Almost since the invention of the radio, it has been known that lightning generates radio waves, since this property of the bolts has long interfered with radio broadcasts. Lightning generates radio waves over a wide range of frequencies, especially in the AM broadcast band. More recently, scientists have become fascinated by lightning’s ability to create X-rays. The theory that this might occur was first proposed in the 1920s by Nobel Prize-winning physicist C.T.R. Wilson (1869–1959), who theorized that lightning could accelerate electrons with sufficient speed to produce X-rays. For decades scientists thought Wilson was wrong, because they believed the Earth’s atmosphere was too thick and that air resistance would slow down electrons too much. However, by the 1990s scientists began to change their minds, and in 2003 experiments with controlled lightning strokes were performed by Martin Uman at the University of Florida and Joseph Dwyer at the Florida Institute of Technology that demonstrated lightning can, indeed, produce enough energy to overcome any atmospheric drag. Such new research is causing scientists to rethink how lightning works.