The United States launches the Starfish Prime high-altitude nuclear weapons test, detonating a 1.4 megaton warhead at an altitude of 250 miles, the largest space-based nuclear test to date. The flash of the detonation creates a brief “false sunrise” over much of the Pacific Ocean, as well as an unusual auroral display resulting from the sudden release of charged particles trapped within Earth’s magnetic field. An electromagnetic pulse is also observed, more powerful than expected, causing some damage to the Hawaiian power grid. The radiation released in low Earth orbit also interferes with some satellites, including shortening their operational life spans (this includes the Telstar communications satellite, not launched until the next day). Starfish Prime is part of the “Fishbowl” series of high-altitude nuclear tests.