AUDIO: One way to produce gamma rays is when photons of lower energy light smash into fast moving electrons. This direct collision steals energy from the electron and boosts the light's energy, producing gamma rays. But detecting these photons can be tricky. Gamma rays shoot right through optical lenses and mirrors. So conventional telescopes can't focus them for detection. To solve this challenge, GLAST borrow techniques from high-energy physics, adopting technologies from Earth-bound laboratories. VIDEO DESCRIPTION: Video of artist concept of photons colliding with electrons, gamma rays shooting through an optical lens and mirror, GLAST in space.