Most recent answer: 04/20/2020
- Keith (age 16)
It's not a silly question given what you've been taught, but what you've been taught isn't right.
Particles that have no rest mass nevertheless do have energy. The classical formula for kinetic energy, E=0.5mv2 is wrong, although it's an excellent approximation when |v|< c.
We discuss some of these issues here:
As it turns out, neutrinos do have some rest mass, so they carry away energy due to both that rest mass itself (E=mc2) and due to their kinetic energy. Your question, however, still is important for understanding how people thought this worked back when they thought that neutrinos were massless.
(published on 04/20/2020)