Four Insanely Eerie Things About the Electron

The electron is one of the the three stable and massive particles of the universe, the other two being the proton and the neutron. The electron is also perhaps the strangest of all particles. Let us look at four aspects of the electron that are downright spooky.

1. Electrons are insanely round, more than 100 million times rounder than the roundest thing men  have ever made

Scientists at the Imperial College in London have done experiments to determine how round the electron is. Their results are astonishing. Their web site says: “So far we've checked the roundness of the electron to an incredible degree of precision: the equivalent would be measuring the diameter of the solar system to better than the width of one human hair. And so far, we've seen no evidence of non-roundness.”

Scientific American summarizes these results here by saying : “The electron is a perfect sphere, give or take barely one part in a million billion.”

In this article the Guardian summarizes these results as follows: “In the most exquisite measurements yet, researchers declared the particle to be a perfect sphere to within one billionth of a billionth of a billionth of a centimeter. Were the electron scaled up to the size of the solar system, any deviation from its roundness would be smaller than the width of a human hair, the team said.”

To get a feel for how remarkable this is, let's compare this degree of roundness to the degree of roundness of the roundest thing humans have ever manufactured.  This 2008 New Scientist story was entitled “Roundest Objects in the World Created.” It told the story of how some super-round spheres were created by a scientific team that included an optical engineer named Achim Leistner, using a slow, careful process that took months. Leistner said, “"If you were to blow up our spheres to the size of the Earth, you would see a small ripple in the smoothness of about 12 to 15 mm, and a variation of only 3 to 5 metres in the roundness."

 

But electrons are 100,000,000 times rounder!

Now the solar system has a diameter about 10,000 times larger than the diameter of the Earth, and a human hair is about one ten thousandth (1 in 10,000) the size of 3 to 5 meters. So the previously mentioned degree of roundness in the electron is actually 100 million times greater than the degree of roundness in Leisnter's spheres (supposedly the roundest ever manufactured).

Think of it: each of the the electrons all around us is at least 100 million times rounder than the roundest thing man ever manufactured, when scientists were deliberately trying to make something as round as possible.

That is insanely eerie, and has no explanation under current theory.

2. All electrons have the same mass and charge

Scientists conclude that all electrons have a mass of 9.10938291 ×10⁻³¹ kilogram, and that all electrons have a charge of −1.60217657 ×10⁻¹⁹ coulomb. To someone who has long read about particle physics, this may not seem surprising or strange. Such a person may just think: that's just the way it is. But to someone who learns about this uniformity for the first time, it often can seem very strange. Why? Because it violates a law of observation that holds true for everything we see.

We might call this law the Law of Mass Variation, and state it like this: every type of natural thing comes in different sizes. We never observe any visible type of thing in nature that is always the same mass. For example, galaxies, stars, planets, rocks, trees and people each have a range of different masses. In fact, the rule that things of a particular type always vary in mass holds true for all natural objects in the universe from the size of galaxies all the way down to molecules and atoms. It is only when we get to the very end of the line size-wise (down to the level of subatomic particles) that the rule is broken. 

3. Electrons behave both as particles and as waves

You may have heard of the wave-particle duality of light, meaning that light can behave like a wave or like a particle. Scientists say that the electron displays the same duality. When electrons are inside an atom, they generally act as if they were waves (and indeed the chemistry needed for life wouldn't work unless electrons acted like waves). You may say: so what's so special about that; an electron is really just a wave. But eerily enough there is one important case when electrons act exactly like particles, not waves. That case is the photoelectric effect, the effect that makes solar energy possible. The photoelectric effect occurs when a special type of surface is exposed to light, and electrons are then ejected from the surface (at a rate proportional to the number of incoming photons of light). When that happens, electrons are behaving exactly like particles, and are not acting like waves. The electron seems to magically behave in whatever way is most convenient for us, a little like an employee who can speak English when handling an American customer, but also speak Chinese when handling a Chinese customer.

4. Even though each proton is 1836 times more massive than each electron, each electron has a charge that is the exact same magnitude as the charge of each proton

Here is an interesting experiment to try on any friend of yours who does not know very much about physics.

1. Ask your friend: guess what is the ratio between the mass of a proton and the mass of an electron. After hearing an answer, tell your friend each proton is 1836 times more massive than each electron.
2. Now ask your friend: guess what is the ratio between the electrical charge of a proton and the electrical charge of an electron.

I would think that the average person (having just heard that protons are 1836 times more massive than electrons) would guess that the electrical charge of a proton is much greater than the electrical charge of an electron – perhaps 1836 times larger. That would be a good “common sense” conclusion, since we almost uniformly observe larger things having larger electrical charges than smaller things.

But such a “common sense” conclusion would be false. The actual fact observed by scientists is that each proton has a charge that is exactly the same as each electron, but with an opposite sign. Each proton has a charge of +1.60217657 ×10⁻¹⁹ coulomb, and each electron has a charge of −1.60217657 ×10⁻¹⁹ coulomb.

An experiment done by J. G. King showed that the magnitude of the proton charge matches the magnitude of the electron charge to 1 part in 100,000,000,000,000,000,000. This scientific paper used a molecular beam deflection method to conclude that the proton charge and the electron charge have a magnitude differing by less than 5 parts in 10,000,000,000,000,000,000.

This amazing coincidence is unexplained by modern science. It is also a coincidence on which our existence depends. Scientists say that if the charge on the electron differed by only one part in a billion billion from the charge of the proton, our planet could not hold together,  and we would not be here.

To see why this is true, we need merely consider the following facts. Our planet is held together by gravity. Gravitation is one of the four fundamental forces in the universe, but it is roughly a billion billion billion billion (1,000,000,000,000,000,000,000,000,000,000,000,000) times weaker than the electromagnetic force, another of the four fundamental forces, the force between electric charges. Even changing the electron charge by 1 part in a billion billion (1 part in 1,000,000,000,000,000,000) would create electromagnetic repulsion effects that would be something very roughly like a billion billion times larger than the gravitational effects holding our planet together. The result is that our planet would fly apart in pieces.

This ends my discussion of 4 insanely eerie things about the electron. I could have discussed one other insanely eerie thing about the electron: its ability to do the ever-so-spooky trick called quantum entanglement, involving instantaneous action at a distance. But I'll save that for another post.