those electrons: They expand into bubblelike entities, that can roam about their helium surroundings.

In the not-yet-released August JOURNAL OF LOW TEMPERATURE PHYSICS, Maris explores what might happen to such a bubble once its electron becomes excited. In accordance with quantum mechanics, he pictures the electron as a wave that fills the bubble.

Maris' calculations show that the bubble could elongate and narrow at its waist, finally splitting into two new bubbles. The shocking part for physicists is that the electron would also split in two, dropping a chunk into each daughter bubble. Maris has dubbed those electron fragments "electrinos."

Physicists are a long way from accepting the new idea. They "bombarded [Mariz] with skeptical questions"at a meeting last June, says Peter V.E. McClintock of Lancaster University in England. He counts himself among the skeptics but says his reservations are based on "instinct or intuition." Maris' ideas "deserve to be taken seriously," he insists.

One reason for hearing Maris out is that his theory appears to solve a long-standing mystery. Experiments on liquid helium dating back to the 1960s produced puzzling results. Researchers found that shining a light on the helium, while it was also subjected to a voltage increased the current of negative charges--presumably electrons--in the fluid.

What's more, some experiments suggested that as many as 13 different types of unidentified negatively charged particles, which researchers came to call "exotic ions," were traversing the illuminated liquid at distinctly different speeds.

Scientists have offered various explanations for the results, including the presence of unknown impurities. None has proven convincing, Maris argues, whereas "the electrino-bubble theory provides a natural explanation."

Accounting for the overall boost in current, Maris calculates that electrino bubbles would experience less drag from the liquid because of their small size. As for the exotic ions, he argues that there could be a plethora of different-size electrino bubbles with different speeds.

While the theory's consistency with old data is encouraging, many new tests are called for, especially because the hypothesis is so bold, physicists say. "We're building an apparatus to do just that right now," says Maris.