# E/M should be constant

1. Nov 29, 2013

### nil1996

As the speed of light is constant in the universe, E/M should be constant.
Suppose that in some corner of universe mass is being converted in energy. So there must be some another corner of universe where mass is being converted into energy at the same time.Is my argument correct??

2. Nov 29, 2013

### ZapperZ

Staff Emeritus
Sorry, but this makes no sense.

You are confusing an equation that describes the conversion of one to another with a conservation law. That equation is not a conservation law just because c is a constant.

Zz.

3. Nov 29, 2013

### sigma_

E=mc^2 is an equation that describes the constant of proportionality between an object's rest mass, and the energy that mass contains.

The sum total of mass and energy in the universe has to remain unchanged by the first law of thermodynamics, but mass energy equivalence does not indicate that there must be a certain proportion between the two when you sum all the mass and energy in the universe.

4. Nov 29, 2013

### nil1996

thanks,
i was thinking that E represents energy of universe while M mass of universe ant that equation works as conservation of energy.

5. Nov 29, 2013

### sigma_

E would represent all the energy due to all the mass in the universe, not the total energy in the universe. Hope that makes sense

6. Nov 29, 2013

### nil1996

yes got now
Thanks :thumbs: