Ok so this is where I'm a bit stumped. I'm trying to figure out where the speed of light comes into the equation E=mc2, in regards to fusion reactions. So correct me if I'm wrong, but if I take 1kg of Hydrogen isotopes and create a fusion reaction I will get 9x10^16 J. (1 x (3x10^8)^2). But where does the speed of light come into this? You can understand the mass being relevant in the equation, being the amount of Hydrogen there is to begin with, but there is nothing in that simple concept/theory that mentions the speed of light. A lot of people have been telling me that it is just a constant and was there due to other equations being relevant to it - that still doesn't explain why it's used. For example, if I was to replace the speed of light with gravity (let's say gravity is effecting the reaction), we know gravity's a constant and is 9.8m/s. You can understand why it is used in the equation, because gravity is a factor in the fusion reactor. But again, there's no mention of the speed of light in the theory. From what I understand (excuse my naivety), the speed of light has nothing to do with fusion reactions. It can't be anything to do with the atoms themselves, they have mass... Therefore, no speed of light. Is it something to do with photons interacting with the atoms on a micro-scale, because that's the only thing I can think of...
So people have also been telling me that it's just a conversion factor. So, being a conversion factor means yea sure, 3 days = 72 hours but it also equals 24x3, 24 being the conversion factor. However that still doesn't explain why "9x10^16" is used in the equation, being in a different form or not.
