• Question: Why are electrons considered as fundamental particles? Can it be made up of anything smaller?

    Asked by rajathjackson to Dave, David, Jack on 26 Jun 2013.
    • Photo: Jack Miller

      Jack Miller answered on 26 Jun 2013:

      Hi Rajath,

      Electrons are considered fundamental because there’s a lot of experimental evidence that suggests they are. In the standard model, they’re fundamental particles, and no experiment ever conducted on earth has indicated otherwise. There’s no a priori reason that they have to be fundamental, however — perhaps at obscenely high energies something more interesting happens.

      In the standard model, the most accurate model of nature ever made by man, electrons are fundamental, and everything we observe about them agrees with that fact.

      Hope that helps!

      — Jack

    • Photo: David Freeborn

      David Freeborn answered on 26 Jun 2013:

      We don’t know for certain that electrons are fundamental. But we think that, if Quantum Electrodynamics is a correct theory (it’s the most precise theory ever measured- correct to 14 decimal places), then an electron-like particle (i.e. a particle of spin-1/2) should be fundamental. Half-spin particles should be the fundamental excitations of the field, according to Quantum Electrodynamics.

      As Jack says, we’ve never measured any structure to the electron, despite a lot of very sensitive experiments looking. So if there is a structure to the electron, then it is very, very small!

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