[deccan]

Originally posted by Phoenix-D:
The photon energy is lost, or absorbed. Some fraction is sent on, which then hits something else and repeats the process. Infinite number of photons..infinite number of barriers. And at any given time, only a finite number of those photons are actually arriving at any given point.

As Jack pointed out, the energy cannot be destroyed. Given enough time, anything that blocks and absorbs those photons will eventually re-radiate it out again.