I have always wondered that- if e=mc^2 then how can it NOT have mass....
E = mc^2, true, but that is an equation where the “equals” symbol must be read as “if possibly converted, then equals”.
Light is energy. Let’s say you have 1000 joules of energy in the form of light. If you could convert this 1000 joules of energy into mass, totally, then you could make as much mass as given by the altered equation,
m = E/[c^2]
Note that the constant ‘c’ doesn’t represent light in the equation, but is a numerical constant that is the same in pure magnitude, as the value of the speed of light. It seems like the same thing, but has a subtle difference.
All of the above, only IIRC.