True fact: there's no such thing as “chemtrails.” The word for the trails of vapor sometimes created by aircraft is "contrails," short for condensation trails. They're water. They’ve been understood for almost a century. There's no mystery about it, and no controversy, except for the controversy created by right-wing nutcases.
One of whom, to our shame, is the top health official of the US.
@gleick The first time I heard about the chemtrail conspiracy I thought it was a Poe. Like the "birds aren't real" people making up a ridiculous fake conspiracy to poke fun at those folks. Nope. It turns out people actually believe something that blatantly wacky.