Note that whether electrons are spherical or not is important to theoretical physics. Right now we do NOT want them to be perfect spheres. But, as you say, our ability to measure this is limited by our instruments.
Keep in mind that many important scientific theories had to wait a very long time until our instruments could reliably measure what was predicted. For example, theories that the earth rotated around the sun were theorized as far back as the 5th Century BC and maybe far before that. Actually proving the Earth rotated around the sun didn't happen until 1728 by measuring aberration in starlight. But what the ancients actually sought, proof by stellar parallax, was far beyond the capabilities of optical instruments until 1854. To be technical, it was actually empirical to believe the sun orbited the earth during this time. Ancients would say "if the earth orbits, I should see stars shift. I do not see stars shifting, therefore the earth does not orbit." Aristotle actually used this very argument!
I was listening to some of the researchers comment on this particular discovery and they are more hopeful about the technique than the findings. There is already talk about improving the resolution a couple of orders of magnitude.
Aspheric electrons help explain the imbalance between matter and antimatter under many current models.
I don't know the full implications if electrons were spherical. But two I can think of are that either our models are wrong or there is something wrong with the way we are measuring the amounts of matter and antimatter in the universe.
Wouldn't it require mathematically perfect instruments to even measure/verify a mathematically perfect sphere? A mathematical sphere is simply an infinite set of points: the set of all points a given distance away from some central point.
The experiment was to detect spherical imperfections. That experiment failed to detect any. You're proposing limitations on how we'll detect spherical perfection, which is the opposite issue.
Although after reading the article from The Economist, physicists need electron's cloud shape to be a 'near-perfect' sphere (but never perfect) to comply with the Standard Model of elementary particles.
It's important to emphasize what you said, though: that the experiments still haven't found any "defect" in the shape of the electron's cloud that makes it a non-perfect sphere.
I wonder what HN predicts? I'd say it's a perfect sphere and the Standard Model is wrong. Time will tell...
Don't mistake me - this isn't a complaint. It's an observation that although technically savvy people pride themselves on assessing data purely on its merits, we are persuaded by words and images in ways we don't fully understand.
This is then really important in web design, marketing, sales, presentations, etc. You can't rely on your technical superiority.
Timing and presentation matter almost more than content. More than you'd hope. More than you'd want. More than is reasonable.
I wonder if it helps to submit when a large number of people are active at HN as opposed to say on a weekend. It seems to me that the sort-order algorithm is based on up-votes and time elapsed since submission. So if a submission is made during off hours, it does not get enough attention or votes, yet the time elapses the same way...
Collectives don't always behave meritocratically, even when composed of people who value meritocracy. I think they probably should, and it's frustrating when they don't, but it's hard to do.
I've always been curious about this. If electrons are spheres and so are protons and neutrons, what type of matter is filling up the area in between? Are protons and neutrons not spheres? Can electrons get squished into different shapes depending on arrangement? Or, does there even have to be matter in the voids surrounding adjacent spheres?
Strictly speaking, I don't think these things have a 'size' with a border where you can be inside or outside of a lepton 'surface'. Its a basically a point source with a field effect as far as we can determine.
http://en.wikipedia.org/wiki/Classical_electron_radius
I think the article is saying that the field affect appears to be completely uniform.
Technically, if the electron can affect something at a great distance via gravity or releasing photons you could say the size of an electron is many light years in diameter. Or you could call it infinitesimally tiny.
Neutrons and protons we know to be complicated little parties of quarks and gluons, each of which are, as far as we know, are also elementary particles like leptons.
I wondered about this too. It's not a point, though, that doesn't make sense in QM. So do they mean that the wave function is totally spherical?
Plus I want to point out that it's pointless to say that something is spherical to within 1e-20m unless you also say what the "radius" is. If the radius is 1e-21m it's not a very good sphere at all...
On microscale it's wrong to think about "in between".
There is no in between, there are vacuum, fields (quantized),
field state evolution and amplitudes between initial and final states and so on.
Protons and neutrons are not spheres exactly. They are made of 3 quarks and have a structure.
Electrons are point particles - they are true 0 dimensional objects - they have no size at all. However they do have an equivalent wavelength due to their mass, and they have an area of influence.
There are voids. A lot of voids. A good deal of matter (even solid) are actually 'nothing'. If you take materials science, you get the 'atoms made of hard ball' approximation of the world (which usually yields pretty good answers), and even then, the densest you can get anything like 75% matter or something. And that's severely high-balling it (the ball radius approximates the electron cloud as a hard continuous shell, when it's really actually mostly just empty.
These voids are actually full of a crazy mess of virtual particles that exist within time/energy uncertainty. Empty space isn't really a meaningful concept when you're dealing with field theories.
When you study quantum field theory one of the first mind blowing things that you learn is that an electron at rest can be thought of as a superposition of an infinite number of somewhat classical scenarios. For instance, the electron can shoot of a virtual photon, which creates an electron/positron pair, which annhilate and create a new photon, which is then absorbed by the original electron. These processes can be arbitrarily complex; just imagine substituting in the whole process we just described for the electron that was pair produced- you can do that as many times as you want. These things are all ocurring at once. This leads to the necessity of renormalization and in turn a great joke. What is positive infinity plus negative infinity? If you ask a mathematician he'll tell you that it's undefined. If you ask a physicist he'll tell you it's the mass of the electron.
In between atoms is nothing. Inside atoms (between the electrons and the nucleus) is more nothing. Electrons are point particles and have no size. In between the protons and neutrons of the nucleus is nothing. Inside a proton are quarks, and between those quarks is nothing. Quarks themself are point particles and have no size.
"If electrons are spheres and so are protons and neutrons, what type of matter is filling up the area in between?"
In quantum theory, a particle is described as a probability field that fills space. For example, an electron might have a 2.5% chance of being in some little cube of space, a 10% chance in a nearby cube, and so forth. The rules for how it works are called quantum mechanics.
So the particles are fuzzy. They have no defined size, they can overlap with each other, and so forth.
As usual, this research has been simplified to the point of silliness for the popular press. What they probably mean is that a particular electron orbital in a particular type of atom was measured to be spherically symmetric. That means that they went looking for lumpiness of that electron's probability cloud and found to be perfectly smooth and round.
Particle accelerators have already measured this smoothness at high energies. They crash electrons together at high speed, watch how they scatter off each other, and the scattering statistics are consistent with electrons having no internal bits and pieces. They're just smooth, continuous electron all the way through. (Proton collisions scatter as if there are lots of lumpy bits inside. The bits turn out the be quarks and gluons.)
"Can electrons get squished into different shapes depending on arrangement?"
Yes. While electrons can overlap because their borders are fuzzy, they repel each other in the process, changing each other's shapes.
"if an electron was the size of the solar system, it would be out from being perfectly round by less than the width of a human hair"
This doesn't seem right:
Radius of an electron: 2.8e-15 m
Off by: 1e-29 m
Thus it's off by 0.0000000000004%
Average distance of pluto from the sun: 5.9e12 m
Thus "size" of the solar system: 1.18e13 m
1.18e13 * 0.0000000000004% = 4.2e-2 = 4.2cm
It's not off by that much , but 4.2cm is way more than the width of a human hair (17-180um, a factor of ~1000-2000-fold)
What actually happened was that they placed a new upper limit on the electric dipole moment of electrons. This has implications for physics beyond the standard model. You can't be a "sphere" unless you have a finite and well defined radius, which electrons don't.
That is, the headline might lead you to believe that they are not perfect spheres, but that is not known to be the case.
Also: cool.