In February 1910, the Yerkes Observatory announced that spectroscopic analysis had detected cyanogen, a deadly poison, in the tail of Halley's Comet. The French astronomer Camille Flammarion suggested that the gas could 'impregnate the atmosphere and possibly snuff out all life,' sparking widespread public anxiety. Despite reassurances from scientists, the panic persisted for months, leading to the sale of 'comet pills' and anti-cyanogen gas masks, though the Earth passed through the comet's tail with no ill effects.

The Halley's Comet panic of 1910 is a vivid example of how scientific discovery can provoke mass irrationality, a theme that has been explored by poets and writers grappling with the relationship between science and the public imagination. The event appears in the works of modernist poets who were fascinated by the intersection of technology, apocalyptic fear, and the fragility of human existence. It also serves as a precursor to later science fiction and poetry that imagines cosmic threats and humanity's response to them.