The purpose of this study is to develop and test a theory for the launching and propagation of extremely low frequency (ELF) waves from lightning discharges. Recent observations have indicated that ELF wavelets from lightning deposit significant energy in the mesosphere and ionosphere. This energy may modify upper atmospheric currents and affect the global electrical circuit. The investigators will develop a theory for ELF propagation and examine its validity by analyzing existing data on lightning discharges on Earth and other planets.