"The astronomer Sir William Huggins frightened the world in 1910. He was minding his own business, doing astronomy, but as a result of his astronomy (the work I'm talking about was done in the last third of the nineteenth century) there were national panics in Japan, in Russia, in much of the southern and midwestern United States. A hundred thousand people in the pajamas emerged onto the roofs of Constantinople. The pope issued a statement condemning the hoarding of cylinders of oxygen in Rome. And there were people all over the world who committed suicide. All because of Sir William Huggins's work..."
~Sagan

During this time, was talk of the possibility of the earth travelling through the tail of Halley's Comet. Huggins used a spectrometer to analyze the chemical quality of the comet. He found bands indicating C2, NH3, NH2, and CN. CN is cyanide. Astronomers tried to tell poeple that it wasn't clear that we would pass through the tail, and if we did there would be such low concentration of CN that everything would be fine. But nobody believed astronomers.