What I am trying to say is this: Your death star blast is like blowing up a building. However, the halos act like a radio tower, it sends a massive gamma pulse throughout the vacuum of space. In all directions, Your math is flawed for the halos because you fail to answer: How did the energy travel there. -what physical obstacles impacted the halo pulse -did [b][i][u]all[/u][/i][/b] of the energy fired necessarily hit the intended target (biological life) [spoiler]as I said, a very miniscule portion of the halos energy actually hit biological life. Most of it is used up traveling through the vacuum of space. However you measured his much the halos destroyed, not emitted.[/spoiler] imagine a radio tower sending out a signal. Just because only a certain number of radios received that signal (biological life) doesn't mean they captured all of the radiowaves in that emission. There still are radiowaves emitting into the sky, the ocean, the west, north,south, east, up, down, left, right, that don't hit there intended target (radios) and eventually disperse by losing energy.