Can Matter be Created or Destroyed?

[Rhondazvous]

Thanks, One more question (I hope) and I shall understand this better.

Since mass is the measure of energy, how can the most massive particle be a fermion? In fact, how can any fermion have mass? Unless mass is the interplay of energy and matter. If that is the case (caveat for what follows: it may not be what actually happens. I'm guessing, so trash it as it deserves. My feelings will not be hurt)then when energy is converted into matter there will be less energy actually converted than was originally present, while the unconverted energy acts as a catalyst, bringing about the conversion. Is that the energy that is lost or that interacts with the new matter to give it mass?

The latter part, while I don't understand it entirely and disagree with the use of terminology, resembles what happens. Particles with low mass but carrying large energy because of their speed can collide and form particles with more mass but less speed. The surplus energy that is not needed for the mass of the new particles goes into their movement.

Mass is just a measure of the energy content of something when it is at rest.

Yes, you understood me.

You know I'm using the terminology of a lay person, while you use it professionally. This is good. As an English grad, I appreciate learning language on a higher level.