# Speed of light, mass equation

1. Mar 22, 2009

### ThoughtProces

I was wondering if there is and what is the equations that show that as an object accelerates towards the speed of light its mass increase to infinite.

2. Mar 23, 2009

### Staff: Mentor

You're probably thinking of this equation:

$$m = \frac {m_0} {\sqrt{1 - v^2 / c^2}}$$

3. Mar 23, 2009

### ThoughtProces

i do believe this is the equation do you have a derivation of where it comes from or could you point me to a site for which it has the derivation.

thanks

4. Mar 23, 2009

### Staff: Mentor

5. Mar 23, 2009

### ThoughtProces

thanks for the link, it should prove to be a good read

6. Mar 24, 2009

### ThoughtProces

I guess another question is how do we measure the initial mass of an object if we are all traveling at a changing velocity due to the constant acceleration of an expanding universe. Or is the initial mass relative to the expanding universe in its own frame of reference?