At the opposite end of the electromagnetic spectrum from low-energy, long radio waves are very high-energy, short X-rays followed by even shorter gamma rays, the shortest of all waves on the electromagnetic spectrum. As is the case with radio waves, X-rays and gamma rays are forms of light invisible to the eye. X-rays range in length from 1 to 100 nanometers, while gamma rays range from 0.1 to 0.001 nanometers. Wavelengths this short, some barely the diameter of individual atoms, explode across the universe with tremendous energy as a result of violent conflagrations in deep space. X-rays and gamma rays have several common characteristics besides their energy levels and lengths. An analysis of their origins reveals that they emanate from the hottest spots in the universe-regions where atoms have been raised to extremely high temperatures exceeding millions of...