Hi all,
I could be wrong here so feel free to correct. The equation E=mc^2 is actually a shortened version of the full equation and is only used to demonstrate the relationship between mass & energy. It does not take into consideration momentum. Also, the
m is actually rest mass. The full equation is :
E^2 - (pc)^2 = (mc^2)^2
where p is momentum and m is
rest mass.
This translates to E^2 = (pc)^2 + (mc^2)^2
As p increases so does the energy, however rest mass actually stays the same. This is why an object with zero rest mass (ie, photons) must travel at c .... if m is zero then (mc^2)^2 would also be zero. A photon travelling at less than c would require m to be greater than zero.
Hope that's correct
.
Andrew.