Why are alpha and beta particles called radiation if they have mass?

[lonewolf219]

Hi, I'm sure this topic is pretty bland, but nonetheless!

Why are alpha and beta particles called radiation when they have mass?

 

[HypnoFunk]

Radiation can be either the emission of electromagnetic waves or sub-atomic particles. In general the definition of radiation is the emission of energy.

At subatomic levels there is no black and white distinction between mass and energy, hence the concept of mass-energy, alluding to the fact they are related to one another.

 

[lonewolf219]

Wow. I haven't heard that before... that's amazing. But these particles are much, much smaller than photons, is that right?