I think this is a fair question that I have asked myself aswell. According to E=mc2, c2 tells us how much energy is retained in a unit of mass. But why is this c2 and not c or c3?

Besides (to me unfulfilling) mathematical explainations, C-squared makes sense to me after watching 'the car example' in this popular video:

http://youtu.be/xvZfx7iwq94?t=2m40s

A lightspeed particle moves at max speed (C) only through the space dimension, because time is theoretically frozen at this speed. C-squared may represent a particle moving through both the space AND time direction at lightspeed. This is practically impossible and therefore we can maximally measure C. However, I think this is theoretically possible if effects of space contraction and time dilation are somehow overcome? Or from another perspective, at C2 speed through both space and time, both space and time would be frozen, eliminating any reference frame. Anyway, rather then C, C-squared may be the asymptote of the universal energetic speed limit, directly relating to mass and energy.

Besides (to me unfulfilling) mathematical explainations, C-squared makes sense to me after watching 'the car example' in this popular video:

http://youtu.be/xvZfx7iwq94?t=2m40s

A lightspeed particle moves at max speed (C) only through the space dimension, because time is theoretically frozen at this speed. C-squared may represent a particle moving through both the space AND time direction at lightspeed. This is practically impossible and therefore we can maximally measure C. However, I think this is theoretically possible if effects of space contraction and time dilation are somehow overcome? Or from another perspective, at C2 speed through both space and time, both space and time would be frozen, eliminating any reference frame. Anyway, rather then C, C-squared may be the asymptote of the universal energetic speed limit, directly relating to mass and energy.

Last edited: