Electrons are spherical

25 May 2011
Posted by Chris Smith.

What's round and measures a billionth of a millimetre?

The answer is the electron, the shape of which scientists at Atom structureImperial College in London have been trying to measure for over ten years! Now they've finally succeeded, proving that the tiny negatively-charged particles which swarm around the nuclei of atoms really are a spherical shape.

Led by researcher Jony Hudson, the London-based team made the breakthrough by studying how a compound called ytterbium fluoride behaves in an electric field. If electrons are any shape other than perfectly round, then in an electrical field they would be expected to wobble and this, in turn, would make the ytterbium fluoride atom wobble too.

But if the electrons are spherical, then any forces will on them will balance out and so they won't wobble and nor will the host atom. And, in fact, this is what the team at Imperial have published this week in the journal Nature - the atoms failed to wobble in the field, indicating that the electrons must be symmetrically round.

This is important, explains Jony Hudson, because it places limits on what theories of atomic structure and behaviour are possible. It also moves us one step closer to answer one of the Universe's biggest questions, which is where has all the antimatter gone?

Theory predicts that matter and antimatter were made by the Big Bang in equal measure, but wherever we look today all we see is material made from matter. The shape of electrons constrains how matter and its anti-matter equivalent can behave and therefore narrows the range of possibilities of where the antimatter might have gone...

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