When you multiply the speed of light (c) by itself in Einstein's equation E=mc², you're squaring the value of the speed of light. Mathematically, c² means c multiplied by itself.
In the equation E=mc², E represents energy, m represents mass, and c represents the speed of light. The equation states that the energy (E) of an object is equal to its mass (m) multiplied by the speed of light (c) squared.
So, when you square the speed of light (c), you get c². This means that c² is simply the square of the speed of light, which is a constant value of approximately 299,792,458 meters per second squared (m²/s²).
Multiplying the speed of light by itself in the equation doesn't change the overall meaning or implications of the equation. It just emphasizes the relationship between energy, mass, and the enormous value of the speed of light.