Gamma ray telescopes can operate only in space. Gamma rays cannot pass through Earth's atmosphere, thank goodness! Otherwise, Earth would most likely be a fried and lifeless place. Gamma rays are the smallest wave and most energetic form of electromagnetic energy (that is, light) that we have been able to detect. Huge bursts of gamma rays have been detected from all parts of the sky, but astronomers do not yet know what events trigger them. The Swift Gamma Ray Burst Explorer space observatory has detected over 500 gamma-ray bursts since its launch in 2004.