(Also at The Guardian.)
This week my favorite particle is the electron (one of the best things about working in particle physics is that it accommodates my fickle heart and mood swings perfectly). 
Electrons occupy every atom in the universe. There is one in the Hydrogen atom, two in the Helium atom, three in Lithium and so on. The electron content of an atom completely governs how likely it is to form a bond with another atom, making a molecule.
So an electron has great power really, but only a very tiny mass. The Hydrogen atom’s other occupant, the proton, has a mass nearly 2000 times bigger. All of the atom’s mass come from its nucleus, but all of its size comes from the fact that the electron refuses to get too close to the proton. Most of the atom is empty space. Vacuum.
Also the mass of the proton is pretty contrived: it comes from the various constituent particles (quarks and gluons) but actually almost all of it comes from virtual particles popping in and out of the vacuum within it. In contrast, the mass of the electron is a constant of nature. We have no idea why it has a mass of 9.11*10-31 kg. Some of us think it might have mass because it interacts with the Higgs field, but as far as I’m aware nobody has anything solid to say on why it has this particular mass.
Electrons also have a property called spin. The spin of all electrons is +/- 1/2. What this means is that if you were an electron the world would not look the same if you spun around once. We are spin 1: we have to turn around 360 degrees to get the same view. Electrons have to turn 720 degrees, as if on some terrible acid trip*. All particles that have this strange property of “spin 1/2” are known as fermions. They are named after the wonderful Enrico Fermi.
Enrico Fermi. Legend.
If you know about particle physics you might be thinking that none of these things are really an argument for electrons being special. It is true that being present in every atom, having an unexplained bare mass and having spin of 1/2 are also equally true of the two lightest quarks, ‘up’ and ‘down’. The up and down quarks are certainly just as much a part of our world as electrons are; in fact every bit of matter in the universe, from a strawberry, to your left hand, to the atmosphere of Jupiter, is basically made up of just these three particles; up quark, down quark and electron. Every other fermion is unstable (well, not the neutrinos, but they have other ‘issues’).
Also, there is a particle even more strikingly similar to the electron: the positron. A positron behaves exactly like an electron in every way that our imaginations and and utilisation of opposable thumbs has allowed us to measure; all except one. They have opposite charge. A positron is the ‘charge reflection’ of an electron. It is the electron’s antiparticle. My only preference for the electron over the positron is that we live in world made of particles (matter) rather than anti-particles (anti-matter), but actually we could just as well live in an anti-matter anti-world with anti-people, we would notice no difference as far as I know. The only thing that matters is that we have more of one kind than of the other, which is a total mystery in itself. A mystery for another day.
So, I don’t really know how to justify my love for the electron. Perhaps it is because an electron has no location.
Electrons interact via the electromagnetic field, aka the photon. All the electrons in the universe and all the photons in the universe are talking to each other all the time. They are all connected, no matter how far apart, by the electromagnetic field, which has infinite range**. They can be thought of as little clouds which have a dense foggy core and then misty edges, but that would be wrong because there are no edges. The mistiness goes on for ever, overlapping with every other misty cloud everywhere in the universe.
If that’s all a bit air- fairy for you, don’t forget that electrons are really very useful. Okay, this is stating the bleeding obvious. I think most people who have experienced a power cut (or even their phone battery dying) are very much aware how heavily we depend on electricity. But our dependence on electricity goes even deeper than light-bulbs and google. We are ‘electric’. Our brain is able to control our body by sending electricity to the nerves, which then send more electricity to our muscles to make them move. Perhaps even more incredible is the electricity in our brain enables us to absorb and process vast amounts of information, then to put this information together in such a way as that we can create. Works of art, inventions, love- all down to electricity.
*A Higgs boson, incidentally, is spin zero…
** unlike the color*** field that deals with quarks, which has a finite range of just 10^{-15}m.
*** I haven’t gone American. It’s not the same as colour.
Life and Physics 