May 26, 2011

Measuring The Shape Of The Electron

If you have stayed up nights wondering about the shape of electrons, you can now sleep easier. Electrons have been found to be almost, but not quite, perfectly round, The Telegraph reports.

Researchers at Imperial College London have recently measuremed the shape of the electron, finding that it is almost a perfect sphere, in a study published in the journal Nature.

The decade-long experiment suggests that the electron differs from being perfectly round by less than 0.000000000000000000000000001 cm. If that is a difficult number to comprehend, consider that if the electron was magnified to the size of the solar system, it would still appear spherical to within the width of a human hair.

Physicists from Imperial's Center for Cold Matter studied the electrons inside molecules of Ytterbium Fluoride. Using a very precise laser, they made careful measurements of the motion of these electrons.

If the electrons were not perfectly round, their motion would exhibit a distinctive wobble, distorting the overall shape of the molecule. The researchers saw no sign of such a wobble.

So does this have any practical purpose? The results are important in the study of antimatter, an elusive substance that behaves in the same way as ordinary matter, except that it has an opposing electrical charge. For example, the antimatter version of the negatively charged electron is the positively charged anti-electron, known as a positron.

Understanding the shape of the electron will aid researchers in understanding how positrons behave and how antimatter and matter differ.

Dr. Jony Hudson, from the Department of Physics at Imperial College London said in a statment: "We're really pleased that we've been able to improve our knowledge of one of the basic building blocks of matter. It's been a very difficult measurement to make, but this knowledge will let us improve our theories of fundamental physics."

"People are often surprised to hear that our theories of physics aren't "Ëœfinished', but in truth they get constantly refined and improved by making ever more accurate measurements like this one."

The Big Bang, the theoretical explosion that began the known universe, created as much antimatter as ordinary matter, according to the currently accepted laws of physics. Antimatter, however, has only been found in minute amounts from sources such as cosmic rays and some radioactive substances since the concept was conceived by Nobel Prize-winning scientist Paul Dirac in 1928.

If the researchers had found that electrons were not round it would have provided proof that the behavior of antimatter and matter differ more than previously believed. This, they say, could explain how all the antimatter disappeared from the universe, leaving only ordinary matter.

"Astronomers have looked right to the edge of the visible universe and even then they see just matter, no great stashes of antimatter. Physicists just do not know what happened to all the antimatter, but this research can help us to confirm or rule out some of the possible explanations," explains Edward Hinds, research co-author and head of the Center for Cold Matter at Imperial College London.


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