evidence: Most geoengineering options are theoretical and untested. Federal researchers have taken only a few small steps toward studying their feasibility, and atmospheric scientists say there is no evidence of any large-scale programs. [...] In recent years, some chemtrails conspiracy theories have evolved, with believers suggesting that contrails are actually aerosols designed to control the weather or the climate. The Tennessee Lookout, a nonprofit news organization, reported that Republican Sen. Steve Southerland, one of the sponsors, referred to the chemtrails theory when he presented his argument for the bill to a reporter. [...] "What you see is the mixing up and conflation of all these things — geoengineering is the same as weather modification is the same as chemtrails or contrails," said Horton, who reviewed video of recent legislative testimony.