Does an object emitting electromagnetic radiation really lose mass?

[Bararontok]

Einstein stated in a paper concerning the discovery of the quantization of electromagnetic force that an object emitting electromagnetic radiation will lose its inertial mass. If this is the case, then why does the gravitational force of the sun not weaken and the sun not become less massive as a result of emitting electromagnetic radiation for billions of years? Is inertial mass equivalent to active gravitational mass or are they merely proportional?

sources:

http://en.wikisource.org/wiki/The_Development_of_Our_Views_on_the_Composition_and_Essence_of_Radiation

http://en.wikipedia.org/wiki/Mass

 

[Matterwave]

The sun does lose mass, a couple of million tons per second actually...it's just that the sun is so massive that this mass loss is negligible.

For comparison, the sun loses about 4*10^9 kg of mass per second. The Sun's mass is something like 2*10^30kg. So, over a year, the sun loses only 6.3*10^-12% of it's mass. That's only .063% of its mass lost due to fusion over 10 billion years!

The sun may well gain more mass than this over its lifetime. Of course, the sun is also losing mass due to jets of material that it sends out in the form of solar wind and CME's.

 

[Bararontok]

And does this figure for mass loss factor out the emission of plasma jets from the sun, and if not, how much mass does the sun lose due to electromagnetic radiation alone?

 

[Matterwave]

the figure I gave is merely due to radiation loss.

 

[Chronos]

See, for example, http://www.astronomycafe.net/qadir/q1491.html