quote:

*Originally posted by simeonie*

why is the speed of light infinite energy?

A body with non zero rest mass (rest mass = the mass it have when it's still) requires an infinite amount of energy to be accelerated to the speed of light, because: E = m*c^2/SQRT[1-(v/c)^2]

E is the total energy of the body

m is its rest mass

v is its speed

c is the speed of light

As you can see, when v approaches c, v/c approaches 1 (and (v/c)^2 too) so the term inside the square root approaches zero (and the square root too), so E approaches infinity (the less the number under a fraction, the greater the result).

Now, where this infinity comes from?

The fact is that

*in practice* the speed of light

*is infinite*. What I mean: when a body's speed is not much, our definition of speed: v = space/time is a good definition, but when the body's speed is very high (that is, near the speed of light) our definition

*is not good anylonger*, because space and time are not (enough) independent each other anylonger.

If you were inside a space-ship moving faster and faster, you would see planets, stars, approaching you in greater and greater amount,

*without any limit*, that is, the number of stars you would see passing by you in one second, e.g., would approach

*infinity*.

Of course we are assuming the average number of stars in a volume of space is constant, but this doesn't change the essence of the concept.