What's round and measures a billionth of a millimetre?
The answer is the electron, the shape of which scientists at Imperial 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...
So how does this square with string theory; that electrons are actually string-shaped? Does this invalidate it? Or are our experiments just not sensitive enough to tell? Supercryptid, Thu, 26th May 2011
The article doesn't explain how they determined the shape or even how they define the shape. I expect that the electron should fill a spherically symmetrical space at ordinary time scales, but at the Planck time scale, its shape will probably never be detected directly. We can only infer the shape from our models; and for now, mainstream science models don't even speculate about time and space at the Planck scale. The prevailing attitude is that what can't be measured doesn't exist.
You make eminent sense there Phractality. I too would assume that a electron should be a 'symmetric' solution if we could 'pin point' it, which we can't. They made a calculation on its symmetry it seems to me, translating that into a 'shape'? Very smart :) and possibly correct but no guarantee for what a 'electron' really is. yor_on, Thu, 26th May 2011
From the published paper in Nature:
shaped like an egg? which came first, electron or egg? CZARCAR, Thu, 26th May 2011
OK, here's the PhD free version
http://www.bbc.co.uk/news/science-environment-13561876 CZARCAR, Thu, 26th May 2011
Did they discover the electron's shape or an electron molecular orbital's shape? lightarrow, Thu, 26th May 2011
In a sense the orbital represents the electron, doesn't it? The probability density is symmetric until you stop 'time' by your measurement, forcing it into a outcome.
Symmetric but not necessarily spherical:
There are hints in various papers that this discovery leads to an advancement in our understanding of CP violation (and hence the imbalance between the amount of matter and antimatter). Can anyone explain how? I can see vague reasons how it maybe related, but I'm sure it must be something specific. graham.d, Tue, 31st May 2011
And how would it explain the electrons ability to be superimposed at two orbitals, simultaneously? yor_on, Tue, 31st May 2011
It's just an idea, I'm not sure at all: since they talk of measuring the electron's electric dipole moment, if it has, then it can be paired with the (existing) magnetic dipole moment in a different way, compared to the positron and this would mean a different energy of the particle. I can have written a stupid thing, however... lightarrow, Tue, 31st May 2011
I don't know what I should see a orbital as Lightarrow. Looking at the Swedish attosecond movie you can see it as having a circular shape, but as there also is a probability density to it, I'm not sure at what I'm looking at there. It's made using a stroboscope with several overlapping photos taken at extreme short time durations. "One attosecond has the same relation to one second, as one second has to the age of the universe" In Swedish, but with the movie.
There's all the difference in the world between the shape of an orbital ( which is different fro different atoms, molecules ions or even different excited states of a given atom) and the shape of an electron.
... and they measured the electron "shape," an intrinsic property of the electron itself, not the orbital's shape. jpetruccelli, Mon, 13th Jun 2011
So we found that it is a defined particle then?
They found it's "perfectly round." They could test to see if it wasn't a perfect sphere and that test came up negative to a high degree of precision. They managed to test despite the fact that it was in an atom. jpetruccelli, Tue, 14th Jun 2011
Let's see. We got a probability density over where it should be, but only before a measurement, and then we got a definition of 'something' in that orbit(al) that's perfectly round :)
The orbit's got nothing to do with this question of electron shape though. I'm assuming they carefully controlled for that in the results.
This one is worthy of a long thread of its own methinks.
Anyway, the fact an electron has electric properties with spherical symmetry, doesn't mean it is a sphere, of course (just for people who could think that...)
:) yor_on, Tue, 14th Jun 2011
A standing wave in a cavity huh :) And atoms are even bigger standing waves, and a molecule is a he* of a lot of standing waves, that moves too :) And humans are he* of a he* of a lot of standing waves, in a countless amount of cavity's, that also posses a will, free or not, that even allow them to choose directions in which to move :)
The electron's wave function takes up the whole box (actually, in the 1st excited state the wave function has a value of zero in the middle of the box and so on) but the electron is still a small thing which has, according to the original article, been shown to be small and spherical.
What they have proved is the fact it has zero electric dipole moment. Now, the say (implicitely) that this fact means "the electron is spherical". Ok, now the question is: what does "the electron is spherical" actually means?
"No I don't mean dimensions."
This is the extreme point of view of Quantum Mechanical non sense... Though QM is widely right from another point of view.
I thought that I held the prize for the most unanswerable useless question by asking how "many Angels can dance on the point of a pin" but now I feel I have been relgated to second place. syhprum, Wed, 6th Jul 2011
i like to sprinkle atoms on my pasta at the university dont they make them in france or something dr thompson, Wed, 4th Sep 2013