[thackney]

The photon is gone. It had mass and energy.

I thought photons had no mass.

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/960731.html

My degree is in electrical engineering, specialized in power systems.

[ColdWater]

My degree is in electrical engineering, specialized in power systems.

Most electrical engineers do not take advanced courses in nuclear phyiscs.

[djf]

No rest mass.

But as they buzz around, they have energy, mass, and momentum.