# Any mass accelarating @ 'c' is light

1. Jul 7, 2010

### kittz

""any mass accelarating @ 'c' is light ""

hii everyone, from E=mc^2 i've seen that "When mass accelarating @ c , its simply called energy".

( light speed is constant everywhere nothing can cross that limit. So, c^2 is considered as c , in fact c^2 is for dimentional accuracy)

so, my doubt is :When mass accl to 'C' , can we say that the resultant energy is LIGHT????

2. Jul 7, 2010

### Pengwuino

Re: ""any mass accelarating @ 'c' is light ""

If I understand your question correctly, no, mass doesn't turn into light when accelerated to the speed of light. Infact, they are two distinct realms. There are particles with mass that can never achieve the speed of light. Then there are particles, with photons being one example, that are massless that travel exclusively at the speed of light.

3. Jul 7, 2010

### Rasalhague

Re: ""any mass accelarating @ 'c' is light ""

c2 isn't a speed. In conventional units, such as http://en.wikipedia.org/wiki/International_System_of_Units" [Broken], which are handy for relativity, length and time are considered to have the same dimensionality, so c is a dimensionless constant. In geometric units, c is set equal to 1, so c2 also equals 1. But in other systems of units, c2 has a different numerical value to c as well as a different dimension.

As Pengwuino says, something is either travelling at speed c (as measured in what's called an "inertial frame of reference") or not. There's no way to accelerate from another speed to c, or from c to any other speed.

Last edited by a moderator: May 4, 2017