* Photo: Jimmy Fishbein * An isotope is an element with a secret. Its atoms have the standard number of electrons and protons but carry an extra-heavy load of neutrons. (That's why the hydrogen isotope deuterium makes "heavy water.") Now, there are limits to how much the nucleus of a given element can hold, but what those limits are remains, for the most part, a mystery. Still, the idea of aluminum atoms with, say, 29 or 30 neutrons instead of the usual 14, or magnesium with 28 instead of 12, would have been considered impolite, if not outlandish.

Then along came Dave Morrissey, who created those mutants with the cyclotron at Michigan State University last year. "The theoretical physicists will have to figure out what's wrong with their models," he says.

To pull off this atomic feat, Morrissey's team shot beryllium with calcium isotope ions accelerated to half the speed of light. The resulting fragments, comprising the all-new isotopes, flew through two mass spectrometers to measure their masses and volumes and hit a radiation detector at the other end of the lab.

All that happens in five-millionths of a second; sorting the data took almost two weeks. But when Morrissey was done, he was rocking some serious heavy metal. He estimates that it'll take another two to five years to find all the isotopes of aluminum, silicon, and magnesium, and far longer for the 107 elements for which isotope limits remain unknown.

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